,a ,,system ,,of ,,logic                
,,ratiocinative ,,and ,,inductive       
,,vol4 ,i4     ,a ,,system ,,of ,,logic 
,,ratiocinative ,,and ,,inductive       
,,being ,a ,,connected ,,view ,,of ,,the
 ,,principles ,,of ,,evidence ,,and     
,,the ,,methods ,,of ,,scientific       
,,investigation  ,,by  ,,john ,,stuart  
,,mill   ,,in ,,two ,,volumes  ,,vol4   
,i4  ,,seventh ,,edition   ,,london3    
,,longmans1 ,,green1 ,,reader1 ,,and    
,,dyer  ,,mdccclxviii     ,,preface ,,to
 ,,the ,,first ,,edition4   ,this book  
makes no pretence of giving to the world
 a new theory of the intellectual       
operations4 ,its claim to attention1 if 
it possess any1 is grounded on the fact 
that it is an attempt not to supersede1 
but to embody and systematize1 the best 
ideas which have been either promulgated
 on its subject by speculative writers1 
or conformed to by accurate thinkers in 
their scientific inquiries4  ,to cement 
together the detached fragments of a    
subject1 never yet treated as a whole2  

to harmonize the true portions of       
discordant theories1 by supplying the   
links of thought necessary to connect   
them1 and by disentangling them from the
 errors with which they are always more 
or less interwoven2 must necessarily    
require a considerable amount of        
original speculation4 ,to other         
originality than this1 the present work 
lays no claim4 ,in the existing state of
 the cultivation of the sciences1 there 
would be a very strong presumption      
against any one who should imagine that 
he had effected a revolution in the     
theory of the investigation of truth1 or
 added any fundamentally new process to 
the practice of it4 ,the improvement    
which remains to be effected in the     
methods of philosophizing 7and the      
author believes that they have much need
 of improvement7 can only consist in    
performing1 more systematically and     
accurately1 operations with which1 at   
least in their elementary form1 the     
human intellect in some one or other of 

its employments is already familiar4    
,in the portion of the work which treats
 of ,ratiocination1 the author has not  
deemed it necessary to enter into       
technical details which may be obtained 
in so perfect a shape from the existing 
treatises on what is termed the ,logic  
of the ,schools4 ,in the contempt       
entertained by many modern philosophers 
for the syllogistic art1 it will be seen
 that he by no means participates2      
though the scientific theory on which   
its defence is usually rested appears to
 him erroneous3 and the view which he   
has suggested of the nature and         
functions of the ,syllogism may1        
perhaps1 afford the means of            
conciliating the principles of the art  
with as much as is well grounded in the 
doctrines and objections of its         
assailants4  ,the same abstinence from  
details could not be observed in the    
,first ,book1 on ,names and             
,propositions2 because many useful      
principles and distinctions which were  

contained in the old ,logic1 have been  
gradually omitted from the writings of  
its later teachers2 and it appeared     
desirable both to revive these1 and to  
reform and rationalize the philosophical
 foundation on which they stood4 ,the   
earlier chapters of this preliminary    
,book will consequently appear1 to some 
readers1 needlessly elementary and      
scholastic4 ,but those who know in what 
darkness the nature of our knowledge1   
and of the processes by which it is     
obtained1 is often involved by a        
confused apprehension of the import of  
the different classes of ,words and     
,assertions1 will not regard these      
discussions as either frivolous1 or     
irrelevant to the topics considered in  
the later ,books4  ,on the subject of   
,induction1 the task to be performed was
 that of generalizing the modes of      
investigating truth and estimating      
evidence1 by which so many important and
 recondite laws of nature have1 in the  
various sciences1 been aggregated to the

 stock of human knowledge4 ,that this is
 not a task free from difficulty may be 
presumed from the fact1 that even at a  
very recent period1 eminent writers     
7among whom it is sufficient to name    
,archbishop ,whately1 and the author of 
a celebrated article on ,bacon in the   
,edinburgh ,review7 have not scrupled to
 pronounce it impossible4#a ,the author 
has endeavoured to combat their theory  
in the manner in which ,diogenes        
confuted the sceptical reasonings       
against the possibility of motion2      
remembering that ,diogenes' argument    
would have been equally conclusive1     
though his individual perambulations    
might not have extended beyond the      
circuit of his own tub4  ,whatever may  
be the value of what the author has     
succeeded in effecting on this branch of
 his subject1 it is a duty to           
acknowledge that for much of it he has  
been indebted to several important      
treatises1 partly historical and partly 
philosophical1 on the generalities and  

processes of physical science1 which    
have been published within the last few 
years4 ,to these treatises1 and to their
 authors1 he has endeavoured to do      
justice in the body of the work4 ,but as
 with one of these writers1 ,dr4        
,whewell1 he has occasion frequently to 
express differences of opinion1 it is   
more particularly incumbent on him in   
this place to declare1 that without the 
aid derived from the facts and ideas    
contained in that gentleman's ,history  
of the ,inductive ,sciences1 the        
corresponding portion of this work would
 probably not have been written4  ,the  
concluding ,book is an attempt to       
contribute towards the solution of a    
question1 which the decay of old        
opinions1 and the agitation that        
disturbs ,european society to its inmost
 depths1 render as important in the     
present day to the practical interests  
of human life1 as it must at all times  
be to the completeness of our           
speculative knowledge3 viz4 ,whether    

moral and social phenomena are really   
exceptions to the general certainty and 
uniformity of the course of nature2 and 
how far the methods1 by which so many of
 the laws of the physical world have    
been numbered among truths irrevocably  
acquired and universally assented to1   
can be made instrumental to the         
formation of a similar body of received 
doctrine in moral and political science4
     ,,preface ,,to ,,the ,,third ,,and 
,,fourth ,,editions4   ,several         
criticisms1 of a more or less           
controversial character1 on this work1  
have appeared since the publication of  
the second edition2 and ,dr4 ,whewell   
has lately published a reply to those   
parts of it in which some of his        
opinions were controverted4#b  ,i have  
carefully reconsidered all the points on
 which my conclusions have been         
assailed4 ,but ,i have not to announce a
 change of opinion on any matter of     
importance4 ,such minor oversights as   
have been detected1 either by myself or 

by my critics1 ,i have1 in general      
silently1 corrected3 but it is not to be
 inferred that ,i agree with the        
objections which have been made to a    
passage1 in every instance in which ,i  
have altered or cancelled it4 ,i have   
often done so1 merely that it might not 
remain a stumbling-block1 when the      
amount of discussion necessary to place 
the matter in its true light would have 
exceeded what was suitable to the       
occasion4  ,to several of the arguments 
which have been urged against me1 ,i    
have thought it useful to reply with    
some degree of minuteness2 not from any 
taste for controversy1 but because the  
opportunity was favourable for placing  
my own conclusions1 and the grounds of  
them1 more clearly and completely before
 the reader4 ,truth1 on these subjects1 
is militant1 and can only establish     
itself by means of conflict4 ,the most  
opposite opinions can make a plausible  
show of evidence while each has the     
statement of its own case2 and it is    

only possible to ascertain which of them
 is in the right1 after hearing and     
comparing what each can say against the 
other1 and what the other can urge in   
its defence4  ,even the criticisms from 
which ,i most dissent have been of great
 service to me1 by showing in what      
places the exposition most needed to be 
improved1 or the argument strengthened4 
,and ,i should have been well pleased if
 the book had undergone a much greater  
amount of attack2 as in that case ,i    
should probably have been enabled to    
improve it still more than ,i believe ,i
 have now done4         99       99     
99       99       99  ,in the subsequent
 editions1 the attempt to improve the   
work by additions and corrections1      
suggested by criticism or by thought1   
has been continued4 ,in the present     
7seventh7 edition1 a few further        
corrections have been made1 but no      
material additions4  ,,footnotes3  #a   
,in the later editions of ,archbishop   
,whately's ,logic1 he states his meaning

 to be1 not that rules for the          
ascertainment of truths by inductive    
investigation cannot be laid down1 or   
that they may not be of eminent service1
 but that they must always be           
comparatively vague and general1 and    
incapable of being built up into a      
regular demonstrative theory like that  
of the ,syllogism4 7,book ,,iv4 ch4 iv4 
#c47 ,and he observes1 that to devise a 
system for this purpose1 capable of     
being brought into a scientific form1   
would be an achievement which he must be
 more sanguine than scientific who      
expects4 7,book ,,iv4 ch4 ii4  #d47 ,to 
effect this1 however1 being the express 
object of the portion of the present    
work which treats of ,induction1 the    
words in the text are no overstatement  
of the difference of opinion between    
,archbishop ,whately and me on the      
subject4  #b ,now forming a chapter in  
his volume on ,the ,philosophy of       
,discovery4     ,,contents ,,of ,,the   
,,first ,,volume4     ,,introduction4   

#a4 ,a definition at the commencement of
 a subject must be        provisional   
#a      #b4 ,is logic the art and       
science of reasoning8                   
#b      #c4 ,or the art and science of  
the pursuit of truth8                #c 
#d4 ,logic is concerned with inferences1
 not with intuitive truths  #e      #e4 
,relation of logic to the other sciences
                        #h      #f4 ,its
 utility1 how shown                     
#aj      #g4 ,definition of logic stated
 and illustrated                    #aa 
,,book ,i4    ,,of ,,names ,,and        
,,propositions4     ,,chapter ,i4 ,of   
the ,necessity of commencing with an    
,analysis of ,language4     #a4 ,theory 
of names1 why a necessary part of logic 
#ag      #b4 ,first step in the analysis
 of ,propositions                    #ah
      #c4 ,names must be studied before 
,things                           #ba   
,,chapter ,,ii4 ,of ,names4     #a4     
,names are names of things1 not of our  
ideas                   #bc      #b4    

,words which are not names1 but parts of
 names                 #bd      #c4     
,general and ,singular names            
#bf      #d4 ,concrete and ,abstract    
#bi      #e4 ,connotative and           
,non-connotative                        
#ca      #f4 ,positive and ,negative    
#db      #g4 ,relative and ,absolute    
#dd      #h4 ,univocal and quivocal     
#dg     ,,chapter ,,iii4 ,of the ,things
 denoted by ,names4     #a4 ,necessity  
of an enumeration of ,nameable ,things4 
,the        ,categories of ,aristotle   
#di      #b4 ,ambiguity of the most     
general names                           
#ea      #c4 ,feelings1 or states of    
consciousness                           
#ed      #d4 ,feelings must be          
distinguished from their physical       
antecedents4 ,perceptions1 what         
#ef      #e4 ,volitions1 and ,actions1  
what                                    
#eh      #f4 ,substance and ,attribute  
#ei      #g4 ,body                      
#fa      #h4 ,mind                      

#fg      #i4 ,qualities                 
#fi     #aj4 ,relations                 
#gb     #aa4 ,resemblance               
#gd     #ab4 ,quantity                  
#gh     #ac4 ,all attributes of bodies  
are grounded on states of               
consciousness                           
#gi     #ad4 ,so also all attributes of 
mind                                #hj 
#ae4 ,recapitulation                    
#ha     ,,chapter ,,iv4 ,of             
,propositions4     #a4 ,nature and      
office of the copula                    
#he      #b4 ,affirmative and ,negative 
propositions                         #hg
      #c4 ,simple and ,complex          
#hi      #d4 ,universal1 ,particular1   
and ,singular                           
#ic     ,,chapter ,v4 ,of the ,import of
 ,propositions4     #a4 ,doctrine that a
 proposition is the expression of a     
relation        between two ideas       
#if      #b4 ,doctrine that it is the   
expression of a relation between the    
meanings of two names                   

#ii      #c4 ,doctrine that it consists 
in referring something to1 or           
excluding something from1 a class       
#ajc      #d4 ,what it really is        
#ajg      #e4 ,it asserts 7or denies7 a 
sequence1 a coexistence1 a simple       
existence1 a causation                  
#aaj      #f4 --or a resemblance        
#aab      #g4 ,propositions of which the
 terms are abstract                 #aae
     ,,chapter ,,vi4 ,of ,propositions  
merely ,verbal4     #a4 ,essential and  
,accidental propositions                
#aai      #b4 ,all essential            
propositions are identical propositions 
#abj      #c4 ,individuals have no      
essences                                
#abd      #d4 ,real propositions1 how   
distinguished from verbal               
#abf      #e4 ,two modes of representing
 the import of a ,real proposition      
#abg     ,,chapter ,,vii4 ,of the       
,nature of ,classification1 and   the   
,five ,predicables4     #a4             
,classification1 how connected with     

,naming                    #abi      #b4
 ,the ,predicables1 what                
#aca      #c4 ,genus and ,species       
#aca      #d4 ,kinds have a real        
existence in nature                     
#acd      #e4 ,differentia              
#aci      #f4 ,differenti for general   
purposes1 and differenti for            
special or technical purposes           
#ada      #g4 ,proprium                 
#add      #h4 ,accidens                 
#adf     ,,chapter ,,viii4 ,of          
,definition4     #a4 ,a definition1 what
                                        
#adh      #b4 ,every name can be        
defined1 whose meaning is susceptible   
of analysis                             
#aej      #c4 ,complete1 how            
distinguished from incomplete           
definitions      #aeb      #d4 --and    
from descriptions                       
#aed      #e4 ,what are called          
definitions of ,things1 are definitions 
of        ,names with an implied        
assumption of the existence of          

,things corresponding to them           
#aeg      #f4 --even when such things do
 not in reality exist              #afe 
#g4 ,definitions1 though of names only1 
must be grounded on        knowledge of 
the corresponding ,things               
#afg     ,,book ,,ii4    ,,of           
,,reasoning4     ,,chapter ,i4 ,of      
,inference1 or ,reasoning1 in general4  
#a4 ,retrospect of the preceding book   
#age      #b4 ,inferences improperly so 
called                              #agg
      #c4 ,inferences proper1           
distinguished into inductions and       
ratiocinations                          
#aha     ,,chapter ,,ii4 ,of            
,ratiocination1 or ,syllogism4     #a4  
,analysis of the ,syllogism             
#ahd      #b4 ,the dictum de omni not   
the foundation of reasoning1        but 
a mere identical proposition            
#aia      #c4 ,what is the really       
fundamental axiom of ,ratiocination     
#aif      #d4 ,the other form of the    
axiom                                   

#aii     ,,chapter ,,iii4 ,of the       
,functions1 and ,logical ,value1 of the 
,syllogism4     #a4 ,is the syllogism a 
petitio principii8                      
#bjb      #b4 ,insufficiency of the     
common theory                           
#bjc      #c4 ,all inference is from    
particulars to particulars              
#bje      #d4 ,general propositions are 
a record of such inferences1 and        
the rules of the syllogism are rules for
 the interpretation        of the record
                                        
#bad      #e4 ,the syllogism not the    
type of reasoning1 but a test of it     
#bah      #f4 ,the true type1 what      
#bbb      #g4 ,relation between         
,induction and ,deduction               
#bbf      #h4 ,objections answered      
#bbg      #i4 ,of ,formal ,logic1 and   
its relation to the ,logic of ,truth    
#bca     ,,chapter ,,iv4 ,of ,trains of 
,reasoning1 and ,deductive   ,sciences4 
#a4 ,for what purpose trains of         
reasoning exist                   #bcd  

#b4 ,a train of reasoning is a series of
 inductive inferences     #bcd      #c4 
--from particulars to particulars       
through marks of marks     #bcg      #d4
 ,why there are deductive sciences      
#bdj      #e4 ,why other sciences still 
remain experimental                 #bdd
      #f4 ,experimental sciences may    
become deductive by the progress        
of experiment                           
#bdf      #g4 ,in what manner this      
usually takes place                     
#bdg     ,,chapter ,v4 ,of              
,demonstration1 and ,necessary ,truths4 
#a4 ,the ,theorems of geometry are      
necessary truths only in        the     
sense of necessarily following from     
hypotheses           #bea      #b4      
,those hypotheses are real facts with   
some of their        circumstances      
exaggerated or omitted                  
#bee      #c4 ,some of the first        
principles of geometry are axioms1 and  
these are not hypothetical              
#bef      #d4 --but are experimental    

truths                                  
#beh      #e4 ,an objection answered    
#bfa      #f4 ,dr4 ,whewell's opinions  
on axioms examined                      
#bfd     ,,chapter ,,vi4 ,the same      
,subject continued4     #a4 ,all        
deductive sciences are inductive        
#bha      #b4 ,the propositions of the  
science of number are not verbal1       
but generalizations from experience     
#bhd      #c4 ,in what sense            
hypothetical                            
#bhi      #d4 ,the characteristic       
property of demonstrative science is to 
be hypothetical                         
#bij      #e4 ,definition of            
demonstrative evidence                  
#bib     ,,chapter ,,vii4 ,examination  
of some ,opinions opposed to   the      
preceding doctrines4     #a4 ,doctrine  
of the ,universal ,postulate            
#bid      #b4 ,the test of              
inconceivability does not represent the 
aggregate of past experience            
#bif      #c4 --nor is implied in every 

process of thought                 #bii 
#d4 ,sir ,w4 ,hamilton's opinion on the 
,principles of        ,contradiction and
 ,excluded ,middle                      
#cjf     ,,book ,,iii4    ,,of          
,,induction4     ,,chapter ,i4          
,preliminary ,observations on ,induction
 in general4     #a4 ,importance of an  
,inductive ,logic                       
#cac      #b4 ,the logic of science is  
also that of business and life          
#cad     ,,chapter ,,ii4 ,of ,inductions
 improperly so called4     #a4          
,inductions distinguished from verbal   
transformations         #cai      #b4   
--from inductions1 falsely so called1 in
 mathematics         #cba      #c4 --and
 from descriptions                      
#cbc      #d4 ,examination of ,dr4      
,whewell's theory of ,induction         
#cbf      #e4 ,further illustration of  
the preceding remarks                   
#ccf     ,,chapter ,,iii4 ,on the       
,ground of ,induction4     #a4 ,axiom of
 the uniformity of the course of nature 

#cda      #b4 ,not true in every sense4 
,induction per enumerationem            
simplicem                               
#cdf      #c4 ,the question of          
,inductive ,logic stated                
#cdh     ,,chapter ,,iv4 ,of ,laws of   
,nature4     #a4 ,the general regularity
 in nature is a tissue of partial       
regularities1 called laws               
#cea      #b4 ,scientific induction must
 be grounded on previous                
spontaneous inductions                  
#cee      #c4 ,are there any inductions 
fitted to be a test of all others8  #ceg
     ,,chapter ,v4 ,of the ,law of      
,universal ,causation4     #a4 ,the     
universal law of successive phenomena is
 the ,law of        ,causation          
#cfj      #b4 --i4e4 the law that every 
consequent has an invariable            
antecedent                              
#cfc      #c4 ,the cause of a phenomenon
 is the assemblage of its               
conditions                              
#cfe      #d4 ,the distinction of agent 

and patient illusory                #cgc
      #e4 ,the cause is not the         
invariable antecedent1 but the          
unconditional invariable antecedent     
#cge      #f4 ,can a cause be           
simultaneous with its effect8           
#chj      #g4 ,idea of a ,permanent     
,cause1 or original natural agent       
#chc      #h4 ,uniformities of          
coexistence between effects of different
        permanent causes1 are not laws  
#chf      #i4 ,doctrine that volition is
 an efficient cause1 examined       #chg
     ,,chapter ,,vi4 ,of the            
,composition of ,causes4     #a4 ,two   
modes of the conjunct action of causes1 
the mechanical        and the chemical  
#dje      #b4 ,the composition of causes
 the general rule2 the other case       
exceptional                             
#djh      #c4 ,are effects proportional 
to their causes8                    #dab
     ,,chapter ,,vii4 ,of ,observation  
and ,experiment4     #a4 ,the first step
 of inductive inquiry is a mental       

analysis of        complex phenomena    
into their elements                     
#dad      #b4 ,the next is an actual    
separation of those elements            
#daf      #c4 ,advantages of experiment 
over observation                    #dag
      #d4 ,advantages of observation    
over experiment                    #dbj 
,,chapter ,,viii4 ,of the ,four ,methods
 of ,experimental   ,inquiry4     #a4   
,method of ,agreement                   
#dbe      #b4 ,method of ,difference    
#dbh      #c4 ,mutual relation of these 
two methods                         #dbi
      #d4 ,joint ,method of ,agreement  
and ,difference                     #dcc
      #e4 ,method of ,residues          
#dcf      #f4 ,method of ,concomitant   
,variations                             
#dcg      #g4 ,limitations of this last 
method                              #ddc
     ,,chapter ,,ix4 ,miscellaneous     
,examples of the ,four ,methods4     #a4
 ,liebig's theory of metallic poisons   
#ddi      #b4 ,theory of induced        

electricity                             
#dec      #c4 ,dr4 ,wells' theory of dew
                                        
#deg      #d4 ,dr4 ,brown-,squard's     
theory of cadaveric rigidity            
#dfe      #e4 ,examples of the ,method  
of ,residues                            
#dga      #f4 ,dr4 ,whewell's objections
 to the ,four ,methods                  
#dge     ,,chapter ,x4 ,of ,plurality of
 ,causes2 and of the ,intermixture   of 
,effects4     #a4 ,one effect may have  
several causes                          
#dhb      #b4 --which is the source of a
 characteristic imperfection of         
the ,method of ,agreement               
#dhc      #c4 ,plurality of ,causes1 how
 ascertained                            
#dhg      #d4 ,concurrence of ,causes   
which do not compound their effects     
#dhi      #e4 ,difficulties of the      
investigation1 when causes compound     
their effects                           
#did      #f4 ,three modes of           
investigating the laws of complex       

effects     #dii      #g4 ,the method of
 simple observation inapplicable        
#ejj      #h4 ,the purely experimental  
method inapplicable                     
#eja     ,,chapter ,,xi4 ,of the        
,deductive ,method4     #a4 ,first      
stage2 ascertainment of the laws of the 
separate        causes by direct        
induction                               
#ejg      #b4 ,second stage2            
ratiocination from the simple laws of   
the        complex cases                
#eab      #c4 ,third stage2 verification
 by specific experience             #ead
     ,,chapter ,,xii4 ,of the           
,explanation of ,laws of ,nature4       
#a4 ,explanation defined                
#eah      #b4 ,first mode of            
explanation1 by resolving the law of a  
complex        effect into the laws of  
the concurrent causes and        the    
fact of their coexistence               
#eah      #c4 ,second mode2 by the      
detection of an intermediate link in    
the sequence                            

#eai      #d4 ,laws are always resolved 
into laws more general than             
themselves                              
#ebj      #e4 ,third mode2 the          
subsumption of less general laws under  
a more general one                      
#ebd      #f4 ,what the explanation of a
 law of nature amounts to           #ebf
     ,,chapter ,,xiii4 ,miscellaneous   
,examples of the ,explanation of   ,laws
 of ,nature4     #a4 ,the general       
theories of the sciences                
#ebi      #b4 ,examples from chemical   
speculations                            
#eca      #c4 ,example from ,dr4        
,brown-,squard's researches on the      
nervous system                          
#ecc      #d4 ,examples of following    
newly-discovered laws into their        
complex manifestations                  
#ecd      #e4 ,examples of empirical    
generalizations1 afterwards confirmed   
and explained deductively               
#ecf      #f4 ,example from mental      
science                                 

#ech      #g4 ,tendency of all the      
sciences to become deductive            
#eci     ,,introduction4    #a4 ,there  
is as great diversity among authors in  
the modes which they have adopted of    
defining logic1 as in their treatment of
 the details of it4 ,this is what might 
naturally be expected on any subject on 
which writers have availed themselves of
 the same language as a means of        
delivering different ideas4 ,ethics and 
jurisprudence are liable to the remark  
in common with logic4 ,almost every     
writer having taken a different view of 
some of the particulars which these     
branches of knowledge are usually       
understood to include2 each has so      
framed his definition as to indicate    
beforehand his own peculiar tenets1 and 
sometimes to beg the question in their  
favour4  ,this diversity is not so much 
an evil to be complained of1 as an      
inevitable and in some degree a proper  
result of the imperfect state of those  
sciences4 ,it is not to be expected that

 there should be agreement about the    
definition of anything1 until there is  
agreement about the thing itself4 ,to   
define1 is to select from among all the 
properties of a thing1 those which shall
 be understood to be designated and     
declared by its name2 and the properties
 must be well known to us before we can 
be competent to determine which of them 
are fittest to be chosen for this       
purpose4 ,accordingly1 in the case of so
 complex an aggregation of particulars  
as are comprehended in anything which   
can be called a science1 the definition 
we set out with is seldom that which a  
more extensive knowledge of the subject 
shows to be the most appropriate4 ,until
 we know the particulars themselves1 we 
cannot fix upon the most correct and    
compact mode of circumscribing them by a
 general description4 ,it was not until 
after an extensive and accurate         
acquaintance with the details of        
chemical phenomena1 that it was found   
possible to frame a rational definition 

of chemistry2 and the definition of the 
science of life and organization is     
still a matter of dispute4 ,so long as  
the sciences are imperfect1 the         
definitions must partake of their       
imperfection2 and if the former are     
progressive1 the latter ought to be so  
too4 ,as much1 therefore1 as is to be   
expected from a definition placed at the
 commencement of a subject1 is that it  
should define the scope of our          
inquiries3 and the definition which ,i  
am about to offer of the science of     
logic1 pretends to nothing more1 than to
 be a statement of the question which ,i
 have put to myself1 and which this book
 is an attempt to resolve4 ,the reader  
is at liberty to object to it as a      
definition of logic2 but it is at all   
events a correct definition of the      
subject of these volumes4    #b4 ,logic 
has often been called the ,art of       
,reasoning4 ,a writer#a who has done    
more than any other person to restore   
this study to the rank from which it had

 fallen in the estimation of the        
cultivated class in our own country1 has
 adopted the above definition with an   
amendment2 he has defined ,logic to be  
the ,science1 as well as the ,art1 of   
reasoning2 meaning by the former term1  
the analysis of the mental process which
 takes place whenever we reason1 and by 
the latter1 the rules1 grounded on that 
analysis1 for conducting the process    
correctly4 ,there can be no doubt as to 
the propriety of the emendation4 ,a     
right understanding of the mental       
process itself1 of the conditions it    
depends on1 and the steps of which it   
consists1 is the only basis on which a  
system of rules1 fitted for the         
direction of the process1 can possibly  
be founded4 ,art necessarily presupposes
 knowledge2 art1 in any but its infant  
state1 presupposes scientific knowledge3
 and if every art does not bear the name
 of a science1 it is only because       
several sciences are often necessary to 
form the groundwork of a single art4 ,so

 complicated are the conditions which   
govern our practical agency1 that to    
enable one thing to be done1 it is often
 requisite to know the nature and       
properties of many things4  ,logic1     
then1 comprises the science of          
reasoning1 as well as an art1 founded on
 that science4 ,but the word ,reasoning1
 again1 like most other scientific terms
 in popular use1 abounds in ambiguities4
 ,in one of its acceptations1 it means  
syllogizing2 or the mode of inference   
which may be called 7with sufficient    
accuracy for the present purpose7       
concluding from generals to particulars4
 ,in another of its senses1 to reason is
 simply to infer any assertion1 from    
assertions already admitted3 and in this
 sense induction is as much entitled to 
be called reasoning as the              
demonstrations of geometry4  ,writers on
 logic have generally preferred the     
former acceptation of the term3 the     
latter1 and more extensive signification
 is that in which ,i mean to use it4 ,i 

do this by virtue of the right ,i claim 
for every author1 to give whatever      
provisional definition he pleases of his
 own subject4 ,but sufficient reasons   
will1 ,i believe1 unfold themselves as  
we advance1 why this should be not only 
the provisional but the final           
definition4 ,it involves1 at all events1
 no arbitrary change in the meaning of  
the word2 for1 with the general usage of
 the ,english language1 the wider       
signification1 ,i believe1 accords      
better than the more restricted one4    
#c4 ,but ,reasoning1 even in the widest 
sense of which the word is susceptible1 
does not seem to comprehend all that is 
included1 either in the best1 or even in
 the most current1 conception of the    
scope and province of our science4 ,the 
employment of the word ,logic to denote 
the theory of argumentation1 is derived 
from the ,aristotelian1 or1 as they are 
commonly termed1 the scholastic1        
logicians4 ,yet even with them1 in their
 systematic treatises1 argumentation was

 the subject only of the third part3 the
 two former treated of ,terms1 and of   
,propositions2 under one or other of    
which heads were also included          
,definition and ,division4 ,by some1    
indeed1 these previous topics were      
professedly introduced only on account  
of their connexion with reasoning1 and  
as a preparation for the doctrine and   
rules of the syllogism4 ,yet they were  
treated with greater minuteness1 and    
dwelt on at greater length1 than was    
required for that purpose alone4 ,more  
recent writers on logic have generally  
understood the term as it was employed  
by the able author of the ,port ,royal  
,logic2 viz4 as equivalent to the ,art  
of ,thinking4 ,nor is this acceptation  
confined to books1 and scientific       
inquiries4 ,even in ordinary            
conversation1 the ideas connected with  
the word ,logic include at least        
precision of language1 and accuracy of  
classification3 and we perhaps oftener  
hear persons speak of a logical         

arrangement1 or of expressions logically
 defined1 than of conclusions logically 
deduced from premises4 ,again1 a man is 
often called a great logician1 or a man 
of powerful logic1 not for the accuracy 
of his deductions1 but for the extent of
 his command over premises2 because the 
general propositions required for       
explaining a difficulty or refuting a   
sophism1 copiously and promptly occur to
 him3 because1 in short1 his knowledge1 
besides being ample1 is well under his  
command for argumentative use4 ,whether1
 therefore1 we conform to the practice  
of those who have made the subject their
 particular study1 or to that of popular
 writers and common discourse1 the      
province of logic will include several  
operations of the intellect not usually 
considered to fall within the meaning of
 the terms ,reasoning and               
,argumentation4  ,these various         
operations might be brought within the  
compass of the science1 and the         
additional advantage be obtained of a   

very simple definition1 if1 by an       
extension of the term1 sanctioned by    
high authorities1 we were to define     
logic as the science which treats of the
 operations of the human understanding  
in the pursuit of truth4 ,for to this   
ultimate end1 naming1 classification1   
definition1 and all other operations    
over which logic has ever claimed       
jurisdiction1 are essentially           
subsidiary4 ,they may all be regarded as
 contrivances for enabling a person to  
know the truths which are needful to    
him1 and to know them at the precise    
moment at which they are needful4 ,other
 purposes1 indeed1 are also served by   
these operations2 for instance1 that of 
imparting our knowledge to others4 ,but1
 viewed with regard to this purpose1    
they have never been considered as      
within the province of the logician4    
,the sole object of ,logic is the       
guidance of one's own thoughts3 the     
communication of those thoughts to      
others falls under the consideration of 

,rhetoric1 in the large sense in which  
that art was conceived by the ancients2 
or of the still more extensive art of   
,education4 ,logic takes cognizance of  
our intellectual operations1 only as    
they conduce to our own knowledge1 and  
to our command over that knowledge for  
our own uses4 ,if there were but one    
rational being in the universe1 that    
being might be a perfect logician2 and  
the science and art of logic would be   
the same for that one person as for the 
whole human race4    #d4 ,but1 if the   
definition which we formerly examined   
included too little1 that which is now  
suggested has the opposite fault of     
including too much4  ,truths are known  
to us in two ways3 some are known       
directly1 and of themselves2 some       
through the medium of other truths4 ,the
 former are the subject of ,intuition1  
or ,consciousness2#b the latter1 of     
,inference4 ,the truths known by        
intuition are the original premises from
 which all others are inferred4 ,our    

assent to the conclusion being grounded 
on the truth of the premises1 we never  
could arrive at any knowledge by        
reasoning1 unless something could be    
known antecedently to all reasoning4    
,examples of truths known to us by      
immediate consciousness1 are our own    
bodily sensations and mental feelings4  
,i know directly1 and of my own         
knowledge1 that ,i was vexed yesterday1 
or that ,i am hungry to-day4 ,examples  
of truths which we know only by way of  
inference1 are occurrences which took   
place while we were absent1 the events  
recorded in history1 or the theorems of 
mathematics4 ,the two former we infer   
from the testimony adduced1 or from the 
traces of those past occurrences which  
still exist2 the latter1 from the       
premises laid down in books of geometry1
 under the title of definitions and     
axioms4 ,whatever we are capable of     
knowing must belong to the one class or 
to the other2 must be in the number of  
the primitive data1 or of the           

conclusions which can be drawn from     
these4  ,with the original data1 or     
ultimate premises of our knowledge2 with
 their number or nature1 the mode in    
which they are obtained1 or the tests by
 which they may be distinguished2 logic1
 in a direct way at least1 has1 in the  
sense in which ,i conceive the science1 
nothing to do4 ,these questions are     
partly not a subject of science at all1 
partly that of a very different science4
  ,whatever is known to us by           
consciousness1 is known beyond          
possibility of question4 ,what one sees 
or feels1 whether bodily or mentally1   
one cannot but be sure that one sees or 
feels4 ,no science is required for the  
purpose of establishing such truths2 no 
rules of art can render our knowledge of
 them more certain than it is in itself4
 ,there is no logic for this portion of 
our knowledge4  ,but we may fancy that  
we see or feel what we in reality infer4
 ,a truth1 or supposed truth1 which is  
really the result of a very rapid       

inference1 may seem to be apprehended   
intuitively4 ,it has long been agreed by
 thinkers of the most opposite schools1 
that this mistake is actually made in so
 familiar an instance as that of the    
eyesight4 ,there is nothing of which we 
appear to ourselves to be more directly 
conscious1 than the distance of an      
object from us4 ,yet it has long been   
ascertained1 that what is perceived by  
the eye1 is at most nothing more than a 
variously coloured surface2 that when we
 fancy we see distance1 all we really   
see is certain variations of apparent   
size1 and degrees of faintness of       
colour2 that our estimate of the        
object's distance from us is the result 
partly of a rapid inference from the    
muscular sensations accompanying the    
adjustment of the focal distance of the 
eye to objects unequally remote from us1
 and partly of a comparison 7made with  
so much rapidity that we are unconscious
 of making it7 between the size and     
colour of the object as they appear at  

the time1 and the size and colour of the
 same or of similar objects as they     
appeared when close at hand1 or when    
their degree of remoteness was known by 
other evidence4 ,the perception of      
distance by the eye1 which seems so like
 intuition1 is thus1 in reality1 an     
inference grounded on experience2 an    
inference1 too1 which we learn to make2 
and which we make with more and more    
correctness as our experience increases2
 though in familiar cases it takes place
 so rapidly as to appear exactly on a   
par with those perceptions of sight     
which are really intuitive1 our         
perceptions of colour4#c  ,of the       
science1 therefore1 which expounds the  
operations of the human understanding in
 the pursuit of truth1 one essential    
part is the inquiry3 ,what are the facts
 which are the objects of intuition or  
consciousness1 and what are those which 
we merely infer8 ,but this inquiry has  
never been considered a portion of      
logic4 ,its place is in another and a   

perfectly distinct department of        
science1 to which the name metaphysics  
more particularly belongs3 that portion 
of mental philosophy which attempts to  
determine what part of the furniture of 
the mind belongs to it originally1 and  
what part is constructed out of         
materials furnished to it from without4 
,to this science appertain the great and
 much debated questions of the existence
 of matter2 the existence of spirit1 and
 of a distinction between it and matter2
 the reality of time and space1 as      
things without the mind1 and            
distinguishable from the objects which  
are said to exist in them4 ,for in the  
present state of the discussion on these
 topics1 it is almost universally       
allowed that the existence of matter or 
of spirit1 of space or of time1 is in   
its nature unsusceptible of being       
proved2 and that if anything is known of
 them1 it must be by immediate          
intuition4 ,to the same science belong  
the inquiries into the nature of        

,conception1 ,perception1 ,memory1 and  
,belief2 all of which are operations of 
the understanding in the pursuit of     
truth2 but with which1 as phenomena of  
the mind1 or with the possibility which 
may or may not exist of analysing any of
 them into simpler phenomena1 the       
logician as such has no concern4 ,to    
this science must also be referred the  
following1 and all analogous questions3 
,to what extent our intellectual        
faculties and our emotions are          
innate--to what extent the result of    
association3 ,whether ,god1 and duty1   
are realities1 the existence of which is
 manifest to us  priori by the          
constitution of our rational faculty2 or
 whether our ideas of them are acquired 
notions1 the origin of which we are able
 to trace and explain2 and the reality  
of the objects themselves a question not
 of consciousness or intuition1 but of  
evidence and reasoning4  ,the province  
of logic must be restricted to that     
portion of our knowledge which consists 

of inferences from truths previously    
known2 whether those antecedent data be 
general propositions1 or particular     
observations and perceptions4 ,logic is 
not the science of ,belief1 but the     
science of ,proof1 or ,evidence4 ,in so 
far as belief professes to be founded on
 proof1 the office of logic is to supply
 a test for ascertaining whether or not 
the belief is well grounded4 ,with the  
claims which any proposition has to     
belief on the evidence of consciousness1
 that is1 without evidence in the proper
 sense of the word1 logic has nothing to
 do4    #e4 ,by far the greatest portion
 of our knowledge1 whether of general   
truths or of particular facts1 being    
avowedly matter of inference1 nearly the
 whole1 not only of science1 but of     
human conduct1 is amenable to the       
authority of logic4 ,to draw inferences 
has been said to be the great business  
of life4 ,every one has daily1 hourly1  
and momentary need of ascertaining facts
 which he has not directly observed2 not

 from any general purpose of adding to  
his stock of knowledge1 but because the 
facts themselves are of importance to   
his interests or to his occupations4    
,the business of the magistrate1 of the 
military commander1 of the navigator1 of
 the physician1 of the agriculturist1 is
 merely to judge of evidence1 and to act
 accordingly4 ,they all have to         
ascertain certain facts1 in order that  
they may afterwards apply certain rules1
 either devised by themselves1 or       
prescribed for their guidance by others2
 and as they do this well or ill1 so    
they discharge well or ill the duties of
 their several callings4 ,it is the only
 occupation in which the mind never     
ceases to be engaged2 and is the        
subject1 not of logic1 but of knowledge 
in general4  ,logic1 however1 is not the
 same thing with knowledge1 though the  
field of logic is coextensive with the  
field of knowledge4 ,logic is the common
 judge and arbiter of all particular    
investigations4 ,it does not undertake  

to find evidence1 but to determine      
whether it has been found4 ,logic       
neither observes1 nor invents1 nor      
discovers2 but judges4 ,it is no part of
 the business of logic to inform the    
surgeon what appearances are found to   
accompany a violent death4 ,this he must
 learn from his own experience and      
observation1 or from that of others1 his
 predecessors in his peculiar pursuit4  
,but logic sits in judgment on the      
sufficiency of that observation and     
experience to justify his rules1 and on 
the sufficiency of his rules to justify 
his conduct4 ,it does not give him      
proofs1 but teaches him what makes them 
proofs1 and how he is to judge of them4 
,it does not teach that any particular  
fact proves any other1 but points out to
 what conditions all facts must conform1
 in order that they may prove other     
facts4 ,to decide whether any given fact
 fulfils these conditions1 or whether   
facts can be found which fulfil them in 
a given case1 belongs exclusively to the

 particular art or science1 or to our   
knowledge of the particular subject4    
,it is in this sense that logic is1 what
 ,bacon so expressively called it1 ars  
artium2 the science of science itself4  
,all science consists of data and       
conclusions from those data1 of proofs  
and what they prove3 now logic points   
out what relations must subsist between 
data and whatever can be concluded from 
them1 between proof and everything which
 it can prove4 ,if there be any such    
indispensable relations1 and if these   
can be precisely determined1 every      
particular branch of science1 as well as
 every individual in the guidance of his
 conduct1 is bound to conform to those  
relations1 under the penalty of making  
false inferences1 of drawing conclusions
 which are not grounded in the realities
 of things4 ,whatever has at any time   
been concluded justly1 whatever         
knowledge has been acquired otherwise   
than by immediate intuition1 depended on
 the observance of the laws which it is 

the province of logic to investigate4   
,if the conclusions are just1 and the   
knowledge real1 those laws1 whether     
known or not1 have been observed4    #f4
 ,we need not1 therefore1 seek any      
farther for a solution of the question1 
so often agitated1 respecting the       
utility of logic4 ,if a science of logic
 exists1 or is capable of existing1 it  
must be useful4 ,if there be rules to   
which every mind consciously or         
unconsciously conforms in every instance
 in which it infers rightly1 there seems
 little necessity for discussing whether
 a person is more likely to observe     
those rules1 when he knows the rules1   
than when he is unacquainted with them4 
,a science may undoubtedly be brought to
 a certain1 not inconsiderable1 stage of
 advancement1 without the application of
 any other logic to it than what all    
persons1 who are said to have a sound   
understanding1 acquire empirically in   
the course of their studies4 ,mankind   
judged of evidence1 and often correctly1

 before logic was a science1 or they    
never could have made it one4 ,and they 
executed great mechanical works before  
they understood the laws of mechanics4  
,but there are limits both to what      
mechanicians can do without principles  
of mechanics1 and to what thinkers can  
do without principles of logic4 ,a few  
individuals1 by extraordinary genius1 or
 by the accidental acquisition of a good
 set of intellectual habits1 may work   
without principles in the same way1 or  
nearly the same way1 in which they would
 have worked if they had been in        
possession of principles4 ,but the bulk 
of mankind require either to understand 
the theory of what they are doing1 or to
 have rules laid down for them by those 
who have understood the theory4 ,in the 
progress of science from its easiest to 
its more difficult problems1 each great 
step in advance has usually had either  
as its precursor1 or as its             
accompaniment and necessary condition1 a
 corresponding improvement in the       

notions and principles of logic received
 among the most advanced thinkers4 ,and 
if several of the more difficult        
sciences are still in so defective a    
state2 if not only so little is proved1 
but disputation has not terminated even 
about the little which seemed to be so2 
the reason perhaps is1 that men's       
logical notions have not yet acquired   
the degree of extension1 or of accuracy1
 requisite for the estimation of the    
evidence proper to those particular     
departments of knowledge4    #g4 ,logic1
 then1 is the science of the operations 
of the understanding which are          
subservient to the estimation of        
evidence3 both the process itself of    
advancing from known truths to unknown1 
and all other intellectual operations in
 so far as auxiliary to this4 ,it       
includes1 therefore1 the operation of   
,naming2 for language is an instrument  
of thought1 as well as a means of       
communicating our thoughts4 ,it         
includes1 also1 ,definition1 and        

,classification4 ,for1 the use of these 
operations 7putting all other minds than
 one's own out of consideration7 is to  
serve not only for keeping our evidences
 and the conclusions from them permanent
 and readily accessible in the memory1  
but for so marshalling the facts which  
we may at any time be engaged in        
investigating1 as to enable us to       
perceive more clearly what evidence     
there is1 and to judge with fewer       
chances of error whether it be          
sufficient4 ,these1 therefore1 are      
operations specially instrumental to the
 estimation of evidence1 and1 as such1  
are within the province of ,logic4      
,there are other more elementary        
processes1 concerned in all thinking1   
such as ,conception1 ,memory1 and the   
like2 but of these it is not necessary  
that ,logic should take any peculiar    
cognizance1 since they have no special  
connexion with the problem of ,evidence1
 further than that1 like all other      
problems addressed to the understanding1

 it presupposes them4  ,our object1     
then1 will be1 to attempt a correct     
analysis of the intellectual process    
called ,reasoning or ,inference1 and of 
such other mental operations as are     
intended to facilitate this2 as well as1
 on the foundation of this analysis1 and
 pari passu with it1 to bring together  
or frame a set of rules or canons for   
testing the sufficiency of any given    
evidence to prove any given proposition4
  ,with respect to the first part of    
this undertaking1 ,i do not attempt to  
decompose the mental operations in      
question into their ultimate elements4  
,it is enough if the analysis as far as 
it goes is correct1 and if it goes far  
enough for the practical purposes of    
logic considered as an art4 ,the        
separation of a complicated phenomenon  
into its component parts is not like a  
connected and interdependent chain of   
proof4 ,if one link of an argument      
breaks1 the whole drops to the ground2  
but one step towards an analysis holds  

good and has an independent value1      
though we should never be able to make a
 second4 ,the results which have been   
obtained by analytical chemistry are not
 the less valuable1 though it should be 
discovered that all which we now call   
simple substances are really compounds4 
,all other things are at any rate       
compounded of those elements3 whether   
the elements themselves admit of        
decomposition1 is an important inquiry1 
but does not affect the certainty of the
 science up to that point4  ,i shall1   
accordingly1 attempt to analyse the     
process of inference1 and the processes 
subordinate to inference1 so far only as
 may be requisite for ascertaining the  
difference between a correct and an     
incorrect performance of those          
processes4 ,the reason for thus limiting
 our design1 is evident4 ,it has been   
said by objectors to logic1 that we do  
not learn to use our muscles by studying
 their anatomy4 ,the fact is not quite  
fairly stated2 for if the action of any 

of our muscles were vitiated by local   
weakness1 or other physical defect1 a   
knowledge of their anatomy might be very
 necessary for effecting a cure4 ,but we
 should be justly liable to the         
criticism involved in this objection1   
were we1 in a treatise on logic1 to     
carry the analysis of the reasoning     
process beyond the point at which any   
inaccuracy which may have crept into it 
must become visible4 ,in learning bodily
 exercises 7to carry on the same        
illustration7 we do1 and must1 analyse  
the bodily motions so far as is         
necessary for distinguishing those which
 ought to be performed from those which 
ought not4 ,to a similar extent1 and no 
further1 it is necessary that the       
logician should analyse the mental      
processes with which ,logic is          
concerned4 ,logic has no interest in    
carrying the analysis beyond the point  
at which it becomes apparent whether the
 operations have in any individual case 
been rightly or wrongly performed3 in   

the same manner as the science of music 
teaches us to discriminate between      
musical notes1 and to know the          
combinations of which they are          
susceptible1 but not what number of     
vibrations in a second correspond to    
each2 which1 though useful to be known1 
is useful for totally different         
purposes4 ,the extension of ,logic as a 
,science is determined by its           
necessities as an ,art3 whatever it does
 not need for its practical ends1 it    
leaves to the larger science which may  
be said to correspond1 not to any       
particular art1 but to art in general2  
the science which deals with the        
constitution of the human faculties2 and
 to which1 in the part of our mental    
nature which concerns ,logic1 as well as
 in all other parts1 it belongs to      
decide what are ultimate facts1 and what
 are resolvable into other facts4 ,and  
,i believe it will be found that most of
 the conclusions arrived at in this work
 have no necessary connexion with any   

particular views respecting the ulterior
 analysis4 ,logic is common ground on   
which the partisans of ,hartley and of  
,reid1 of ,locke and of ,kant1 may meet 
and join hands4 ,particular and detached
 opinions of all these thinkers will no 
doubt occasionally be controverted1     
since all of them were logicians as well
 as metaphysicians2 but the field on    
which their principal battles have been 
fought1 lies beyond the boundaries of   
our science4  ,it cannot1 indeed1 be    
pretended that logical principles can be
 altogether irrelevant to those more    
abstruse discussions2 nor is it possible
 but that the view we are led to take of
 the problem which logic proposes1 must 
have a tendency favourable to the       
adoption of some one opinion1 on these  
controverted subjects1 rather than      
another4 ,for metaphysics1 in           
endeavouring to solve its own peculiar  
problem1 must employ means1 the validity
 of which falls under the cognizance of 
logic4 ,it proceeds1 no doubt1 as far as

 possible1 merely by a closer and more  
attentive interrogation of our          
consciousness1 or more properly         
speaking1 of our memory2 and so far is  
not amenable to logic4 ,but wherever    
this method is insufficient to attain   
the end of its inquiries1 it must       
proceed1 like other sciences1 by means  
of evidence4 ,now1 the moment this      
science begins to draw inferences from  
evidence1 logic becomes the sovereign   
judge whether its inferences are well   
grounded1 or what other inferences would
 be so4  ,this1 however1 constitutes no 
nearer or other relation between logic  
and metaphysics1 than that which exists 
between logic and every other science4  
,and ,i can conscientiously affirm1 that
 no one proposition laid down in this   
work has been adopted for the sake of   
establishing1 or with any reference to  
its fitness for being employed in       
establishing1 preconceived opinions in  
any department of knowledge or of       
inquiry on which the speculative world  

is still undecided4#d  ,,footnotes3  #a 
,archbishop ,whately4  #b ,i use these  
terms indiscriminately1 because1 for the
 purpose in view1 there is no need for  
making any distinction between them4    
,but metaphysicians usually restrict the
 name ,intuition to the direct knowledge
 we are supposed to have of things      
external to our minds1 and              
,consciousness to our knowledge of our  
own mental phenomena4  #c ,this         
important theory has of late been called
 in question by a writer of deserved    
reputation1 ,mr4 ,samuel ,bailey2 but ,i
 do not conceive that the grounds on    
which it has been admitted as an        
established doctrine for a century past1
 have been at all shaken by that        
gentleman's objections4 ,i have         
elsewhere said what appeared to me      
necessary in reply to his arguments4    
7,westminster ,review for ,october      
#ahdb2 reprinted in ,dissertations and  
,discussions1 vol4 ii47  #d ,the view   
taken in the text1 of the definition and

 purpose of ,logic1 stands in marked    
opposition to that of the school of     
philosophy which1 in this country1 is   
represented by the writings of ,sir     
,william ,hamilton and of his numerous  
pupils4 ,logic1 as this school conceives
 it1 is the ,science of the ,formal     
,laws of ,thought2 a definition framed  
for the express purpose of excluding1 as
 irrelevant to ,logic1 whatever relates 
to ,belief and ,disbelief1 or to the    
pursuit of truth as such1 and           
restricting the science to that very    
limited portion of its total province1  
which has reference to the conditions1  
not of ,truth1 but of ,consistency4     
,what ,i have thought it useful to say  
in opposition to this limitation of the 
field of ,logic1 has been said at some  
length in a separate work1 first        
published in #ahfe1 and entitled ,an    
,examination of ,sir ,william           
,hamilton's ,philosophy1 and of the     
,principal ,philosophical ,questions    
discussed in his ,writings4 ,for the    

purposes of the present ,treatise1 ,i am
 content that the justification of the  
larger extension which ,i give to the   
domain of the science1 should rest on   
the sequel of the ,treatise itself4     
,some remarks on the relation which the 
,logic of ,consistency bears to the     
,logic of ,truth1 and on the place which
 that particular part occupies in the   
whole to which it belongs1 will be found
 in the present volume 7,book ,,ii4     
chap4 iii4  #i74     ,,book ,i4  ,,of   
,,names ,,and ,,propositions4   ',la    
scolastique1 qui produisit dans la      
logique1 comme dans la morale1 et dans  
une partie de la mtaphysique1 une       
subtilit1 une prcision d'ides1 dont     
l'habitude inconnue aux anciens1 a      
contribu plus qu'on ne croit au progrs  
de la bonne philosophie4'--,,condorcet1 
,vie de ,turgot4  ',to the schoolmen the
 vulgar languages are principally       
indebted for what precision and analytic
 subtlety they possess4'--,,sir ,w4     
,,hamilton1 ,discussions in ,philosophy4

     ,,chapter ,i4  ,,of ,,the          
,,necessity ,,of ,,commencing ,,with    
,,an ,,analysis ,,of ,,language4    #a4 
,it is so much the established practice 
of writers on logic to commence their   
treatises by a few general observations 
7in most cases1 it is true1 rather      
meagre7 on ,terms and their varieties1  
that it will1 perhaps1 scarcely be      
required from me in merely following the
 common usage1 to be as particular in   
assigning my reasons1 as it is usually  
expected that those should be who       
deviate from it4  ,the practice1 indeed1
 is recommended by considerations far   
too obvious to require a formal         
justification4 ,logic is a portion of   
the ,art of ,thinking3 ,language is     
evidently1 and by the admission of all  
philosophers1 one of the principal      
instruments or helps of thought2 and any
 imperfection in the instrument1 or in  
the mode of employing it1 is confessedly
 liable1 still more than in almost any  
other art1 to confuse and impede the    

process1 and destroy all ground of      
confidence in the result4 ,for a mind   
not previously versed in the meaning and
 right use of the various kinds of      
words1 to attempt the study of methods  
of philosophizing1 would be as if some  
one should attempt to become an         
astronomical observer1 having never     
learned to adjust the focal distance of 
his optical instruments so as to see    
distinctly4  ,since ,reasoning1 or      
,inference1 the principal subject of    
logic1 is an operation which usually    
takes place by means of words1 and in   
complicated cases can take place in no  
other way2 those who have not a thorough
 insight into the signification and     
purposes of words1 will be under        
chances1 amounting almost to certainty1 
of reasoning or inferring incorrectly4  
,and logicians have generally felt that 
unless1 in the very first stage1 they   
removed this source of error2 unless    
they taught their pupil to put away the 
glasses which distort the object1 and to

 use those which are adapted to his     
purpose in such a manner as to assist1  
not perplex1 his vision2 he would not be
 in a condition to practise the         
remaining part of their discipline with 
any prospect of advantage4 ,therefore it
 is that an inquiry into language1 so   
far as is needful to guard against the  
errors to which it gives rise1 has at   
all times been deemed a necessary       
preliminary to the study of logic4  ,but
 there is another reason1 of a still    
more fundamental nature1 why the import 
of words should be the earliest subject 
of the logician's consideration3 because
 without it he cannot examine into the  
import of ,propositions4 ,now this is a 
subject which stands on the very        
threshold of the science of logic4  ,the
 object of logic1 as defined in the     
,introductory ,chapter1 is to ascertain 
how we come by that portion of our      
knowledge 7much the greatest portion7   
which is not intuitive3 and by what     
criterion we can1 in matters not        

self-evident1 distinguish between things
 proved and things not proved1 between  
what is worthy and what is unworthy of  
belief4 ,of the various questions which 
present themselves to our inquiring     
faculties1 some receive an answer from  
direct consciousness1 others1 if        
resolved at all1 can only be resolved by
 means of evidence4 ,logic is concerned 
with these last4 ,but before inquiring  
into the mode of resolving questions1 it
 is necessary to inquire what are those 
which offer themselves2 what questions  
are conceivable2 what inquiries are     
there1 to which mankind have either     
obtained1 or been able to imagine it    
possible that they should obtain1 an    
answer4 ,this point is best ascertained 
by a survey and analysis of             
,propositions4    #b4 ,the answer to    
every question which it is possible to  
frame1 must be contained in a           
,proposition1 or ,assertion4 ,whatever  
can be an object of belief1 or even of  
disbelief1 must1 when put into words1   

assume the form of a proposition4 ,all  
truth and all error lie in propositions4
 ,what1 by a convenient misapplication  
of an abstract term1 we call a ,truth1  
means simply a ,true ,proposition2 and  
errors are false propositions4 ,to know 
the import of all possible propositions1
 would be to know all questions which   
can be raised1 all matters which are    
susceptible of being either believed or 
disbelieved4 ,how many kinds of         
inquiries can be propounded2 how many   
kinds of judgments can be made2 and how 
many kinds of propositions it is        
possible to frame with a meaning2 are   
but different forms of one and the same 
question4 ,since1 then1 the objects of  
all ,belief and of all ,inquiry express 
themselves in propositions2 a sufficient
 scrutiny of ,propositions and of their 
varieties will apprize us what questions
 mankind have actually asked of         
themselves1 and what1 in the nature of  
answers to those questions1 they have   
actually thought they had grounds to    

believe4  ,now the first glance at a    
proposition shows that it is formed by  
putting together two names4 ,a          
proposition1 according to the common    
simple definition1 which is sufficient  
for our purpose1 is1 discourse1 in which
 something is affirmed or denied of     
something4 ,thus1 in the proposition1   
,gold is yellow1 the quality yellow is  
affirmed of the substance gold4 ,in the 
proposition1 ,franklin was not born in  
,england1 the fact expressed by the     
words born in ,england is denied of the 
man ,franklin4  ,every proposition      
consists of three parts3 the ,subject1  
the ,predicate1 and the ,copula4 ,the   
predicate is the name denoting that     
which is affirmed or denied4 ,the       
subject is the name denoting the person 
or thing which something is affirmed or 
denied of4 ,the copula is the sign      
denoting that there is an affirmation or
 denial2 and thereby enabling the hearer
 or reader to distinguish a proposition 
from any other kind of discourse4 ,thus1

 in the proposition1 ,the earth is      
round1 the ,predicate is the word round1
 which denotes the quality affirmed1 or 
7as the phrase is7 predicated3 the      
earth1 words denoting the object which  
that quality is affirmed of1 compose the
 ,subject2 the word is1 which serves as 
the connecting mark between the subject 
and predicate1 to show that one of them 
is affirmed of the other1 is called the 
,copula4  ,dismissing1 for the present1 
the copula1 of which more will be said  
hereafter1 every proposition1 then1     
consists of at least two names2 brings  
together two names1 in a particular     
manner4 ,this is already a first step   
towards what we are in quest of4 ,it    
appears from this1 that for an act of   
belief1 one object is not sufficient2   
the simplest act of belief supposes1 and
 has something to do with1 two objects3 
two names1 to say the least2 and 7since 
the names must be names of something7   
two nameable things4 ,a large class of  
thinkers would cut the matter short by  

saying1 two ideas4 ,they would say1 that
 the subject and predicate are both of  
them names of ideas2 the idea of gold1  
for instance1 and the idea of yellow2   
and that what takes place 7or part of   
what takes place7 in the act of belief1 
consists in bringing 7as it is often    
expressed7 one of these ideas under the 
other4 ,but this we are not yet in a    
condition to say3 whether such be the   
correct mode of describing the          
phenomenon1 is an after consideration4  
,the result with which for the present  
we must be contented1 is1 that in every 
act of belief two objects are in some   
manner taken cognizance of2 that there  
can be no belief claimed1 or question   
propounded1 which does not embrace two  
distinct 7either material or            
intellectual7 subjects of thought2 each 
of them capable1 or not1 of being       
conceived by itself1 but incapable of   
being believed by itself4  ,i may say1  
for instance1 the sun4 ,the word has a  
meaning1 and suggests that meaning to   

the mind of any one who is listening to 
me4 ,but suppose ,i ask him1 ,whether it
 is true3 whether he believes it8 ,he   
can give no answer4 ,there is as yet    
nothing to believe1 or to disbelieve4   
,now1 however1 let me make1 of all      
possible assertions respecting the sun1 
the one which involves the least of     
reference to any object besides itself2 
let me say1 the sun exists4 ,here1 at   
once1 is something which a person can   
say he believes4 ,but here1 instead of  
only one1 we find two distinct objects  
of conception3 the sun is one object2   
existence is another4 ,let it not be    
said that this second conception1       
existence1 is involved in the first2 for
 the sun may be conceived as no longer  
existing4 ,the sun does not convey all  
the meaning that is conveyed by the sun 
exists3 my father does not include all  
the meaning of my father exists1 for he 
may be dead2 a round square does not    
include the meaning of a round square   
exists1 for it does not and cannot      

exist4 ,when ,i say the sun1 my father1 
or a round square1 ,i do not call upon  
the hearer for any belief or disbelief1 
nor can either the one or the other be  
afforded me2 but if ,i say1 the sun     
exists1 my father exists1 or a round    
square exists1 ,i call for belief2 and  
should1 in the first of the three       
instances1 meet with it2 in the second1 
with belief or disbelief1 as the case   
might be2 in the third1 with disbelief4 
#c4 ,this first step in the analysis of 
the object of belief1 which1 though so  
obvious1 will be found to be not        
unimportant1 is the only one which we   
shall find it practicable to make       
without a preliminary survey of         
language4 ,if we attempt to proceed     
further in the same path1 that is1 to   
analyse any further the import of       
,propositions2 we find forced upon us1  
as a subject of previous consideration1 
the import of ,names4 ,for every        
proposition consists of two names2 and  
every proposition affirms or denies one 

of these names1 of the other4 ,now what 
we do1 what passes in our mind1 when we 
affirm or deny two names of one another1
 must depend on what they are names of2 
since it is with reference to that1 and 
not to the mere names themselves1 that  
we make the affirmation or denial4      
,here1 therefore1 we find a new reason  
why the signification of names1 and the 
relation generally between names and the
 things signified by them1 must occupy  
the preliminary stage of the inquiry we 
are engaged in4  ,it may be objected    
that the meaning of names can guide us  
at most only to the opinions1 possibly  
the foolish and groundless opinions1    
which mankind have formed concerning    
things1 and that as the object of       
philosophy is truth1 not opinion1 the   
philosopher should dismiss words and    
look into things themselves1 to         
ascertain what questions can be asked   
and answered in regard to them4 ,this   
advice 7which no one has it in his power
 to follow7 is in reality an exhortation

 to discard the whole fruits of the     
labours of his predecessors1 and conduct
 himself as if he were the first person 
who had ever turned an inquiring eye    
upon nature4 ,what does any one's       
personal knowledge of ,things amount to1
 after subtracting all which he has     
acquired by means of the words of other 
people8 ,even after he has learned as   
much as people usually do learn from    
others1 will the notions of things      
contained in his individual mind afford 
as sufficient a basis for a catalogue   
raisonn as the notions which are in the 
minds of all mankind8  ,in any          
enumeration and classification of       
,things1 which does not set out from    
their names1 no varieties of things will
 of course be comprehended but those    
recognised by the particular inquirer2  
and it will still remain to be          
established1 by a subsequent examination
 of names1 that the enumeration has     
omitted nothing which ought to have been
 included4 ,but if we begin with names1 

and use them as our clue to the things1 
we bring at once before us all the      
distinctions which have been recognised1
 not by a single inquirer1 but by all   
inquirers taken together4 ,it doubtless 
may1 and ,i believe it will1 be found1  
that mankind have multiplied the        
varieties unnecessarily1 and have       
imagined distinctions among things1     
where there were only distinctions in   
the manner of naming them4 ,but we are  
not entitled to assume this in the      
commencement4 ,we must begin by         
recognising the distinctions made by    
ordinary language4 ,if some of these    
appear1 on a close examination1 not to  
be fundamental1 the enumeration of the  
different kinds of realities may be     
abridged accordingly4 ,but to impose    
upon the facts in the first instance the
 yoke of a theory1 while the grounds of 
the theory are reserved for discussion  
in a subsequent stage1 is not a course  
which a logician can reasonably adopt4  
,,chapter ,,ii4  ,,of ,,names4    #a4 ,a

 name1 says ,hobbes1#a is a word taken  
at pleasure to serve for a mark which   
may raise in our mind a thought like to 
some thought we had before1 and which   
being pronounced to others1 may be to   
them a sign of what thought the speaker 
had#b before in his mind4 ,this simple  
definition of a name1 as a word 7or set 
of words7 serving the double purpose of 
a mark to recall to ourselves the       
likeness of a former thought1 and a sign
 to make it known to others1 appears    
unexceptionable4 ,names1 indeed1 do much
 more than this2 but whatever else they 
do1 grows out of1 and is the result of  
this3 as will appear in its proper      
place4  ,are names more properly said to
 be the names of things1 or of our ideas
 of things8 ,the first is the expression
 in common use2 the last is that of some
 metaphysicians1 who conceived that in  
adopting it they were introducing a     
highly important distinction4 ,the      
eminent thinker1 just quoted1 seems to  
countenance the latter opinion4 ,but    

seeing1 he continues1 names ordered in  
speech 7as is defined7 are signs of our 
conceptions1 it is manifest they are not
 signs of the things themselves2 for    
that the sound of this word stone should
 be the sign of a stone1 cannot be      
understood in any sense but this1 that  
he that hears it collects that he that  
pronounces it thinks of a stone4  ,if it
 be merely meant that the conception    
alone1 and not the thing itself1 is     
recalled by the name1 or imparted to the
 hearer1 this of course cannot be       
denied4 ,nevertheless1 there seems good 
reason for adhering to the common usage1
 and calling the word sun the name of   
the sun1 and not the name of our idea of
 the sun4 ,for names are not intended   
only to make the hearer conceive what we
 conceive1 but also to inform him what  
we believe4 ,now1 when ,i use a name for
 the purpose of expressing a belief1 it 
is a belief concerning the thing itself1
 not concerning my idea of it4 ,when ,i 
say1 the sun is the cause of day1 ,i do 

not mean that my idea of the sun causes 
or excites in me the idea of day2 or in 
other words1 that thinking of the sun   
makes me think of day4 ,i mean1 that a  
certain physical fact1 which is called  
the sun's presence 7and which1 in the   
ultimate analysis1 resolves itself into 
sensations1 not ideas7 causes another   
physical fact1 which is called day4 ,it 
seems proper to consider a word as the  
name of that which we intend to be      
understood by it when we use it2 of that
 which any fact that we assert of it is 
to be understood of2 that1 in short1    
concerning which1 when we employ the    
word1 we intend to give information4    
,names1 therefore1 shall always be      
spoken of in this work as the names of  
things themselves1 and not merely of our
 ideas of things4  ,but the question now
 arises1 of what things8 and to answer  
this it is necessary to take into       
consideration the different kinds of    
names4    #b4 ,it is usual1 before      
examining the various classes into which

 names are commonly divided1 to begin by
 distinguishing from names of every     
description1 those words which are not  
names1 but only parts of names4 ,among  
such are reckoned particles1 as of1 to1 
truly1 often2 the inflected cases of    
nouns substantive1 as me1 him1 ,john's2 
and even adjectives1 as large1 heavy4   
,these words do not express things of   
which anything can be affirmed or       
denied4 ,we cannot say1 ,heavy fell1 or 
,a heavy fell2 ,truly1 or ,a truly1 was 
asserted2 ,of1 or ,an of1 was in the    
room4 ,unless1 indeed1 we are speaking  
of the mere words themselves1 as when we
 say1 ,truly is an ,english word1 or1   
,heavy is an adjective4 ,in that case   
they are complete names1 viz4 names of  
those particular sounds1 or of those    
particular collections of written       
characters4 ,this employment of a word  
to denote the mere letters and syllables
 of which it is composed1 was termed by 
the schoolmen the suppositio materialis 
of the word4 ,in any other sense we     

cannot introduce one of these words into
 the subject of a proposition1 unless in
 combination with other words2 as1 ,a   
heavy body fell1 ,a truly important fact
 was asserted1 ,a member of parliament  
was in the room4  ,an adjective1        
however1 is capable of standing by      
itself as the predicate of a            
proposition2 as when we say1 ,snow is   
white2 and occasionally even as the     
subject1 for we may say1 ,white is an   
agreeable colour4 ,the adjective is     
often said to be so used by a           
grammatical ellipsis3 ,snow is white1   
instead of ,snow is a white object2     
,white is an agreeable colour1 instead  
of1 ,a white colour1 or1 ,the colour    
white1 is agreeable4 ,the ,greeks and   
,romans were allowed1 by the rules of   
their language1 to employ this ellipsis 
universally in the subject as well as in
 the predicate of a proposition4 ,in    
,english this cannot1 generally         
speaking1 be done4 ,we may say1 ,the    
earth is round2 but we cannot say1      

,round is easily moved2 we must say1 ,a 
round object4 ,this distinction1        
however1 is rather grammatical than     
logical4 ,since there is no difference  
of meaning between round1 and a round   
object1 it is only custom which         
prescribes that on any given occasion   
one shall be used1 and not the other4   
,we shall1 therefore1 without scruple1  
speak of adjectives as names1 whether in
 their own right1 or as representative  
of the more circuitous forms of         
expression above exemplified4 ,the other
 classes of subsidiary words have no    
title whatever to be considered as      
names4 ,an adverb1 or an accusative     
case1 cannot under any circumstances    
7except when their mere letters and     
syllables are spoken of7 figure as one  
of the terms of a proposition4  ,words  
which are not capable of being used as  
names1 but only as parts of names1 were 
called by some of the schoolmen         
,syncategorematic terms3 from ,greek3   
syn1 with1 and ,greek3 katgore1 to      

predicate1 because it was only with some
 other word that they could be          
predicated4 ,a word which could be used 
either as the subject or predicate of a 
proposition without being accompanied by
 any other word1 was termed by the same 
authorities a ,categorematic term4 ,a   
combination of one or more              
,categorematic1 and one or more         
,syncategorematic words1 as ,a heavy    
body1 or ,a court of justice1 they      
sometimes called a mixed term2 but this 
seems a needless multiplication of      
technical expressions4 ,a mixed term is1
 in the only useful sense of the word1  
,categorematic4 ,it belongs to the class
 of what have been called many-worded   
names4  ,for1 as one word is frequently 
not a name1 but only part of a name1 so 
a number of words often compose one     
single name1 and no more4 ,these words1 
the place which the wisdom or policy of 
antiquity had destined for the residence
 of the ,abyssinian princes1 form in the
 estimation of the logician only one    

name2 one ,categorematic term4 ,a mode  
of determining whether any set of words 
makes only one name1 or more than one1  
is by predicating something of it1 and  
observing whether1 by this predication1 
we make only one assertion or several4  
,thus1 when we say1 ,john ,nokes1 who   
was the mayor of the town1 died         
yesterday--by this predication we make  
but one assertion2 whence it appears    
that ,john ,nokes1 who was the mayor of 
the town1 is no more than one name4 ,it 
is true that in this proposition1       
besides the assertion that ,john ,nokes 
died yesterday1 there is included       
another assertion1 namely1 that ,john   
,nokes was mayor of the town4 ,but this 
last assertion was already made3 we did 
not make it by adding the predicate1    
died yesterday4 ,suppose1 however1 that 
the words had been1 ,john ,nokes and the
 mayor of the town1 they would have     
formed two names instead of one4 ,for   
when we say1 ,john ,nokes and the mayor 
of the town died yesterday1 we make two 

assertions2 one1 that ,john ,nokes died 
yesterday2 the other1 that the mayor of 
the town died yesterday4  ,it being     
needless to illustrate at any greater   
length the subject of many-worded names1
 we proceed to the distinctions which   
have been established among names1 not  
according to the words they are composed
 of1 but according to their             
signification4    #c4 ,all names are    
names of something1 real or imaginary2  
but all things have not names           
appropriated to them individually4 ,for 
some individual objects we require1 and 
consequently have1 separate             
distinguishing names2 there is a name   
for every person1 and for every         
remarkable place4 ,other objects1 of    
which we have not occasion to speak so  
frequently1 we do not designate by a    
name of their own2 but when the         
necessity arises for naming them1 we do 
so by putting together several words1   
each of which1 by itself1 might be and  
is used for an indefinite number of     

other objects2 as when ,i say1 this     
stone3 this and stone being1 each of    
them1 names that may be used of many    
other objects besides the particular one
 meant1 though the only object of which 
they can both be used at the given      
moment1 consistently with their         
signification1 may be the one of which  
,i wish to speak4  ,were this the sole  
purpose for which names1 that are common
 to more things than one1 could be      
employed2 if they only served1 by       
mutually limiting each other1 to afford 
a designation for such individual       
objects as have no names of their own2  
they could only be ranked among         
contrivances for economizing the use of 
language4 ,but it is evident that this  
is not their sole function4 ,it is by   
their means that we are enabled to      
assert general propositions2 to affirm  
or deny any predicate of an indefinite  
number of things at once4 ,the          
distinction1 therefore1 between general 
names1 and individual or singular names1

 is fundamental2 and may be considered  
as the first grand division of names4   
,a general name is familiarly defined1 a
 name which is capable of being truly   
affirmed1 in the same sense1 of each of 
an indefinite number of things4 ,an     
individual or singular name is a name   
which is only capable of being truly    
affirmed1 in the same sense1 of one     
thing4  ,thus1 man is capable of being  
truly affirmed of ,john1 ,george1 ,mary1
 and other persons without assignable   
limit2 and it is affirmed of all of them
 in the same sense2 for the word man    
expresses certain qualities1 and when we
 predicate it of those persons1 we      
assert that they all possess those      
qualities4 ,but ,john is only capable of
 being truly affirmed of one single     
person1 at least in the same sense4 ,for
 though there are many persons who bear 
that name1 it is not conferred upon them
 to indicate any qualities1 or anything 
which belongs to them in common2 and    
cannot be said to be affirmed of them in

 any sense at all1 consequently not in  
the same sense4 ,the king who succeeded 
,william the ,conqueror1 is also an     
individual name4 ,for1 that there cannot
 be more than one person of whom it can 
be truly affirmed1 is implied in the    
meaning of the words4 ,even the king1   
when the occasion or the context defines
 the individual of whom it is to be     
understood1 may justly be regarded as an
 individual name4  ,it is not unusual1  
by way of explaining what is meant by a 
general name1 to say that it is the name
 of a class4 ,but this1 though a        
convenient mode of expression for some  
purposes1 is objectionable as a         
definition1 since it explains the       
clearer of two things by the more       
obscure4 ,it would be more logical to   
reverse the proposition1 and turn it    
into a definition of the word class3 ,a 
class is the indefinite multitude of    
individuals denoted by a general name4  
,it is necessary to distinguish general 
from collective names4 ,a general name  

is one which can be predicated of each  
individual of a multitude2 a collective 
name cannot be predicated of each       
separately1 but only of all taken       
together4 ,the #gfth regiment of foot in
 the ,british army1 which is a          
collective name1 is not a general but an
 individual name2 for though it can be  
predicated of a multitude of individual 
soldiers taken jointly1 it cannot be    
predicated of them severally4 ,we may   
say1 ,jones is a soldier1 and ,thompson 
is a soldier1 and ,smith is a soldier1  
but we cannot say1 ,jones is the #gfth  
regiment1 and ,thompson is the #gfth    
regiment1 and ,smith is the #gfth       
regiment4 ,we can only say1 ,jones1 and 
,thompson1 and ,smith1 and ,brown1 and  
so forth 7enumerating all the soldiers71
 are the #gfth regiment4  ,the #gfth    
regiment is a collective name1 but not a
 general one3 a regiment is both a      
collective and a general name4 ,general 
with respect to all individual          
regiments1 of each of which separately  

it can be affirmed2 collective with     
respect to the individual soldiers of   
whom any regiment is composed4    #d4   
,the second general division of names is
 into concrete and abstract4 ,a concrete
 name is a name which stands for a      
thing2 an abstract name is a name which 
stands for an attribute of a thing4     
,thus ,john1 the sea1 this table1 are   
names of things4 ,white1 also1 is a name
 of a thing1 or rather of things4       
,whiteness1 again1 is the name of a     
quality or attribute of those things4   
,man is a name of many things2 humanity 
is a name of an attribute of those      
things4 ,old is a name of things2 old   
age is a name of one of their           
attributes4  ,i have used the words     
concrete and abstract in the sense      
annexed to them by the schoolmen1 who1  
notwithstanding the imperfections of    
their philosophy1 were unrivalled in the
 construction of technical language1 and
 whose definitions1 in logic at least1  
though they never went more than a      

little way into the subject1 have       
seldom1 ,i think1 been altered but to be
 spoiled4 ,a practice1 however1 has     
grown up in more modern times1 which1 if
 not introduced by ,locke1 has gained   
currency chiefly from his example1 of   
applying the expression abstract name to
 all names which are the result of      
abstraction or generalization1 and      
consequently to all general names1      
instead of confining it to the names of 
attributes4 ,the metaphysicians of the  
,condillac school1--whose admiration of 
,locke1 passing over the profoundest    
speculations of that truly original     
genius1 usually fastens with peculiar   
eagerness upon his weakest points1--have
 gone on imitating him in this abuse of 
language1 until there is now some       
difficulty in restoring the word to its 
original signification4 ,a more wanton  
alteration in the meaning of a word is  
rarely to be met with2 for the          
expression general name1 the exact      
equivalent of which exists in all       

languages ,i am acquainted with1 was    
already available for the purpose to    
which abstract has been misappropriated1
 while the misappropriation leaves that 
important class of words1 the names of  
attributes1 without any compact         
distinctive appellation4 ,the old       
acceptation1 however1 has not gone so   
completely out of use1 as to deprive    
those who still adhere to it of all     
chance of being understood4 ,by         
abstract1 then1 ,i shall always1 in     
,logic1 mean the opposite of concrete3  
by an abstract name1 the name of an     
attribute2 by a concrete name1 the name 
of an object4  ,do abstract names belong
 to the class of general1 or to that of 
singular names8 ,some of them are       
certainly general4 ,i mean those which  
are names not of one single and definite
 attribute1 but of a class of           
attributes4 ,such is the word colour1   
which is a name common to whiteness1    
redness1 c4 ,such is even the word      
whiteness1 in respect of the different  

shades of whiteness to which it is      
applied in common2 the word magnitude1  
in respect of the various degrees of    
magnitude and the various dimensions of 
space2 the word weight1 in respect of   
the various degrees of weight4 ,such    
also is the word attribute itself1 the  
common name of all particular           
attributes4 ,but when only one          
attribute1 neither variable in degree   
nor in kind1 is designated by the name2 
as visibleness2 tangibleness2 equality2 
squareness2 milkwhiteness2 then the name
 can hardly be considered general2 for  
though it denotes an attribute of many  
different objects1 the attribute itself 
is always conceived as one1 not many4#c 
,to avoid needless logomachies1 the best
 course would probably be to consider   
these names as neither general nor      
individual1 and to place them in a class
 apart4  ,it may be objected to our     
definition of an abstract name1 that not
 only the names which we have called    
abstract1 but adjectives1 which we have 

placed in the concrete class1 are names 
of attributes2 that white1 for example1 
is as much the name of the colour as    
whiteness is4 ,but 7as before remarked7 
a word ought to be considered as the    
name of that which we intend to be      
understood by it when we put it to its  
principal use1 that is1 when we employ  
it in predication4 ,when we say snow is 
white1 milk is white1 linen is white1 we
 do not mean it to be understood that   
snow1 or linen1 or milk1 is a colour4   
,we mean that they are things having the
 colour4 ,the reverse is the case with  
the word whiteness2 what we affirm to be
 whiteness is not snow1 but the colour  
of snow4 ,whiteness1 therefore1 is the  
name of the colour exclusively3 white is
 a name of all things whatever having   
the colour2 a name1 not of the quality  
whiteness1 but of every white object4   
,it is true1 this name was given to all 
those various objects on account of the 
quality2 and we may therefore say1      
without impropriety1 that the quality   

forms part of its signification2 but a  
name can only be said to stand for1 or  
to be a name of1 the things of which it 
can be predicated4 ,we shall presently  
see that all names which can be said to 
have any signification1 all names by    
applying which to an individual we give 
any information respecting that         
individual1 may be said to imply an     
attribute of some sort2 but they are not
 names of the attribute2 it has its own 
proper abstract name4    #e4 ,this leads
 to the consideration of a third great  
division of names1 into connotative and 
non-connotative1 the latter sometimes1  
but improperly1 called absolute4 ,this  
is one of the most important            
distinctions which we shall have        
occasion to point out1 and one of those 
which go deepest into the nature of     
language4  ,a non-connotative term is   
one which signifies a subject only1 or  
an attribute only4 ,a connotative term  
is one which denotes a subject1 and     
implies an attribute4 ,by a subject is  

here meant anything which possesses     
attributes4 ,thus ,john1 or ,london1 or 
,england1 are names which signify a     
subject only4 ,whiteness1 length1       
virtue1 signify an attribute only4 ,none
 of these names1 therefore1 are         
connotative4 ,but white1 long1 virtuous1
 are connotative4 ,the word white1      
denotes all white things1 as snow1      
paper1 the foam of the sea1 c41 and     
implies1 or as it was termed by the     
schoolmen1 connotes#d1 the attribute    
whiteness4 ,the word white is not       
predicated of the attribute1 but of the 
subjects1 snow1 c42 but when we         
predicate it of them1 we imply1 or      
connote1 that the attribute whiteness   
belongs to them4 ,the same may be said  
of the other words above cited4         
,virtuous1 for example1 is the name of a
 class1 which includes ,socrates1       
,howard1 the ,man of ,ross1 and an      
undefinable number of other individuals1
 past1 present1 and to come4 ,these     
individuals1 collectively and severally1

 can alone be said with propriety to be 
denoted by the word3 of them alone can  
it properly be said to be a name4 ,but  
it is a name applied to all of them in  
consequence of an attribute which they  
are supposed to possess in common1 the  
attribute which has received the name of
 virtue4 ,it is applied to all beings   
that are considered to possess this     
attribute2 and to none which are not so 
considered4  ,all concrete general names
 are connotative4 ,the word man1 for    
example1 denotes ,peter1 ,jane1 ,john1  
and an indefinite number of other       
individuals1 of whom1 taken as a class1 
it is the name4 ,but it is applied to   
them1 because they possess1 and to      
signify that they possess1 certain      
attributes4 ,these seem to be1          
corporeity1 animal life1 rationality1   
and a certain external form1 which for  
distinction we call the human4 ,every   
existing thing1 which possessed all     
these attributes1 would be called a man2
 and anything which possessed none of   

them1 or only one1 or two1 or even three
 of them without the fourth1 would not  
be so called4 ,for example1 if in the   
interior of ,africa there were to be    
discovered a race of animals possessing 
reason equal to that of human beings1   
but with the form of an elephant1 they  
would not be called men4 ,swift's       
,houyhnhnms would not be so called4 ,or 
if such newly-discovered beings         
possessed the form of man without any   
vestige of reason1 it is probable that  
some other name than that of man would  
be found for them4 ,how it happens that 
there can be any doubt about the matter1
 will appear hereafter4 ,the word man1  
therefore1 signifies all these          
attributes1 and all subjects which      
possess these attributes4 ,but it can be
 predicated only of the subjects4 ,what 
we call men1 are the subjects1 the      
individual ,stiles and ,nokes2 not the  
qualities by which their humanity is    
constituted4 ,the name1 therefore1 is   
said to signify the subjects directly1  

the attributes indirectly2 it denotes   
the subjects1 and implies1 or involves1 
or indicates1 or as we shall say        
henceforth connotes1 the attributes4 ,it
 is a connotative name4  ,connotative   
names have hence been also called       
denominative1 because the subject which 
they denote is denominated by1 or       
receives a name from1 the attribute     
which they connote4 ,snow1 and other    
objects1 receive the name white1 because
 they possess the attribute which is    
called whiteness2 ,peter1 ,james1 and   
others receive the name man1 because    
they possess the attributes which are   
considered to constitute humanity4 ,the 
attribute1 or attributes1 may therefore 
be said to denominate those objects1 or 
to give them a common name4#e  ,it has  
been seen that all concrete general     
names are connotative4 ,even abstract   
names1 though the names only of         
attributes1 may in some instances be    
justly considered as connotative2 for   
attributes themselves may have          

attributes ascribed to them2 and a word 
which denotes attributes may connote an 
attribute of those attributes4 ,of this 
description1 for example1 is such a word
 as fault2 equivalent to bad or hurtful 
quality4 ,this word is a name common to 
many attributes1 and connotes           
hurtfulness1 an attribute of those      
various attributes4 ,when1 for example1 
we say that slowness1 in a horse1 is a  
fault1 we do not mean that the slow     
movement1 the actual change of place of 
the slow horse1 is a bad thing1 but that
 the property or peculiarity of the     
horse1 from which it derives that name1 
the quality of being a slow mover1 is an
 undesirable peculiarity4  ,in regard to
 those concrete names which are not     
general but individual1 a distinction   
must be made4  ,proper names are not    
connotative3 they denote the individuals
 who are called by them2 but they do not
 indicate or imply any attributes as    
belonging to those individuals4 ,when we
 name a child by the name ,paul1 or a   

dog by the name ,csar1 these names are  
simply marks used to enable those       
individuals to be made subjects of      
discourse4 ,it may be said1 indeed1 that
 we must have had some reason for giving
 them those names rather than any       
others2 and this is true2 but the name1 
once given1 is independent of the       
reason4 ,a man may have been named      
,john1 because that was the name of his 
father2 a town may have been named      
,dartmouth1 because it is situated at   
the mouth of the ,dart4 ,but it is no   
part of the signification of the word   
,john1 that the father of the person so 
called bore the same name2 nor even of  
the word ,dartmouth1 to be situated at  
the mouth of the ,dart4 ,if sand should 
choke up the mouth of the river1 or an  
earthquake change its course1 and remove
 it to a distance from the town1 the    
name of the town would not necessarily  
be changed4 ,that fact1 therefore1 can  
form no part of the signification of the
 word2 for otherwise1 when the fact     

confessedly ceased to be true1 no one   
would any longer think of applying the  
name4 ,proper names are attached to the 
objects themselves1 and are not         
dependent on the continuance of any     
attribute of the object4  ,but there is 
another kind of names1 which1 although  
they are individual names1 that is1     
predicable only of one object1 are      
really connotative4 ,for1 though we may 
give to an individual a name utterly    
unmeaning1 which we call a proper       
name1--a word which answers the purpose 
of showing what thing it is we are      
talking about1 but not of telling       
anything about it2 yet a name peculiar  
to an individual is not necessarily of  
this description4 ,it may be significant
 of some attribute1 or some union of    
attributes1 which1 being possessed by no
 object but one1 determines the name    
exclusively to that individual4 ,the sun
 is a name of this description2 ,god1   
when used by a monotheist1 is another4  
,these1 however1 are scarcely examples  

of what we are now attempting to        
illustrate1 being1 in strictness of     
language1 general1 not individual names3
 for1 however they may be in fact       
predicable only of one object1 there is 
nothing in the meaning of the words     
themselves which implies this3 and1     
accordingly1 when we are imagining and  
not affirming1 we may speak of many     
suns2 and the majority of mankind have  
believed1 and still believe1 that there 
are many gods4 ,but it is easy to       
produce words which are real instances  
of connotative individual names4 ,it may
 be part of the meaning of the          
connotative name itself1 that there can 
exist but one individual possessing the 
attribute which it connotes3 as1 for    
instance1 the only son of ,john ,stiles2
 the first emperor of ,rome4 ,or the    
attribute connoted may be a connexion   
with some determinate event1 and the    
connexion may be of such a kind as only 
one individual could have2 or may at    
least be such as only one individual    

actually had2 and this may be implied in
 the form of the expression4 ,the father
 of ,socrates is an example of the one  
kind 7since ,socrates could not have had
 two fathers72 the author of the ,iliad1
 the murderer of ,henri ,quatre1 of the 
second4 ,for1 though it is conceivable  
that more persons than one might have   
participated in the authorship of the   
,iliad1 or in the murder of ,henri      
,quatre1 the employment of the article  
the implies that1 in fact1 this was not 
the case4 ,what is here done by the word
 the1 is done in other cases by the     
context3 thus1 ,csar's army is an       
individual name1 if it appears from the 
context that the army meant is that     
which ,csar commanded in a particular   
battle4 ,the still more general         
expressions1 the ,roman army1 or the    
,christian army1 may be individualized  
in a similar manner4 ,another case of   
frequent occurrence has already been    
noticed2 it is the following4 ,the name1
 being a many-worded one1 may consist1  

in the first place1 of a general name1  
capable therefore in itself of being    
affirmed of more things than one1 but   
which is1 in the second place1 so       
limited by other words joined with it1  
that the entire expression can only be  
predicated of one object1 consistently  
with the meaning of the general term4   
,this is exemplified in such an instance
 as the following3 the present prime    
minister of ,england4 ,prime ,minister  
of ,england is a general name2 the      
attributes which it connotes may be     
possessed by an indefinite number of    
persons3 in succession however1 not     
simultaneously2 since the meaning of the
 name itself imports 7among other       
things7 that there can be only one such 
person at a time4 ,this being the case1 
and the application of the name being   
afterwards limited by the article and   
the word present1 to such individuals as
 possess the attributes at one          
indivisible point of time1 it becomes   
applicable only to one individual4 ,and 

as this appears from the meaning of the 
name1 without any extrinsic proof1 it is
 strictly an individual name4  ,from the
 preceding observations it will easily  
be collected1 that whenever the names   
given to objects convey any information1
 that is1 whenever they have properly   
any meaning1 the meaning resides not in 
what they denote1 but in what they      
connote4 ,the only names of objects     
which connote nothing are proper names2 
and these have1 strictly speaking1 no   
signification4#f  ,if1 like the robber  
in the ,arabian ,nights1 we make a mark 
with chalk on a house to enable us to   
know it again1 the mark has a purpose1  
but it has not properly any meaning4    
,the chalk does not declare anything    
about the house2 it does not mean1 ,this
 is such a person's house1 or ,this is a
 house which contains booty4 ,the object
 of making the mark is merely           
distinction4 ,i say to myself1 ,all     
these houses are so nearly alike that if
 ,i lose sight of them ,i shall not     

again be able to distinguish that which 
,i am now looking at1 from any of the   
others2 ,i must therefore contrive to   
make the appearance of this one house   
unlike that of the others1 that ,i may  
hereafter know1 when ,i see the         
mark--not indeed any attribute of the   
house--but simply that it is the same   
house which ,i am now looking at4       
,morgiana chalked all the other houses  
in a similar manner1 and defeated the   
scheme3 how8 simply by obliterating the 
difference of appearance between that   
house and the others4 ,the chalk was    
still there1 but it no longer served the
 purpose of a distinctive mark4  ,when  
we impose a proper name1 we perform an  
operation in some degree analogous to   
what the robber intended in chalking the
 house4 ,we put a mark1 not indeed upon 
the object itself1 but1 so to speak1    
upon the idea of the object4 ,a proper  
name is but an unmeaning mark which we  
connect in our minds with the idea of   
the object1 in order that whenever the  

mark meets our eyes or occurs to our    
thoughts1 we may think of that          
individual object4 ,not being attached  
to the thing itself1 it does not1 like  
the chalk1 enable us to distinguish the 
object when we see it2 but it enables us
 to distinguish it when it is spoken of1
 either in the records of our own       
experience1 or in the discourse of      
others2 to know that what we find       
asserted in any proposition of which it 
is the subject1 is asserted of the      
individual thing with which we were     
previously acquainted4  ,when we        
predicate of anything its proper name2  
when we say1 pointing to a man1 this is 
,brown or ,smith1 or pointing to a city1
 that it is ,york1 we do not1 merely by 
so doing1 convey to the hearer any      
information about them1 except that     
those are their names4 ,by enabling him 
to identify the individuals1 we may     
connect them with information previously
 possessed by him2 by saying1 ,this is  
,york1 we may tell him that it contains 

the ,minster4 ,but this is in virtue of 
what he has previously heard concerning 
,york2 not by anything implied in the   
name4 ,it is otherwise when objects are 
spoken of by connotative names4 ,when we
 say1 ,the town is built of marble1 we  
give the hearer what may be entirely new
 information1 and this merely by the    
signification of the many-worded        
connotative name1 built of marble4 ,such
 names are not signs of the mere        
objects1 invented because we have       
occasion to think and speak of those    
objects individually2 but signs which   
accompany an attribute3 a kind of livery
 in which the attribute clothes all     
objects which are recognised as         
possessing it4 ,they are not mere marks1
 but more1 that is to say1 significant  
marks2 and the connotation is what      
constitutes their significance4  ,as a  
proper name is said to be the name of   
the one individual which it is          
predicated of1 so 7as well from the     
importance of adhering to analogy1 as   

for the other reasons formerly assigned7
 a connotative name ought to be         
considered a name of all the various    
individuals which it is predicable of1  
or in other words denotes1 and not of   
what it connotes4 ,but by learning what 
things it is a name of1 we do not learn 
the meaning of the name3 for to the same
 thing we may1 with equal propriety1    
apply many names1 not equivalent in     
meaning4 ,thus1 ,i call a certain man by
 the name ,sophroniscus3 ,i call him by 
another name1 ,the father of ,socrates4 
,both these are names of the same       
individual1 but their meaning is        
altogether different2 they are applied  
to that individual for two different    
purposes2 the one1 merely to distinguish
 him from other persons who are spoken  
of2 the other to indicate a fact        
relating to him1 the fact that ,socrates
 was his son4 ,i further apply to him   
these other expressions3 a man1 a       
,greek1 an ,athenian1 a sculptor1 an old
 man1 an honest man1 a brave man4 ,all  

these are1 or may be1 names of          
,sophroniscus1 not indeed of him alone1 
but of him and each of an indefinite    
number of other human beings4 ,each of  
these names is applied to ,sophroniscus 
for a different reason1 and by each     
whoever understands its meaning is      
apprised of a distinct fact or number of
 facts concerning him2 but those who    
knew nothing about the names except that
 they were applicable to ,sophroniscus1 
would be altogether ignorant of their   
meaning4 ,it is even possible that ,i   
might know every single individual of   
whom a given name could be with truth   
affirmed1 and yet could not be said to  
know the meaning of the name4 ,a child  
knows who are its brothers and sisters1 
long before it has any definite         
conception of the nature of the facts   
which are involved in the signification 
of those words4  ,in some cases it is   
not easy to decide precisely how much a 
particular word does or does not        
connote2 that is1 we do not exactly know

 7the case not having arisen7 what      
degree of difference in the object would
 occasion a difference in the name4     
,thus1 it is clear that the word man1   
besides animal life and rationality1    
connotes also a certain external form2  
but it would be impossible to say       
precisely what form2 that is1 to decide 
how great a deviation from the form     
ordinarily found in the beings whom we  
are accustomed to call men1 would       
suffice in a newly-discovered race to   
make us refuse them the name of man4    
,rationality1 also1 being a quality     
which admits of degrees1 it has never   
been settled what is the lowest degree  
of that quality which would entitle any 
creature to be considered a human being4
 ,in all such cases1 the meaning of the 
general name is so far unsettled and    
vague2 mankind have not come to any     
positive agreement about the matter4    
,when we come to treat of               
,classification1 we shall have occasion 
to show under what conditions this      

vagueness may exist without practical   
inconvenience2 and cases will appear in 
which the ends of language are better   
promoted by it than by complete         
precision2 in order that1 in natural    
history for instance1 individuals or    
species of no very marked character may 
be ranged with those more strongly      
characterized individuals or species to 
which1 in all their properties taken    
together1 they bear the nearest         
resemblance4  ,but this partial         
uncertainty in the connotation of names 
can only be free from mischief when     
guarded by strict precautions4 ,one of  
the chief sources1 indeed1 of lax habits
 of thought1 is the custom of using     
connotative terms without a distinctly  
ascertained connotation1 and with no    
more precise notion of their meaning    
than can be loosely collected from      
observing what objects they are used to 
denote4 ,it is in this manner that we   
all acquire1 and inevitably so1 our     
first knowledge of our vernacular       

language4 ,a child learns the meaning of
 the words man1 or white1 by hearing    
them applied to a variety of individual 
objects1 and finding out1 by a process  
of generalization and analysis which he 
could not himself describe1 what those  
different objects have in common4 ,in   
the case of these two words the process 
is so easy as to require no assistance  
from culture2 the objects called human  
beings1 and the objects called white1   
differing from all others by qualities  
of a peculiarly definite and obvious    
character4 ,but in many other cases1    
objects bear a general resemblance to   
one another1 which leads to their being 
familiarly classed together under a     
common name1 while1 without more        
analytic habits than the generality of  
mankind possess1 it is not immediately  
apparent what are the particular        
attributes1 upon the possession of which
 in common by them all1 their general   
resemblance depends4 ,when this is the  
case1 people use the name without any   

recognised connotation1 that is1 without
 any precise meaning2 they talk1 and    
consequently think1 vaguely1 and remain 
contented to attach only the same degree
 of significance to their own words1    
which a child three years old attaches  
to the words brother and sister4 ,the   
child at least is seldom puzzled by the 
starting up of new individuals1 on whom 
he is ignorant whether or not to confer 
the title2 because there is usually an  
authority close at hand competent to    
solve all doubts4 ,but a similar        
resource does not exist in the          
generality of cases2 and new objects are
 continually presenting themselves to   
men1 women1 and children1 which they are
 called upon to class proprio motu4     
,they1 accordingly1 do this on no other 
principle than that of superficial      
similarity1 giving to each new object   
the name of that familiar object1 the   
idea of which it most readily recalls1  
or which1 on a cursory inspection1 it   
seems to them most to resemble3 as an   

unknown substance found in the ground   
will be called1 according to its        
texture1 earth1 sand1 or a stone4 ,in   
this manner1 names creep on from subject
 to subject1 until all traces of a      
common meaning sometimes disappear1 and 
the word comes to denote a number of    
things not only independently of any    
common attribute1 but which have        
actually no attribute in common2 or none
 but what is shared by other things to  
which the name is capriciously refused4 
,even scientific writers have aided in  
this perversion of general language from
 its purpose2 sometimes because1 like   
the vulgar1 they knew no better2 and    
sometimes in deference to that aversion 
to admit new words1 which induces       
mankind1 on all subjects not considered 
technical1 to attempt to make the       
original stock of names serve with but  
little augmentation to express a        
constantly increasing number of objects 
and distinctions1 and1 consequently1 to 
express them in a manner progressively  

more and more imperfect4  ,to what a    
degree this loose mode of classing and  
denominating objects has rendered the   
vocabulary of mental and moral          
philosophy unfit for the purposes of    
accurate thinking1 is best known to     
whoever has most meditated on the       
present condition of those branches of  
knowledge4 ,since1 however1 the         
introduction of a new technical language
 as the vehicle of speculations on      
subjects belonging to the domain of     
daily discussion1 is extremely difficult
 to effect1 and would not be free from  
inconvenience even if effected1 the     
problem for the philosopher1 and one of 
the most difficult which he has to      
resolve1 is1 in retaining the existing  
phraseology1 how best to alleviate its  
imperfections4 ,this can only be        
accomplished by giving to every general 
concrete name which there is frequent   
occasion to predicate1 a definite and   
fixed connotation2 in order that it may 
be known what attributes1 when we call  

an object by that name1 we really mean  
to predicate of the object4 ,and the    
question of most nicety is1 how to give 
this fixed connotation to a name1 with  
the least possible change in the objects
 which the name is habitually employed  
to denote2 with the least possible      
disarrangement1 either by adding or     
subtraction1 of the group of objects    
which1 in however imperfect a manner1 it
 serves to circumscribe and hold        
together2 and with the least vitiation  
of the truth of any propositions which  
are commonly received as true4  ,this   
desirable purpose1 of giving a fixed    
connotation where it is wanting1 is the 
end aimed at whenever any one attempts  
to give a definition of a general name  
already in use2 every definition of a   
connotative name being an attempt either
 merely to declare1 or to declare and   
analyse1 the connotation of the name4   
,and the fact1 that no questions which  
have arisen in the moral sciences have  
been subjects of keener controversy than

 the definitions of almost all the      
leading expressions1 is a proof how     
great an extent the evil to which we    
have adverted has attained4  ,names with
 indeterminate connotation are not to be
 confounded with names which have more  
than one connotation1 that is to say1   
ambiguous words4 ,a word may have       
several meanings1 but all of them fixed 
and recognised ones2 as the word post1  
for example1 or the word box1 the       
various senses of which it would be     
endless to enumerate4 ,and the paucity  
of existing names1 in comparison with   
the demand for them1 may often render it
 advisable and even necessary to retain 
a name in this multiplicity of          
acceptations1 distinguishing these so   
clearly as to prevent their being       
confounded with one another4 ,such a    
word may be considered as two or more   
names1 accidentally written and spoken  
alike4#g    #f4 ,the fourth principal   
division of names1 is into positive and 
negative4 ,positive1 as man1 tree1 good2

 negative1 as not-man1 not-tree1        
not-good4 ,to every positive concrete   
name1 a corresponding negative one might
 be framed4 ,after giving a name to any 
one thing1 or to any plurality of       
things1 we might create a second name   
which should be a name of all things    
whatever1 except that particular thing  
or things4 ,these negative names are    
employed whenever we have occasion to   
speak collectively of all things other  
than some thing or class of things4     
,when the positive name is connotative1 
the corresponding negative name is      
connotative likewise2 but in a peculiar 
way1 connoting not the presence but the 
absence of an attribute4 ,thus1         
not-white denotes all things whatever   
except white things2 and connotes the   
attribute of not possessing whiteness4  
,for the non-possession of any given    
attribute is also an attribute1 and may 
receive a name as such2 and thus        
negative concrete names may obtain      
negative abstract names to correspond to

 them4  ,names which are positive in    
form are often negative in reality1 and 
others are really positive though their 
form is negative4 ,the word             
inconvenient1 for example1 does not     
express the mere absence of convenience2
 it expresses a positive attribute1 that
 of being the cause of discomfort or    
annoyance4 ,so the word unpleasant1     
notwithstanding its negative form1 does 
not connote the mere absence of         
pleasantness1 but a less degree of what 
is signified by the word painful1 which1
 it is hardly necessary to say1 is      
positive4 ,idle1 on the other hand1 is a
 word which1 though positive in form1   
expresses nothing but what would be     
signified either by the phrase not      
working1 or by the phrase not disposed  
to work2 and sober1 either by not drunk 
or by not drunken4  ,there is a class of
 names called privative4 ,a privative   
name is equivalent in its signification 
to a positive and a negative name taken 
together2 being the name of something   

which has once had a particular         
attribute1 or for some other reason     
might have been expected to have it1 but
 which has it not4 ,such is the word    
blind1 which is not equivalent to not   
seeing1 or to not capable of seeing1 for
 it would not1 except by a poetical or  
rhetorical figure1 be applied to stocks 
and stones4 ,a thing is not usually said
 to be blind1 unless the class to which 
it is most familiarly referred1 or to   
which it is referred on the particular  
occasion1 be chiefly composed of things 
which can see1 as in the case of a blind
 man1 or a blind horse2 or unless it is 
supposed for any reason that it ought to
 see2 as in saying of a man1 that he    
rushed blindly into an abyss1 or of     
philosophers or the clergy that the     
greater part of them are blind guides4  
,the names called privative1 therefore1 
connote two things3 the absence of      
certain attributes1 and the presence of 
others1 from which the presence also of 
the former might naturally have been    

expected4    #g4 ,the fifth leading     
division of names is into relative and  
absolute1 or let us rather say1 relative
 and non-relative2 for the word absolute
 is put upon much too hard duty in      
metaphysics1 not to be willingly spared 
when its services can be dispensed with4
 ,it resembles the word civil in the    
language of jurisprudence1 which stands 
for the opposite of criminal1 the       
opposite of ecclesiastical1 the opposite
 of military1 the opposite of           
political--in short1 the opposite of any
 positive word which wants a negative4  
,relative names are such as father1 son2
 ruler1 subject2 like2 equal2 unlike2   
unequal2 longer1 shorter2 cause1 effect4
 ,their characteristic property is1 that
 they are always given in pairs4 ,every 
relative name which is predicated of an 
object1 supposes another object 7or     
objects71 of which we may predicate     
either that same name or another        
relative name which is said to be the   
correlative of the former4 ,thus1 when  

we call any person a son1 we suppose    
other persons who must be called        
parents4 ,when we call any event a      
cause1 we suppose another event which is
 an effect4 ,when we say of any distance
 that it is longer1 we suppose another  
distance which is shorter4 ,when we say 
of any object that it is like1 we mean  
that it is like some other object1 which
 is also said to be like the first4 ,in 
this last case both objects receive the 
same name2 the relative term is its own 
correlative4  ,it is evident that these 
words1 when concrete1 are1 like other   
concrete general names1 connotative2    
they denote a subject1 and connote an   
attribute2 and each of them has or might
 have a corresponding abstract name1 to 
denote the attribute connoted by the    
concrete4 ,thus the concrete like has   
its abstract likeness2 the concretes1   
father and son1 have1 or might have1 the
 abstracts1 paternity1 and filiety1 or  
sonship4 ,the concrete name connotes an 
attribute1 and the abstract name which  

answers to it denotes that attribute4   
,but of what nature is the attribute8   
,wherein consists the peculiarity in the
 connotation of a relative name8  ,the  
attribute signified by a relative name1 
say some1 is a relation2 and this they  
give1 if not as a sufficient            
explanation1 at least as the only one   
attainable4 ,if they are asked1 ,what   
then is a relation8 they do not profess 
to be able to tell4 ,it is generally    
regarded as something peculiarly        
recondite and mysterious4 ,i cannot1    
however1 perceive in what respect it is 
more so than any other attribute2       
indeed1 it appears to me to be so in a  
somewhat less degree4 ,i conceive1      
rather1 that it is by examining into the
 signification of relative names1 or1 in
 other words1 into the nature of the    
attribute which they connote1 that a    
clear insight may best be obtained into 
the nature of all attributes3 of all    
that is meant by an attribute4  ,it is  
obvious1 in fact1 that if we take any   

two correlative names1 father and son   
for instance1 though the objects denoted
 by the names are different1 they both1 
in a certain sense1 connote the same    
thing4 ,they cannot1 indeed1 be said to 
connote the same attribute3 to be a     
father1 is not the same thing as to be a
 son4 ,but when we call one man a       
father1 another a son1 what we mean to  
affirm is a set of facts1 which are     
exactly the same in both cases4 ,to     
predicate of ,a that he is the father of
 ,b1 and of ,b that he is the son of ,a1
 is to assert one and the same fact in  
different words4 ,the two propositions  
are exactly equivalent3 neither of them 
asserts more or asserts less than the   
other4 ,the paternity of ,a and the     
filiety of ,b are not two facts1 but two
 modes of expressing the same fact4     
,that fact1 when analysed1 consists of a
 series of physical events or phenomena1
 in which both ,a and ,b are parties    
concerned1 and from which they both     
derive names4 ,what those names really  

connote1 is this series of events3 that 
is the meaning1 and the whole meaning1  
which either of them is intended to     
convey4 ,the series of events may be    
said to constitute the relation2 the    
schoolmen called it the foundation of   
the relation1 fundamentum relationis4   
,in this manner any fact1 or series of  
facts1 in which two different objects   
are implicated1 and which is therefore  
predicable of both of them1 may be      
either considered as constituting an    
attribute of the one1 or an attribute of
 the other4 ,according as we consider it
 in the former1 or in the latter aspect1
 it is connoted by the one or the other 
of the two correlative names4 ,father   
connotes the fact1 regarded as          
constituting an attribute of ,a3 son    
connotes the same fact1 as constituting 
an attribute of ,b4 ,it may evidently be
 regarded with equal propriety in either
 light4 ,and all that appears necessary 
to account for the existence of relative
 names1 is1 that whenever there is a    

fact in which two individuals are       
concerned1 an attribute grounded on that
 fact may be ascribed to either of these
 individuals4  ,a name1 therefore1 is   
said to be relative1 when1 over and     
above the object which it denotes1 it   
implies in its signification the        
existence of another object1 also       
deriving a denomination from the same   
fact which is the ground of the first   
name4 ,or 7to express the same meaning  
in other words7 a name is relative1     
when1 being the name of one thing1 its  
signification cannot be explained but by
 mentioning another4 ,or we may state it
 thus--when the name cannot be employed 
in discourse so as to have a meaning1   
unless the name of some other thing than
 what it is itself the name of1 be      
either expressed or understood4 ,these  
definitions are all1 at bottom1         
equivalent1 being modes of variously    
expressing this one distinctive         
circumstance--that every other attribute
 of an object might1 without any        

contradiction1 be conceived still to    
exist if no object besides that one had 
ever existed2#h but those of its        
attributes which are expressed by       
relative names1 would on that           
supposition be swept away4    #h4 ,names
 have been further distinguished into   
univocal and quivocal3 these1 however1  
are not two kinds of names1 but two     
different modes of employing names4 ,a  
name is univocal1 or applied univocally1
 with respect to all things of which it 
can be predicated in the same sense3 it 
is quivocal1 or applied quivocally1 as  
respects those things of which it is    
predicated in different senses4 ,it is  
scarcely necessary to give instances of 
a fact so familiar as the double meaning
 of a word4 ,in reality1 as has been    
already observed1 an quivocal or        
ambiguous word is not one name1 but two 
names1 accidentally coinciding in sound4
 ,file meaning a steel instrument1 and  
file meaning a line of soldiers1 have no
 more title to be considered one word1  

because written alike1 than grease and  
,greece have1 because they are          
pronounced alike4 ,they are one sound1  
appropriated to form two different      
words4  ,an intermediate case is that of
 a name used analogically or            
metaphorically2 that is1 a name which is
 predicated of two things1 not          
univocally1 or exactly in the same      
signification1 but in significations    
somewhat similar1 and which being       
derived one from the other1 one of them 
may be considered the primary1 and the  
other a secondary signification4 ,as    
when we speak of a brilliant light and a
 brilliant achievement4 ,the word is not
 applied in the same sense to the light 
and to the achievement2 but having been 
applied to the light in its original    
sense1 that of brightness to the eye1 it
 is transferred to the achievement in a 
derivative signification1 supposed to be
 somewhat like the primitive one4 ,the  
word1 however1 is just as properly two  
names instead of one1 in this case1 as  

in that of the most perfect ambiguity4  
,and one of the commonest forms of      
fallacious reasoning arising from       
ambiguity1 is that of arguing from a    
metaphorical expression as if it were   
literal2 that is1 as if a word1 when    
applied metaphorically1 were the same   
name as when taken in its original      
sense3 which will be seen more          
particularly in its place4     ,,chapter
 ,,iii4  ,,of ,,the ,,things ,,denoted  
,,by ,,names4    #a4 ,looking back now  
to the commencement of our inquiry1 let 
us attempt to measure how far it has    
advanced4 ,logic1 we found1 is the      
,theory of ,proof4 ,but proof supposes  
something provable1 which must be a     
,proposition or ,assertion2 since       
nothing but a ,proposition can be an    
object of belief1 or therefore of proof4
 ,a ,proposition is1 discourse which    
affirms or denies something of some     
other thing4 ,this is one step3 there   
must1 it seems1 be two things concerned 
in every act of belief4 ,but what are   

these ,things8 ,they can be no other    
than those signified by the two names1  
which being joined together by a copula 
constitute the ,proposition4 ,if1       
therefore1 we knew what all names       
signify1 we should know everything which
 in the existing state of human         
knowledge1 is capable either of being   
made a subject of affirmation or denial1
 or of being itself affirmed or denied  
of a subject4 ,we have accordingly1 in  
the preceding chapter1 reviewed the     
various kinds of ,names1 in order to    
ascertain what is signified by each of  
them4 ,and we have now carried this     
survey far enough to be able to take an 
account of its results1 and to exhibit  
an enumeration of all kinds of ,things  
which are capable of being made         
predicates1 or of having anything       
predicated of them3 after which to      
determine the import of ,predication1   
that is1 of ,propositions1 can be no    
arduous task4  ,the necessity of an     
enumeration of ,existences1 as the basis

 of ,logic1 did not escape the attention
 of the schoolmen1 and of their master  
,aristotle1 the most comprehensive1 if  
not also the most sagacious1 of the     
ancient philosophers4 ,the ,categories1 
or ,predicaments--the former a ,greek   
word1 the latter its literal translation
 in the ,latin language--were intended  
by him and his followers as an          
enumeration of all things capable of    
being named2 an enumeration by the summa
 genera1 i4e4 the most extensive classes
 into which things could be distributed2
 which1 therefore1 were so many highest 
,predicates1 one or other of which was  
supposed capable of being affirmed with 
truth of every nameable thing           
whatsoever4 ,the following are the      
classes into which1 according to this   
school of philosophy1 ,things in general
 might be reduced3--    ,greek3 ,ousia1 
,substantia4   ,greek3 ,poson1          
,quantitas4   ,greek3 ,poion1           
,qualitas4   ,greek3 ,pros ti1          
,relatio4   ,greek3 ,poiein1            

,actio4   ,greek3 ,paschein1    ,passio4
   ,greek3 ,pou1         ,ubi4   ,greek3
 ,pote1        ,quando4   ,greek3       
,keisthai1    ,situs4   ,greek3 ,echein1
      ,habitus4  ,the imperfections of  
this classification are too obvious to  
require1 and its merits are not         
sufficient to reward1 a minute          
examination4 ,it is a mere catalogue of 
the distinctions rudely marked out by   
the language of familiar life1 with     
little or no attempt to penetrate1 by   
philosophic analysis1 to the rationale  
even of those common distinctions4 ,such
 an analysis1 however superficially     
conducted1 would have shown the         
enumeration to be both redundant and    
defective4 ,some objects are omitted1   
and others repeated several times under 
different heads4 ,it is like a division 
of animals into men1 quadrupeds1 horses1
 asses1 and ponies4 ,that1 for instance1
 could not be a very comprehensive view 
of the nature of ,relation which could  
exclude action1 passivity1 and local    

situation from that category4 ,the same 
observation applies to the categories   
,quando 7or position in time71 and ,ubi 
7or position in space72 while the       
distinction between the latter and      
,situs is merely verbal4 ,the           
incongruity of erecting into a summum   
genus the class which forms the tenth   
category is manifest4 ,on the other     
hand1 the enumeration takes no notice of
 anything besides substances and        
attributes4 ,in what category are we to 
place sensations1 or any other feelings 
and states of mind2 as hope1 joy1 fear2 
sound1 smell1 taste2 pain1 pleasure2    
thought1 judgment1 conception1 and the  
like8 ,probably all these would have    
been placed by the ,aristotelian school 
in the categories of actio and passio2  
and the relation of such of them as are 
active1 to their objects1 and of such of
 them as are passive1 to their causes1  
would rightly be so placed2 but the     
things themselves1 the feelings or      
states of mind1 wrongly4 ,feelings1 or  

states of consciousness1 are assuredly  
to be counted among realities1 but they 
cannot be reckoned either among         
substances or attributes4    #b4 ,before
 recommencing1 under better auspices1   
the attempt made with such imperfect    
success by the great founder of the     
science of logic1 we must take notice of
 an unfortunate ambiguity in all the    
concrete names which correspond to the  
most general of all abstract terms1 the 
word ,existence4 ,when we have occasion 
for a name which shall be capable of    
denoting whatever exists1 as            
contradistinguished from non-entity or  
,nothing1 there is hardly a word        
applicable to the purpose which is not  
also1 and even more familiarly1 taken in
 a sense in which it denotes only       
substances4 ,but substances are not all 
that exists2 attributes1 if such things 
are to be spoken of1 must be said to    
exist2 feelings certainly exist4 ,yet   
when we speak of an object1 or of a     
thing1 we are almost always supposed to 

mean a substance4 ,there seems a kind of
 contradiction in using such an         
expression as that one thing is merely  
an attribute of another thing4 ,and the 
announcement of a ,classification of    
,things would1 ,i believe1 prepare most 
readers for an enumeration like those in
 natural history1 beginning with the    
great divisions of animal1 vegetable1   
and mineral1 and subdividing them into  
classes and orders4 ,if1 rejecting the  
word ,thing1 we endeavour to find       
another of a more general import1 or at 
least more exclusively confined to that 
general import1 a word denoting all that
 exists1 and connoting only simple      
existence2 no word might be presumed    
fitter for such a purpose than being3   
originally the present participle of a  
verb which in one of its meanings is    
exactly equivalent to the verb exists2  
and therefore suitable1 even by its     
grammatical formation1 to be the        
concrete of the abstract existence4 ,but
 this word1 strange as the fact may     

appear1 is still more completely spoiled
 for the purpose which it seemed        
expressly made for1 than the word       
,thing4 ,being is1 by custom1 exactly   
synonymous with substance2 except that  
it is free from a slight taint of a     
second ambiguity2 being applied         
impartially to matter and to mind1 while
 substance1 though originally and in    
strictness applicable to both1 is apt to
 suggest in preference the idea of      
matter4 ,attributes are never called    
,beings2 nor are feelings4 ,a ,being is 
that which excites feelings1 and which  
possesses attributes4 ,the soul is      
called a ,being2 ,god and angels are    
called ,beings2 but if we were to say1  
extension1 colour1 wisdom1 virtue1 are  
beings1 we should perhaps be suspected  
of thinking with some of the ancients1  
that the cardinal virtues are animals2  
or1 at the least1 of holding with the   
,platonic school the doctrine of        
self-existent ,ideas1 or with the       
followers of ,epicurus that of ,sensible

 ,forms1 which detach themselves in     
every direction from bodies1 and by     
coming in contact with our organs1 cause
 our perceptions4 ,we should be         
supposed1 in short1 to believe that     
,attributes are ,substances4  ,in       
consequence of this perversion of the   
word ,being1 philosophers looking about 
for something to supply its place1 laid 
their hands upon the word ,entity1 a    
piece of barbarous ,latin1 invented by  
the schoolmen to be used as an abstract 
name1 in which class its grammatical    
form would seem to place it2 but being  
seized by logicians in distress to stop 
a leak in their terminology1 it has ever
 since been used as a concrete name4    
,the kindred word essence1 born at the  
same time and of the same parents1      
scarcely underwent a more complete      
transformation when1 from being the     
abstract of the verb to be1 it came to  
denote something sufficiently concrete  
to be enclosed in a glass bottle4 ,the  
word ,entity1 since it settled down into

 a concrete name1 has retained its      
universality of signification somewhat  
less impaired than any of the names     
before mentioned4 ,yet the same gradual 
decay to which1 after a certain age1 all
 the language of psychology seems       
liable1 has been at work even here4 ,if 
you call virtue an entity1 you are      
indeed somewhat less strongly suspected 
of believing it to be a substance than  
if you called it a being2 but you are by
 no means free from the suspicion4      
,every word which was originally        
intended to connote mere existence1     
seems1 after a long time1 to enlarge its
 connotation to separate existence1 or  
existence freed from the condition of   
belonging to a substance2 which         
condition being precisely what          
constitutes an attribute1 attributes are
 gradually shut out2 and along with them
 feelings1 which in ninety-nine cases   
out of a hundred have no other name than
 that of the attribute which is grounded
 on them4 ,strange that when the        

greatest embarrassment felt by all who  
have any considerable number of thoughts
 to express1 is to find a sufficient    
variety of precise words fitted to      
express them1 there should be no        
practice to which even scientific       
thinkers are more addicted than that of 
taking valuable words to express ideas  
which are sufficiently expressed by     
other words already appropriated to     
them4  ,when it is impossible to obtain 
good tools1 the next best thing is to   
understand thoroughly the defects of    
those we have4 ,i have therefore warned 
the reader of the ambiguity of the names
 which1 for want of better1 ,i am       
necessitated to employ4 ,it must now be 
the writer's endeavour so to employ them
 as in no case to leave the meaning     
doubtful or obscure4 ,no one of the     
above terms being altogether            
unambiguous1 ,i shall not confine myself
 to any one1 but shall employ on each   
occasion the word which seems least     
likely in the particular case to lead to

 misunderstanding2 nor do ,i pretend to 
use either these or any other words with
 a rigorous adherence to one single     
sense4 ,to do so would often leave us   
without a word to express what is       
signified by a known word in some one or
 other of its senses3 unless authors had
 an unlimited licence to coin new words1
 together with 7what it would be more   
difficult to assume7 unlimited power of 
making readers understand them4 ,nor    
would it be wise in a writer1 on a      
subject involving so much of            
abstraction1 to deny himself the        
advantage derived from even an improper 
use of a term1 when1 by means of it1    
some familiar association is called up  
which brings the meaning home to the    
mind1 as it were by a flash4  ,the      
difficulty both to the writer and       
reader1 of the attempt which must be    
made to use vague words so as to convey 
a precise meaning1 is not wholly a      
matter of regret4 ,it is not unfitting  
that logical treatises should afford an 

example of that1 to facilitate which is 
among the most important uses of logic4 
,philosophical language will for a long 
time1 and popular language still longer1
 retain so much of vagueness and        
ambiguity1 that logic would be of little
 value if it did not1 among its other   
advantages1 exercise the understanding  
in doing its work neatly and correctly  
with these imperfect tools4  ,after this
 preamble it is time to proceed to our  
enumeration4 ,we shall commence with    
,feelings1 the simplest class of        
nameable things2 the term ,feeling being
 of course understood in its most       
enlarged sense4   ,i4 ,,feelings1 ,,or  
,,states ,,of ,,consciousness4   #c4 ,a 
,feeling and a ,state of ,consciousness 
are1 in the language of philosophy1     
equivalent expressions3 everything is a 
feeling of which the mind is conscious2 
everything which it feels1 or1 in other 
words1 which forms a part of its own    
sentient existence4 ,in popular language
 ,feeling is not always synonymous with 

,state of ,consciousness2 being often   
taken more peculiarly for those states  
which are conceived as belonging to the 
sensitive1 or to the emotional1 phasis  
of our nature1 and sometimes1 with a    
still narrower restriction1 to the      
emotional alone1 as distinguished from  
what are conceived as belonging to the  
percipient or to the intellectual       
phasis4 ,but this is an admitted        
departure from correctness of language2 
just as1 by a popular perversion the    
exact converse of this1 the word ,mind  
is withdrawn from its rightful          
generality of signification1 and        
restricted to the intellect4 ,the still 
greater perversion by which ,feeling is 
sometimes confined not only to bodily   
sensations1 but to the sensations of a  
single sense1 that of touch1 needs not  
be more particularly adverted to4       
,feeling1 in the proper sense of the    
term1 is a genus1 of which ,sensation1  
,emotion1 and ,thought1 are subordinate 
species4 ,under the word ,thought is    

here to be included whatever we are     
internally conscious of when we are said
 to think2 from the consciousness we    
have when we think of a red colour      
without having it before our eyes1 to   
the most recondite thoughts of a        
philosopher or poet4 ,be it remembered1 
however1 that by a thought is to be     
understood what passes in the mind      
itself1 and not any object external to  
the mind1 which the person is commonly  
said to be thinking of4 ,he may be      
thinking of the sun1 or of ,god1 but the
 sun and ,god are not thoughts2 his     
mental image1 however1 of the sun1 and  
his idea of ,god1 are thoughts2 states  
of his mind1 not of the objects         
themselves2 and so also is his belief of
 the existence of the sun1 or of ,god2  
or his disbelief1 if the case be so4    
,even imaginary objects 7which are said 
to exist only in our ideas7 are to be   
distinguished from our ideas of them4 ,i
 may think of a hobgoblin1 as ,i may    
think of the loaf which was eaten       

yesterday1 or of the flower which will  
bloom to-morrow4 ,but the hobgoblin     
which never existed is not the same     
thing with my idea of a hobgoblin1 any  
more than the loaf which once existed is
 the same thing with my idea of a loaf1 
or the flower which does not yet exist1 
but which will exist1 is the same with  
my idea of a flower4 ,they are all1 not 
thoughts1 but objects of thought2 though
 at the present time all the objects are
 alike non-existent4  ,in like manner1 a
 ,sensation is to be carefully          
distinguished from the object which     
causes the sensation2 our sensation of  
white from a white object3 nor is it    
less to be distinguished from the       
attribute whiteness1 which we ascribe to
 the object in consequence of its       
exciting the sensation4 ,unfortunately  
for clearness and due discrimination in 
considering these subjects1 our         
sensations seldom receive separate      
names4 ,we have a name for the objects  
which produce in us a certain sensation3

 the word white4 ,we have a name for the
 quality in those objects1 to which we  
ascribe the sensation3 the name         
whiteness4 ,but when we speak of the    
sensation itself 7as we have not        
occasion to do this often except in our 
scientific speculations71 language1     
which adapts itself for the most part   
only to the common uses of life1 has    
provided us with no single-worded or    
immediate designation2 we must employ a 
circumlocution1 and say1 ,the sensation 
of white1 or ,the sensation of          
whiteness2 we must denominate the       
sensation either from the object1 or    
from the attribute1 by which it is      
excited4 ,yet the sensation1 though it  
never does1 might very well be conceived
 to exist1 without anything whatever to 
excite it4 ,we can conceive it as       
arising spontaneously in the mind4 ,but 
if it so arose1 we should have no name  
to denote it which would not be a       
misnomer4 ,in the case of our sensations
 of hearing we are better provided2 we  

have the word ,sound1 and a whole       
vocabulary of words to denote the       
various kinds of sounds4 ,for as we are 
often conscious of these sensations in  
the absence of any perceptible object1  
we can more easily conceive having them 
in the absence of any object whatever4  
,we need only shut our eyes and listen  
to music1 to have a conception of an    
universe with nothing in it except      
sounds1 and ourselves hearing them3 and 
what is easily conceived separately1    
easily obtains a separate name4 ,but in 
general our names of sensations denote  
indiscriminately the sensation and the  
attribute4 ,thus1 colour stands for the 
sensations of white1 red1 c41 but also  
for the quality in the coloured object4 
,we talk of the colours of things as    
among their properties4    #d4 ,in the  
case of sensations1 another distinction 
has also to be kept in view1 which is   
often confounded1 and never without     
mischievous consequences4 ,this is1 the 
distinction between the sensation       

itself1 and the state of the bodily     
organs which precedes the sensation1 and
 which constitutes the physical agency  
by which it is produced4 ,one of the    
sources of confusion on this subject is 
the division commonly made of feelings  
into ,bodily and ,mental4               
,philosophically speaking1 there is no  
foundation at all for this distinction3 
even sensations are states of the       
sentient mind1 not states of the body1  
as distinguished from it4 ,what ,i am   
conscious of when ,i see the colour     
blue1 is a feeling of blue colour1 which
 is one thing2 the picture on my retina1
 or the phenomenon of hitherto          
mysterious nature which takes place in  
my optic nerve or in my brain1 is       
another thing1 of which ,i am not at all
 conscious1 and which scientific        
investigation alone could have apprised 
me of4 ,these are states of my body2 but
 the sensation of blue1 which is the    
consequence of these states of body1 is 
not a state of body3 that which         

perceives and is conscious is called    
,mind4 ,when sensations are called      
bodily feelings1 it is only as being the
 class of feelings which are immediately
 occasioned by bodily states2 whereas   
the other kinds of feelings1 thoughts1  
for instance1 or emotions1 are          
immediately excited not by anything     
acting upon the bodily organs1 but by   
sensations1 or by previous thoughts4    
,this1 however1 is a distinction not in 
our feelings1 but in the agency which   
produces our feelings3 all of them when 
actually produced are states of mind4   
,besides the affection of our bodily    
organs from without1 and the sensation  
thereby produced in our minds1 many     
writers admit a third link in the chain 
of phenomena1 which they call a         
,perception1 and which consists in the  
recognition of an external object as the
 exciting cause of the sensation4 ,this 
perception1 they say1 is an act of the  
mind1 proceeding from its own           
spontaneous activity2 while in a        

sensation the mind is passive1 being    
merely acted upon by the outward object4
 ,and according to some metaphysicians1 
it is by an act of the mind1 similar to 
perception1 except in not being preceded
 by any sensation1 that the existence of
 ,god1 the soul1 and other              
hyper-physical objects is recognised4   
,these acts of what is termed           
perception1 whatever be the conclusion  
ultimately come to respecting their     
nature1 must1 ,i conceive1 take their   
place among the varieties of feelings or
 states of mind4 ,in so classing them1  
,i have not the smallest intention of   
declaring or insinuating any theory as  
to the law of mind in which these mental
 processes may be supposed to originate1
 or the conditions under which they may 
be legitimate or the reverse4 ,far less 
do ,i mean 7as ,dr4 ,whewell seems to   
suppose must be meant in an analogous   
case#i7 to indicate that as they are    
merely states of mind1 it is superfluous
 to inquire into their distinguishing   

peculiarities4 ,i abstain from the      
inquiry as irrelevant to the science of 
logic4 ,in these so-called perceptions1 
or direct recognitions by the mind1 of  
objects1 whether physical or spiritual1 
which are external to itself1 ,i can see
 only cases of belief2 but of belief    
which claims to be intuitive1 or        
independent of external evidence4 ,when 
a stone lies before me1 ,i am conscious 
of certain sensations which ,i receive  
from it2 but if ,i say that these       
sensations come to me from an external  
object which ,i perceive1 the meaning of
 these words is1 that receiving the     
sensations1 ,i intuitively believe that 
an external cause of those sensations   
exists4 ,the laws of intuitive belief1  
and the conditions under which it is    
legitimate1 are a subject which1 as we  
have already so often remarked1 belongs 
not to logic1 but to the science of the 
ultimate laws of the human mind4  ,to   
the same region of speculation belongs  
all that can be said respecting the     

distinction which the ,german           
metaphysicians and their ,french and    
,english followers so elaborately draw  
between the acts of the mind and its    
merely passive states2 between what it  
receives from1 and what it gives to1 the
 crude materials of its experience4 ,i  
am aware that with reference to the view
 which those writers take of the primary
 elements of thought and knowledge1 this
 distinction is fundamental4 ,but for   
the present purpose1 which is to        
examine1 not the original groundwork of 
our knowledge1 but how we come by that  
portion of it which is not original2 the
 difference between active and passive  
states of mind is of secondary          
importance4 ,for us1 they all are states
 of mind1 they all are feelings2 by     
which1 let it be said once more1 ,i mean
 to imply nothing of passivity1 but     
simply that they are psychological      
facts1 facts which take place in the    
mind1 and are to be carefully           
distinguished from the external or      

physical facts with which they may be   
connected either as effects or as       
causes4    #e4 ,among active states of  
mind1 there is1 however1 one species    
which merits particular attention1      
because it forms a principal part of the
 connotation of some important classes  
of names4 ,i mean volitions1 or acts of 
the will4 ,when we speak of sentient    
beings by relative names1 a large       
portion of the connotation of the name  
usually consists of the actions of those
 beings2 actions past1 present1 and     
possible or probable future4 ,take1 for 
instance1 the words ,sovereign and      
,subject4 ,what meaning do these words  
convey1 but that of innumerable actions1
 done or to be done by the sovereign and
 the subjects1 to or in regard to one   
another reciprocally8 ,so with the words
 physician and patient1 leader and      
follower1 tutor and pupil4 ,in many     
cases the words also connote actions    
which would be done under certain       
contingencies by persons other than     

those denoted3 as the words mortgagor   
and mortgagee1 obligor and obligee1 and 
many other words expressive of legal    
relation1 which connote what a court of 
justice would do to enforce the legal   
obligation if not fulfilled4 ,there are 
also words which connote actions        
previously done by persons other than   
those denoted either by the name itself 
or by its correlative2 as the word      
brother4 ,from these instances1 it may  
be seen how large a portion of the      
connotation of names consists of        
actions4 ,now what is an action8 ,not   
one thing1 but a series of two things3  
the state of mind called a volition1    
followed by an effect4 ,the volition or 
intention to produce the effect1 is one 
thing2 the effect produced in           
consequence of the intention1 is another
 thing2 the two together constitute the 
action4 ,i form the purpose of instantly
 moving my arm2 that is a state of my   
mind3 my arm 7not being tied or         
paralytic7 moves in obedience to my     

purpose2 that is a physical fact1       
consequent on a state of mind4 ,the     
intention1 followed by the fact1 or 7if 
we prefer the expression7 the fact when 
preceded and caused by the intention1 is
 called the action of moving my arm4    
#f4 ,of the first leading division of   
nameable things1 viz4 ,feelings or      
,states of ,consciousness1 we began by  
recognising three subdivisions2         
,sensations1 ,thoughts1 and ,emotions4  
,the first two of these we have         
illustrated at considerable length2 the 
third1 ,emotions1 not being perplexed by
 similar ambiguities1 does not require  
similar exemplification4 ,and1 finally1 
we have found it necessary to add to    
these three a fourth species1 commonly  
known by the name ,volitions4 ,without  
seeking to prejudge the metaphysical    
question whether any mental state or    
phenomenon can be found which is not    
included in one or other of these four  
species1 it appears to me that the      
amount of illustration bestowed upon    

these may1 so far as we are concerned1  
suffice for the whole genus4 ,we shall1 
therefore1 proceed to the two remaining 
classes of nameable things2 all things  
which are external to the mind being    
considered as belonging either to the   
class of ,substances or to that of      
,attributes4  ,,ii4 ,,substances4       
,logicians have endeavoured to define   
,substance and ,attribute2 but their    
definitions are not so much attempts to 
draw a distinction between the things   
themselves1 as instructions what        
difference it is customary to make in   
the grammatical structure of the        
sentence1 according as we are speaking  
of substances or of attributes4 ,such   
definitions are rather lessons of       
,english1 or of ,greek1 ,latin1 or      
,german1 than of mental philosophy4 ,an 
attribute1 say the school logicians1    
must be the attribute of something2     
colour1 for example1 must be the colour 
of something2 goodness must be the      
goodness of something3 and if this      

something should cease to exist1 or     
should cease to be connected with the   
attribute1 the existence of the         
attribute would be at an end4 ,a        
substance1 on the contrary1 is          
self-existent2 in speaking about it1 we 
need not put of after its name4 ,a stone
 is not the stone of anything2 the moon 
is not the moon of anything1 but simply 
the moon4 ,unless1 indeed1 the name     
which we choose to give to the substance
 be a relative name2 if so1 it must be  
followed either by of1 or by some other 
particle1 implying1 as that preposition 
does1 a reference to something else3 but
 then the other characteristic          
peculiarity of an attribute would fail2 
the something might be destroyed1 and   
the substance might still subsist4      
,thus1 a father must be the father of   
something1 and so far resembles an      
attribute1 in being referred to         
something besides himself3 if there were
 no child1 there would be no father3 but
 this1 when we look into the matter1    

only means that we should not call him  
father4 ,the man called father might    
still exist though there were no child1 
as he existed before there was a child3 
and there would be no contradiction in  
supposing him to exist1 though the whole
 universe except himself were destroyed4
 ,but destroy all white substances1 and 
where would be the attribute whiteness8 
,whiteness1 without any white thing1 is 
a contradiction in terms4  ,this is the 
nearest approach to a solution of the   
difficulty1 that will be found in the   
common treatises on logic4 ,it will     
scarcely be thought to be a satisfactory
 one4 ,if an attribute is distinguished 
from a substance by being the attribute 
of something1 it seems highly necessary 
to understand what is meant by of2 a    
particle which needs explanation too    
much itself1 to be placed in front of   
the explanation of anything else4 ,and  
as for the self-existence of substance1 
it is very true that a substance may be 
conceived to exist without any other    

substance1 but so also may an attribute 
without any other attribute3 and we can 
no more imagine a substance without     
attributes than we can imagine          
attributes without a substance4         
,metaphysicians1 however1 have probed   
the question deeper1 and given an       
account of ,substance considerably more 
satisfactory than this4 ,substances are 
usually distinguished as ,bodies or     
,minds4 ,of each of these1 philosophers 
have at length provided us with a       
definition which seems unexceptionable4 
#g4 ,a ,body1 according to the received 
doctrine of modern metaphysicians1 may  
be defined1 the external cause to which 
we ascribe our sensations4 ,when ,i see 
and touch a piece of gold1 ,i am        
conscious of a sensation of yellow      
colour1 and sensations of hardness and  
weight2 and by varying the mode of      
handling1 ,i may add to these sensations
 many others completely distinct from   
them4 ,the sensations are all of which  
,i am directly conscious2 but ,i        

consider them as produced by something  
not only existing independently of my   
will1 but external to my bodily organs  
and to my mind4 ,this external something
 ,i call a body4  ,it may be asked1 how 
come we to ascribe our sensations to any
 external cause8 ,and is there          
sufficient ground for so ascribing them8
 ,it is known1 that there are           
metaphysicians who have raised a        
controversy on the point2 maintaining   
that we are not warranted in referring  
our sensations to a cause such as we    
understand by the word ,body1 or to any 
external cause whatever4 ,though we have
 no concern here with this controversy1 
nor with the metaphysical niceties on   
which it turns1 one of the best ways of 
showing what is meant by ,substance is1 
to consider what position it is         
necessary to take up1 in order to       
maintain its existence against          
opponents4  ,it is certain1 then1 that a
 part of our notion of a body consists  
of the notion of a number of sensations 

of our own1 or of other sentient beings1
 habitually occurring simultaneously4   
,my conception of the table at which ,i 
am writing is compounded of its visible 
form and size1 which are complex        
sensations of sight2 its tangible form  
and size1 which are complex sensations  
of our organs of touch and of our       
muscles2 its weight1 which is also a    
sensation of touch and of the muscles2  
its colour1 which is a sensation of     
sight2 its hardness1 which is a         
sensation of the muscles2 its           
composition1 which is another word for  
all the varieties of sensation which we 
receive under various circumstances from
 the wood of which it is made1 and so   
forth4 ,all or most of these various    
sensations frequently are1 and1 as we   
learn by experience1 always might be1   
experienced simultaneously1 or in many  
different orders of succession1 at our  
own choice3 and hence the thought of any
 one of them makes us think of the      
others1 and the whole becomes mentally  

amalgamated into one mixed state of     
consciousness1 which1 in the language of
 the school of ,locke and ,hartley1 is  
termed a ,complex ,idea4  ,now1 there   
are philosophers who have argued as     
follows4 ,if we conceive an orange to be
 divested of its natural colour without 
acquiring any new one2 to lose its      
softness without becoming hard1 its     
roundness without becoming square or    
pentagonal1 or of any other regular or  
irregular figure whatever2 to be        
deprived of size1 of weight1 of taste1  
of smell2 to lose all its mechanical and
 all its chemical properties1 and       
acquire no new ones2 to become1 in      
short1 invisible1 intangible1           
imperceptible not only by all our       
senses1 but by the senses of all other  
sentient beings1 real or possible2      
nothing1 say these thinkers1 would      
remain4 ,for of what nature1 they ask1  
could be the residuum8 and by what token
 could it manifest its presence8 ,to the
 unreflecting its existence seems to    

rest on the evidence of the senses4 ,but
 to the senses nothing is apparent      
except the sensations4 ,we know1 indeed1
 that these sensations are bound        
together by some law2 they do not come  
together at random1 but according to a  
systematic order1 which is part of the  
order established in the universe4 ,when
 we experience one of these sensations1 
we usually experience the others also1  
or know that we have it in our power to 
experience them4 ,but a fixed law of    
connexion1 making the sensations occur  
together1 does not1 say these           
philosophers1 necessarily require what  
is called a substratum to support them4 
,the conception of a substratum is but  
one of many possible forms in which that
 connexion presents itself to our       
imagination2 a mode of1 as it were1     
realizing the idea4 ,if there be such a 
substratum1 suppose it this instant     
miraculously annihilated1 and let the   
sensations continue to occur in the same
 order1 and how would the substratum be 

missed8 ,by what signs should we be able
 to discover that its existence had     
terminated8 ,should we not have as much 
reason to believe that it still existed 
as we now have8 ,and if we should not   
then be warranted in believing it1 how  
can we be so now8 ,a body1 therefore1   
according to these metaphysicians1 is   
not anything intrinsically different    
from the sensations which the body is   
said to produce in us2 it is1 in short1 
a set of sensations1 or rather1 of      
possibilities of sensation1 joined      
together according to a fixed law4  ,the
 controversies to which these           
speculations have given rise1 and the   
doctrines which have been developed in  
the attempt to find a conclusive answer 
to them1 have been fruitful of important
 consequences to the ,science of ,mind4 
,the sensations 7it was answered7 which 
we are conscious of1 and which we       
receive1 not at random1 but joined      
together in a certain uniform manner1   
imply not only a law or laws of         

connexion1 but a cause external to our  
mind1 which cause1 by its own laws1     
determines the laws according to which  
the sensations are connected and        
experienced4 ,the schoolmen used to call
 this external cause by the name we have
 already employed1 a substratum2 and its
 attributes 7as they expressed          
themselves7 inhered1 literally stuck1 in
 it4 ,to this substratum the name       
,matter is usually given in             
philosophical discussions4 ,it was soon1
 however1 acknowledged by all who       
reflected on the subject1 that the      
existence of matter cannot be proved by 
extrinsic evidence4 ,the answer1        
therefore1 now usually made to ,berkeley
 and his followers1 is1 that the belief 
is intuitive2 that mankind1 in all ages1
 have felt themselves compelled1 by a   
necessity of their nature1 to refer     
their sensations to an external cause3  
that even those who deny it in theory1  
yield to the necessity in practice1 and 
both in speech1 thought1 and feeling1   

do1 equally with the vulgar1 acknowledge
 their sensations to be the effects of  
something external to them3 this        
knowledge1 therefore1 it is affirmed1 is
 as evidently intuitive as our knowledge
 of our sensations themselves is        
intuitive4 ,and here the question merges
 in the fundamental problem of          
metaphysics properly so called2 to which
 science we leave it4  ,but although the
 extreme doctrine of the ,idealist      
metaphysicians1 that objects are nothing
 but our sensations and the laws which  
connect them1 has not been generally    
adopted by subsequent thinkers2 the     
point of most real importance is one on 
which those metaphysicians are now very 
generally considered to have made out   
their case3 viz41 that all we know of   
objects is the sensations which they    
give us1 and the order of the occurrence
 of those sensations4 ,kant himself1 on 
this point1 is as explicit as ,berkeley 
or ,locke4 ,however firmly convinced    
that there exists an universe of ,things

 in themselves1 totally distinct from   
the universe of phenomena1 or of things 
as they appear to our senses2 and even  
when bringing into use a technical      
expression 7,noumenon7 to denote what   
the thing is in itself1 as contrasted   
with the representation of it in our    
minds2 he allows that this              
representation 7the matter of which1 he 
says1 consists of our sensations1 though
 the form is given by the laws of the   
mind itself7 is all we know of the      
object3 and that the real nature of the 
,thing is1 and by the constitution of   
our faculties ever must remain1 at least
 in the present state of existence1 an  
impenetrable mystery to us4 ,of things  
absolutely or in themselves1 says ,sir  
,william ,hamilton1#aj be they external1
 be they internal1 we know nothing1 or  
know them only as incognisable2 and     
become aware of their incomprehensible  
existence1 only as this is indirectly   
and accidentally revealed to us1 through
 certain qualities related to our       

faculties of knowledge1 and which       
qualities1 again1 we cannot think as    
unconditioned1 irrelative1 existent in  
and of themselves4 ,all that we know is 
therefore phnomenal1--phnomenal of the  
unknown4#aa ,the same doctrine is laid  
down in the clearest and strongest terms
 by ,m4 ,cousin1 whose observations on  
the subject are the more worthy of      
attention1 as1 in consequence of the    
ultra-,german and ontological character 
of his philosophy in other respects1    
they may be regarded as the admissions  
of an opponent4#ab  ,there is not the   
slightest reason for believing that what
 we call the sensible qualities of the  
object are a type of anything inherent  
in itself1 or bear any affinity to its  
own nature4 ,a cause does not1 as such1 
resemble its effects2 an east wind is   
not like the feeling of cold1 nor heat  
like the steam of boiling water4 ,why   
then should matter resemble our         
sensations8 ,why should the inmost      
nature of fire or water resemble the    

impressions made by those objects upon  
our senses8#ac ,or on what principle are
 we authorized to deduce from the       
effects1 anything concerning the cause1 
except that it is a cause adequate to   
produce those effects8 ,it may1         
therefore1 safely be laid down as a     
truth both obvious in itself1 and       
admitted by all whom it is at present   
necessary to take into consideration1   
that1 of the outward world1 we know and 
can know absolutely nothing1 except the 
sensations which we experience from     
it4#ad    #h4 ,body having now been     
defined the external cause1 and         
7according to the more reasonable       
opinion7 the unknown external cause1 to 
which we refer our sensations2 it       
remains to frame a definition of ,mind4 
,nor1 after the preceding observations1 
will this be difficult4 ,for1 as our    
conception of a body is that of an      
unknown exciting cause of sensations1 so
 our conception of a mind is that of an 
unknown recipient1 or percipient1 of    

them2 and not of them alone1 but of all 
our other feelings4 ,as body is         
understood to be the mysterious         
something which excites the mind to     
feel1 so mind is the mysterious         
something which feels and thinks4 ,it is
 unnecessary to give in the case of     
mind1 as we gave in the case of matter1 
a particular statement of the sceptical 
system by which its existence as a      
,thing in itself1 distinct from the     
series of what are denominated its      
states1 is called in question4 ,but it  
is necessary to remark1 that on the     
inmost nature 7whatever be meant by     
inmost nature7 of the thinking          
principle1 as well as on the inmost     
nature of matter1 we are1 and with our  
faculties must always remain1 entirely  
in the dark4 ,all which we are aware of1
 even in our own minds1 is 7in the words
 of ,mr4 ,james ,mill7 a certain thread 
of consciousness2 a series of feelings1 
that is1 of sensations1 thoughts1       
emotions1 and volitions1 more or less   

numerous and complicated4 ,there is a   
something ,i call ,myself1 or1 by       
another form of expression1 my mind1    
which ,i consider as distinct from these
 sensations1 thoughts1 c42 a something  
which ,i conceive to be not the         
thoughts1 but the being that has the    
thoughts1 and which ,i can conceive as  
existing for ever in a state of         
quiescence1 without any thoughts at all4
 ,but what this being is1 though it is  
myself1 ,i have no knowledge1 other than
 the series of its states of            
consciousness4 ,as bodies manifest      
themselves to me only through the       
sensations of which ,i regard them as   
the causes1 so the thinking principle1  
or mind1 in my own nature1 makes itself 
known to me only by the feelings of     
which it is conscious4 ,i know nothing  
about myself1 save my capacities of     
feeling or being conscious 7including1  
of course1 thinking and willing73 and   
were ,i to learn anything new concerning
 my own nature1 ,i cannot with my       

present faculties conceive this new     
information to be anything else1 than   
that ,i have some additional capacities1
 as yet unknown to me1 of feeling1      
thinking1 or willing4  ,thus1 then1 as  
body is the unsentient cause to which we
 are naturally prompted to refer a      
certain portion of our feelings1 so mind
 may be described as the sentient       
subject 7in the scholastic sense of the 
term7 of all feelings2 that which has or
 feels them4 ,but of the nature of      
either body or mind1 further than the   
feelings which the former excites1 and  
which the latter experiences1 we do not1
 according to the best existing         
doctrine1 know anything2 and if         
anything1 logic has nothing to do with  
it1 or with the manner in which the     
knowledge is acquired4 ,with this result
 we may conclude this portion of our    
subject1 and pass to the third and only 
remaining class or division of ,nameable
 ,things4   ,,iii4 ,,attributes3 ,,and1 
,,first1 ,,qualities4   #i4 ,from what  

has already been said of ,substance1    
what is to be said of ,attribute is     
easily deducible4 ,for if we know not1  
and cannot know1 anything of bodies but 
the sensations which they excite in us  
or in others1 those sensations must be  
all that we can1 at bottom1 mean by     
their attributes2 and the distinction   
which we verbally make between the      
properties of things and the sensations 
we receive from them1 must originate in 
the convenience of discourse rather than
 in the nature of what is signified by  
the terms4  ,attributes are usually     
distributed under the three heads of    
,quality1 ,quantity1 and ,relation4 ,we 
shall come to the two latter presently3 
in the first place we shall confine     
ourselves to the former4  ,let us take1 
then1 as our example1 one of what are   
termed the sensible qualities of        
objects1 and let that example be        
whiteness4 ,when we ascribe whiteness to
 any substance1 as1 for instance1 snow2 
when we say that snow has the quality   

whiteness1 what do we really assert8    
,simply1 that when snow is present to   
our organs1 we have a particular        
sensation1 which we are accustomed to   
call the sensation of white4 ,but how do
 ,i know that snow is present8          
,obviously by the sensations which ,i   
derive from it1 and not otherwise4 ,i   
infer that the object is present1       
because it gives me a certain assemblage
 or series of sensations4 ,and when ,i  
ascribe to it the attribute whiteness1  
my meaning is only1 that1 of the        
sensations composing this group or      
series1 that which ,i call the sensation
 of white colour is one4  ,this is one  
view which may be taken of the subject4 
,but there is also another and a        
different view4 ,it may be said1 that it
 is true we know nothing of sensible    
objects1 except the sensations they     
excite in us2 that the fact of our      
receiving from snow the particular      
sensation which is called a sensation of
 white1 is the ground on which we       

ascribe to that substance the quality   
whiteness2 the sole proof of its        
possessing that quality4 ,but because   
one thing may be the sole evidence of   
the existence of another thing1 it does 
not follow that the two are one and the 
same4 ,the attribute whiteness 7it may  
be said7 is not the fact of receiving   
the sensation1 but something in the     
object itself2 a power inherent in it2  
something in virtue of which the object 
produces the sensation4 ,and when we    
affirm that snow possesses the attribute
 whiteness1 we do not merely assert that
 the presence of snow produces in us    
that sensation1 but that it does so     
through1 and by reason of1 that power or
 quality4  ,for the purposes of logic it
 is not of material importance which of 
these opinions we adopt4 ,the full      
discussion of the subject belongs to the
 other department of scientific inquiry1
 so often alluded to under the name of  
metaphysics2 but it may be said here1   
that for the doctrine of the existence  

of a peculiar species of entities called
 qualities1 ,i can see no foundation    
except in a tendency of the human mind  
which is the cause of many delusions4 ,i
 mean1 the disposition1 wherever we meet
 with two names which are not precisely 
synonymous1 to suppose that they must be
 the names of two different things2     
whereas in reality they may be names of 
the same thing viewed in two different  
lights1 or under different suppositions 
as to surrounding circumstances4        
,because quality and sensation cannot be
 put indiscriminately one for the other1
 it is supposed that they cannot both   
signify the same thing1 namely1 the     
impression or feeling with which we are 
affected through our senses by the      
presence of an object2 though there is  
at least no absurdity in supposing that 
this identical impression or feeling may
 be called a sensation when considered  
merely in itself1 and a quality when    
looked at in relation to any one of the 
numerous objects1 the presence of which 

to our organs excites in our minds that 
among various other sensations or       
feelings4 ,and if this be admissible as 
a supposition1 it rests with those who  
contend for an entity per se called a   
quality1 to show that their opinion is  
preferable1 or is anything in fact but a
 lingering remnant of the scholastic    
doctrine of occult causes2 the very     
absurdity which ,molire so happily      
ridiculed when he made one of his       
pedantic physicians account for the fact
 that l'opium endormit1 by the maxim    
parcequ'il a une vertu soporifique4  ,it
 is evident that when the physician     
stated that opium had une vertu         
soporifique1 he did not account for1 but
 merely asserted over again1 the fact   
that it endormit4 ,in like manner1 when 
we say that snow is white because it has
 the quality of whiteness1 we are only  
re-asserting in more technical language 
the fact that it excites in us the      
sensation of white4 ,if it be said that 
the sensation must have some cause1 ,i  

answer1 its cause is the presence of the
 assemblage of phenomena which is termed
 the object4 ,when we have asserted that
 as often as the object is present1 and 
our organs in their normal state1 the   
sensation takes place1 we have stated   
all that we know about the matter4      
,there is no need1 after assigning a    
certain and intelligible cause1 to      
suppose an occult cause besides1 for the
 purpose of enabling the real cause to  
produce its effect4 ,if ,i am asked1 why
 does the presence of the object cause  
this sensation in me1 ,i cannot tell3 ,i
 can only say that such is my nature1   
and the nature of the object2 that the  
fact forms a part of the constitution of
 things4 ,and to this we must at last   
come1 even after interpolating the      
imaginary entity4 ,whatever number of   
links the chain of causes and effects   
may consist of1 how any one link        
produces the one which is next to it1   
remains equally inexplicable to us4 ,it 
is as easy to comprehend that the object

 should produce the sensation directly  
and at once1 as that it should produce  
the same sensation by the aid of        
something else called the power of      
producing it4  ,but1 as the difficulties
 which may be felt in adopting this view
 of the subject cannot be removed       
without discussions transcending the    
bounds of our science1 ,i content myself
 with a passing indication1 and shall1  
for the purposes of logic1 adopt a      
language compatible with either view of 
the nature of qualities4 ,i shall       
say1--what at least admits of no        
dispute1--that the quality of whiteness 
ascribed to the object snow1 is grounded
 on its exciting in us the sensation of 
white2 and adopting the language already
 used by the school logicians in the    
case of the kind of attributes called   
,relations1 ,i shall term the sensation 
of white the foundation of the quality  
whiteness4 ,for logical purposes the    
sensation is the only essential part of 
what is meant by the word2 the only part

 which we ever can be concerned in      
proving4 ,when that is proved1 the      
quality is proved2 if an object excites 
a sensation1 it has1 of course1 the     
power of exciting it4   ,,iv4           
,,relations4   #aj4 ,the qualities of a 
body1 we have said1 are the attributes  
grounded on the sensations which the    
presence of that particular body to our 
organs excites in our minds4 ,but when  
we ascribe to any object the kind of    
attribute called a ,relation1 the       
foundation of the attribute must be     
something in which other objects are    
concerned besides itself and the        
percipient4  ,as there may with         
propriety be said to be a relation      
between any two things to which two     
correlative names are or may be given1  
we may expect to discover what          
constitutes a relation in general1 if we
 enumerate the principal cases in which 
mankind have imposed correlative names1 
and observe what these cases have in    
common4  ,what1 then1 is the character  

which is possessed in common by states  
of circumstances so heterogeneous and   
discordant as these3 one thing like     
another2 one thing unlike another2 one  
thing near another2 one thing far from  
another2 one thing before1 after1 along 
with another2 one thing greater1 equal1 
less1 than another2 one thing the cause 
of another1 the effect of another2 one  
person the master1 servant1 child1      
parent1 debtor1 creditor1 sovereign1    
subject1 attorney1 client1 of another1  
and so on8  ,omitting1 for the present1 
the case of ,resemblance1 7a relation   
which requires to be considered         
separately17 there seems to be one thing
 common to all these cases1 and only    
one2 that in each of them there exists  
or occurs1 or has existed or occurred1  
or may be expected to exist or occur1   
some fact or phenomenon1 into which the 
two things which are said to be related 
to each other1 both enter as parties    
concerned4 ,this fact1 or phenomenon1 is
 what the ,aristotelian logicians called

 the fundamentum relationis4 ,thus in   
the relation of greater and less between
 two magnitudes1 the fundamentum        
relationis is the fact that one of the  
two magnitudes could1 under certain     
conditions1 be included in1 without     
entirely filling1 the space occupied by 
the other magnitude4 ,in the relation of
 master and servant1 the fundamentum    
relationis is the fact that the one has 
undertaken1 or is compelled1 to perform 
certain services for the benefit and at 
the bidding of the other4 ,examples     
might be indefinitely multiplied2 but it
 is already obvious that whenever two   
things are said to be related1 there is 
some fact1 or series of facts1 into     
which they both enter2 and that whenever
 any two things are involved in some one
 fact1 or series of facts1 we may       
ascribe to those two things a mutual    
relation grounded on the fact4 ,even if 
they have nothing in common but what is 
common to all things1 that they are     
members of the universe1 we call that a 

relation1 and denominate them           
fellow-creatures1 fellow-beings1 or     
fellow-denizens of the universe4 ,but in
 proportion as the fact into which the  
two objects enter as parts is of a more 
special and peculiar1 or of a more      
complicated nature1 so also is the      
relation grounded upon it4 ,and there   
are as many conceivable relations as    
there are conceivable kinds of fact in  
which two things can be jointly         
concerned4  ,in the same manner1        
therefore1 as a quality is an attribute 
grounded on the fact that a certain     
sensation or sensations are produced in 
us by the object1 so an attribute       
grounded on some fact into which the    
object enters jointly with another      
object1 is a relation between it and    
that other object4 ,but the fact in the 
latter case consists of the very same   
kind of elements as the fact in the     
former2 namely1 states of consciousness4
 ,in the case1 for example1 of any legal
 relation1 as debtor and creditor1      

principal and agent1 guardian and ward1 
the fundamentum relationis consists     
entirely of thoughts1 feelings1 and     
volitions 7actual or contingent71 either
 of the persons themselves or of other  
persons concerned in the same series of 
transactions2 as1 for instance1 the     
intentions which would be formed by a   
judge1 in case a complaint were made to 
his tribunal of the infringement of any 
of the legal obligations imposed by the 
relation2 and the acts which the judge  
would perform in consequence2 acts being
 7as we have already seen7 another word 
for intentions followed by an effect1   
and that effect being but another word  
for sensations1 or some other feelings1 
occasioned either to the agent himself  
or to somebody else4 ,there is no part  
of what the names expressive of the     
relation imply1 that is not resolvable  
into states of consciousness2 outward   
objects being1 no doubt1 supposed       
throughout as the causes by which some  
of those states of consciousness are    

excited1 and minds as the subjects by   
which all of them are experienced1 but  
neither the external objects nor the    
minds making their existence known      
otherwise than by the states of         
consciousness4  ,cases of relation are  
not always so complicated as those to   
which we last alluded4 ,the simplest of 
all cases of relation are those         
expressed by the words antecedent and   
consequent1 and by the word             
simultaneous4 ,if we say1 for instance1 
that dawn preceded sunrise1 the fact in 
which the two things1 dawn and sunrise1 
were jointly concerned1 consisted only  
of the two things themselves2 no third  
thing entered into the fact or          
phenomenon at all4 ,unless1 indeed1 we  
choose to call the succession of the two
 objects a third thing2 but their       
succession is not something added to the
 things themselves2 it is something     
involved in them4 ,dawn and sunrise     
announce themselves to our consciousness
 by two successive sensations4 ,our     

consciousness of the succession of these
 sensations is not a third sensation or 
feeling added to them2 we have not first
 the two feelings1 and then a feeling of
 their succession4 ,to have two feelings
 at all1 implies having them either     
successively1 or else simultaneously4   
,sensations1 or other feelings1 being   
given1 succession and simultaneousness  
are the two conditions1 to the          
alternative of which they are subjected 
by the nature of our faculties2 and no  
one has been able1 or needs expect1 to  
analyse the matter any farther4    #aa4 
,in a somewhat similar position are two 
other sorts of relations1 ,likeness and 
,unlikeness4 ,i have two sensations2 we 
will suppose them to be simple ones2 two
 sensations of white1 or one sensation  
of white and another of black4 ,i call  
the first two sensations like2 the last 
two unlike4 ,what is the fact or        
phenomenon constituting the fundamentum 
of this relation8 ,the two sensations   
first1 and then what we call a feeling  

of resemblance1 or of want of           
resemblance4 ,let us confine ourselves  
to the former case4 ,resemblance is     
evidently a feeling2 a state of the     
consciousness of the observer4 ,whether 
the feeling of the resemblance of the   
two colours be a third state of         
consciousness1 which ,i have after      
having the two sensations of colour1 or 
whether 7like the feeling of their      
succession7 it is involved in the       
sensations themselves1 may be a matter  
of discussion4 ,but in either case1     
these feelings of resemblance1 and of   
its opposite dissimilarity1 are parts of
 our nature2 and parts so far from being
 capable of analysis1 that they are     
presupposed in every attempt to analyse 
any of our other feelings4 ,likeness and
 unlikeness1 therefore1 as well as      
antecedence1 sequence1 and              
simultaneousness1 must stand apart among
 relations1 as things sui generis4 ,they
 are attributes grounded on facts1 that 
is1 on states of consciousness1 but on  

states which are peculiar1 unresolvable1
 and inexplicable4  ,but1 though        
likeness or unlikeness cannot be        
resolved into anything else1 complex    
cases of likeness or unlikeness can be  
resolved into simpler ones4 ,when we say
 of two things which consist of parts1  
that they are like one another1 the     
likeness of the wholes does admit of    
analysis2 it is compounded of likenesses
 between the various parts respectively1
 and of likeness in their arrangement4  
,of how vast a variety of resemblances  
of parts must that resemblance be       
composed1 which induces us to say that a
 portrait1 or a landscape1 is like its  
original4 ,if one person mimics another 
with any success1 of how many simple    
likenesses must the general or complex  
likeness be compounded3 likeness in a   
succession of bodily postures2 likeness 
in voice1 or in the accents and         
intonations of the voice2 likeness in   
the choice of words1 and in the thoughts
 or sentiments expressed1 whether by    

word1 countenance1 or gesture4  ,all    
likeness and unlikeness of which we have
 any cognizance1 resolve themselves into
 likeness and unlikeness between states 
of our own1 or some other1 mind4 ,when  
we say that one body is like another1   
7since we know nothing of bodies but the
 sensations which they excite17 we mean 
really that there is a resemblance      
between the sensations excited by the   
two bodies1 or between some portions at 
least of those sensations4 ,if we say   
that two attributes are like one        
another1 7since we know nothing of      
attributes except the sensations or     
states of feeling on which they are     
grounded17 we mean really that those    
sensations1 or states of feeling1       
resemble each other4 ,we may also say   
that two relations are alike4 ,the fact 
of resemblance between relations is     
sometimes called analogy1 forming one of
 the numerous meanings of that word4    
,the relation in which ,priam stood to  
,hector1 namely1 that of father and son1

 resembles the relation in which ,philip
 stood to ,alexander2 resembles it so   
closely that they are called the same   
relation4 ,the relation in which        
,cromwell stood to ,england resembles   
the relation in which ,napoleon stood to
 ,france1 though not so closely as to be
 called the same relation4 ,the meaning 
in both these instances must be1 that a 
resemblance existed between the facts   
which constituted the fundamentum       
relationis4  ,this resemblance may exist
 in all conceivable gradations1 from    
perfect undistinguishableness to        
something extremely slight4 ,when we    
say1 that a thought suggested to the    
mind of a person of genius is like a    
seed cast into the ground1 because the  
former produces a multitude of other    
thoughts1 and the latter a multitude of 
other seeds1 this is saying that between
 the relation of an inventive mind to a 
thought contained in it1 and the        
relation of a fertile soil to a seed    
contained in it1 there exists a         

resemblance3 the real resemblance being 
in the two fundamenta relationis1 in    
each of which there occurs a germ1      
producing by its development a multitude
 of other things similar to itself4 ,and
 as1 whenever two objects are jointly   
concerned in a phenomenon1 this         
constitutes a relation between those    
objects1 so1 if we suppose a second pair
 of objects concerned in a second       
phenomenon1 the slightest resemblance   
between the two phenomena is sufficient 
to admit of its being said that the two 
relations resemble2 provided1 of course1
 the points of resemblance are found in 
those portions of the two phenomena     
respectively which are connoted by the  
relative names4  ,while speaking of     
resemblance1 it is necessary to take    
notice of an ambiguity of language1     
against which scarcely any one is       
sufficiently on his guard4 ,resemblance1
 when it exists in the highest degree of
 all1 amounting to                      
undistinguishableness1 is often called  

identity1 and the two similar things are
 said to be the same4 ,i say often1 not 
always2 for we do not say that two      
visible objects1 two persons for        
instance1 are the same1 because they are
 so much alike that one might be        
mistaken for the other3 but we          
constantly use this mode of expression  
when speaking of feelings2 as when ,i   
say that the sight of any object gives  
me the same sensation or emotion to-day 
that it did yesterday1 or the same which
 it gives to some other person4 ,this is
 evidently an incorrect application of  
the word same2 for the feeling which ,i 
had yesterday is gone1 never to return2 
what ,i have to-day is another feeling1 
exactly like the former perhaps1 but    
distinct from it2 and it is evident that
 two different persons cannot be        
experiencing the same feeling1 in the   
sense in which we say that they are both
 sitting at the same table4 ,by a       
similar ambiguity we say1 that two      
persons are ill of the same disease2    

that two persons hold the same office2  
not in the sense in which we say that   
they are engaged in the same adventure1 
or sailing in the same ship1 but in the 
sense that they fill offices exactly    
similar1 though1 perhaps1 in distant    
places4 ,great confusion of ideas is    
often produced1 and many fallacies      
engendered1 in otherwise enlightened    
understandings1 by not being            
sufficiently alive to the fact 7in      
itself not always to be avoided71 that  
they use the same name to express ideas 
so different as those of identity and   
undistinguishable resemblance4 ,among   
modern writers1 ,archbishop ,whately    
stands almost alone in having drawn     
attention to this distinction1 and to   
the ambiguity connected with it4        
,several relations1 generally called by 
other names1 are really cases of        
resemblance4 ,as1 for example1 equality2
 which is but another word for the exact
 resemblance commonly called identity1  
considered as subsisting between things 

in respect of their quantity4 ,and this 
example forms a suitable transition to  
the third and last of the three heads   
under which1 as already remarked1       
,attributes are commonly arranged4   ,v4
 ,,quantity4   #ab4 ,let us imagine two 
things1 between which there is no       
difference 7that is1 no dissimilarity71 
except in quantity alone3 for instance1 
a gallon of water1 and more than a      
gallon of water4 ,a gallon of water1    
like any other external object1 makes   
its presence known to us by a set of    
sensations which it excites4 ,ten       
gallons of water are also an external   
object1 making its presence known to us 
in a similar manner2 and as we do not   
mistake ten gallons of water for a      
gallon of water1 it is plain that the   
set of sensations is more or less       
different in the two cases4 ,in like    
manner1 a gallon of water1 and a gallon 
of wine1 are two external objects1      
making their presence known by two sets 
of sensations1 which sensations are     

different from each other4 ,in the first
 case1 however1 we say that the         
difference is in quantity2 in the last  
there is a difference in quality1 while 
the quantity of the water and of the    
wine is the same4 ,what is the real     
distinction between the two cases8 ,it  
is not the province of ,logic to analyse
 it2 nor to decide whether it is        
susceptible of analysis or not4 ,for us 
the following considerations are        
sufficient4 ,it is evident that the     
sensations ,i receive from the gallon of
 water1 and those ,i receive from the   
gallon of wine1 are not the same1 that  
is1 not precisely alike2 neither are    
they altogether unlike3 they are partly 
similar1 partly dissimilar2 and that in 
which they resemble is precisely that in
 which alone the gallon of water and the
 ten gallons do not resemble4 ,that in  
which the gallon of water and the gallon
 of wine are like each other1 and in    
which the gallon and the ten gallons of 
water are unlike each other1 is called  

their quantity4 ,this likeness and      
unlikeness ,i do not pretend to explain1
 no more than any other kind of likeness
 or unlikeness4 ,but my object is to    
show1 that when we say of two things    
that they differ in quantity1 just as   
when we say that they differ in quality1
 the assertion is always grounded on a  
difference in the sensations which they 
excite4 ,nobody1 ,i presume1 will say1  
that to see1 or to lift1 or to drink1   
ten gallons of water1 does not include  
in itself a different set of sensations 
from those of seeing1 lifting1 or       
drinking one gallon2 or that to see or  
handle a foot-rule1 and to see or handle
 a yard-measure made exactly like it1   
are the same sensations4 ,i do not      
undertake to say what the difference in 
the sensations is4 ,everybody knows1 and
 nobody can tell2 no more than any one  
could tell what white is to a person who
 had never had the sensation4 ,but the  
difference1 so far as cognizable by our 
faculties1 lies in the sensations4      

,whatever difference we say there is in 
the things themselves1 is1 in this as in
 all other cases1 grounded1 and grounded
 exclusively1 on a difference in the    
sensations excited by them4   ,,vi4     
,,attributes ,,concluded4   #ac4 ,thus1 
then1 all the attributes of bodies which
 are classed under ,quality or          
,quantity1 are grounded on the          
sensations which we receive from those  
bodies1 and may be defined1 the powers  
which the bodies have of exciting those 
sensations4 ,and the same general       
explanation has been found to apply to  
most of the attributes usually classed  
under the head of ,relation4 ,they1 too1
 are grounded on some fact or phenomenon
 into which the related objects enter as
 parts2 that fact or phenomenon having  
no meaning and no existence to us1      
except the series of sensations or other
 states of consciousness by which it    
makes itself known2 and the relation    
being simply the power or capacity which
 the object possesses of taking part    

along with the correlated object in the 
production of that series of sensations 
or states of consciousness4 ,we have    
been obliged1 indeed1 to recognise a    
somewhat different character in certain 
peculiar relations1 those of succession 
and simultaneity1 of likeness and       
unlikeness4 ,these1 not being grounded  
on any fact or phenomenon distinct from 
the related objects themselves1 do not  
admit of the same kind of analysis4 ,but
 these relations1 though not1 like other
 relations1 grounded on states of       
consciousness1 are themselves states of 
consciousness3 resemblance is nothing   
but our feeling of resemblance2         
succession is nothing but our feeling of
 succession4 ,or1 if this be disputed   
7and we cannot1 without transgressing   
the bounds of our science1 discuss it   
here71 at least our knowledge of these  
relations1 and even our possibility of  
knowledge1 is confined to those which   
subsist between sensations1 or other    
states of consciousness2 for1 though we 

ascribe resemblance1 or succession1 or  
simultaneity1 to objects and to         
attributes1 it is always in virtue of   
resemblance or succession or            
simultaneity in the sensations or states
 of consciousness which those objects   
excite1 and on which those attributes   
are grounded4    #ad4 ,in the preceding 
investigation we have1 for the sake of  
simplicity1 considered bodies only1 and 
omitted minds4 ,but what we have said1  
is applicable1 mutatis mutandis1 to the 
latter4 ,the attributes of minds1 as    
well as those of bodies1 are grounded on
 states of feeling or consciousness4    
,but in the case of a mind1 we have to  
consider its own states1 as well as     
those which it produces in other minds4 
,every attribute of a mind consists     
either in being itself affected in a    
certain way1 or affecting other minds in
 a certain way4 ,considered in itself1  
we can predicate nothing of it but the  
series of its own feelings4 ,when we say
 of any mind1 that it is devout1 or     

superstitious1 or meditative1 or        
cheerful1 we mean that the ideas1       
emotions1 or volitions implied in those 
words1 form a frequently recurring part 
of the series of feelings1 or states of 
consciousness1 which fill up the        
sentient existence of that mind4  ,in   
addition1 however1 to those attributes  
of a mind which are grounded on its own 
states of feeling1 attributes may also  
be ascribed to it1 in the same manner as
 to a body1 grounded on the feelings    
which it excites in other minds4 ,a mind
 does not1 indeed1 like a body1 excite  
sensations1 but it may excite thoughts  
or emotions4 ,the most important example
 of attributes ascribed on this ground1 
is the employment of terms expressive of
 approbation or blame4 ,when1 for       
example1 we say of any character1 or 7in
 other words7 of any mind1 that it is   
admirable1 we mean that the             
contemplation of it excites the         
sentiment of admiration2 and indeed     
somewhat more1 for the word implies that

 we not only feel admiration1 but       
approve that sentiment in ourselves4 ,in
 some cases1 under the semblance of a   
single attribute1 two are really        
predicated3 one of them1 a state of the 
mind itself2 the other1 a state with    
which other minds are affected by       
thinking of it4 ,as when we say of any  
one that he is generous4 ,the word      
generosity expresses a certain state of 
mind1 but being a term of praise1 it    
also expresses that this state of mind  
excites in us another mental state1     
called approbation4 ,the assertion made1
 therefore1 is twofold1 and of the      
following purport3 ,certain feelings    
form habitually a part of this person's 
sentient existence2 and the idea of     
those feelings of his1 excites the      
sentiment of approbation in ourselves or
 others4  ,as we thus ascribe attributes
 to minds on the ground of ideas and    
emotions1 so may we to bodies on similar
 grounds1 and not solely on the ground  
of sensations3 as in speaking of the    

beauty of a statue2 since this attribute
 is grounded on the peculiar feeling of 
pleasure which the statue produces in   
our minds2 which is not a sensation1 but
 an emotion4   ,,vii4 ,,general         
,,results4   #ae4 ,our survey of the    
varieties of ,things which have been1 or
 which are capable of being1            
named--which have been1 or are capable  
of being1 either predicated of other    
,things1 or themselves made the subject 
of predications--is now concluded4  ,our
 enumeration commenced with ,feelings4  
,these we scrupulously distinguished    
from the objects which excite them1 and 
from the organs by which they are1 or   
may be supposed to be1 conveyed4        
,feelings are of four sorts3            
,sensations1 ,thoughts1 ,emotions1 and  
,volitions4 ,what are called            
,perceptions are merely a particular    
case of ,belief1 and belief is a kind of
 thought4 ,actions are merely volitions 
followed by an effect4 ,if there be any 
other kind of mental state not included 

under these subdivisions1 we did not    
think it necessary or proper in this    
place to discuss its existence1 or the  
rank which ought to be assigned to it4  
,after ,feelings we proceeded to        
,substances4 ,these are either ,bodies  
or ,minds4 ,without entering into the   
grounds of the metaphysical doubts which
 have been raised concerning the        
existence of ,matter and ,mind as       
objective realities1 we stated as       
sufficient for us the conclusion in     
which the best thinkers are now for the 
most part agreed1 that all we can know  
of ,matter is the sensations which it   
gives us1 and the order of occurrence of
 those sensations2 and that while the   
substance ,body is the unknown cause of 
our sensations1 the substance ,mind is  
the unknown recipient4  ,the only       
remaining class of ,nameable ,things is 
,attributes2 and these are of three     
kinds1 ,quality1 ,relation1 and         
,quantity4 ,qualities1 like substances1 
are known to us no otherwise than by the

 sensations or other states of          
consciousness which they excite3 and    
while1 in compliance with common usage1 
we have continued to speak of them as a 
distinct class of ,things1 we showed    
that in predicating them no one means to
 predicate anything but those sensations
 or states of consciousness1 on which   
they may be said to be grounded1 and by 
which alone they can be defined or      
described4 ,relations1 except the simple
 cases of likeness and unlikeness1      
succession and simultaneity1 are        
similarly grounded on some fact or      
phenomenon1 that is1 on some series of  
sensations or states of consciousness1  
more or less complicated4 ,the third    
species of ,attribute1 ,quantity1 is    
also manifestly grounded on something in
 our sensations or states of feeling1   
since there is an indubitable difference
 in the sensations excited by a larger  
and a smaller bulk1 or by a greater or a
 less degree of intensity1 in any object
 of sense or of consciousness4 ,all     

attributes1 therefore1 are to us nothing
 but either our sensations and other    
states of feeling1 or something         
inextricably involved therein2 and to   
this even the peculiar and simple       
relations just adverted to are not      
exceptions4 ,those peculiar relations1  
however1 are so important1 and1 even if 
they might in strictness be classed     
among states of consciousness1 are so   
fundamentally distinct from any other of
 those states1 that it would be a vain  
subtlety to bring them under that common
 description1 and it is necessary that  
they should be classed apart4  ,as the  
result1 therefore1 of our analysis1 we  
obtain the following as an enumeration  
and classification of all ,nameable     
,things3--  #ast4 ,feelings1 or ,states 
of ,consciousness4  #bnd4 ,the ,minds   
which experience those feelings4  #crd4 
,the ,bodies1 or external objects1 which
 excite certain of those feelings1      
together with the powers or properties  
whereby they excite them2 these last    

being included rather in compliance with
 common opinion1 and because their      
existence is taken for granted in the   
common language from which ,i cannot    
prudently deviate1 than because the     
recognition of such powers or properties
 as real existences appears to be       
warranted by a sound philosophy4  #dth1 
and last4 ,the ,successions and         
,co-existences1 the ,likenesses and     
,unlikenesses1 between feelings or      
states of consciousness4 ,those         
relations1 when considered as subsisting
 between other things1 exist in reality 
only between the states of consciousness
 which those things1 if bodies1 excite1 
if minds1 either excite or experience4  
,this1 until a better can be suggested1 
may serve as a substitute for the       
abortive ,classification of ,existences1
 termed the ,categories of ,aristotle4  
,the practical application of it will   
appear when we commence the inquiry into
 the ,import of ,propositions2 in other 
words1 when we inquire what it is which 

the mind actually believes1 when it     
gives what is called its assent to a    
proposition4  ,these four classes       
comprising1 if the classification be    
correct1 all ,nameable ,things1 these or
 some of them must of course compose the
 signification of all names2 and of     
these1 or some of them1 is made up      
whatever we call a fact4  ,for          
distinction's sake1 every fact which is 
solely composed of feelings or states of
 consciousness considered as such1 is   
often called a ,psychological or        
,subjective fact2 while every fact which
 is composed1 either wholly or in part1 
of something different from these1 that 
is1 of substances and attributes1 is    
called an ,objective fact4 ,we may say1 
then1 that every objective fact is      
grounded on a corresponding subjective  
one2 and has no meaning to us1 7apart   
from the subjective fact which          
corresponds to it17 except as a name for
 the unknown and inscrutable process by 
which that subjective or psychological  

fact is brought to pass4     ,,chapter  
,,iv4  ,,of ,,propositions4    #a4 ,in  
treating of ,propositions1 as already in
 treating of ,names1 some considerations
 of a comparatively elementary nature   
respecting their form and varieties must
 be premised1 before entering upon that 
analysis of the import conveyed by them1
 which is the real subject and purpose  
of this preliminary book4  ,a           
proposition1 we have before said1 is a  
portion of discourse in which a         
predicate is affirmed or denied of a    
subject4 ,a predicate and a subject are 
all that is necessarily required to make
 up a proposition3 but as we cannot     
conclude from merely seeing two names   
put together1 that they are a predicate 
and a subject1 that is1 that one of them
 is intended to be affirmed or denied of
 the other1 it is necessary that there  
should be some mode or form of          
indicating that such is the intention2  
some sign to distinguish a predication  
from any other kind of discourse4 ,this 

is sometimes done by a slight alteration
 of one of the words1 called an         
inflection2 as when we say1 ,fire burns2
 the change of the second word from burn
 to burns showing that we mean to affirm
 the predicate burn of the subject fire4
 ,but this function is more commonly    
fulfilled by the word is1 when an       
affirmation is intended1 is not1 when a 
negation2 or by some other part of the  
verb to be4 ,the word which thus serves 
the purpose of a sign of predication is 
called1 as we formerly observed1 the    
copula4 ,it is important that there     
should be no indistinctness in our      
conception of the nature and office of  
the copula2 for confused notions        
respecting it are among the causes which
 have spread mysticism over the field of
 logic1 and perverted its speculations  
into logomachies4  ,it is apt to be     
supposed that the copula is something   
more than a mere sign of predication2   
that it also signifies existence4 ,in   
the proposition1 ,socrates is just1 it  

may seem to be implied not only that the
 quality just can be affirmed of        
,socrates1 but moreover that ,socrates  
is1 that is to say1 exists4 ,this1      
however1 only shows that there is an    
ambiguity in the word is2 a word which  
not only performs the function of the   
copula in affirmations1 but has also a  
meaning of its own1 in virtue of which  
it may itself be made the predicate of a
 proposition4 ,that the employment of it
 as a copula does not necessarily       
include the affirmation of existence1   
appears from such a proposition as this1
 ,a centaur is a fiction of the poets2  
where it cannot possibly be implied that
 a centaur exists1 since the proposition
 itself expressly asserts that the thing
 has no real existence4  ,many volumes  
might be filled with the frivolous      
speculations concerning the nature of   
,being1 7,greek3 to on1 ousia1 ,ens1    
,entitas1 ,essentia1 and the like7 which
 have arisen from overlooking this      
double meaning of the word to be2 from  

supposing that when it signifies to     
exist1 and when it signifies to be some 
specified thing1 as to be a man1 to be  
,socrates1 to be seen or spoken of1 to  
be a phantom1 even to be a nonentity1 it
 must still1 at bottom1 answer to the   
same idea2 and that a meaning must be   
found for it which shall suit all these 
cases4 ,the fog which rose from this    
narrow spot diffused itself at an early 
period over the whole surface of        
metaphysics4 ,yet it becomes us not to  
triumph over the great intellects of    
,plato and ,aristotle because we are now
 able to preserve ourselves from many   
errors into which they1 perhaps         
inevitably1 fell4 ,the fire-teazer of a 
modern steam-engine produces by his     
exertions far greater effects than ,milo
 of ,crotona could1 but he is not       
therefore a stronger man4 ,the ,greeks  
seldom knew any language but their own4 
,this rendered it far more difficult for
 them than it is for us1 to acquire a   
readiness in detecting ambiguities4 ,one

 of the advantages of having accurately 
studied a plurality of languages1       
especially of those languages which     
eminent thinkers have used as the       
vehicle of their thoughts1 is the       
practical lesson we learn respecting the
 ambiguities of words1 by finding that  
the same word in one language           
corresponds1 on different occasions1 to 
different words in another4 ,when not   
thus exercised1 even the strongest      
understandings find it difficult to     
believe that things which have a common 
name1 have not in some respect or other 
a common nature2 and often expend much  
labour very unprofitably 7as was        
frequently done by the two philosophers 
just mentioned7 in vain attempts to     
discover in what this common nature     
consists4 ,but1 the habit once formed1  
intellects much inferior are capable of 
detecting even ambiguities which are    
common to many languages3 and it is     
surprising that the one now under       
consideration1 though it exists in the  

modern languages as well as in the      
ancient1 should have been overlooked by 
almost all authors4 ,the quantity of    
futile speculation which had been caused
 by a misapprehension of the nature of  
the copula1 was hinted at by ,hobbes2   
but ,mr4 ,james ,mill#ae was1 ,i        
believe1 the first who distinctly       
characterized the ambiguity1 and pointed
 out how many errors in the received    
systems of philosophy it has had to     
answer for4 ,it has indeed misled the   
moderns scarcely less than the ancients1
 though their mistakes1 because our     
understandings are not yet so completely
 emancipated from their influence1 do   
not appear equally irrational4  ,we     
shall now briefly review the principal  
distinctions which exist among          
propositions1 and the technical terms   
most commonly in use to express those   
distinctions4    #b4 ,a proposition     
being a portion of discourse in which   
something is affirmed or denied of      
something1 the first division of        

propositions is into affirmative and    
negative4 ,an affirmative proposition is
 that in which the predicate is affirmed
 of the subject2 as1 ,csar is dead4 ,a  
negative proposition is that in which   
the predicate is denied of the subject2 
as1 ,csar is not dead4 ,the copula1 in  
this last species of proposition1       
consists of the words is not1 which are 
the sign of negation2 is being the sign 
of affirmation4  ,some logicians1 among 
whom may be mentioned ,hobbes1 state    
this distinction differently2 they      
recognise only one form of copula1 is1  
and attach the negative sign to the     
predicate4 ,csar is dead1 and ,csar is  
not dead1 according to these writers1   
are propositions agreeing not in the    
subject and predicate1 but in the       
subject only4 ,they do not consider     
dead1 but not dead1 to be the predicate 
of the second proposition1 and they     
accordingly define a negative           
proposition to be one in which the      
predicate is a negative name4 ,the      

point1 though not of much practical     
moment1 deserves notice as an example   
7not unfrequent in logic7 where by means
 of an apparent simplification1 but     
which is merely verbal1 matters are made
 more complex than before4 ,the notion  
of these writers was1 that they could   
get rid of the distinction between      
affirming and denying1 by treating every
 case of denying as the affirming of a  
negative name4 ,but what is meant by a  
negative name8 ,a name expressive of the
 absence of an attribute4 ,so that when 
we affirm a negative name1 what we are  
really predicating is absence and not   
presence2 we are asserting not that     
anything is1 but that something is not2 
to express which operation no word seems
 so proper as the word denying4 ,the    
fundamental distinction is between a    
fact and the non-existence of that fact2
 between seeing something and not seeing
 it1 between ,csar's being dead and his 
not being dead2 and if this were a      
merely verbal distinction1 the          

generalization which brings both within 
the same form of assertion would be a   
real simplification3 the distinction1   
however1 being real1 and in the facts1  
it is the generalization confounding the
 distinction that is merely verbal2 and 
tends to obscure the subject1 by        
treating the difference between two     
kinds of truths as if it were only a    
difference between two kinds of words4  
,to put things together1 and to put them
 or keep them asunder1 will remain      
different operations1 whatever tricks we
 may play with language4  ,a remark of a
 similar nature may be applied to most  
of those distinctions among propositions
 which are said to have reference to    
their modality2 as1 difference of tense 
or time2 the sun did rise1 the sun is   
rising1 the sun will rise4 ,these       
differences1 like that between          
affirmation and negation1 might be      
glossed over by considering the incident
 of time as a mere modification of the  
predicate3 thus1 ,the sun is an object  

having risen1 ,the sun is an object now 
rising1 ,the sun is an object to rise   
hereafter4 ,but the simplification would
 be merely verbal4 ,past1 present1 and  
future1 do not constitute so many       
different kinds of rising2 they are     
designations belonging to the event     
asserted1 to the sun's rising to-day4   
,they affect1 not the predicate1 but the
 applicability of the predicate to the  
particular subject4 ,that which we      
affirm to be past1 present1 or future1  
is not what the subject signifies1 nor  
what the predicate signifies1 but       
specifically and expressly what the     
predication signifies2 what is expressed
 only by the proposition as such1 and   
not by either or both of the terms4     
,therefore the circumstance of time is  
properly considered as attaching to the 
copula1 which is the sign of            
predication1 and not to the predicate4  
,if the same cannot be said of such     
modifications as these1 ,csar may be    
dead2 ,csar is perhaps dead2 it is      

possible that ,csar is dead2 it is only 
because these fall altogether under     
another head1 being properly assertions 
not of anything relating to the fact    
itself1 but of the state of our own mind
 in regard to it2 namely1 our absence of
 disbelief of it4 ,thus ,csar may be    
dead means ,i am not sure that ,csar is 
alive4    #c4 ,the next division of     
propositions is into ,simple and        
,complex4 ,a simple proposition is that 
in which one predicate is affirmed or   
denied of one subject4 ,a complex       
proposition is that in which there is   
more than one predicate1 or more than   
one subject1 or both4  ,at first sight  
this division has the air of an         
absurdity2 a solemn distinction of      
things into one and more than one2 as if
 we were to divide horses into single   
horses and teams of horses4 ,and it is  
true that what is called a complex      
proposition is often not a proposition  
at all1 but several propositions1 held  
together by a conjunction4 ,such1 for   

example1 is this3 ,csar is dead1 and    
,brutus is alive3 or even this1 ,csar is
 dead1 but ,brutus is alive4 ,there are 
here two distinct assertions2 and we    
might as well call a street a complex   
house1 as these two propositions a      
complex proposition4 ,it is true that   
the syncategorematic words and and but  
have a meaning2 but that meaning is so  
far from making the two propositions    
one1 that it adds a third proposition to
 them4 ,all particles are abbreviations1
 and generally abbreviations of         
propositions2 a kind of short-hand1     
whereby something which1 to be expressed
 fully1 would have required a           
proposition or a series of propositions1
 is suggested to the mind at once4 ,thus
 the words1 ,csar is dead and ,brutus is
 alive1 are equivalent to these3 ,csar  
is dead2 ,brutus is alive2 it is desired
 that the two preceding propositions    
should be thought of together4 ,if the  
words were1 ,csar is dead but ,brutus is
 alive1 the sense would be equivalent to

 the same three propositions together   
with a fourth2 between the two preceding
 propositions there exists a contrast3  
viz4 either between the two facts       
themselves1 or between the feelings with
 which it is desired that they should be
 regarded4  ,in the instances cited the 
two propositions are kept visibly       
distinct1 each subject having its       
separate predicate1 and each predicate  
its separate subject4 ,for brevity1     
however1 and to avoid repetition1 the   
propositions are often blended together3
 as in this1 ,peter and ,james preached 
at ,jerusalem and in ,galilee1 which    
contains four propositions3 ,peter      
preached at ,jerusalem1 ,peter preached 
in ,galilee1 ,james preached at         
,jerusalem1 ,james preached in ,galilee4
  ,we have seen that when the two or    
more propositions comprised in what is  
called a complex proposition are stated 
absolutely1 and not under any condition 
or proviso1 it is not a proposition at  
all1 but a plurality of propositions2   

since what it expresses is not a single 
assertion1 but several assertions1      
which1 if true when joined1 are true    
also when separated4 ,but there is a    
kind of proposition which1 though it    
contains a plurality of subjects and of 
predicates1 and may be said in one sense
 of the word to consist of several      
propositions1 contains but one          
assertion2 and its truth does not at all
 imply that of the simple propositions  
which compose it4 ,an example of this   
is1 when the simple propositions are    
connected by the particle or2 as1       
,either ,a is ,b or ,c is ,d2 or by the 
particle if2 as1 ,a is ,b if ,c is ,d4  
,in the former case1 the proposition is 
called disjunctive1 in the latter1      
conditional3 the name hypothetical was  
originally common to both4 ,as has been 
well remarked by ,archbishop ,whately   
and others1 the disjunctive form is     
resolvable into the conditional2 every  
disjunctive proposition being equivalent
 to two or more conditional ones4       

,either ,a is ,b or ,c is ,d1 means1 if 
,a is not ,b1 ,c is ,d2 and if ,c is not
 ,d1 ,a is ,b4 ,all hypothetical        
propositions1 therefore1 though         
disjunctive in form1 are conditional in 
meaning2 and the words hypothetical and 
conditional may be1 as indeed they      
generally are1 used synonymously4       
,propositions in which the assertion is 
not dependent on a condition1 are said1 
in the language of logicians1 to be     
categorical4  ,an hypothetical          
proposition is not1 like the pretended  
complex propositions which we previously
 considered1 a mere aggregation of      
simple propositions4 ,the simple        
propositions which form part of the     
words in which it is couched1 form no   
part of the assertion which it conveys4 
,when we say1 ,if the ,koran comes from 
,god1 ,mahomet is the prophet of ,god1  
we do not intend to affirm either that  
the ,koran does come from ,god1 or that 
,mahomet is really his prophet4 ,neither
 of these simple propositions may be    

true1 and yet the truth of the          
hypothetical proposition may be         
indisputable4 ,what is asserted is not  
the truth of either of the propositions1
 but the inferribility of the one from  
the other4 ,what1 then1 is the subject1 
and what the predicate of the           
hypothetical proposition8 ,the ,koran is
 not the subject of it1 nor is ,mahomet3
 for nothing is affirmed or denied      
either of the ,koran or of ,mahomet4    
,the real subject of the predication is 
the entire proposition1 ,mahomet is the 
prophet of ,god2 and the affirmation is1
 that this is a legitimate inference    
from the proposition1 ,the ,koran comes 
from ,god4 ,the subject and predicate1  
therefore1 of an hypothetical           
proposition are names of propositions4  
,the subject is some one proposition4   
,the predicate is a general relative    
name applicable to propositions2 of this
 form--an inference from so and so4 ,a  
fresh instance is here afforded of the  
remark1 that particles are              

abbreviations2 since ,if ,a is ,b1 ,c is
 ,d1 is found to be an abbreviation of  
the following3 ,the proposition ,c is   
,d1 is a legitimate inference from the  
proposition ,a is ,b4  ,the distinction1
 therefore1 between hypothetical and    
categorical propositions1 is not so     
great as it at first appears4 ,in the   
conditional1 as well as in the          
categorical form1 one predicate is      
affirmed of one subject1 and no more3   
but a conditional proposition is a      
proposition concerning a proposition2   
the subject of the assertion is itself  
an assertion4 ,nor is this a property   
peculiar to hypothetical propositions4  
,there are other classes of assertions  
concerning propositions4 ,like other    
things1 a proposition has attributes    
which may be predicated of it4 ,the     
attribute predicated of it in an        
hypothetical proposition1 is that of    
being an inference from a certain other 
proposition4 ,but this is only one of   
many attributes that might be           

predicated4 ,we may say1 ,that the whole
 is greater than its part1 is an axiom  
in mathematics3 ,that the ,holy ,ghost  
proceeds from the ,father alone1 is a   
tenet of the ,greek ,church3 ,the       
doctrine of the divine right of kings   
was renounced by ,parliament at the     
,revolution3 ,the infallibility of the  
,pope has no countenance from           
,scripture4 ,in all these cases the     
subject of the predication is an entire 
proposition4 ,that which these different
 predicates are affirmed of1 is the     
proposition1 the whole is greater than  
its part2 the proposition1 the ,holy    
,ghost proceeds from the ,father alone2 
the proposition1 kings have a divine    
right2 the proposition1 the ,pope is    
infallible4  ,seeing1 then1 that there  
is much less difference between         
hypothetical propositions and any       
others1 than one might be led to imagine
 from their form1 we should be at a loss
 to account for the conspicuous position
 which they have been selected to fill  

in treatises on logic1 if we did not    
remember that what they predicate of a  
proposition1 namely1 its being an       
inference from something else1 is       
precisely that one of its attributes    
with which most of all a logician is    
concerned4    #d4 ,the next of the      
common divisions of ,propositions is    
into ,universal1 ,particular1           
,indefinite1 and ,singular3 a           
distinction founded on the degree of    
generality in which the name1 which is  
the subject of the proposition1 is to be
 understood4 ,the following are         
examples3    ,all men are mortal--      
,universal4   ,some men are mortal--    
,particular4   ,man is mortal--         
,indefinite4   ,julius ,csar is mortal--
   ,singular4  ,the proposition is      
,singular1 when the subject is an       
individual name4 ,the individual name   
needs not be a proper name4 ,the        
,founder of ,christianity was crucified1
 is as much a singular proposition as   
,christ was crucified4  ,when the name  

which is the subject of the proposition 
is a general name1 we may intend to     
affirm or deny the predicate1 either of 
all the things that the subject denotes1
 or only of some4 ,when the predicate is
 affirmed or denied of all and each of  
the things denoted by the subject1 the  
proposition is universal2 when of some  
undefined portion of them only1 it is   
particular4 ,thus1 ,all men are mortal2 
,every man is mortal2 are universal     
propositions4 ,no man is immortal1 is   
also an universal proposition1 since the
 predicate1 immortal1 is denied of each 
and every individual denoted by the term
 man2 the negative proposition being    
exactly equivalent to the following1    
,every man is not-immortal4 ,but some   
men are wise1 some men are not wise1 are
 particular propositions2 the predicate 
wise being in the one case affirmed and 
in the other denied not of each and     
every individual denoted by the term    
man1 but only of each and every one of  
some portion of those individuals1      

without specifying what portion2 for if 
this were specified1 the proposition    
would be changed either into a singular 
proposition1 or into an universal       
proposition with a different subject2   
as1 for instance1 all properly          
instructed men are wise4 ,there are     
other forms of particular propositions2 
as1 ,most men are imperfectly educated3 
it being immaterial how large a portion 
of the subject the predicate is asserted
 of1 as long as it is left uncertain how
 that portion is to be distinguished    
from the rest4  ,when the form of the   
expression does not clearly show whether
 the general name which is the subject  
of the proposition is meant to stand for
 all the individuals denoted by it1 or  
only for some of them1 the proposition  
is1 by some logicians1 called           
,indefinite2 but this1 as ,archbishop   
,whately observes1 is a solecism1 of the
 same nature as that committed by some  
grammarians when in their list of       
genders they enumerate the doubtful     

gender4 ,the speaker must mean to assert
 the proposition either as an universal 
or as a particular proposition1 though  
he has failed to declare which3 and it  
often happens that though the words do  
not show which of the two he intends1   
the context1 or the custom of speech1   
supplies the deficiency4 ,thus1 when it 
is affirmed that ,man is mortal1 nobody 
doubts that the assertion is intended of
 all human beings2 and the word         
indicative of universality is commonly  
omitted1 only because the meaning is    
evident without it4 ,in the proposition1
 ,wine is good1 it is understood with   
equal readiness1 though for somewhat    
different reasons1 that the assertion is
 not intended to be universal1 but      
particular4#af  ,when a general name    
stands for each and every individual    
which it is a name of1 or in other      
words1 which it denotes1 it is said by  
logicians to be distributed1 or taken   
distributively4 ,thus1 in the           
proposition1 ,all men are mortal1 the   

subject1 ,man1 is distributed1 because  
mortality is affirmed of each and every 
man4 ,the predicate1 ,mortal1 is not    
distributed1 because the only mortals   
who are spoken of in the proposition are
 those who happen to be men2 while the  
word may1 for aught that appears1 and in
 fact does1 comprehend within it an     
indefinite number of objects besides    
men4 ,in the proposition1 ,some men are 
mortal1 both the predicate and the      
subject are undistributed4 ,in the      
following1 ,no men have wings1 both the 
predicate and the subject are           
distributed4 ,not only is the attribute 
of having wings denied of the entire    
class ,man1 but that class is severed   
and cast out from the whole of the class
 ,winged1 and not merely from some part 
of that class4  ,this phraseology1 which
 is of great service in stating and     
demonstrating the rules of the          
syllogism1 enables us to express very   
concisely the definitions of an         
universal and a particular proposition4 

,an universal proposition is that of    
which the subject is distributed2 a     
particular proposition is that of which 
the subject is undistributed4  ,there   
are many more distinctions among        
propositions than those we have here    
stated1 some of them of considerable    
importance4 ,but1 for explaining and    
illustrating these1 more suitable       
opportunities will occur in the sequel4 
,,chapter ,v4  ,,of ,,the ,,import ,,of 
,,propositions4    #a4 ,an inquiry into 
the nature of propositions must have one
 of two objects3 to analyse the state of
 mind called ,belief1 or to analyse what
 is believed4 ,all language recognises a
 difference between a doctrine or       
opinion1 and the fact of entertaining   
the opinion2 between assent1 and what is
 assented to4  ,logic1 according to the 
conception here formed of it1 has no    
concern with the nature of the act of   
judging or believing2 the consideration 
of that act1 as a phenomenon of the     
mind1 belongs to another science4       

,philosophers1 however1 from ,descartes 
downwards1 and especially from the era  
of ,leibnitz and ,locke1 have by no     
means observed this distinction2 and    
would have treated with great disrespect
 any attempt to analyse the import of   
,propositions1 unless founded on an     
analysis of the act of ,judgment4 ,a    
proposition1 they would have said1 is   
but the expression in words of a        
,judgment4 ,the thing expressed1 not the
 mere verbal expression1 is the         
important matter4 ,when the mind assents
 to a proposition1 it judges4 ,let us   
find out what the mind does when it     
judges1 and we shall know what          
propositions mean1 and not otherwise4   
,conformably to these views1 almost all 
the writers on ,logic in the last two   
centuries1 whether ,english1 ,german1 or
 ,french1 have made their theory of     
,propositions1 from one end to the      
other1 a theory of ,judgments4 ,they    
considered a ,proposition1 or a         
,judgment1 for they used the two words  

indiscriminately1 to consist in         
affirming or denying one idea of        
another4 ,to judge1 was to put two ideas
 together1 or to bring one idea under   
another1 or to compare two ideas1 or to 
perceive the agreement or disagreement  
between two ideas3 and the whole        
doctrine of ,propositions1 together with
 the theory of ,reasoning1 7always      
necessarily founded on the theory of    
,propositions17 was stated as if ,ideas1
 or ,conceptions1 or whatever other term
 the writer preferred as a name for     
mental representations generally1       
constituted essentially the subject     
matter and substance of those           
operations4  ,it is1 of course1 true1   
that in any case of judgment1 as for    
instance when we judge that gold is     
yellow1 a process takes place in our    
minds1 of which some one or other of    
these theories is a partially correct   
account4 ,we must have the idea of gold 
and the idea of yellow1 and these two   
ideas must be brought together in our   

mind4 ,but in the first place1 it is    
evident that this is only a part of what
 takes place2 for we may put two ideas  
together without any act of belief2 as  
when we merely imagine something1 such  
as a golden mountain2 or when we        
actually disbelieve3 for in order even  
to disbelieve that ,mahomet was an      
apostle of ,god1 we must put the idea of
 ,mahomet and that of an apostle of ,god
 together4 ,to determine what it is that
 happens in the case of assent or       
dissent besides putting two ideas       
together1 is one of the most intricate  
of metaphysical problems4 ,but whatever 
the solution may be1 we may venture to  
assert that it can have nothing whatever
 to do with the import of propositions2 
for this reason1 that propositions      
7except sometimes when the mind itself  
is the subject treated of7 are not      
assertions respecting our ideas of      
things1 but assertions respecting the   
things themselves4 ,in order to believe 
that gold is yellow1 ,i must1 indeed1   

have the idea of gold1 and the idea of  
yellow1 and something having reference  
to those ideas must take place in my    
mind2 but my belief has not reference to
 the ideas1 it has reference to the     
things4 ,what ,i believe1 is a fact     
relating to the outward thing1 gold1 and
 to the impression made by that outward 
thing upon the human organs2 not a fact 
relating to my conception of gold1 which
 would be a fact in my mental history1  
not a fact of external nature4 ,it is   
true1 that in order to believe this fact
 in external nature1 another fact must  
take place in my mind1 a process must be
 performed upon my ideas2 but so it must
 in everything else that ,i do4 ,i      
cannot dig the ground unless ,i have the
 idea of the ground1 and of a spade1 and
 of all the other things ,i am operating
 upon1 and unless ,i put those ideas    
together4#ag ,but it would be a very    
ridiculous description of digging the   
ground to say that it is putting one    
idea into another4 ,digging is an       

operation which is performed upon the   
things themselves1 though it cannot be  
performed unless ,i have in my mind the 
ideas of them4 ,and in like manner1     
believing is an act which has for its   
subject the facts themselves1 though a  
previous mental conception of the facts 
is an indispensable condition4 ,when ,i 
say that fire causes heat1 do ,i mean   
that my idea of fire causes my idea of  
heat8 ,no3 ,i mean that the natural     
phenomenon1 fire1 causes the natural    
phenomenon1 heat4 ,when ,i mean to      
assert anything respecting the ideas1 ,i
 give them their proper name1 ,i call   
them ideas3 as when ,i say1 that a      
child's idea of a battle is unlike the  
reality1 or that the ideas entertained  
of the ,deity have a great effect on the
 characters of mankind4  ,the notion    
that what is of primary importance to   
the logician in a proposition1 is the   
relation between the two ideas          
corresponding to the subject and        
predicate1 7instead of the relation     

between the two phenomena which they    
respectively express17 seems to me one  
of the most fatal errors ever introduced
 into the philosophy of ,logic2 and the 
principal cause why the theory of the   
science has made such inconsiderable    
progress during the last two centuries4 
,the treatises on ,logic1 and on the    
branches of ,mental ,philosophy         
connected with ,logic1 which have been  
produced since the intrusion of this    
cardinal error1 though sometimes written
 by men of extraordinary abilities and  
attainments1 almost always tacitly imply
 a theory that the investigation of     
truth consists in contemplating and     
handling our ideas1 or conceptions of   
things1 instead of the things           
themselves3 a doctrine tantamount to the
 assertion1 that the only mode of       
acquiring knowledge of nature is to     
study it at second hand1 as represented 
in our own minds4 ,meanwhile1 inquiries 
into every kind of natural phenomena    
were incessantly establishing great and 

fruitful truths on most important       
subjects1 by processes upon which these 
views of the nature of ,judgment and    
,reasoning threw no light1 and in which 
they afforded no assistance whatever4   
,no wonder that those who knew by       
practical experience how truths are     
arrived at1 should deem a science       
futile1 which consisted chiefly of such 
speculations4 ,what has been done for   
the advancement of ,logic since these   
doctrines came into vogue1 has been done
 not by professed logicians1 but by     
discoverers in the other sciences2 in   
whose methods of investigation many     
principles of logic1 not previously     
thought of1 have successively come forth
 into light1 but who have generally     
committed the error of supposing that   
nothing whatever was known of the art of
 philosophizing by the old logicians1   
because their modern interpreters have  
written to so little purpose respecting 
it4  ,we have to inquire1 then1 on the  
present occasion1 not into ,judgment1   

but judgments2 not into the act of      
believing1 but into the thing believed4 
,what is the immediate object of belief 
in a ,proposition8 ,what is the matter  
of fact signified by it8 ,what is it to 
which1 when ,i assert the proposition1  
,i give my assent1 and call upon others 
to give theirs8 ,what is that which is  
expressed by the form of discourse      
called a ,proposition1 and the          
conformity of which to fact constitutes 
the truth of the proposition8    #b4    
,one of the clearest and most           
consecutive thinkers whom this country  
or the world has produced1 ,i mean      
,hobbes1 has given the following answer 
to this question4 ,in every proposition 
7says he7 what is signified is1 the     
belief of the speaker that the predicate
 is a name of the same thing of which   
the subject is a name2 and if it really 
is so1 the proposition is true4 ,thus   
the proposition1 ,all men are living    
beings 7he would say7 is true1 because  
living being is a name of everything of 

which man is a name4 ,all men are six   
feet high1 is not true1 because six feet
 high is not a name of everything       
7though it is of some things7 of which  
man is a name4  ,what is stated in this 
theory as the definition of a true      
proposition1 must be allowed to be a    
property which all true propositions    
possess4 ,the subject and predicate     
being both of them names of things1 if  
they were names of quite different      
things the one name could not1          
consistently with its signification1 be 
predicated of the other4 ,if it be true 
that some men are copper-coloured1 it   
must be true--and the proposition does  
really assert--that among the           
individuals denoted by the name man1    
there are some who are also among those 
denoted by the name copper-coloured4 ,if
 it be true that all oxen ruminate1 it  
must be true that all the individuals   
denoted by the name ox are also among   
those denoted by the name ruminating2   
and whoever asserts that all oxen       

ruminate1 undoubtedly does assert that  
this relation subsists between the two  
names4  ,the assertion1 therefore1      
which1 according to ,hobbes1 is the only
 one made in any proposition1 really is 
made in every proposition3 and his      
analysis has consequently one of the    
requisites for being the true one4 ,we  
may go a step farther2 it is the only   
analysis that is rigorously true of all 
propositions without exception4 ,what he
 gives as the meaning of propositions1  
is part of the meaning of all           
propositions1 and the whole meaning of  
some4 ,this1 however1 only shows what an
 extremely minute fragment of meaning it
 is quite possible to include within the
 logical formula of a proposition4 ,it  
does not show that no proposition means 
more4 ,to warrant us in putting together
 two words with a copula between them1  
it is really enough that the thing or   
things denoted by one of the names      
should be capable1 without violation of 
usage1 of being called by the other name

 also4 ,if1 then1 this be all the       
meaning necessarily implied in the form 
of discourse called a ,proposition1 why 
do ,i object to it as the scientific    
definition of what a proposition means8 
,because1 though the mere collocation   
which makes the proposition a           
proposition1 conveys no more than this  
scanty amount of meaning1 that same     
collocation combined with other         
circumstances1 that form combined with  
other matter1 does convey more1 and much
 more4  ,the only propositions of which 
,hobbes' principle is a sufficient      
account1 are that limited and           
unimportant class in which both the     
predicate and the subject are proper    
names4 ,for1 as has already been        
remarked1 proper names have strictly no 
meaning2 they are mere marks for        
individual objects3 and when a proper   
name is predicated of another proper    
name1 all the signification conveyed is1
 that both the names are marks for the  
same object4 ,but this is precisely what

 ,hobbes produces as a theory of        
predication in general4 ,his doctrine is
 a full explanation of such predications
 as these3 ,hyde was ,clarendon1 or1    
,tully is ,cicero4 ,it exhausts the     
meaning of those propositions4 ,but it  
is a sadly inadequate theory of any     
others4 ,that it should ever have been  
thought of as such1 can be accounted for
 only by the fact1 that ,hobbes1 in     
common with the other ,nominalists1     
bestowed little or no attention upon the
 connotation of words2 and sought for   
their meaning exclusively in what they  
denote3 as if all names had been 7what  
none but proper names really are7 marks 
put upon individuals2 and as if there   
were no difference between a proper and 
a general name1 except that the first   
denotes only one individual1 and the    
last a greater number4  ,it has been    
seen1 however1 that the meaning of all  
names1 except proper names and that     
portion of the class of abstract names  
which are not connotative1 resides in   

the connotation4 ,when1 therefore1 we   
are analysing the meaning of any        
proposition in which the predicate and  
the subject1 or either of them1 are     
connotative names1 it is to the         
connotation of those terms that we must 
exclusively look1 and not to what they  
denote1 or in the language of ,hobbes   
7language so far correct7 are names of4 
,in asserting that the truth of a       
proposition depends on the conformity of
 import between its terms1 as1 for      
instance1 that the proposition1         
,socrates is wise1 is a true            
proposition1 because ,socrates and wise 
are names applicable to1 or1 as he      
expresses it1 names of1 the same person2
 it is very remarkable that so powerful 
a thinker should not have asked himself 
the question1 ,but how came they to be  
names of the same person8 ,surely not   
because such was the intention of those 
who invented the words4 ,when mankind   
fixed the meaning of the word wise1 they
 were not thinking of ,socrates1 nor1   

when his parents gave him the name of   
,socrates1 were they thinking of wisdom4
 ,the names happen to fit the same      
person because of a certain fact1 which 
fact was not known1 nor in being1 when  
the names were invented4 ,if we want to 
know what the fact is1 we shall find the
 clue to it in the connotation of the   
names4  ,a bird or a stone1 a man1 or a 
wise man1 means simply1 an object having
 such and such attributes4 ,the real    
meaning of the word man1 is those       
attributes1 and not ,smith1 ,brown1 and 
the remainder of the individuals4 ,the  
word mortal1 in like manner connotes a  
certain attribute or attributes2 and    
when we say1 ,all men are mortal1 the   
meaning of the proposition is1 that all 
beings which possess the one set of     
attributes1 possess also the other4 ,if1
 in our experience1 the attributes      
connoted by man are always accompanied  
by the attribute connoted by mortal1 it 
will follow as a consequence1 that the  
class man will be wholly included in the

 class mortal1 and that mortal will be a
 name of all things of which man is a   
name3 but why8 ,those objects are       
brought under the name1 by possessing   
the attributes connoted by it3 but their
 possession of the attributes is the    
real condition on which the truth of the
 proposition depends2 not their being   
called by the name4 ,connotative names  
do not precede1 but follow1 the         
attributes which they connote4 ,if one  
attribute happens to be always found in 
conjunction with another attribute1 the 
concrete names which answer to those    
attributes will of course be predicable 
of the same subjects1 and may be said1  
in ,hobbes' language1 7in the propriety 
of which on this occasion ,i fully      
concur17 to be two names for the same   
things4 ,but the possibility of a       
concurrent application of the two names1
 is a mere consequence of the           
conjunction between the two attributes1 
and was1 in most cases1 never thought of
 when the names were introduced and     

their signification fixed4 ,that the    
diamond is combustible1 was a           
proposition certainly not dreamt of when
 the words ,diamond and ,combustible    
first received their meaning2 and could 
not have been discovered by the most    
ingenious and refined analysis of the   
signification of those words4 ,it was   
found out by a very different process1  
namely1 by exerting the senses1 and     
learning from them1 that the attribute  
of combustibility existed in the        
diamonds upon which the experiment was  
tried2 the number or character of the   
experiments being such1 that what was   
true of those individuals might be      
concluded to be true of all substances  
called by the name1 that is1 of all     
substances possessing the attributes    
which the name connotes4 ,the assertion1
 therefore1 when analysed1 is1 that     
wherever we find certain attributes1    
there will be found a certain other     
attribute3 which is not a question of   
the signification of names1 but of laws 

of nature2 the order existing among     
phenomena4    #c4 ,although ,hobbes'    
theory of ,predication has not1 in the  
terms in which he stated it1 met with a 
very favourable reception from          
subsequent thinkers1 a theory virtually 
identical with it1 and not by any means 
so perspicuously expressed1 may almost  
be said to have taken the rank of an    
established opinion4 ,the most generally
 received notion of ,predication        
decidedly is that it consists in        
referring something to a class1 i4e41   
either placing an individual under a    
class1 or placing one class under       
another class4 ,thus1 the proposition1  
,man is mortal1 asserts1 according to   
this view of it1 that the class man is  
included in the class mortal4 ,plato is 
a philosopher1 asserts that the         
individual ,plato is one of those who   
compose the class philosopher4 ,if the  
proposition is negative1 then instead of
 placing something in a class1 it is    
said to exclude something from a class4 

,thus1 if the following be the          
proposition1 ,the elephant is not       
carnivorous2 what is asserted 7according
 to this theory7 is1 that the elephant  
is excluded1 from the class carnivorous1
 or is not numbered among the things    
comprising that class4 ,there is no real
 difference1 except in language1 between
 this theory of ,predication and the    
theory of ,hobbes4 ,for a class is      
absolutely nothing but an indefinite    
number of individuals denoted by a      
general name4 ,the name given to them in
 common1 is what makes them a class4 ,to
 refer anything to a class1 therefore1  
is to look upon it as one of the things 
which are to be called by that common   
name4 ,to exclude it from a class1 is to
 say that the common name is not        
applicable to it4  ,how widely these    
views of predication have prevailed1 is 
evident from this1 that they are the    
basis of the celebrated dictum de omni  
et nullo4 ,when the syllogism is        
resolved1 by all who treat of it1 into  

an inference that what is true of a     
class is true of all things whatever    
that belong to the class2 and when this 
is laid down by almost all professed    
logicians as the ultimate principle to  
which all reasoning owes its validity2  
it is clear that in the general         
estimation of logicians1 the            
propositions of which reasonings are    
composed can be the expression of       
nothing but the process of dividing     
things into classes1 and referring      
everything to its proper class4  ,this  
theory appears to me a signal example of
 a logical error very often committed in
 logic1 that of ,greek3 hysteron        
proteron1 or explaining a thing by      
something which presupposes it4 ,when ,i
 say that snow is white1 ,i may and     
ought to be thinking of snow as a class1
 because ,i am asserting a proposition  
as true of all snow3 but ,i am certainly
 not thinking of white objects as a     
class2 ,i am thinking of no white object
 whatever except snow1 but only of that1

 and of the sensation of white which it 
gives me4 ,when1 indeed1 ,i have judged1
 or assented to the propositions1 that  
snow is white1 and that several other   
things are also white1 ,i gradually     
begin to think of white objects as a    
class1 including snow and those other   
things4 ,but this is a conception which 
followed1 not preceded1 those judgments1
 and therefore cannot be given as an    
explanation of them4 ,instead of        
explaining the effect by the cause1 this
 doctrine explains the cause by the     
effect1 and is1 ,i conceive1 founded on 
a latent misconception of the nature of 
classification4  ,there is a sort of    
language very generally prevalent in    
these discussions1 which seems to       
suppose that classification is an       
arrangement and grouping of definite and
 known individuals3 that when names were
 imposed1 mankind took into             
consideration all the individual objects
 in the universe1 distributed them into 
parcels or lists1 and gave to the       

objects of each list a common name1     
repeating this operation toties quoties 
until they had invented all the general 
names of which language consists2 which 
having been once done1 if a question    
subsequently arises whether a certain   
general name can be truly predicated of 
a certain particular object1 we have    
only 7as it were7 to read the roll of   
the objects upon which that name was    
conferred1 and see whether the object   
about which the question arises is to be
 found among them4 ,the framers of      
language 7it would seem to be supposed7 
have predetermined all the objects that 
are to compose each class1 and we have  
only to refer to the record of an       
antecedent decision4  ,so absurd a      
doctrine will be owned by nobody when   
thus nakedly stated2 but if the commonly
 received explanations of classification
 and naming do not imply this theory1 it
 requires to be shown how they admit of 
being reconciled with any other4        
,general names are not marks put upon   

definite objects2 classes are not made  
by drawing a line round a given number  
of assignable individuals4 ,the objects 
which compose any given class are       
perpetually fluctuating4 ,we may frame a
 class without knowing the individuals1 
or even any of the individuals1 of which
 it may be composed2 we may do so while 
believing that no such individuals      
exist4 ,if by the meaning of a general  
name are to be understood the things    
which it is the name of1 no general     
name1 except by accident1 has a fixed   
meaning at all1 or ever long retains the
 same meaning4 ,the only mode in which  
any general name has a definite meaning1
 is by being a name of an indefinite    
variety of things2 namely1 of all       
things1 known or unknown1 past1 present1
 or future1 which possess certain       
definite attributes4 ,when1 by studying 
not the meaning of words1 but the       
phenomena of nature1 we discover that   
these attributes are possessed by some  
object not previously known to possess  

them1 7as when chemists found that the  
diamond was combustible71 we include    
this new object in the class2 but it did
 not already belong to the class4 ,we   
place the individual in the class       
because the proposition is true2 the    
proposition is not true because the     
object is placed in the class4  ,it will
 appear hereafter1 in treating of       
reasoning1 how much the theory of that  
intellectual process has been vitiated  
by the influence of these erroneous     
notions1 and by the habit which they    
exemplify of assimilating all the       
operations of the human understanding   
which have truth for their object1 to   
processes of mere classification and    
naming4 ,unfortunately1 the minds which 
have been entangled in this net are     
precisely those which have escaped the  
other cardinal error commented upon in  
the beginning of the present chapter4   
,since the revolution which dislodged   
,aristotle from the schools1 logicians  
may almost be divided into those who    

have looked upon reasoning as           
essentially an affair of ,ideas1 and    
those who have looked upon it as        
essentially an affair of ,names4        
,although1 however1 ,hobbes' theory of  
,predication1 according to the          
well-known remark of ,leibnitz1 and the 
avowal of ,hobbes himself1#ah renders   
truth and falsity completely arbitrary1 
with no standard but the will of men1 it
 must not be concluded that either      
,hobbes1 or any of the other thinkers   
who have in the main agreed with him1   
did in fact consider the distinction    
between truth and error as less real1 or
 attached less importance to it1 than   
other people4 ,to suppose that they did 
so would argue total unacquaintance with
 their other speculations4 ,but this    
shows how little hold their doctrine    
possessed over their own minds4 ,no     
person1 at bottom1 ever imagined that   
there was nothing more in truth than    
propriety of expression2 than using     
language in conformity to a previous    

convention4 ,when the inquiry was       
brought down from generals to a         
particular case1 it has always been     
acknowledged that there is a distinction
 between verbal and real questions2 that
 some false propositions are uttered    
from ignorance of the meaning of words1 
but that in others the source of the    
error is a misapprehension of things2   
that a person who has not the use of    
language at all may form propositions   
mentally1 and that they may be untrue1  
that is1 he may believe as matters of   
fact what are not really so4 ,this last 
admission cannot be made in stronger    
terms than it is by ,hobbes himself2#ai 
though he will not allow such erroneous 
belief to be called falsity1 but only   
error4 ,and he has himself laid down1 in
 other places1 doctrines in which the   
true theory of predication is by        
implication contained4 ,he distinctly   
says that general names are given to    
things on account of their attributes1  
and that abstract names are the names of

 those attributes4 ,abstract is that    
which in any subject denotes the cause  
of the concrete name4444 ,and these     
causes of names are the same with the   
causes of our conceptions1 namely1 some 
power of action1 or affection1 of the   
thing conceived1 which some call the    
manner by which anything works upon our 
senses1 but by most men they are called 
accidents4#bj ,it is strange that having
 gone so far1 he should not have gone   
one step farther1 and seen that what he 
calls the cause of the concrete name1 is
 in reality the meaning of it2 and that 
when we predicate of any subject a name 
which is given because of an attribute  
7or1 as he calls it1 an accident71 our  
object is not to affirm the name1 but1  
by means of the name1 to affirm the     
attribute4    #d4 ,let the predicate be1
 as we have said1 a connotative term2   
and to take the simplest case first1 let
 the subject be a proper name3 ,the     
summit of ,chimborazo is white4 ,the    
word white connotes an attribute which  

is possessed by the individual object   
designated by the words summit of       
,chimborazo2 which attribute consists in
 the physical fact1 of its exciting in  
human beings the sensation which we call
 a sensation of white4 ,it will be      
admitted that1 by asserting the         
proposition1 we wish to communicate     
information of that physical fact1 and  
are not thinking of the names1 except as
 the necessary means of making that     
communication4 ,the meaning of the      
proposition1 therefore1 is1 that the    
individual thing denoted by the subject1
 has the attributes connoted by the     
predicate4  ,if we now suppose the      
subject also to be a connotative name1  
the meaning expressed by the proposition
 has advanced a step farther in         
complication4 ,let us first suppose the 
proposition to be universal1 as well as 
affirmative3 ,all men are mortal4 ,in   
this case1 as in the last1 what the     
proposition asserts 7or expresses a     
belief of7 is1 of course1 that the      

objects denoted by the subject 7man7    
possess the attributes connoted by the  
predicate 7mortal74 ,but the            
characteristic of this case is1 that the
 objects are no longer individually     
designated4 ,they are pointed out only  
by some of their attributes3 they are   
the objects called men1 that is1        
possessing the attributes connoted by   
the name man2 and the only thing known  
of them may be those attributes3 indeed1
 as the proposition is general1 and the 
objects denoted by the subject are      
therefore indefinite in number1 most of 
them are not known individually at all4 
,the assertion1 therefore1 is not1 as   
before1 that the attributes which the   
predicate connotes are possessed by any 
given individual1 or by any number of   
individuals previously known as ,john1  
,thomas1 c41 but that those attributes  
are possessed by each and every         
individual possessing certain other     
attributes2 that whatever has the       
attributes connoted by the subject1 has 

also those connoted by the predicate2   
that the latter set of attributes       
constantly accompany the former set4    
,whatever has the attributes of man has 
the attribute of mortality2 mortality   
constantly accompanies the attributes of
 man4#ba  ,if it be remembered that     
every attribute is grounded on some fact
 or phenomenon1 either of outward sense 
or of inward consciousness1 and that to 
possess an attribute is another phrase  
for being the cause of1 or forming part 
of1 the fact or phenomenon upon which   
the attribute is grounded2 we may add   
one more step to complete the analysis4 
,the proposition which asserts that one 
attribute always accompanies another    
attribute1 really asserts thereby no    
other thing than this1 that one         
phenomenon always accompanies another   
phenomenon2 insomuch that where we find 
the one1 we have assurance of the       
existence of the other4 ,thus1 in the   
proposition1 ,all men are mortal1 the   
word man connotes the attributes which  

we ascribe to a certain kind of living  
creatures1 on the ground of certain     
phenomena which they exhibit1 and which 
are partly physical phenomena1 namely   
the impressions made on our senses by   
their bodily form and structure1 and    
partly mental phenomena1 namely the     
sentient and intellectual life which    
they have of their own4 ,all this is    
understood when we utter the word man1  
by any one to whom the meaning of the   
word is known4 ,now1 when we say1 ,man  
is mortal1 we mean that wherever these  
various physical and mental phenomena   
are all found1 there we have assurance  
that the other physical and mental      
phenomenon1 called death1 will not fail 
to take place4 ,the proposition does not
 affirm when2 for the connotation of the
 word mortal goes no farther than to the
 occurrence of the phenomenon at some   
time or other1 leaving the precise time 
undecided4    #e4 ,we have already      
proceeded far enough1 not only to       
demonstrate the error of ,hobbes1 but to

 ascertain the real import of by far the
 most numerous class of propositions4   
,the object of belief in a proposition1 
when it asserts anything more than the  
meaning of words1 is generally1 as in   
the cases which we have examined1 either
 the co-existence or the sequence of two
 phenomena4 ,at the very commencement of
 our inquiry1 we found that every act of
 belief implied two ,things3 we have now
 ascertained what1 in the most frequent 
case1 these two things are1 namely two  
,phenomena1 in other words1 two states  
of consciousness2 and what it is which  
the proposition affirms 7or denies7 to  
subsist between them1 namely either     
succession or co-existence4 ,and this   
case includes innumerable instances     
which no one1 previous to reflection1   
would think of referring to it4 ,take   
the following example3 ,a generous      
person is worthy of honour4 ,who would  
expect to recognise here a case of      
co-existence between phenomena8 ,but so 
it is4 ,the attribute which causes a    

person to be termed generous1 is        
ascribed to him on the ground of states 
of his mind1 and particulars of his     
conduct3 both are phenomena3 the former 
are facts of internal consciousness2 the
 latter1 so far as distinct from the    
former1 are physical facts1 or          
perceptions of the senses4 ,worthy of   
honour admits of a similar analysis4    
,honour1 as here used1 means a state of 
approving and admiring emotion1 followed
 on occasion by corresponding outward   
acts4 ,worthy of honour connotes all    
this1 together with our approval of the 
act of showing honour4 ,all these are   
phenomena2 states of internal           
consciousness1 accompanied or followed  
by physical facts4 ,when we say1 ,a     
generous person is worthy of honour1 we 
affirm co-existence between the two     
complicated phenomena connoted by the   
two terms respectively4 ,we affirm1 that
 wherever and whenever the inward       
feelings and outward facts implied in   
the word generosity have place1 then and

 there the existence and manifestation  
of an inward feeling1 honour1 would be  
followed in our minds by another inward 
feeling1 approval4  ,after the analysis1
 in a former chapter1 of the import of  
names1 many examples are not needed to  
illustrate the import of propositions4  
,when there is any obscurity1 or        
difficulty1 it does not lie in the      
meaning of the proposition1 but in the  
meaning of the names which compose it2  
in the extremely complicated connotation
 of many words2 the immense multitude   
and prolonged series of facts which     
often constitute the phenomenon connoted
 by a name4 ,but where it is seen what  
the phenomenon is1 there is seldom any  
difficulty in seeing that the assertion 
conveyed by the proposition is1 the     
co-existence of one such phenomenon with
 another2 or the succession of one such 
phenomenon to another3 their            
conjunction1 in short1 so that where the
 one is found1 we may calculate on      
finding both4  ,this1 however1 though   

the most common1 is not the only meaning
 which propositions are ever intended to
 convey4 ,in the first place1 sequences 
and co-existences are not only asserted 
respecting ,phenomena2 we make          
propositions also respecting those      
hidden causes of phenomena1 which are   
named substances and attributes4 ,a     
substance1 however1 being to us nothing 
but either that which causes1 or that   
which is conscious of1 phenomena2 and   
the same being true1 mutatis mutandis1  
of attributes2 no assertion can be made1
 at least with a meaning1 concerning    
these unknown and unknowable entities1  
except in virtue of the ,phenomena by   
which alone they manifest themselves to 
our faculties4 ,when we say1 ,socrates  
was cotemporary with the ,peloponnesian 
war1 the foundation of this assertion1  
as of all assertions concerning         
substances1 is an assertion concerning  
the phenomena which they                
exhibit1--namely1 that the series of    
facts by which ,socrates manifested     

himself to mankind1 and the series of   
mental states which constituted his     
sentient existence1 went on             
simultaneously with the series of facts 
known by the name of the ,peloponnesian 
war4 ,still1 the proposition does not   
assert that alone2 it asserts that the  
,thing in itself1 the noumenon          
,socrates1 was existing1 and doing or   
experiencing those various facts during 
the same time4 ,co-existence and        
sequence1 therefore1 may be affirmed or 
denied not only between phenomena1 but  
between noumena1 or between a noumenon  
and phenomena4 ,and both of noumena and 
of phenomena we may affirm simple       
existence4 ,but what is a noumenon8 ,an 
unknown cause4 ,in affirming1 therefore1
 the existence of a noumenon1 we affirm 
causation4 ,here1 therefore1 are two    
additional kinds of fact1 capable of    
being asserted in a proposition4        
,besides the propositions which assert  
,sequence or ,coexistence1 there are    
some which assert simple ,existence2 and

 others assert ,causation1 which1       
subject to the explanations which will  
follow in the ,third ,book1 must be     
considered provisionally as a distinct  
and peculiar kind of assertion4    #f4  
,to these four kinds of matter-of-fact  
or assertion1 must be added a fifth1    
,resemblance4 ,this was a species of    
attribute which we found it impossible  
to analyse2 for which no fundamentum1   
distinct from the objects themselves1   
could be assigned4 ,besides propositions
 which assert a sequence or co-existence
 between two phenomena1 there are       
therefore also propositions which assert
 resemblance between them3 as1 ,this    
colour is like that colour2--,the heat  
of to-day is equal to the heat of       
yesterday4 ,it is true that such an     
assertion might with some plausibility  
be brought within the description of an 
affirmation of sequence1 by considering 
it as an assertion that the simultaneous
 contemplation of the two colours is    
followed by a specific feeling termed   

the feeling of resemblance4 ,but there  
would be nothing gained by encumbering  
ourselves1 especially in this place1    
with a generalization which may be      
looked upon as strained4 ,logic does not
 undertake to analyse mental facts into 
their ultimate elements4 ,resemblance   
between two phenomena is more           
intelligible in itself than any         
explanation could make it1 and under any
 classification must remain specifically
 distinct from the ordinary cases of    
sequence and co-existence4  ,it is      
sometimes said1 that all propositions   
whatever1 of which the predicate is a   
general name1 do1 in point of fact1     
affirm or deny resemblance4 ,all such   
propositions affirm that a thing belongs
 to a class2 but things being classed   
together according to their resemblance1
 everything is of course classed with   
the things which it is supposed to      
resemble most2 and thence1 it may be    
said1 when we affirm that ,gold is a    
metal1 or that ,socrates is a man1 the  

affirmation intended is1 that gold      
resembles other metals1 and ,socrates   
other men1 more nearly than they        
resemble the objects contained in any   
other of the classes co-ordinate with   
these4  ,there is some slight degree of 
foundation for this remark1 but no more 
than a slight degree4 ,the arrangement  
of things into classes1 such as the     
class metal1 or the class man1 is       
grounded indeed on a resemblance among  
the things which are placed in the same 
class1 but not on a mere general        
resemblance3 the resemblance it is      
grounded on consists in the possession  
by all those things1 of certain common  
peculiarities2 and those peculiarities  
it is which the terms connote1 and which
 the propositions consequently assert2  
not the resemblance3 for though when ,i 
say1 ,gold is a metal1 ,i say by        
implication that if there be any other  
metals it must resemble them1 yet if    
there were no other metals ,i might     
still assert the proposition with the   

same meaning as at present1 namely1 that
 gold has the various properties implied
 in the word metal2 just as it might be 
said1 ,christians are men1 even if there
 were no men who were not ,christians4  
,propositions1 therefore1 in which      
objects are referred to a class because 
they possess the attributes constituting
 the class1 are so far from asserting   
nothing but resemblance1 that they do   
not1 properly speaking1 assert          
resemblance at all4  ,but we remarked   
some time ago 7and the reasons of the   
remark will be more fully entered into  
in a subsequent ,book#bb7 that there is 
sometimes a convenience in extending the
 boundaries of a class so as to include 
things which possess in a very inferior 
degree1 if in any1 some of the          
characteristic properties of the        
class1--provided they resemble that     
class more than any other1 insomuch that
 the general propositions which are true
 of the class1 will be nearer to being  
true of those things than any other     

equally general propositions4 ,for      
instance1 there are substances called   
metals which have very few of the       
properties by which metals are commonly 
recognised2 and almost every great      
family of plants or animals has a few   
anomalous genera or species on its      
borders1 which are admitted into it by a
 sort of courtesy1 and concerning which 
it has been matter of discussion to what
 family they properly belonged4 ,now    
when the class-name is predicated of any
 object of this description1 we do1 by  
so predicating it1 affirm resemblance   
and nothing more4 ,and in order to be   
scrupulously correct it ought to be     
said1 that in every case in which we    
predicate a general name1 we affirm1 not
 absolutely that the object possesses   
the properties designated by the name1  
but that it either possesses those      
properties1 or if it does not1 at any   
rate resembles the things which do so1  
more than it resembles any other things4
 ,in most cases1 however1 it is         

unnecessary to suppose any such         
alternative1 the latter of the two      
grounds being very seldom that on which 
the assertion is made3 and when it is1  
there is generally some slight          
difference in the form of the           
expression1 as1 ,this species 7or genus7
 is considered1 or may be ranked1 as    
belonging to such and such a family3 we 
should hardly say positively that it    
does belong to it1 unless it possessed  
unequivocally the properties of which   
the class-name is scientifically        
significant4  ,there is still another   
exceptional case1 in which1 though the  
predicate is the name of a class1 yet in
 predicating it we affirm nothing but   
resemblance1 the class being founded not
 on resemblance in any given particular1
 but on general unanalysable            
resemblance4 ,the classes in question   
are those into which our simple         
sensations1 or other simple feelings1   
are divided4 ,sensations of white1 for  
instance1 are classed together1 not     

because we can take them to pieces1 and 
say they are alike in this1 and not     
alike in that1 but because we feel them 
to be alike altogether1 though in       
different degrees4 ,when1 therefore1 ,i 
say1 ,the colour ,i saw yesterday was a 
white colour1 or1 ,the sensation ,i feel
 is one of tightness1 in both cases the 
attribute ,i affirm of the colour or of 
the other sensation is mere             
resemblance--simple likeness to         
sensations which ,i have had before1 and
 which have had those names bestowed    
upon them4 ,the names of feelings1 like 
other concrete general names1 are       
connotative2 but they connote a mere    
resemblance4 ,when predicated of any    
individual feeling1 the information they
 convey is that of its likeness to the  
other feelings which we have been       
accustomed to call by the same name4    
,thus much may suffice in illustration  
of the kind of propositions in which the
 matter-of-fact asserted 7or denied7 is 
simple ,resemblance4  ,existence1       

,coexistence1 ,sequence1 ,causation1    
,resemblance3 one or other of these is  
asserted 7or denied7 in every           
proposition which is not merely verbal4 
,this five-fold division is an          
exhaustive classification of            
matters-of-fact2 of all things that can 
be believed1 or tendered for belief2 of 
all questions that can be propounded1   
and all answers that can be returned to 
them4 ,instead of ,coexistence and      
,sequence1 we shall sometimes say1 for  
greater particularity1 ,order in ,place1
 and ,order in ,time3 ,order in ,place  
being the specific mode of coexistence1 
not necessary to be more particularly   
analysed here2 while the mere fact of   
coexistence1 or simultaneousness1 may be
 classed1 together with ,sequence1 under
 the head of ,order in ,time4    #g4 ,in
 the foregoing inquiry into the import  
of ,propositions1 we have thought it    
necessary to analyse directly those     
alone1 in which the terms of the        
proposition 7or the predicate at least7 

are concrete terms4 ,but1 in doing so1  
we have indirectly analysed those in    
which the terms are abstract4 ,the      
distinction between an abstract term and
 its corresponding concrete1 does not   
turn upon any difference in what they   
are appointed to signify2 for the real  
signification of a concrete general name
 is1 as we have so often said1 its      
connotation2 and what the concrete term 
connotes1 forms the entire meaning of   
the abstract name4 ,since there is      
nothing in the import of an abstract    
name which is not in the import of the  
corresponding concrete1 it is natural to
 suppose that neither can there be      
anything in the import of a proposition 
of which the terms are abstract1 but    
what there is in some proposition which 
can be framed of concrete terms4  ,and  
this presumption a closer examination   
will confirm4 ,an abstract name is the  
name of an attribute1 or combination of 
attributes4 ,the corresponding concrete 
is a name given to things1 because of1  

and in order to express1 their          
possessing that attribute1 or that      
combination of attributes4 ,when1       
therefore1 we predicate of anything a   
concrete name1 the attribute is what we 
in reality predicate of it4 ,but it has 
now been shown that in all propositions 
of which the predicate is a concrete    
name1 what is really predicated is one  
of five things3 ,existence1             
,coexistence1 ,causation1 ,sequence1 or 
,resemblance4 ,an attribute1 therefore1 
is necessarily either an existence1 a   
coexistence1 a causation1 a sequence1 or
 a resemblance4 ,when a proposition     
consists of a subject and predicate     
which are abstract terms1 it consists of
 terms which must necessarily signify   
one or other of these things4 ,when we  
predicate of anything an abstract name1 
we affirm of the thing that it is one or
 other of these five things2 that it is 
a case of ,existence1 or of             
,coexistence1 or of ,causation1 or of   
,sequence1 or of ,resemblance4  ,it is  

impossible to imagine any proposition   
expressed in abstract terms1 which      
cannot be transformed into a precisely  
equivalent proposition in which the     
terms are concrete2 namely1 either the  
concrete names which connote the        
attributes themselves1 or the names of  
the fundamenta of those attributes2 the 
facts or phenomena on which they are    
grounded4 ,to illustrate the latter     
case1 let us take this proposition1 of  
which the subject only is an abstract   
name1 ,thoughtlessness is dangerous4    
,thoughtlessness is an attribute1       
grounded on the facts which we call     
thoughtless actions2 and the proposition
 is equivalent to this1 ,thoughtless    
actions are dangerous4 ,in the next     
example the predicate as well as the    
subject are abstract names3 ,whiteness  
is a colour2 or ,the colour of snow is a
 whiteness4 ,these attributes being     
grounded on sensations1 the equivalent  
propositions in the concrete would be1  
,the sensation of white is one of the   

sensations called those of colour1--,the
 sensation of sight1 caused by looking  
at snow1 is one of the sensations called
 sensations of white4 ,in these         
propositions1 as we have before seen1   
the matter-of-fact asserted is a        
,resemblance4 ,in the following         
examples1 the concrete terms are those  
which directly correspond to the        
abstract names2 connoting the attribute 
which these denote4 ,prudence is a      
virtue3 this may be rendered1 ,all      
prudent persons1 in so far as prudent1  
are virtuous3 ,courage is deserving of  
honour1 thus1 ,all courageous persons   
are deserving of honour in so far as    
they are courageous3 which is equivalent
 to this--,all courageous persons       
deserve an addition to the honour1 or a 
diminution of the disgrace1 which would 
attach to them on other grounds4  ,in   
order to throw still further light upon 
the import of propositions of which the 
terms are abstract1 we will subject one 
of the examples given above to a minuter

 analysis4 ,the proposition we shall    
select is the following3--,prudence is a
 virtue4 ,let us substitute for the word
 virtue an equivalent but more definite 
expression1 such as a mental quality    
beneficial to society1 or a mental      
quality pleasing to ,god1 or whatever   
else we adopt as the definition of      
virtue4 ,what the proposition asserts is
 a sequence1 accompanied with causation2
 namely1 that benefit to society1 or    
that the approval of ,god1 is consequent
 on1 and caused by1 prudence4 ,here is a
 sequence2 but between what8 ,we        
understand the consequent of the        
sequence1 but we have yet to analyse the
 antecedent4 ,prudence is an attribute2 
and1 in connexion with it1 two things   
besides itself are to be considered2    
prudent persons1 who are the subjects of
 the attribute1 and prudential conduct1 
which may be called the foundation of   
it4 ,now is either of these the         
antecedent8 and1 first1 is it meant1    
that the approval of ,god1 or benefit to

 society1 is attendant upon all prudent 
persons8 ,no2 except in so far as they  
are prudent2 for prudent persons who are
 scoundrels can seldom on the whole be  
beneficial to society1 nor can they be  
acceptable to a good being4 ,is it upon 
prudential conduct1 then1 that divine   
approbation and benefit to mankind are  
supposed to be invariably consequent8   
,neither is this the assertion meant1   
when it is said that prudence is a      
virtue2 except with the same reservation
 as before1 and for the same reason1    
namely1 that prudential conduct1        
although in so far as it is prudential  
it is beneficial to society1 may yet1 by
 reason of some other of its qualities1 
be productive of an injury outweighing  
the benefit1 and deserve a displeasure  
exceeding the approbation which would be
 due to the prudence4 ,neither the      
substance1 therefore1 7viz4 the person17
 nor the phenomenon1 7the conduct17 is  
an antecedent on which the other term of
 the sequence is universally consequent4

 ,but the proposition1 ,prudence is a   
virtue1 is an universal proposition4    
,what is it1 then1 upon which the       
proposition affirms the effects in      
question to be universally consequent8  
,upon that in the person1 and in the    
conduct1 which causes them to be called 
prudent1 and which is equally in them   
when the action1 though prudent1 is     
wicked2 namely1 a correct foresight of  
consequences1 a just estimation of their
 importance to the object in view1 and  
repression of any unreflecting impulse  
at variance with the deliberate purpose4
 ,these1 which are states of the        
person's mind1 are the real antecedent  
in the sequence1 the real cause in the  
causation1 asserted by the proposition4 
,but these are also the real ground1 or 
foundation1 of the attribute ,prudence2 
since wherever these states of mind     
exist we may predicate prudence1 even   
before we know whether any conduct has  
followed4 ,and in this manner every     
assertion respecting an attribute1 may  

be transformed into an assertion exactly
 equivalent respecting the fact or      
phenomenon which is the ground of the   
attribute4 ,and no case can be assigned1
 where that which is predicated of the  
fact or phenomenon1 does not belong to  
one or other of the five species        
formerly enumerated3 it is either simple
 ,existence1 or it is some ,sequence1   
,coexistence1 ,causation1 or            
,resemblance4  ,and as these five are   
the only things which can be affirmed1  
so are they the only things which can be
 denied4 ,no horses are web-footed      
denies that the attributes of a horse   
ever coexist with web-feet4 ,it is      
scarcely necessary to apply the same    
analysis to ,particular affirmations and
 negations4 ,some birds are web-footed1 
affirms that1 with the attributes       
connoted by bird1 the phenomenon        
web-feet is sometimes co-existent3 ,some
 birds are not web-footed1 asserts that 
there are other instances in which this 
coexistence does not have place4 ,any   

further explanation of a thing which1 if
 the previous exposition has been       
assented to1 is so obvious1 may here be 
spared4     ,,chapter ,,vi4  ,,of       
,,propositions ,,merely ,,verbal4    #a4
 ,as a preparation for the inquiry which
 is the proper object of ,logic1 namely1
 in what manner propositions are to be  
proved1 we have found it necessary to   
inquire what they contain which         
requires1 or is susceptible of1 proof2  
or 7which is the same thing7 what they  
assert4 ,in the course of this          
preliminary investigation into the      
import of ,propositions1 we examined the
 opinion of the ,conceptualists1 that a 
proposition is the expression of a      
relation between two ideas2 and the     
doctrine of the ,nominalists1 that it is
 the expression of an agreement or      
disagreement between the meanings of two
 names4 ,we decided that1 as general    
theories1 both of these are erroneous2  
and that1 though propositions may be    
made both respecting names and          

respecting ideas1 neither the one nor   
the other are the subject-matter of     
,propositions considered generally4 ,we 
then examined the different kinds of    
,propositions1 and found that1 with the 
exception of those which are merely     
verbal1 they assert five different kinds
 of matters of fact1 namely1 ,existence1
 ,order in ,place1 ,order in ,time1     
,causation1 and ,resemblance2 that in   
every proposition one of these five is  
either affirmed1 or denied1 of some fact
 or phenomenon1 or of some object the   
unknown source of a fact or phenomenon4 
,in distinguishing1 however1 the        
different kinds of matters of fact      
asserted in propositions1 we reserved   
one class of propositions1 which do not 
relate to any matter of fact1 in the    
proper sense of the term1 at all1 but to
 the meaning of names4 ,since names and 
their signification are entirely        
arbitrary1 such propositions are not1   
strictly speaking1 susceptible of truth 
or falsity1 but only of conformity or   

disconformity to usage or convention2   
and all the proof they are capable of1  
is proof of usage2 proof that the words 
have been employed by others in the     
acceptation in which the speaker or     
writer desires to use them4 ,these      
propositions occupy1 however1 a         
conspicuous place in philosophy2 and    
their nature and characteristics are of 
as much importance in logic1 as those of
 any of the other classes of            
propositions previously adverted to4    
,if all propositions respecting the     
signification of words were as simple   
and unimportant as those which served us
 for examples when examining ,hobbes'   
theory of predication1 viz4 those of    
which the subject and predicate are     
proper names1 and which assert only that
 those names have1 or that they have    
not1 been conventionally assigned to the
 same individual1 there would be little 
to attract to such propositions the     
attention of philosophers4 ,but the     
class of merely verbal propositions     

embraces not only much more than these1 
but much more than any propositions     
which at first sight present themselves 
as verbal2 comprehending a kind of      
assertions which have been regarded not 
only as relating to things1 but as      
having actually a more intimate relation
 with them than any other propositions  
whatever4 ,the student in philosophy    
will perceive that ,i allude to the     
distinction on which so much stress was 
laid by the schoolmen1 and which has    
been retained either under the same or  
under other names by most metaphysicians
 to the present day1 viz4 between what  
were called essential1 and what were    
called accidental1 propositions1 and    
between essential and accidental        
properties or attributes4    #b4 ,almost
 all metaphysicians prior to ,locke1 as 
well as many since his time1 have made a
 great mystery of ,essential            
,predication1 and of predicates which   
are said to be of the essence of the    
subject4 ,the essence of a thing1 they  

said1 was that without which the thing  
could neither be1 nor be conceived to   
be4 ,thus1 rationality was of the       
essence of man1 because without         
rationality1 man could not be conceived 
to exist4 ,the different attributes     
which made up the essence of the thing  
were called its essential properties2   
and a proposition in which any of these 
were predicated of it was called an     
,essential ,proposition1 and was        
considered to go deeper into the nature 
of the thing1 and to convey more        
important information respecting it1    
than any other proposition could do4    
,all properties1 not of the essence of  
the thing1 were called its accidents2   
were supposed to have nothing at all1 or
 nothing comparatively1 to do with its  
inmost nature2 and the propositions in  
which any of these were predicated of it
 were called ,accidental ,propositions4 
,a connexion may be traced between this 
distinction1 which originated with the  
schoolmen1 and the well-known dogmas of 

substanti secund or general substances1 
and substantial forms1 doctrines which  
under varieties of language pervaded    
alike the ,aristotelian and the         
,platonic schools1 and of which more of 
the spirit has come down to modern times
 than might be conjectured from the     
disuse of the phraseology4 ,the false   
views of the nature of classification   
and generalization which prevailed among
 the schoolmen1 and of which these      
dogmas were the technical expression1   
afford the only explanation which can be
 given of their having misunderstood the
 real nature of those ,essences which   
held so conspicuous a place in their    
philosophy4 ,they said1 truly1 that man 
cannot be conceived without rationality4
 ,but though man cannot1 a being may be 
conceived exactly like a man in all     
points except that one quality1 and     
those others which are the conditions or
 consequences of it4 ,all therefore     
which is really true in the assertion   
that man cannot be conceived without    

rationality1 is only1 that if he had not
 rationality1 he would not be reputed a 
man4 ,there is no impossibility in      
conceiving the thing1 nor1 for aught we 
know1 in its existing3 the impossibility
 is in the conventions of language1     
which will not allow the thing1 even if 
it exist1 to be called by the name which
 is reserved for rational beings4       
,rationality1 in short1 is involved in  
the meaning of the word man3 is one of  
the attributes connoted by the name4    
,the essence of man1 simply means the   
whole of the attributes connoted by the 
word2 and any one of those attributes   
taken singly1 is an essential property  
of man4  ,but these reflections1 so easy
 to us1 would have been difficult to    
persons who thought1 as most of the     
later ,aristotelians did1 that objects  
were made what they were called1 that   
gold 7for instance7 was made gold1 not  
by the possession of certain properties 
to which mankind have chosen to attach  
that name1 but by participation in the  

nature of a certain general substance1  
called gold in general1 which substance1
 together with all the properties that  
belonged to it1 inhered in every        
individual piece of gold4#bc ,as they   
did not consider these universal        
substances to be attached to all general
 names1 but only to some1 they thought  
that an object borrowed only a part of  
its properties from an universal        
substance1 and that the rest belonged to
 it individually3 the former they called
 its essence1 and the latter its        
accidents4 ,the scholastic doctrine of  
essences long survived the theory on    
which it rested1 that of the existence  
of real entities corresponding to       
general terms2 and it was reserved for  
,locke at the end of the seventeenth    
century1 to convince philosophers that  
the supposed essences of classes were   
merely the signification of their names2
 nor1 among the signal services which   
his writings rendered to philosophy1 was
 there one more needful or more         

valuable4  ,now1 as the most familiar of
 the general names by which an object is
 designated usually connotes not one    
only1 but several attributes of the     
object1 each of which attributes        
separately forms also the bond of union 
of some class1 and the meaning of some  
general name2 we may predicate of a name
 which connotes a variety of attributes1
 another name which connotes only one of
 these attributes1 or some smaller      
number of them than all4 ,in such cases1
 the universal affirmative proposition  
will be true2 since whatever possesses  
the whole of any set of attributes1 must
 possess any part of that same set4 ,a  
proposition of this sort1 however1      
conveys no information to any one who   
previously understood the whole meaning 
of the terms4 ,the propositions1 ,every 
man is a corporeal being1 ,every man is 
a living creature1 ,every man is        
rational1 convey no knowledge to any one
 who was already aware of the entire    
meaning of the word man1 for the meaning

 of the word includes all this3 and that
 every man has the attributes connoted  
by all these predicates1 is already     
asserted when he is called a man4 ,now1 
of this nature are all the propositions 
which have been called essential4 ,they 
are1 in fact1 identical propositions4   
,it is true that a proposition which    
predicates any attribute1 even though it
 be one implied in the name1 is in most 
cases understood to involve a tacit     
assertion that there exists a thing     
corresponding to the name1 and          
possessing the attributes connoted by   
it2 and this implied assertion may      
convey information1 even to those who   
understood the meaning of the name4 ,but
 all information of this sort1 conveyed 
by all the essential propositions of    
which man can be made the subject1 is   
included in the assertion1 ,men exist4  
,and this assumption of real existence  
is1 after all1 the result of an         
imperfection of language4 ,it arises    
from the ambiguity of the copula1 which1

 in addition to its proper office of a  
mark to show that an assertion is made1 
is also1 as formerly remarked1 a        
concrete word connoting existence4 ,the 
actual existence of the subject of the  
proposition is therefore only           
apparently1 not really1 implied in the  
predication1 if an essential one3 we may
 say1 ,a ghost is a disembodied spirit1 
without believing in ghosts4 ,but an    
accidental1 or non-essential1           
affirmation1 does imply the real        
existence of the subject1 because in the
 case of a non-existent subject there is
 nothing for the proposition to assert4 
,such a proposition as1 ,the ghost of a 
murdered person haunts the couch of the 
murderer1 can only have a meaning if    
understood as implying a belief in      
ghosts2 for since the signification of  
the word ghost implies nothing of the   
kind1 the speaker either means nothing1 
or means to assert a thing which he     
wishes to be believed to have really    
taken place4  ,it will be hereafter seen

 that when any important consequences   
seem to follow1 as in mathematics1 from 
an essential proposition1 or1 in other  
words1 from a proposition involved in   
the meaning of a name1 what they really 
flow from is the tacit assumption of the
 real existence of the objects so named4
 ,apart from this assumption of real    
existence1 the class of propositions in 
which the predicate is of the essence of
 the subject 7that is1 in which the     
predicate connotes the whole or part of 
what the subject connotes1 but nothing  
besides7 answer no purpose but that of  
unfolding the whole or some part of the 
meaning of the name1 to those who did   
not previously know it4 ,accordingly1   
the most useful1 and in strictness the  
only useful kind of essential           
propositions1 are ,definitions3 which1  
to be complete1 should unfold the whole 
of what is involved in the meaning of   
the word defined2 that is1 7when it is a
 connotative word17 the whole of what it
 connotes4 ,in defining a name1 however1

 it is not usual to specify its entire  
connotation1 but so much only as is     
sufficient to mark out the objects      
usually denoted by it from all other    
known objects4 ,and sometimes a merely  
accidental property1 not involved in the
 meaning of the name1 answers this      
purpose equally well4 ,the various kinds
 of definition which these distinctions 
give rise to1 and the purposes to which 
they are respectively subservient1 will 
be minutely considered in the proper    
place4    #c4 ,according to the above   
view of essential propositions1 no      
proposition can be reckoned such which  
relates to an individual by name1 that  
is1 in which the subject is a proper    
name4 ,individuals have no essences4    
,when the schoolmen talked of the       
essence of an individual1 they did not  
mean the properties implied in its name1
 for the names of individuals imply no  
properties4 ,they regarded as of the    
essence of an individual1 whatever was  
of the essence of the species in which  

they were accustomed to place that      
individual2 i4e4 of the class to which  
it was most familiarly referred1 and to 
which1 therefore1 they conceived that it
 by nature belonged4 ,thus1 because the 
proposition ,man is a rational being1   
was an essential proposition1 they      
affirmed the same thing of the          
proposition1 ,julius ,csar is a rational
 being4 ,this followed very naturally if
 genera and species were to be          
considered as entities1 distinct from1  
but inhering in1 the individuals        
composing them4 ,if man was a substance 
inhering in each individual man1 the    
essence of man 7whatever that might     
mean7 was naturally supposed to         
accompany it2 to inhere in ,john        
,thompson1 and to form the common       
essence of ,thompson and ,julius ,csar4 
,it might then be fairly said1 that     
rationality1 being of the essence of    
,man1 was of the essence also of        
,thompson4 ,but if ,man altogether be   
only the individual men and a name      

bestowed upon them in consequence of    
certain common properties1 what becomes 
of ,john ,thompson's essence8  ,a       
fundamental error is seldom expelled    
from philosophy by a single victory4 ,it
 retreats slowly1 defends every inch of 
ground1 and often1 after it has been    
driven from the open country1 retains a 
footing in some remote fastness4 ,the   
essences of individuals were an         
unmeaning figment arising from a        
misapprehension of the essences of      
classes1 yet even ,locke1 when he       
extirpated the parent error1 could not  
shake himself free from that which was  
its fruit4 ,he distinguished two sorts  
of essences1 ,real and ,nominal4 ,his   
nominal essences were the essences of   
classes1 explained nearly as we have now
 explained them4 ,nor is anything       
wanting to render the third book of     
,locke's ,essay a nearly unexceptionable
 treatise on the connotation of names1  
except to free its language from the    
assumption of what are called ,abstract 

,ideas1 which unfortunately is involved 
in the phraseology1 though not          
necessarily connected with the thoughts 
contained in that immortal ,third       
,book4#bd ,but1 besides nominal         
essences1 he admitted real essences1 or 
essences of individual objects1 which he
 supposed to be the causes of the       
sensible properties of those objects4   
,we know not 7said he7 what these are2  
7and this acknowledgment rendered the   
fiction comparatively innocuous27 but if
 we did1 we could1 from them alone1     
demonstrate the sensible properties of  
the object1 as the properties of the    
triangle are demonstrated from the      
definition of the triangle4 ,i shall    
have occasion to revert to this theory  
in treating of ,demonstration1 and of   
the conditions under which one property 
of a thing admits of being demonstrated 
from another property4 ,it is enough    
here to remark that1 according to this  
definition1 the real essence of an      
object has1 in the progress of physics1 

come to be conceived as nearly          
equivalent1 in the case of bodies1 to   
their corpuscular structure3 what it is 
now supposed to mean in the case of any 
other entities1 ,i would not take upon  
myself to define4    #d4 ,an essential  
proposition1 then1 is one which is      
purely verbal2 which asserts of a thing 
under a particular name1 only what is   
asserted of it in the fact of calling it
 by that name2 and which therefore      
either gives no information1 or gives it
 respecting the name1 not the thing4    
,non-essential1 or accidental           
propositions1 on the contrary1 may be   
called ,real ,propositions1 in          
opposition to ,verbal4 ,they predicate  
of a thing some fact not involved in the
 signification of the name by which the 
proposition speaks of it2 some attribute
 not connoted by that name4 ,such are   
all propositions concerning things      
individually designated1 and all general
 or particular propositions in which the
 predicate connotes any attribute not   

connoted by the subject4 ,all these1 if 
true1 add to our knowledge3 they convey 
information1 not already involved in the
 names employed4 ,when ,i am told that  
all1 or even that some objects1 which   
have certain qualities1 or which stand  
in certain relations1 have also certain 
other qualities1 or stand in certain    
other relations1 ,i learn from this     
proposition a new fact2 a fact not      
included in my knowledge of the meaning 
of the words1 nor even of the existence 
of ,things answering to the             
signification of those words4 ,it is    
this class of propositions only which   
are in themselves instructive1 or from  
which any instructive propositions can  
be inferred4#be  ,nothing has probably  
contributed more to the opinion so long 
prevalent of the futility of the school 
logic1 than the circumstance that almost
 all the examples used in the common    
school books to illustrate the doctrine 
of predication and that of the          
syllogism1 consist of essential         

propositions4 ,they were usually taken  
either from the branches or from the    
main trunk of the ,predicamental ,tree1 
which included nothing but what was of  
the essence of the species3 ,omne corpus
 est substantia1 ,omne animal est       
corpus1 ,omnis homo est corpus1 ,omnis  
homo est animal1 ,omnis homo est        
rationalis1 and so forth4 ,it is far    
from wonderful that the syllogistic art 
should have been thought to be of no use
 in assisting correct reasoning1 when   
almost the only propositions which1 in  
the hands of its professed teachers1 it 
was employed to prove1 were such as     
every one assented to without proof the 
moment he comprehended the meaning of   
the words2 and stood exactly on a level1
 in point of evidence1 with the premises
 from which they were drawn4 ,i have1   
therefore1 throughout this work1 avoided
 the employment of essential            
propositions as examples1 except where  
the nature of the principle to be       
illustrated specifically required them4 

#e4 ,with respect to propositions which 
do convey information--which assert     
something of a ,thing1 under a name that
 does not already presuppose what is    
about to be asserted2 there are two     
different aspects in which these1 or    
rather such of them as are general      
propositions1 may be considered3 we may 
either look at them as portions of      
speculative truth1 or as memoranda for  
practical use4 ,according as we consider
 propositions in one or the other of    
these lights1 their import may be       
conveniently expressed in one or in the 
other of two formulas4  ,according to   
the formula which we have hitherto      
employed1 and which is best adapted to  
express the import of the proposition as
 a portion of our theoretical knowledge1
 ,all men are mortal1 means that the    
attributes of man are always accompanied
 by the attribute mortality3 ,no men are
 gods1 means that the attributes of man 
are never accompanied by the attributes1
 or at least never by all the           

attributes1 signified by the word god4  
,but when the proposition is considered 
as a memorandum for practical use1 we   
shall find a different mode of          
expressing the same meaning better      
adapted to indicate the office which the
 proposition performs4 ,the practical   
use of a proposition is1 to apprise or  
remind us what we have to expect1 in any
 individual case which comes within the 
assertion contained in the proposition4 
,in reference to this purpose1 the      
proposition1 ,all men are mortal1 means 
that the attributes of man are evidence 
of1 are a mark of1 mortality2 an        
indication by which the presence of that
 attribute is made manifest4 ,no men are
 gods1 means that the attributes of man 
are a mark or evidence that some or all 
of the attributes understood to belong  
to a god are not there2 that where the  
former are1 we need not expect to find  
the latter4  ,these two forms of        
expression are at bottom equivalent2 but
 the one points the attention more      

directly to what a proposition means1   
the latter to the manner in which it is 
to be used4  ,now it is to be observed  
that ,reasoning 7the subject to which we
 are next to proceed7 is a process into 
which propositions enter not as ultimate
 results1 but as means to the           
establishment of other propositions4 ,we
 may expect1 therefore1 that the mode of
 exhibiting the import of a general     
proposition which shows it in its       
application to practical use1 will best 
express the function which propositions 
perform in ,reasoning4 ,and accordingly1
 in the theory of ,reasoning1 the mode  
of viewing the subject which considers a
 ,proposition as asserting that one fact
 or phenomenon is a mark or evidence of 
another fact or phenomenon1 will be     
found almost indispensable4 ,for the    
purposes of that ,theory1 the best mode 
of defining the import of a proposition 
is not the mode which shows most clearly
 what it is in itself1 but that which   
most distinctly suggests the manner in  

which it may be made available for      
advancing from it to other propositions4
     ,,chapter ,,vii4  ,,of ,,the       
,,nature ,,of ,,classification1 ,,and   
,,the ,,five ,,predicables4    #a4 ,in  
examining into the nature of general    
propositions1 we have adverted much less
 than is usual with logicians to the    
ideas of a ,class1 and ,classification2 
ideas which1 since the ,realist doctrine
 of ,general ,substances went out of    
vogue1 have formed the basis of almost  
every attempt at a philosophical theory 
of general terms and general            
propositions4 ,we have considered       
general names as having a meaning1 quite
 independently of their being the names 
of classes4 ,that circumstance is in    
truth accidental1 it being wholly       
immaterial to the signification of the  
name whether there are many objects1 or 
only one1 to which it happens to be     
applicable1 or whether there be any at  
all4 ,god is as much a general term to  
the ,christian or ,jew as to the        

,polytheist2 and dragon1 hippogriff1    
chimera1 mermaid1 ghost1 are as much so 
as if real objects existed1             
corresponding to those names4 ,every    
name the signification of which is      
constituted by attributes1 is           
potentially a name of an indefinite     
number of objects2 but it needs not be  
actually the name of any2 and if of any1
 it may be the name of only one4 ,as    
soon as we employ a name to connote     
attributes1 the things1 be they more or 
fewer1 which happen to possess those    
attributes1 are constituted ipso facto a
 class4 ,but in predicating the name we 
predicate only the attributes2 and the  
fact of belonging to a class does not1  
in many cases1 come into view at all4   
,although1 however1 ,predication does   
not presuppose ,classification1 and     
though the theory of ,names and of      
,propositions is not cleared up1 but    
only encumbered1 by intruding the idea  
of classification into it1 there is     
nevertheless a close connexion between  

,classification and the employment of   
,general ,names4 ,by every general name 
which we introduce1 we create a class1  
if there be any things1 real or         
imaginary1 to compose it2 that is1 any  
,things corresponding to the            
signification of the name4 ,classes1    
therefore1 mostly owe their existence to
 general language4 ,but general         
language1 also1 though that is not the  
most common case1 sometimes owes its    
existence to classes4 ,a general1 which 
is as much as to say a significant1     
name1 is indeed mostly introduced       
because we have a signification to      
express by it2 because we need a word by
 means of which to predicate the        
attributes which it connotes4 ,but it is
 also true that a name is sometimes     
introduced because we have found it     
convenient to create a class2 because we
 have thought it useful for the         
regulation of our mental operations1    
that a certain group of objects should  
be thought of together4 ,a naturalist1  

for purposes connected with his         
particular science1 sees reason to      
distribute the animal or vegetable      
creation into certain groups rather than
 into any others1 and he requires a name
 to bind1 as it were1 each of his groups
 together4 ,it must not however be      
supposed that such names1 when          
introduced1 differ in any respect1 as to
 their mode of signification1 from other
 connotative names4 ,the classes which  
they denote are1 as much as any other   
classes1 constituted by certain common  
attributes1 and their names are         
significant of those attributes1 and of 
nothing else4 ,the names of ,cuvier's   
classes and orders1 ,plantigrades1      
,digitigrades1 c41 are as much the      
expression of attributes as if those    
names had preceded1 instead of grown out
 of1 his classification of animals4 ,the
 only peculiarity of the case is1 that  
the convenience of classification was   
here the primary motive for introducing 
the names2 while in other cases the name

 is introduced as a means of            
predication1 and the formation of a     
class denoted by it is only an indirect 
consequence4  ,the principles which     
ought to regulate ,classification as a  
logical process subservient to the      
investigation of truth1 cannot be       
discussed to any purpose until a much   
later stage of our inquiry4 ,but1 of    
,classification as resulting from1 and  
implied in1 the fact of employing       
general language1 we cannot forbear to  
treat here1 without leaving the theory  
of general names and of their employment
 in predication1 mutilated and formless4
    #b4 ,this portion of the theory of  
general language is the subject of what 
is termed the doctrine of the           
,predicables2 a set of distinctions     
handed down from ,aristotle1 and his    
follower ,porphyry1 many of which have  
taken a firm root in scientific1 and    
some of them even in popular1           
phraseology4 ,the predicables are a     
five-fold division of ,general ,names1  

not grounded as usual on a difference in
 their meaning1 that is1 in the         
attribute which they connote1 but on a  
difference in the kind of class which   
they denote4 ,we may predicate of a     
thing five different varieties of       
class-name3--    ,a genus of the thing  
7,greek3 genos74   ,a species           
7,greek3 eidos74   ,a differentia       
7,greek3 diaphora74   ,a proprium       
7,greek3 idion74   ,an accidens         
7,greek3 symbebkos74  ,it is to be      
remarked of these distinctions1 that    
they express1 not what the predicate is 
in its own meaning1 but what relation it
 bears to the subject of which it       
happens on the particular occasion to be
 predicated4 ,there are not some names  
which are exclusively genera1 and others
 which are exclusively species1 or      
differenti2 but the same name is        
referred to one or another predicable1  
according to the subject of which it is 
predicated on the particular occasion4  
,animal1 for instance1 is a genus with  

respect to man1 or ,john2 a species with
 respect to ,substance1 or ,being4      
,rectangular is one of the ,differenti  
of a geometrical square2 it is merely   
one of the ,accidentia of the table at  
which ,i am writing4 ,the words genus1  
species1 c4 are therefore relative      
terms2 they are names applied to certain
 predicates1 to express the relation    
between them and some given subject3 a  
relation grounded1 as we shall see1 not 
on what the predicate connotes1 but on  
the class which it denotes1 and on the  
place which1 in some given              
classification1 that class occupies     
relatively to the particular subject4   
#c4 ,of these five names1 two1 ,genus   
and ,species1 are not only used by      
naturalists in a technical acceptation  
not precisely agreeing with their       
philosophical meaning1 but have also    
acquired a popular acceptation1 much    
more general than either4 ,in this      
popular sense any two classes1 one of   
which includes the whole of the other   

and more1 may be called a ,genus and a  
,species4 ,such1 for instance1 are      
,animal and ,man2 ,man and              
,mathematician4 ,animal is a ,genus2    
,man and ,brute are its two species2 or 
we may divide it into a greater number  
of species1 as man1 horse1 dog1 c4      
,biped1 or two-footed animal1 may also  
be considered a genus1 of which man and 
bird are two species4 ,taste is a genus1
 of which sweet taste1 sour taste1 salt 
taste1 c4 are species4 ,virtue is a     
genus2 justice1 prudence1 courage1      
fortitude1 generosity1 c4 are its       
species4  ,the same class which is a    
genus with reference to the sub-classes 
or species included in it1 may be itself
 a species with reference to a more     
comprehensive1 or1 as it is often       
called1 a superior genus4 ,man is a     
species with reference to animal1 but a 
genus with reference to the species     
,mathematician4 ,animal is a genus1     
divided into two species1 man and brute2
 but animal is also a species1 which1   

with another species1 vegetable1 makes  
up the genus1 organized being4 ,biped is
 a genus with reference to man and bird1
 but a species with respect to the      
superior genus1 animal4 ,taste is a     
genus divided into species1 but also a  
species of the genus sensation4 ,virtue1
 a genus with reference to justice1     
temperance1 c41 is one of the species of
 the genus1 mental quality4  ,in this   
popular sense the words ,genus and      
,species have passed into common        
discourse4 ,and it should be observed   
that in ordinary parlance1 not the name 
of the class1 but the class itself1 is  
said to be the genus or species2 not1 of
 course1 the class in the sense of each 
individual of the class1 but the        
individuals collectively1 considered as 
an aggregate whole2 the name by which   
the class is designated being then      
called not the genus or species1 but the
 generic or specific name4 ,and this is 
an admissible form of expression2 nor is
 it of any importance which of the two  

modes of speaking we adopt1 provided the
 rest of our language is consistent with
 it2 but1 if we call the class itself   
the genus1 we must not talk of          
predicating the genus4 ,we predicate of 
man the name mortal2 and by predicating 
the name1 we may be said1 in an         
intelligible sense1 to predicate what   
the name expresses1 the attribute       
mortality2 but in no allowable sense of 
the word predication do we predicate of 
man the class mortal4 ,we predicate of  
him the fact of belonging to the class4 
,by the ,aristotelian logicians1 the    
terms genus and species were used in a  
more restricted sense4 ,they did not    
admit every class which could be divided
 into other classes to be a genus1 or   
every class which could be included in a
 larger class to be a species4 ,animal  
was by them considered a genus2 man and 
brute co-ordinate species under that    
genus3 biped1 however1 would not have   
been admitted to be a genus with        
reference to man1 but a proprium or     

accidens only4 ,it was requisite1       
according to their theory1 that genus   
and species should be of the essence of 
the subject4 ,animal was of the essence 
of man2 biped was not4 ,and in every    
classification they considered some one 
class as the lowest or infima species4  
,man1 for instance1 was a lowest        
species4 ,any further divisions into    
which the class might be capable of     
being broken down1 as man into white1   
black1 and red man1 or into priest and  
layman1 they did not admit to be        
species4  ,it has been seen1 however1 in
 the preceding chapter1 that the        
distinction between the essence of a    
class1 and the attributes or properties 
which are not of its essence--a         
distinction which has given occasion to 
so much abstruse speculation1 and to    
which so mysterious a character was     
formerly1 and by many writers is still1 
attached1--amounts to nothing more than 
the difference between those attributes 
of the class which are1 and those which 

are not1 involved in the signification  
of the class-name4 ,as applied to       
individuals1 the word ,essence1 we      
found1 has no meaning1 except in        
connexion with the exploded tenets of   
the ,realists2 and what the schoolmen   
chose to call the essence of an         
individual1 was simply the essence of   
the class to which that individual was  
most familiarly referred4  ,is there no 
difference1 then1 save this merely      
verbal one1 between the classes which   
the schoolmen admitted to be genera or  
species1 and those to which they refused
 the title8 ,is it an error to regard   
some of the differences which exist     
among objects as differences in kind    
7genere or specie71 and others only as  
differences in the accidents8 ,were the 
schoolmen right or wrong in giving to   
some of the classes into which things   
may be divided1 the name of kinds1 and  
considering others as secondary         
divisions1 grounded on differences of a 
comparatively superficial nature8       

,examination will show that the         
,aristotelians did mean something by    
this distinction1 and something         
important2 but which1 being but         
indistinctly conceived1 was inadequately
 expressed by the phraseology of        
essences1 and the various other modes of
 speech to which they had recourse4     
#d4 ,it is a fundamental principle in   
logic1 that the power of framing classes
 is unlimited1 as long as there is any  
7even the smallest7 difference to found 
a distinction upon4 ,take any attribute 
whatever1 and if some things have it1   
and others have not1 we may ground on   
the attribute a division of all things  
into two classes2 and we actually do so1
 the moment we create a name which      
connotes the attribute4 ,the number of  
possible classes1 therefore1 is         
boundless2 and there are as many actual 
classes 7either of real or of imaginary 
things7 as there are general names1     
positive and negative together4  ,but if
 we contemplate any one of the classes  

so formed1 such as the class animal or  
plant1 or the class sulphur or          
phosphorus1 or the class white or red1  
and consider in what particulars the    
individuals included in the class differ
 from those which do not come within it1
 we find a very remarkable diversity in 
this respect between some classes and   
others4 ,there are some classes1 the    
things contained in which differ from   
other things only in certain particulars
 which may be numbered1 while others    
differ in more than can be numbered1    
more even than we need ever expect to   
know4 ,some classes have little or      
nothing in common to characterize them  
by1 except precisely what is connoted by
 the name3 white things1 for example1   
are not distinguished by any common     
properties1 except whiteness2 or if they
 are1 it is only by such as are in some 
way dependent on1 or connected with1    
whiteness4 ,but a hundred generations   
have not exhausted the common properties
 of animals or of plants1 of sulphur or 

of phosphorus2 nor do we suppose them to
 be exhaustible1 but proceed to new     
observations and experiments1 in the    
full confidence of discovering new      
properties which were by no means       
implied in those we previously knew4    
,while1 if any one were to propose for  
investigation the common properties of  
all things which are of the same colour1
 the same shape1 or the same specific   
gravity1 the absurdity would be         
palpable4 ,we have no ground to believe 
that any such common properties exist1  
except such as may be shown to be       
involved in the supposition itself1 or  
to be derivable from it by some law of  
causation4 ,it appears1 therefore1 that 
the properties1 on which we ground our  
classes1 sometimes exhaust all that the 
class has in common1 or contain it all  
by some mode of implication2 but in     
other instances we make a selection of a
 few properties from among not only a   
greater number1 but a number            
inexhaustible by us1 and to which as we 

know no bounds1 they may1 so far as we  
are concerned1 be regarded as infinite4 
,there is no impropriety in saying that1
 of these two classifications1 the one  
answers to a much more radical          
distinction in the things themselves1   
than the other does4 ,and if any one    
even chooses to say that the one        
classification is made by nature1 the   
other by us for our convenience1 he will
 be right2 provided he means no more    
than this3 ,where a certain apparent    
difference between things 7though       
perhaps in itself of little moment7     
answers to we know not what number of   
other differences1 pervading not only   
their known properties1 but properties  
yet undiscovered1 it is not optional but
 imperative to recognise this difference
 as the foundation of a specific        
distinction2 while1 on the contrary1    
differences that are merely finite and  
determinate1 like those designated by   
the words white1 black1 or red1 may be  
disregarded if the purpose for which the

 classification is made does not require
 attention to those particular          
properties4 ,the differences1 however1  
are made by nature1 in both cases2 while
 the recognition of those differences as
 grounds of classification and of       
naming1 is1 equally in both cases1 the  
act of man3 only in the one case1 the   
ends of language and of classification  
would be subverted if no notice were    
taken of the difference1 while in the   
other case1 the necessity of taking     
notice of it depends on the importance  
or unimportance of the particular       
qualities in which the difference       
happens to consist4  ,now1 these        
classes1 distinguished by unknown       
multitudes of properties1 and not solely
 by a few determinate ones--which are   
parted off from one another by an       
unfathomable chasm1 instead of a mere   
ordinary ditch with a visible           
bottom--are the only classes which1 by  
the ,aristotelian logicians1 were       
considered as genera or species4        

,differences which extended only to a   
certain property or properties1 and     
there terminated1 they considered as    
differences only in the accidents of    
things2 but where any class differed    
from other things by an infinite series 
of differences1 known and unknown1 they 
considered the distinction as one of    
kind1 and spoke of it as being an       
essential difference1 which is also one 
of the current meanings of that vague   
expression at the present day4          
,conceiving the schoolmen to have been  
justified in drawing a broad line of    
separation between these two kinds of   
classes and of class-distinctions1 ,i   
shall not only retain the division      
itself1 but continue to express it in   
their language4 ,according to that      
language1 the proximate 7or lowest7     
,kind to which any individual is        
referrible1 is called its species4      
,conformably to this1 ,sir ,isaac       
,newton would be said to be of the      
species man4 ,there are indeed numerous 

sub-classes included in the class man1  
to which ,newton also belongs2 for      
example1 ,christian1 and ,englishman1   
and ,mathematician4 ,but these1 though  
distinct classes1 are not1 in our sense 
of the term1 distinct ,kinds of men4 ,a 
,christian1 for example1 differs from   
other human beings2 but he differs only 
in the attribute which the word         
expresses1 namely1 belief in            
,christianity1 and whatever else that   
implies1 either as involved in the fact 
itself1 or connected with it through    
some law of cause and effect4 ,we should
 never think of inquiring what          
properties1 unconnected with            
,christianity either as cause or effect1
 are common to all ,christians and      
peculiar to them2 while in regard to all
 ,men1 physiologists are perpetually    
carrying on such an inquiry2 nor is the 
answer ever likely to be completed4     
,man1 therefore1 we may call a species2 
,christian1 or ,mathematician1 we       
cannot4  ,note here1 that it is by no   

means intended to imply that there may  
not be different ,kinds1 or logical     
species1 of man4 ,the various races and 
temperaments1 the two sexes1 and even   
the various ages1 may be differences of 
kind1 within our meaning of the term4 ,i
 do not say that they are so4 ,for in   
the progress of physiology it may almost
 be said to be made out1 that the       
differences which really exist between  
different races1 sexes1 c41 follow as   
consequences1 under laws of nature1 from
 a small number of primary differences  
which can be precisely determined1 and  
which1 as the phrase is1 account for all
 the rest4 ,if this be so1 these are not
 distinctions in kind2 no more than     
,christian1 ,jew1 ,mussulman1 and       
,pagan1 a difference which also carries 
many consequences along with it4 ,and in
 this way classes are often mistaken for
 real ,kinds1 which are afterwards      
proved not to be so4 ,but if it turned  
out that the differences were not       
capable of being thus accounted for1    

then ,caucasian1 ,mongolian1 ,negro1 c4 
would be really different ,kinds of     
human beings1 and entitled to be ranked 
as species by the logician2 though not  
by the naturalist4 ,for 7as already     
noticed7 the word species is used in a  
different signification in logic and in 
natural history4 ,by the naturalist1    
organized beings are not usually said to
 be of different species1 if it is      
supposed that they could possibly have  
descended from the same stock4 ,that1   
however1 is a sense artificially given  
to the word1 for the technical purposes 
of a particular science4 ,to the        
logician1 if a negro and a white man    
differ in the same manner 7however less 
in degree7 as a horse and a camel do1   
that is1 if their differences are       
inexhaustible1 and not referrible to any
 common cause1 they are different       
species1 whether they are descended from
 common ancestors or not4 ,but if their 
differences can all be traced to climate
 and habits1 or to some one or a few    

special differences in structure1 they  
are not1 in the logician's view1        
specially distinct4  ,when the infima   
species1 or proximate ,kind1 to which an
 individual belongs1 has been           
ascertained1 the properties common to   
that ,kind include necessarily the whole
 of the common properties of every other
 real ,kind to which the individual can 
be referrible4 ,let the individual1 for 
example1 be ,socrates1 and the proximate
 ,kind1 man4 ,animal1 or living         
creature1 is also a real ,kind1 and     
includes ,socrates2 but1 since it       
likewise includes man1 or in other      
words1 since all men are animals1 the   
properties common to animals form a     
portion of the common properties of the 
sub-class1 man4 ,and if there be any    
class which includes ,socrates without  
including man1 that class is not a real 
,kind4 ,let the class for example1 be   
flat-nosed2 that being a class which    
includes ,socrates1 without including   
all men4 ,to determine whether it is a  

real ,kind1 we must ask ourselves this  
question3 ,have all flat-nosed animals1 
in addition to whatever is implied in   
their flat noses1 any common properties1
 other than those which are common to   
all animals whatever8 ,if they had2 if a
 flat nose were a mark or index to an   
indefinite number of other              
peculiarities1 not deducible from the   
former by an ascertainable law1 then out
 of the class man we might cut another  
class1 flat-nosed man1 which according  
to our definition1 would be a ,kind4    
,but if we could do this1 man would not 
be1 as it was assumed to be1 the        
proximate ,kind4 ,therefore1 the        
properties of the proximate ,kind do    
comprehend those 7whether known or      
unknown7 of all other ,kinds to which   
the individual belongs2 which was the   
point we undertook to prove4 ,and hence1
 every other ,kind which is predicable  
of the individual1 will be to the       
proximate ,kind in the relation of a    
genus1 according to even the popular    

acceptation of the terms genus and      
species2 that is1 it will be a larger   
class1 including it and more4  ,we are  
now able to fix the logical meaning of  
these terms4 ,every class which is a    
real ,kind1 that is1 which is           
distinguished from all other classes by 
an indeterminate multitude of properties
 not derivable from one another1 is     
either a genus or a species4 ,a ,kind   
which is not divisible into other       
,kinds1 cannot be a genus1 because it   
has no species under it2 but it is      
itself a species1 both with reference to
 the individuals below and to the genera
 above 7,species ,prdicabilis and       
,species ,subjicibilis47 ,but every     
,kind which admits of division into real
 ,kinds 7as animal into mammal1 bird1   
fish1 c41 or bird into various species  
of birds7 is a genus to all below it1 a 
species to all genera in which it is    
itself included4 ,and here we may close 
this part of the discussion1 and pass to
 the three remaining predicables1       

,differentia1 ,proprium1 and ,accidens4 
#e4 ,to begin with ,differentia4 ,this  
word is correlative with the words genus
 and species1 and as all admit1 it      
signifies the attribute which           
distinguishes a given species from every
 other species of the same genus4 ,this 
is so far clear3 but we may still ask1  
which of the distinguishing attributes  
it signifies4 ,for we have seen that    
every ,kind 7and a species must be a    
,kind7 is distinguished from other      
,kinds not by any one attribute1 but by 
an indefinite number4 ,man1 for         
instance1 is a species of the genus     
animal3 ,rational 7or rationality1 for  
it is of no consequence here whether we 
use the concrete or the abstract form7  
is generally assigned by logicians as   
the ,differentia2 and doubtless this    
attribute serves the purpose of         
distinction3 but it has also been       
remarked of man1 that he is a cooking   
animal2 the only animal that dresses its
 food4 ,this1 therefore1 is another of  

the attributes by which the species man 
is distinguished from other species of  
the same genus3 would this attribute    
serve equally well for a differentia8   
,the ,aristotelians say ,no2 having laid
 it down that the differentia must1 like
 the genus and species1 be of the       
essence of the subject4  ,and here we   
lose even that vestige of a meaning     
grounded in the nature of the things    
themselves1 which may be supposed to be 
attached to the word essence when it is 
said that genus and species must be of  
the essence of the thing4 ,there can be 
no doubt that when the schoolmen talked 
of the essences of things as opposed to 
their accidents1 they had confusedly in 
view the distinction between differences
 of kind1 and the differences which are 
not of kind2 they meant to intimate that
 genera and species must be ,kinds4     
,their notion of the essence of a thing 
was a vague notion of a something which 
makes it what it is1 i4 e4 which makes  
it the ,kind of thing that it is--which 

causes it to have all that variety of   
properties which distinguish its ,kind4 
,but when the matter came to be looked  
at more closely1 nobody could discover  
what caused the thing to have all those 
properties1 nor even that there was     
anything which caused it to have them4  
,logicians1 however1 not liking to admit
 this1 and being unable to detect what  
made the thing to be what it was1       
satisfied themselves with what made it  
to be what it was called4 ,of the       
innumerable properties1 known and       
unknown1 that are common to the class   
man1 a portion only1 and of course a    
very small portion1 are connoted by its 
name2 these few1 however1 will naturally
 have been thus distinguished from the  
rest either for their greater           
obviousness1 or for greater supposed    
importance4 ,these properties1 then1    
which were connoted by the name1        
logicians seized upon1 and called them  
the essence of the species2 and not     
stopping there1 they affirmed them1 in  

the case of the infima species1 to be   
the essence of the individual too2 for  
it was their maxim1 that the species    
contained the whole essence of the      
thing4 ,metaphysics1 that fertile field 
of delusion propagated by language1 does
 not afford a more signal instance of   
such delusion4 ,on this account it was  
that rationality1 being connoted by the 
name man1 was allowed to be a           
differentia of the class2 but the       
peculiarity of cooking their food1 not  
being connoted1 was relegated to the    
class of accidental properties4  ,the   
distinction1 therefore1 between         
,differentia1 ,proprium1 and ,accidens1 
is not grounded in the nature of things1
 but in the connotation of names2 and we
 must seek it there1 if we wish to find 
what it is4  ,from the fact that the    
genus includes the species1 in other    
words denotes more than the species1 or 
is predicable of a greater number of    
individuals1 it follows that the species
 must connote more than the genus4 ,it  

must connote all the attributes which   
the genus connotes1 or there would be   
nothing to prevent it from denoting     
individuals not included in the genus4  
,and it must connote something besides1 
otherwise it would include the whole    
genus4 ,animal denotes all the          
individuals denoted by man1 and many    
more4 ,man1 therefore1 must connote all 
that animal connotes1 otherwise there   
might be men who are not animals2 and it
 must connote something more than animal
 connotes1 otherwise all animals would  
be men4 ,this surplus of                
connotation--this which the species     
connotes over and above the connotation 
of the genus--is the ,differentia1 or   
specific difference2 or1 to state the   
same proposition in other words1 the    
,differentia is that which must be added
 to the connotation of the genus1 to    
complete the connotation of the species4
  ,the word man1 for instance1          
exclusively of what it connotes in      
common with animal1 also connotes       

rationality1 and at least some          
approximation to that external form     
which we all know1 but which as we have 
no name for it considered in itself1 we 
are content to call the human4 ,the     
,differentia1 or specific difference1   
therefore1 of man1 as referred to the   
genus animal1 is that outward form and  
the possession of reason4 ,the          
,aristotelians said1 the possession of  
reason1 without the outward form4 ,but  
if they adhered to this1 they would have
 been obliged to call the ,houyhnhnms   
men4 ,the question never arose1 and they
 were never called upon to decide how   
such a case would have affected their   
notion of essentiality4 ,however this   
may be1 they were satisfied with taking 
such a portion of the differentia as    
sufficed to distinguish the species from
 all other existing things1 though by so
 doing they might not exhaust the       
connotation of the name4    #f4 ,and    
here1 to prevent the notion of          
differentia from being restricted within

 too narrow limits1 it is necessary to  
remark1 that a species1 even as referred
 to the same genus1 will not always have
 the same differentia1 but a different  
one1 according to the principle and     
purpose which preside over the          
particular classification4 ,for example1
 a naturalist surveys the various kinds 
of animals1 and looks out for the       
classification of them most in          
accordance with the order in which1 for 
zoological purposes1 he considers it    
desirable that we should think of them4 
,with this view he finds it advisable   
that one of his fundamental divisions   
should be into warm-blooded and         
cold-blooded animals2 or into animals   
which breathe with lungs and those which
 breathe with gills2 or into            
carnivorous1 and frugivorous or         
graminivorous2 or into those which walk 
on the flat part and those which walk on
 the extremity of the foot1 a           
distinction on which two of ,cuvier's   
families are founded4 ,in doing this1   

the naturalist creates as many new      
classes2 which are by no means those to 
which the individual animal is          
familiarly and spontaneously referred2  
nor should we ever think of assigning to
 them so prominent a position in our    
arrangement of the animal kingdom1      
unless for a preconceived purpose of    
scientific convenience4 ,and to the     
liberty of doing this there is no limit4
 ,in the examples we have given1 most of
 the classes are real ,kinds1 since each
 of the peculiarities is an index to a  
multitude of properties belonging to the
 class which it characterizes3 but even 
if the case were otherwise--if the other
 properties of those classes could all  
be derived1 by any process known to us1 
from the one peculiarity on which the   
class is founded--even then1 if these   
derivative properties were of primary   
importance for the purposes of the      
naturalist1 he would be warranted in    
founding his primary divisions on them4 
,if1 however1 practical convenience is a

 sufficient warrant for making the main 
demarcations in our arrangement of      
objects run in lines not coinciding with
 any distinction of ,kind1 and so       
creating genera and species in the      
popular sense which are not genera or   
species in the rigorous sense at all1   
fortiori must we be warranted1 when our 
genera and species are real genera and  
species1 in marking the distinction     
between them by those of their          
properties which considerations of      
practical convenience most strongly     
recommend4 ,if we cut a species out of a
 given genus--the species man1 for      
instance1 out of the genus animal--with 
an intention on our part that the       
peculiarity by which we are to be guided
 in the application of the name man     
should be rationality1 then rationality 
is the differentia of the species man4  
,suppose1 however1 that being           
naturalists1 we1 for the purposes of our
 particular study1 cut out of the genus 
animal the same species man1 but with an

 intention that the distinction between 
man and all other species of animal     
should be1 not rationality1 but the     
possession of four incisors in each jaw1
 tusks solitary1 and erect posture4 ,it 
is evident that the word man1 when used 
by us as naturalists1 no longer connotes
 rationality1 but connotes the three    
other properties specified2 for that    
which we have expressly in view when we 
impose a name1 assuredly forms part of  
the meaning of that name4 ,we may1      
therefore1 lay it down as a maxim1 that 
wherever there is a ,genus1 and a       
,species marked out from that genus by  
an assignable differentia1 the name of  
the species must be connotative1 and    
must connote the differentia2 but the   
connotation may be special--not involved
 in the signification of the term as    
ordinarily used1 but given to it when   
employed as a term of art or science4   
,the word ,man in common use1 connotes  
rationality and a certain form1 but does
 not connote the number or character of 

the teeth2 in the ,linnan system it     
connotes the number of incisor and      
canine teeth1 but does not connote      
rationality nor any particular form4    
,the word man has1 therefore1 two       
different meanings2 though not commonly 
considered as ambiguous1 because it     
happens in both cases to denote the same
 individual objects4 ,but a case is     
conceivable in which the ambiguity would
 become evident3 we have only to imagine
 that some new kind of animal were      
discovered1 having ,linnus's three      
characteristics of humanity1 but not    
rational1 or not of the human form4 ,in 
ordinary parlance1 these animals would  
not be called men2 but in natural       
history they must still be called so by 
those1 if any there be1 who adhere to   
the ,linnan classification2 and the     
question would arise1 whether the word  
should continue to be used in two       
senses1 or the classification be given  
up1 and the technical sense of the term 
be abandoned along with it4  ,words not 

otherwise connotative may1 in the mode  
just adverted to1 acquire a special or  
technical connotation4 ,thus the word   
whiteness1 as we have so often remarked1
 connotes nothing2 it merely denotes the
 attribute corresponding to a certain   
sensation3 but if we are making a       
classification of colours1 and desire to
 justify1 or even merely to point out1  
the particular place assigned to        
whiteness in our arrangement1 we may    
define it the colour produced by the    
mixture of all the simple rays2 and this
 fact1 though by no means implied in the
 meaning of the word whiteness as       
ordinarily used1 but only known by      
subsequent scientific investigation1 is 
part of its meaning in the particular   
essay or treatise1 and becomes the      
differentia of the species4#bf  ,the    
differentia1 therefore1 of a species may
 be defined to be1 that part of the     
connotation of the specific name1       
whether ordinary or special and         
technical1 which distinguishes the      

species in question from all other      
species of the genus to which on the    
particular occasion we are referring it4
    #g4 ,having disposed of ,genus1     
,species1 and ,differentia1 we shall not
 find much difficulty in attaining a    
clear conception of the distinction     
between the other two predicables1 as   
well as between them and the first      
three4  ,in the ,aristotelian           
phraseology1 ,genus and ,differentia are
 of the essence of the subject2 by      
which1 as we have seen1 is really meant 
that the properties signified by the    
genus and those signified by the        
differentia1 form part of the           
connotation of the name denoting the    
species4 ,proprium and ,accidens1 on the
 other hand1 form no part of the        
essence1 but are predicated of the      
species only accidentally4 ,both are    
,accidents1 in the wider sense in which 
the accidents of a thing are opposed to 
its essence2 though1 in the doctrine of 
the ,predicables1 ,accidens is used for 

one sort of accident only1 ,proprium    
being another sort4 ,proprium1 continue 
the schoolmen1 is predicated            
accidentally1 indeed1 but necessarily2  
or1 as they further explain it1         
signifies an attribute which is not     
indeed part of the essence1 but which   
flows from1 or is a consequence of1 the 
essence1 and is1 therefore1 inseparably 
attached to the species2 e4 g4 the      
various properties of a triangle1 which1
 though no part of its definition1 must 
necessarily be possessed by whatever    
comes under that definition4 ,accidens1 
on the contrary1 has no connexion       
whatever with the essence1 but may come 
and go1 and the species still remain    
what it was before4 ,if a species could 
exist without its ,propria1 it must be  
capable of existing without that on     
which its ,propria are necessarily      
consequent1 and therefore without its   
essence1 without that which constitutes 
it a species4 ,but an ,accidens1 whether
 separable or inseparable from the      

species in actual experience1 may be    
supposed separated1 without the         
necessity of supposing any other        
alteration2 or at least1 without        
supposing any of the essential          
properties of the species to be altered1
 since with them an ,accidens has no    
connexion4  ,a ,proprium1 therefore1 of 
the species1 may be defined1 any        
attribute which belongs to all the      
individuals included in the species1 and
 which1 though not connoted by the      
specific name1 7either ordinarily if the
 classification we are considering be   
for ordinary purposes1 or specially if  
it be for a special purpose17 yet       
follows from some attribute which the   
name either ordinarily or specially     
connotes4  ,one attribute may follow    
from another in two ways2 and there are 
consequently two kinds of ,proprium4 ,it
 may follow as a conclusion follows     
premises1 or it may follow as an effect 
follows a cause4 ,thus1 the attribute of
 having the opposite sides equal1 which 

is not one of those connoted by the word
 ,parallelogram1 nevertheless follows   
from those connoted by it1 namely1 from 
having the opposite sides straight lines
 and parallel1 and the number of sides  
four4 ,the attribute1 therefore1 of     
having the opposite sides equal1 is a   
,proprium of the class parallelogram2   
and a ,proprium of the first kind1 which
 follows from the connoted attributes by
 way of demonstration4 ,the attribute of
 being capable of understanding         
language1 is a ,proprium of the species 
man1 since without being connoted by the
 word1 it follows from an attribute     
which the word does connote1 viz4 from  
the attribute of rationality4 ,but this 
is a ,proprium of the second kind1 which
 follows by way of causation4 ,how it is
 that one property of a thing follows1  
or can be inferred1 from another2 under 
what conditions this is possible1 and   
what is the exact meaning of the phrase2
 are among the questions which will     
occupy us in the two succeeding ,books4 

,at present it needs only be said1 that 
whether a ,proprium follows by          
demonstration or by causation1 it       
follows necessarily2 that is to say1 its
 not following would be inconsistent    
with some law which we regard as a part 
of the constitution either of our       
thinking faculty or of the universe4    
#h4 ,under the remaining predicable1    
,accidens1 are included all attributes  
of a thing which are neither involved in
 the signification of the name 7whether 
ordinarily or as a term of art71 nor    
have1 so far as we know1 any necessary  
connexion with attributes which are so  
involved4 ,they are commonly divided    
into ,separable and ,inseparable        
,accidents4 ,inseparable accidents are  
those which--although we know of no     
connexion between them and the          
attributes constitutive of the species1 
and although1 therefore1 so far as we   
are aware1 they might be absent without 
making the name inapplicable and the    
species a different species--are yet    

never in fact known to be absent4 ,a    
concise mode of expressing the same     
meaning is1 that inseparable accidents  
are properties which are universal to   
the species1 but not necessary to it4   
,thus1 blackness is an attribute of a   
crow1 and1 as far as we know1 an        
universal one4 ,but if we were to       
discover a race of white birds1 in other
 respects resembling crows1 we should   
not say1 ,these are not crows2 we should
 say1 ,these are white crows4 ,crow1    
therefore1 does not connote blackness2  
nor1 from any of the attributes which it
 does connote1 whether as a word in     
popular use or as a term of art1 could  
blackness be inferred4 ,not only1       
therefore1 can we conceive a white crow1
 but we know of no reason why such an   
animal should not exist4 ,since1        
however1 none but black crows are known 
to exist1 blackness1 in the present     
state of our knowledge1 ranks as an     
accident1 but an inseparable accident1  
of the species crow4  ,separable        

,accidents are those which are found1 in
 point of fact1 to be sometimes absent  
from the species2 which are not only not
 necessary1 but not even universal4     
,they are such as do not belong to every
 individual of the species1 but only to 
some individuals2 or if to all1 not at  
all times4 ,thus the colour of an       
,european is one of the separable       
accidents of the species man1 because it
 is not an attribute of all human       
creatures4 ,being born1 is also         
7speaking in the logical sense7 a       
separable accident of the species man1  
because1 though an attribute of all     
human beings1 it is so only at one      
particular time4  fortiori those        
attributes which are not constant even  
in the same individual1 as1 to be in one
 or in another place1 to be hot or cold1
 sitting or walking1 must be ranked as  
separable accidents4     ,,chapter      
,,viii4  ,,of ,,definition4    #a4 ,one 
necessary part of the theory of ,names  
and of ,propositions remains to be      

treated of in this place3 the theory of 
,definitions4 ,as being the most        
important of the class of propositions  
which we have characterized as purely   
verbal1 they have already received some 
notice in the chapter preceding the     
last4 ,but their fuller treatment was at
 that time postponed1 because definition
 is so closely connected with           
classification1 that1 until the nature  
of the latter process is in some measure
 understood1 the former cannot be       
discussed to much purpose4  ,the        
simplest and most correct notion of a   
,definition is1 a proposition           
declaratory of the meaning of a word2   
namely1 either the meaning which it     
bears in common acceptation1 or that    
which the speaker or writer1 for the    
particular purposes of his discourse1   
intends to annex to it4  ,the definition
 of a word being the proposition which  
enunciates its meaning1 words which have
 no meaning are unsusceptible of        
definition4 ,proper names1 therefore1   

cannot be defined4 ,a proper name being 
a mere mark put upon an individual1 and 
of which it is the characteristic       
property to be destitute of meaning1 its
 meaning cannot of course be declared2  
though we may indicate by language1 as  
we might indicate still more            
conveniently by pointing with the       
finger1 upon what individual that       
particular mark has been1 or is intended
 to be1 put4 ,it is no definition of    
,john ,thomson to say he is the son of  
,general ,thomson2 for the name ,john   
,thomson does not express this4 ,neither
 is it any definition of ,john ,thomson 
to say he is the man now crossing the   
street4 ,these propositions may serve to
 make known who is the particular man to
 whom the name belongs1 but that may be 
done still more unambiguously by        
pointing to him1 which1 however1 has not
 been esteemed one of the modes of      
definition4  ,in the case of connotative
 names1 the meaning1 as has been so     
often observed1 is the connotation2 and 

the definition of a connotative name1 is
 the proposition which declares its     
connotation4 ,this might be done either 
directly or indirectly4 ,the direct mode
 would be by a proposition in this form3
 ,man 7or whatsoever the word may be7 is
 a name connoting such and such         
attributes1 or is a name which1 when    
predicated of anything1 signifies the   
possession of such and such attributes  
by that thing4 ,or thus3 ,man is        
everything which possesses such and such
 attributes3 ,man is everything which   
possesses corporeity1 organization1     
life1 rationality1 and certain          
peculiarities of external form4  ,this  
form of definition is the most precise  
and least equivocal of any2 but it is   
not brief enough1 and is besides too    
technical for common discourse4 ,the    
more usual mode of declaring the        
connotation of a name1 is to predicate  
of it another name or names of known    
signification1 which connote the same   
aggregation of attributes4 ,this may be 

done either by predicating of the name  
intended to be defined1 another         
connotative name exactly synonymous1 as1
 ,man is a human being1 which is not    
commonly accounted a definition at all2 
or by predicating two or more           
connotative names1 which make up among  
them the whole connotation of the name  
to be defined4 ,in this last case1      
again1 we may either compose our        
definition of as many connotative names 
as there are attributes1 each attribute 
being connoted by one1 as1 ,man is a    
corporeal1 organized1 animated1 rational
 being1 shaped so and so2 or we may     
employ names which connote several of   
the attributes at once1 as1 ,man is a   
rational animal1 shaped so and so4  ,the
 definition of a name1 according to this
 view of it1 is the sum total of all the
 essential propositions which can be    
framed with that name for their subject4
 ,all propositions the truth of which is
 implied in the name1 all those which we
 are made aware of by merely hearing the

 name1 are included in the definition1  
if complete1 and may be evolved from it 
without the aid of any other premises2  
whether the definition expresses them in
 two or three words1 or in a larger     
number4 ,it is1 therefore1 not without  
reason that ,condillac and other writers
 have affirmed a definition to be an    
analysis4 ,to resolve any complex whole 
into the elements of which it is        
compounded1 is the meaning of analysis3 
and this we do when we replace one word 
which connotes a set of attributes      
collectively1 by two or more which      
connote the same attributes singly1 or  
in smaller groups4    #b4 ,from this1   
however1 the question naturally arises1 
in what manner are we to define a name  
which connotes only a single attribute3 
for instance1 white1 which connotes     
nothing but whiteness2 rational1 which  
connotes nothing but the possession of  
reason4 ,it might seem that the meaning 
of such names could only be declared in 
two ways2 by a synonymous term1 if any  

such can be found2 or in the direct way 
already alluded to3 ,white is a name    
connoting the attribute whiteness4 ,let 
us see1 however1 whether the analysis of
 the meaning of the name1 that is1 the  
breaking down of that meaning into      
several parts1 admits of being carried  
farther4 ,without at present deciding   
this question as to the word white1 it  
is obvious that in the case of rational 
some further explanation may be given of
 its meaning than is contained in the   
proposition1 ,rational is that which    
possesses the attribute of reason2 since
 the attribute reason itself admits of  
being defined4 ,and here we must turn   
our attention to the definitions of     
attributes1 or rather of the names of   
attributes1 that is1 of abstract names4 
,in regard to such names of attributes  
as are connotative1 and express         
attributes of those attributes1 there is
 no difficulty3 like other connotative  
names they are defined by declaring     
their connotation4 ,thus1 the word fault

 may be defined1 a quality productive of
 evil or inconvenience4 ,sometimes1     
again1 the attribute to be defined is   
not one attribute1 but an union of      
several3 we have only1 therefore1 to put
 together the names of all the          
attributes taken separately1 and we     
obtain the definition of the name which 
belongs to them all taken together2 a   
definition which will correspond exactly
 to that of the corresponding concrete  
name4 ,for1 as we define a concrete name
 by enumerating the attributes which it 
connotes1 and as the attributes connoted
 by a concrete name form the entire     
signification of the corresponding      
abstract name1 the same enumeration will
 serve for the definition of both4      
,thus1 if the definition of a human     
being be this1 a being1 corporeal1      
animated1 rational1 shaped so and so1   
the definition of humanity will be      
corporeity and animal life1 combined    
with rationality1 and with such and such
 a shape4  ,when1 on the other hand1 the

 abstract name does not express a       
complication of attributes1 but a single
 attribute1 we must remember that every 
attribute is grounded on some fact or   
phenomenon1 from which1 and which alone1
 it derives its meaning4 ,to that fact  
or phenomenon1 called in a former       
chapter the foundation of the attribute1
 we must1 therefore1 have recourse for  
its definition4 ,now1 the foundation of 
the attribute may be a phenomenon of any
 degree of complexity1 consisting of    
many different parts1 either coexistent 
or in succession4 ,to obtain a          
definition of the attribute1 we must    
analyse the phenomenon into these parts4
 ,eloquence1 for example1 is the name of
 one attribute only2 but this attribute 
is grounded on external effects of a    
complicated nature1 flowing from acts of
 the person to whom we ascribed the     
attribute2 and by resolving this        
phenomenon of causation into its two    
parts1 the cause and the effect1 we     
obtain a definition of eloquence1 viz4  

the power of influencing the feelings by
 speech or writing4  ,a name1 therefore1
 whether concrete or abstract1 admits of
 definition1 provided we are able to    
analyse1 that is1 to distinguish into   
parts1 the attribute or set of          
attributes which constitute the meaning 
both of the concrete name and of the    
corresponding abstract3 if a set of     
attributes1 by enumerating them2 if a   
single attribute1 by dissecting the fact
 or phenomenon 7whether of perception or
 of internal consciousness7 which is the
 foundation of the attribute4 ,but1     
further1 even when the fact is one of   
our simple feelings or states of        
consciousness1 and therefore            
unsusceptible of analysis1 the names    
both of the object and of the attribute 
still admit of definition3 or rather1   
would do so if all our simple feelings  
had names4 ,whiteness may be defined1   
the property or power of exciting the   
sensation of white4 ,a white object may 
be defined1 an object which excites the 

sensation of white4 ,the only names     
which are unsusceptible of definition1  
because their meaning is unsusceptible  
of analysis1 are the names of the simple
 feelings themselves4 ,these are in the 
same condition as proper names4 ,they   
are not indeed1 like proper names1      
unmeaning2 for the words sensation of   
white signify1 that the sensation which 
,i so denominate resembles other        
sensations which ,i remember to have had
 before1 and to have called by that     
name4 ,but as we have no words by which 
to recal those former sensations1 except
 the very word which we seek to define1 
or some other which1 being exactly      
synonymous with it1 requires definition 
as much1 words cannot unfold the        
signification of this class of names2   
and we are obliged to make a direct     
appeal to the personal experience of the
 individual whom we address4    #c4     
,having stated what seems to be the true
 idea of a ,definition1 we proceed to   
examine some opinions of philosophers1  

and some popular conceptions on the     
subject1 which conflict more or less    
with that idea4  ,the only adequate     
definition of a name is1 as already     
remarked1 one which declares the facts1 
and the whole of the facts1 which the   
name involves in its signification4 ,but
 with most persons the object of a      
definition does not embrace so much2    
they look for nothing more1 in a        
definition1 than a guide to the correct 
use of the term--a protection against   
applying it in a manner inconsistent    
with custom and convention4 ,anything1  
therefore1 is to them a sufficient      
definition of a term1 which will serve  
as a correct index to what the term     
denotes2 though not embracing the whole1
 and sometimes1 perhaps1 not even any   
part1 of what it connotes4 ,this gives  
rise to two sorts of imperfect1 or      
unscientific definition2 ,essential but 
incomplete ,definitions1 and ,accidental
 ,definitions1 or ,descriptions4 ,in the
 former1 a connotative name is defined  

by a part only of its connotation2 in   
the latter1 by something which forms no 
part of the connotation at all4  ,an    
example of the first kind of imperfect  
definitions is the following3--,man is a
 rational animal4 ,it is impossible to  
consider this as a complete definition  
of the word ,man1 since 7as before      
remarked7 if we adhered to it we should 
be obliged to call the ,houyhnhnms men2 
but as there happen to be no            
,houyhnhnms1 this imperfect definition  
is sufficient to mark out and           
distinguish from all other things1 the  
objects at present denoted by man2 all  
the beings actually known to exist1 of  
whom the name is predicable4 ,though the
 word is defined by some only among the 
attributes which it connotes1 not by    
all1 it happens that all known objects  
which possess the enumerated attributes1
 possess also those which are omitted2  
so that the field of predication which  
the word covers1 and the employment of  
it which is conformable to usage1 are as

 well indicated by the inadequate       
definition as by an adequate one4 ,such 
definitions1 however1 are always liable 
to be overthrown by the discovery of new
 objects in nature4  ,definitions of    
this kind are what logicians have had in
 view1 when they laid down the rule1    
that the definition of a species should 
be per genus et differentiam4           
,differentia being seldom taken to mean 
the whole of the peculiarities          
constitutive of the species1 but some   
one of those peculiarities only1 a      
complete definition would be per genus  
et differentias1 rather than            
differentiam4 ,it would include1 with   
the name of the superior genus1 not     
merely some attribute which             
distinguishes the species intended to be
 defined from all other species of the  
same genus1 but all the attributes      
implied in the name of the species1     
which the name of the superior genus has
 not already implied4 ,the assertion1   
however1 that a definition must of      

necessity consist of a genus and        
differenti1 is not tenable4 ,it was     
early remarked by logicians1 that the   
summum genus in any classification1     
having no genus superior to itself1     
could not be defined in this manner4    
,yet we have seen that all names1 except
 those of our elementary feelings1 are  
susceptible of definition in the        
strictest sense2 by setting forth in    
words the constituent parts of the fact 
or phenomenon1 of which the connotation 
of every word is ultimately composed4   
#d4 ,although the first kind of         
imperfect definition1 7which defines a  
connotative term by a part only of what 
it connotes1 but a part sufficient to   
mark out correctly the boundaries of its
 denotation17 has been considered by the
 ancients1 and by logicians in general1 
as a complete definition2 it has always 
been deemed necessary that the          
attributes employed should really form  
part of the connotation2 for the rule   
was that the definition must be drawn   

from the essence of the class2 and this 
would not have been the case if it had  
been in any degree made up of attributes
 not connoted by the name4 ,the second  
kind of imperfect definition1 therefore1
 in which the name of a class is defined
 by any of its accidents1--that is1 by  
attributes which are not included in its
 connotation1--has been rejected from   
the rank of genuine ,definition by all  
logicians1 and has been termed          
,description4  ,this kind of imperfect  
definition1 however1 takes its rise from
 the same cause as the other1 namely1   
the willingness to accept as a          
definition anything which1 whether it   
expounds the meaning of the name or not1
 enables us to discriminate the things  
denoted by the name from all other      
things1 and consequently to employ the  
term in predication without deviating   
from established usage4 ,this purpose is
 duly answered by stating any 7no matter
 what7 of the attributes which are      
common to the whole of the class1 and   

peculiar to it2 or any combination of   
attributes which happens to be peculiar 
to it1 though separately each of those  
attributes may be common to it with some
 other things4 ,it is only necessary    
that the definition 7or description7    
thus formed1 should be convertible with 
the name which it professes to define2  
that is1 should be exactly co-extensive 
with it1 being predicable of everything 
of which it is predicable1 and of       
nothing of which it is not predicable2  
though the attributes specified may have
 no connexion with those which mankind  
had in view when they formed or         
recognised the class1 and gave it a     
name4 ,the following are correct        
definitions of ,man1 according to this  
test3 ,man is a mammiferous animal1     
having 7by nature7 two hands 7for the   
human species answers to this           
description1 and no other animal does73 
,man is an animal who cooks his food3   
,man is a featherless biped4  ,what     
would otherwise be a mere description1  

may be raised to the rank of a real     
definition by the peculiar purpose which
 the speaker or writer has in view4 ,as 
was seen in the preceding chapter1 it   
may1 for the ends of a particular art or
 science1 or for the more convenient    
statement of an author's particular     
doctrines1 be advisable to give to some 
general name1 without altering its      
denotation1 a special connotation1      
different from its ordinary one4 ,when  
this is done1 a definition of the name  
by means of the attributes which make up
 the special connotation1 though in     
general a mere accidental definition or 
description1 becomes on the particular  
occasion and for the particular purpose 
a complete and genuine definition4 ,this
 actually occurs with respect to one of 
the preceding examples1 ,man is a       
mammiferous animal having two hands1    
which is the scientific definition of   
man1 considered as one of the species in
 ,cuvier's distribution of the animal   
kingdom4  ,in cases of this sort1 though

 the definition is still a declaration  
of the meaning which in the particular  
instance the name is appointed to       
convey1 it cannot be said that to state 
the meaning of the word is the purpose  
of the definition4 ,the purpose is not  
to expound a name1 but a classification4
 ,the special meaning which ,cuvier     
assigned to the word ,man1 7quite       
foreign to its ordinary meaning1 though 
involving no change in the denotation of
 the word17 was incidental to a plan of 
arranging animals into classes on a     
certain principle1 that is1 according to
 a certain set of distinctions4 ,and    
since the definition of ,man according  
to the ordinary connotation of the word1
 though it would have answered every    
other purpose of a definition1 would not
 have pointed out the place which the   
species ought to occupy in that         
particular classification2 he gave the  
word a special connotation1 that he     
might be able to define it by the kind  
of attributes on which1 for reasons of  

scientific convenience1 he had resolved 
to found his division of animated       
nature4  ,scientific definitions1       
whether they are definitions of         
scientific terms1 or of common terms    
used in a scientific sense1 are almost  
always of the kind last spoken of3 their
 main purpose is to serve as the        
landmarks of scientific classification4 
,and since the classifications in any   
science are continually modified as     
scientific knowledge advances1 the      
definitions in the sciences are also    
constantly varying4 ,a striking instance
 is afforded by the words ,acid and     
,alkali1 especially the former4 ,as     
experimental discovery advanced1 the    
substances classed with acids have been 
constantly multiplying1 and by a natural
 consequence the attributes connoted by 
the word have receded and become fewer4 
,at first it connoted the attributes1 of
 combining with an alkali to form a     
neutral substance 7called a salt72 being
 compounded of a base and oxygen2       

causticity to the taste and touch2      
fluidity1 c4 ,the true analysis of      
muriatic acid1 into chlorine and        
hydrogen1 caused the second property1   
composition from a base and oxygen1 to  
be excluded from the connotation4 ,the  
same discovery fixed the attention of   
chemists upon hydrogen as an important  
element in acids2 and more recent       
discoveries having led to the           
recognition of its presence in          
sulphuric1 nitric1 and many other acids1
 where its existence was not previously 
suspected1 there is now a tendency to   
include the presence of this element in 
the connotation of the word4 ,but       
carbonic acid1 silica1 sulphurous acid1 
have no hydrogen in their composition2  
that property cannot therefore be       
connoted by the term1 unless those      
substances are no longer to be          
considered acids4 ,causticity and       
fluidity have long since been excluded  
from the characteristics of the class1  
by the inclusion of silica and many     

other substances in it2 and the         
formation of neutral bodies by          
combination with alkalis1 together with 
such electro-chemical peculiarities as  
this is supposed to imply1 are now the  
only differenti which form the fixed    
connotation of the word ,acid1 as a term
 of chemical science4  ,what is true of 
the definition of any term of science1  
is of course true of the definition of a
 science itself3 and accordingly1 7as   
observed in the ,introductory ,chapter  
of this work17 the definition of a      
science must necessarily be progressive 
and provisional4 ,any extension of      
knowledge or alteration in the current  
opinions respecting the subject matter1 
may lead to a change more or less       
extensive in the particulars included in
 the science2 and its composition being 
thus altered1 it may easily happen that 
a different set of characteristics will 
be found better adapted as differenti   
for defining its name4  ,in the same    
manner in which a special or technical  

definition has for its object to expound
 the artificial classification out of   
which it grows2 the ,aristotelian       
logicians seem to have imagined that it 
was also the business of ordinary       
definition to expound the ordinary1 and 
what they deemed the natural1           
classification of things1 namely1 the   
division of them into ,kinds2 and to    
show the place which each ,kind         
occupies1 as superior1 collateral1 or   
subordinate1 among other ,kinds4 ,this  
notion would account for the rule that  
all definition must necessarily be per  
genus et differentiam1 and would also   
explain why a single differentia was    
deemed sufficient4 ,but to expound1 or  
express in words1 a distinction of      
,kind1 has already been shown to be an  
impossibility3 the very meaning of a    
,kind is1 that the properties which     
distinguish it do not grow out of one   
another1 and cannot therefore be set    
forth in words1 even by implication1    
otherwise than by enumerating them all3 

and all are not known1 nor are ever     
likely to be so4 ,it is idle1 therefore1
 to look to this as one of the purposes 
of a definition3 while1 if it be only   
required that the definition of a ,kind 
should indicate what ,kinds include it  
or are included by it1 any definitions  
which expound the connotation of the    
names will do this3 for the name of each
 class must necessarily connote enough  
of its properties to fix the boundaries 
of the class4 ,if the definition1       
therefore1 be a full statement of the   
connotation1 it is all that a definition
 can be required to be4    #e4 ,of the  
two incomplete and popular modes of     
definition1 and in what they differ from
 the complete or philosophical mode1    
enough has now been said4 ,we shall next
 examine an ancient doctrine1 once      
generally prevalent and still by no     
means exploded1 which ,i regard as the  
source of a great part of the obscurity 
hanging over some of the most important 
processes of the understanding in the   

pursuit of truth4 ,according to this1   
the definitions of which we have now    
treated are only one of two sorts into  
which definitions may be divided1 viz4  
definitions of names1 and definitions of
 things4 ,the former are intended to    
explain the meaning of a term2 the      
latter1 the nature of a thing2 the last 
being incomparably the most important4  
,this opinion was held by the ancient   
philosophers1 and by their followers1   
with the exception of the ,nominalists2 
but as the spirit of modern metaphysics1
 until a recent period1 has been on the 
whole a ,nominalist spirit1 the notion  
of definitions of things has been to a  
certain extent in abeyance1 still       
continuing1 however1 to breed confusion 
in logic1 by its consequences indeed    
rather than by itself4 ,yet the doctrine
 in its own proper form now and then    
breaks out1 and has appeared 7among     
other places7 where it was scarcely to  
be expected1 in a justly admired work1  
,archbishop ,whately's ,logic4#bg ,in a 

review of that work published by me in  
the ,westminster ,review for ,january   
#ahbh1 and containing some opinions     
which ,i no longer entertain1 ,i find   
the following observations on the       
question now before us2 observations    
with which my present view of that      
question is still sufficiently in       
accordance4  ,the distinction between   
nominal and real definitions1 between   
definitions of words and what are called
 definitions of things1 though          
conformable to the ideas of most of the 
,aristotelian logicians1 cannot1 as it  
appears to us1 be maintained4 ,we       
apprehend that no definition is ever    
intended to 'explain and unfold the     
nature of a thing4' ,it is some         
confirmation of our opinion1 that none  
of those writers who have thought that  
there were definitions of things1 have  
ever succeeded in discovering any       
criterion by which the definition of a  
thing can be distinguished from any     
other proposition relating to the thing4

 ,the definition1 they say1 unfolds the 
nature of the thing3 but no definition  
can unfold its whole nature2 and every  
proposition in which any quality        
whatever is predicated of the thing1    
unfolds some part of its nature4 ,the   
true state of the case we take to be    
this4 ,all definitions are of names1 and
 of names only2 but1 in some            
definitions1 it is clearly apparent1    
that nothing is intended except to      
explain the meaning of the word2 while  
in others1 besides explaining the       
meaning of the word1 it is intended to  
be implied that there exists a thing1   
corresponding to the word4 ,whether this
 be or be not implied in any given case1
 cannot be collected from the mere form 
of the expression4 ',a centaur is an    
animal with the upper parts of a man and
 the lower parts of a horse1' and ',a   
triangle is a rectilineal figure with   
three sides1' are1 in form1 expressions 
precisely similar2 although in the      
former it is not implied that any thing1

 conformable to the term1 really exists1
 while in the latter it is2 as may be   
seen by substituting1 in both           
definitions1 the word means for is4 ,in 
the first expression1 ',a centaur means 
an animal1' c41 the sense would remain  
unchanged3 in the second1 ',a triangle  
means1' c41 the meaning would be        
altered1 since it would be obviously    
impossible to deduce any of the truths  
of geometry from a proposition          
expressive only of the manner in which  
we intend to employ a particular sign4  
,there are1 therefore1 expressions1     
commonly passing for definitions1 which 
include in themselves more than the mere
 explanation of the meaning of a term4  
,but it is not correct to call an       
expression of this sort a peculiar kind 
of definition4 ,its difference from the 
other kind consists in this1 that it is 
not a definition1 but a definition and  
something more4 ,the definition above   
given of a triangle1 obviously comprises
 not one1 but two propositions1         

perfectly distinguishable4 ,the one is1 
',there may exist a figure1 bounded by  
three straight lines2' the other1 ',and 
this figure may be termed a triangle4'  
,the former of these propositions is not
 a definition at all3 the latter is a   
mere nominal definition1 or explanation 
of the use and application of a term4   
,the first is susceptible of truth or   
falsehood1 and may therefore be made the
 foundation of a train of reasoning4    
,the latter can neither be true nor     
false2 the only character it is         
susceptible of is that of conformity or 
disconformity to the ordinary usage of  
language4  ,there is a real distinction1
 then1 between definitions of names1 and
 what are erroneously called definitions
 of things2 but it is1 that the latter1 
along with the meaning of a name1       
covertly asserts a matter of fact4 ,this
 covert assertion is not a definition1  
but a postulate4 ,the definition is a   
mere identical proposition1 which gives 
information only about the use of       

language1 and from which no conclusions 
affecting matters of fact can possibly  
be drawn4 ,the accompanying postulate1  
on the other hand1 affirms a fact1 which
 may lead to consequences of every      
degree of importance4 ,it affirms the   
actual or possible existence of ,things 
possessing the combination of attributes
 set forth in the definition2 and this1 
if true1 may be foundation sufficient on
 which to build a whole fabric of       
scientific truth4  ,we have already     
made1 and shall often have to repeat1   
the remark1 that the philosophers who   
overthrew ,realism by no means got rid  
of the consequences of ,realism1 but    
retained long afterwards1 in their own  
philosophy1 numerous propositions which 
could only have a rational meaning as   
part of a ,realistic system4 ,it had    
been handed down from ,aristotle1 and   
probably from earlier times1 as an      
obvious truth1 that the science of      
,geometry is deduced from definitions4  
,this1 so long as a definition was      

considered to be a proposition unfolding
 the nature of the thing1 did well      
enough4 ,but ,hobbes followed1 and      
rejected utterly the notion that a      
definition declares the nature of the   
thing1 or does anything but state the   
meaning of a name2 yet he continued to  
affirm as broadly as any of his         
predecessors1 that the ,greek3 archai1  
principia1 or original premises of      
mathematics1 and even of all science1   
are definitions2 producing the singular 
paradox1 that systems of scientific     
truth1 nay1 all truths whatever at which
 we arrive by reasoning1 are deduced    
from the arbitrary conventions of       
mankind concerning the signification of 
words4  ,to save the credit of the      
doctrine that definitions are the       
premises of scientific knowledge1 the   
proviso is sometimes added1 that they   
are so only under a certain condition1  
namely1 that they be framed conformably 
to the phenomena of nature2 that is1    
that they ascribe such meanings to terms

 as shall suit objects actually         
existing4 ,but this is only an instance 
of the attempt so often made1 to escape 
from the necessity of abandoning old    
language after the ideas which it       
expresses have been exchanged for       
contrary ones4 ,from the meaning of a   
name 7we are told7 it is possible to    
infer physical facts1 provided the name 
has corresponding to it an existing     
thing4 ,but if this proviso be          
necessary1 from which of the two is the 
inference really drawn8 ,from the       
existence of a thing having the         
properties1 or from the existence of a  
name meaning them8  ,take1 for instance1
 any of the definitions laid down as    
premises in ,euclid's ,elements2 the    
definition1 let us say1 of a circle4    
,this1 being analysed1 consists of two  
propositions2 the one an assumption with
 respect to a matter of fact1 the other 
a genuine definition4 ,a figure may     
exist1 having all the points in the line
 which bounds it equally distant from a 

single point within it3 ,any figure     
possessing this property is called a    
circle4 ,let us look at one of the      
demonstrations which are said to depend 
on this definition1 and observe to which
 of the two propositions contained in it
 the demonstration really appeals4      
,about the centre ,a1 describe the      
circle ,b ,c ,d4 ,here is an assumption 
that a figure1 such as the definition   
expresses1 may be described2 which is no
 other than the postulate1 or covert    
assumption1 involved in the so-called   
definition4 ,but whether that figure be 
called a circle or not is quite         
immaterial4 ,the purpose would be as    
well answered1 in all respects except   
brevity1 were we to say1 ,through the   
point ,b1 draw a line returning into    
itself1 of which every point shall be at
 an equal distance from the point ,a4   
,by this the definition of a circle     
would be got rid of1 and rendered       
needless2 but not the postulate implied 
in it2 without that the demonstration   

could not stand4 ,the circle being now  
described1 let us proceed to the        
consequence4 ,since ,b ,c ,d is a       
circle1 the radius ,b ,a is equal to the
 radius ,c ,a4 ,b ,a is equal to ,c ,a1 
not because ,b ,c ,d is a circle1 but   
because ,b ,c ,d is a figure with the   
radii equal4 ,our warrant for assuming  
that such a figure about the centre ,a1 
with the radius ,b ,a1 may be made to   
exist1 is the postulate4 ,whether the   
admissibility of these postulates rests 
on intuition1 or on proof1 may be a     
matter of dispute2 but in either case   
they are the premises on which the      
theorems depend2 and while these are    
retained it would make no difference in 
the certainty of geometrical truths1    
though every definition in ,euclid1 and 
every technical term therein defined1   
were laid aside4  ,it is1 perhaps1      
superfluous to dwell at so much length  
on what is so nearly self-evident2 but  
when a distinction1 obvious as it may   
appear1 has been confounded1 and by     

powerful intellects1 it is better to say
 too much than too little for the       
purpose of rendering such mistakes      
impossible in future4 ,i will1          
therefore1 detain the reader while ,i   
point out one of the absurd consequences
 flowing from the supposition that      
definitions1 as such1 are the premises  
in any of our reasonings1 except such as
 relate to words only4 ,if this         
supposition were true1 we might argue   
correctly from true premises1 and arrive
 at a false conclusion4 ,we should only 
have to assume as a premise the         
definition of a nonentity2 or rather of 
a name which has no entity corresponding
 to it4 ,let this1 for instance1 be our 
definition3    ,a dragon is a serpent   
breathing flame4  ,this proposition1    
considered only as a definition1 is     
indisputably correct4 ,a dragon is a    
serpent breathing flame3 the word means 
that4 ,the tacit assumption1 indeed1 7if
 there were any such understood         
assertion71 of the existence of an      

object with properties corresponding to 
the definition1 would1 in the present   
instance1 be false4 ,out of this        
definition we may carve the premises of 
the following syllogism3    ,a dragon is
 a thing which breathes flame3   ,a     
dragon is a serpent3  ,from which the   
conclusion is1    ,therefore some       
serpent or serpents breathe flame3--  an
 unexceptionable syllogism in the first 
mode of the third figure1 in which both 
premises are true and yet the conclusion
 false2 which every logician knows to be
 an absurdity4 ,the conclusion being    
false and the syllogism correct1 the    
premises cannot be true4 ,but the       
premises1 considered as parts of a      
definition1 are true4 ,therefore1 the   
premises considered as parts of a       
definition cannot be the real ones4 ,the
 real premises must be--    ,a dragon is
 a really existing thing which breathes 
flame3   ,a dragon is a really existing 
serpent3  which implied premises being  
false1 the falsity of the conclusion    

presents no absurdity4  ,if we would    
determine what conclusion follows from  
the same ostensible premises when the   
tacit assumption of real existence is   
left out1 let us1 according to the      
recommendation in a previous page1      
substitute means for is4 ,we then have--
    ,dragon is a word meaning a thing   
which breathes flame3   ,dragon is a    
word meaning a serpent3  ,from which the
 conclusion is1    ,some word or words  
which mean a serpent1 also mean a thing 
which   breathes flame3  where the      
conclusion 7as well as the premises7 is 
true1 and is the only kind of conclusion
 which can ever follow from a           
definition1 namely1 a proposition       
relating to the meaning of words4       
,there is still another shape into which
 we may transform this syllogism4 ,we   
may suppose the middle term to be the   
designation neither of a thing nor of a 
name1 but of an idea4 ,we then have--   
,the idea of a dragon is an idea of a   
thing which breathes     flame3   ,the  

idea of a dragon is an idea of a        
serpent3   ,therefore1 there is an idea 
of a serpent1 which is an idea of     a 
thing breathing flame4  ,here the       
conclusion is true1 and also the        
premises2 but the premises are not      
definitions4 ,they are propositions     
affirming that an idea existing in the  
mind1 includes certain ideal elements4  
,the truth of the conclusion follows    
from the existence of the psychological 
phenomenon called the idea of a dragon2 
and therefore still from the tacit      
assumption of a matter of fact4#bh      
,when1 as in this last syllogism1 the   
conclusion is a proposition respecting  
an idea1 the assumption on which it     
depends may be merely that of the       
existence of an idea4 ,but when the     
conclusion is a proposition concerning a
 ,thing1 the postulate involved in the  
definition which stands as the apparent 
premise1 is the existence of a thing    
conformable to the definition1 and not  
merely of an idea conformable to it4    

,this assumption of real existence will 
always convey the impression that we    
intend to make1 when we profess to      
define any name which is already known  
to be a name of really existing objects4
 ,on this account it is1 that the       
assumption was not necessarily implied  
in the definition of a dragon1 while    
there was no doubt of its being included
 in the definition of a circle4    #f4  
,one of the circumstances which have    
contributed to keep up the notion1 that 
demonstrative truths follow from        
definitions rather than from the        
postulates implied in those definitions1
 is1 that the postulates1 even in those 
sciences which are considered to surpass
 all others in demonstrative certainty1 
are not always exactly true4 ,it is not 
true that a circle exists1 or can be    
described1 which has all its radii      
exactly equal4 ,such accuracy is ideal  
only2 it is not found in nature1 still  
less can it be realized by art4 ,people 
had a difficulty1 therefore1 in         

conceiving that the most certain of all 
conclusions could rest on premises      
which1 instead of being certainly true1 
are certainly not true to the full      
extent asserted4 ,this apparent paradox 
will be examined when we come to treat  
of ,demonstration2 where we shall be    
able to show that as much of the        
postulate is true1 as is required to    
support as much as is true of the       
conclusion4 ,philosophers1 however1 to  
whom this view had not occurred1 or whom
 it did not satisfy1 have thought it    
indispensable that there should be found
 in definitions something more certain1 
or at least more accurately true1 than  
the implied postulate of the real       
existence of a corresponding object4    
,and this something they flattered      
themselves they had found1 when they    
laid it down that a definition is a     
statement and analysis not of the mere  
meaning of a word1 nor yet of the nature
 of a thing1 but of an idea4 ,thus1 the 
proposition1 ,a circle is a plane figure

 bounded by a line all the points of    
which are at an equal distance from a   
given point within it1 was considered by
 them1 not as an assertion that any real
 circle has that property1 7which would 
not be exactly true17 but that we       
conceive a circle as having it2 that our
 abstract idea of a circle is an idea of
 a figure with its radii exactly equal4 
,conformably to this it is said1 that   
the subject-matter of mathematics1 and  
of every other demonstrative science1 is
 not things as they really exist1 but   
abstractions of the mind4 ,a geometrical
 line is a line without breadth2 but no 
such line exists in nature2 it is a     
notion merely suggested to the mind by  
its experience of nature4 ,the          
definition 7it is said7 is a definition 
of this mental line1 not of any actual  
line3 and it is only of the mental line1
 not of any line existing in nature1    
that the theorems of geometry are       
accurately true4  ,allowing this        
doctrine respecting the nature of       

demonstrative truth to be correct       
7which1 in a subsequent place1 ,i shall 
endeavour to prove that it is not27 even
 on that supposition1 the conclusions   
which seem to follow from a definition1 
do not follow from the definition as    
such1 but from an implied postulate4    
,even if it be true that there is no    
object in nature answering to the       
definition of a line1 and that the      
geometrical properties of lines are not 
true of any lines in nature1 but only of
 the idea of a line2 the definition1 at 
all events1 postulates the real         
existence of such an idea3 it assumes   
that the mind can frame1 or rather has  
framed1 the notion of length without    
breadth1 and without any other sensible 
property whatever4 ,to me1 indeed1 it   
appears that the mind cannot form any   
such notion2 it cannot conceive length  
without breadth2 it can only1 in        
contemplating objects1 attend to their  
length1 exclusively of their other      
sensible qualities1 and so determine    

what properties may be predicated of    
them in virtue of their length alone4   
,if this be true1 the postulate involved
 in the geometrical definition of a     
line1 is the real existence1 not of     
length without breadth1 but merely of   
length1 that is1 of long objects4 ,this 
is quite enough to support all the      
truths of geometry1 since every property
 of a geometrical line is really a      
property of all physical objects in so  
far as possessing length4 ,but even what
 ,i hold to be the false doctrine on the
 subject1 leaves the conclusion that our
 reasonings are grounded on the matters 
of fact postulated in definitions1 and  
not on the definitions themselves1      
entirely unaffected2 and accordingly    
this conclusion is one which ,i have in 
common with ,dr4 ,whewell1 in his       
,philosophy of the ,inductive ,sciences3
 though1 on the nature of demonstrative 
truth1 ,dr4 ,whewell's opinions are     
greatly at variance with mine4 ,and     
here1 as in many other instances1 ,i    

gladly acknowledge that his writings are
 eminently serviceable in clearing from 
confusion the initial steps in the      
analysis of the mental processes1 even  
where his views respecting the ultimate 
analysis are such as 7though with       
unfeigned respect7 ,i cannot but regard 
as fundamentally erroneous4    #g4      
,although1 according to the opinion here
 presented1 ,definitions are properly of
 names only1 and not of things1 it does 
not follow from this that definitions   
are arbitrary4 ,how to define a name1   
may not only be an inquiry of           
considerable difficulty and intricacy1  
but may involve considerations going    
deep into the nature of the things which
 are denoted by the name4 ,such1 for    
instance1 are the inquiries which form  
the subjects of the most important of   
,plato's ,dialogues2 as1 ,what is       
rhetoric8 the topic of the ,gorgias1 or 
,what is justice8 that of the ,republic4
 ,such1 also1 is the question scornfully
 asked by ,pilate1 ,what is truth8 and  

the fundamental question with           
speculative moralists in all ages1 ,what
 is virtue8  ,it would be a mistake to  
represent these difficult and noble     
inquiries as having nothing in view     
beyond ascertaining the conventional    
meaning of a name4 ,they are inquiries  
not so much to determine what is1 as    
what should be1 the meaning of a name2  
which1 like other practical questions of
 terminology1 requires for its solution 
that we should enter1 and sometimes     
enter very deeply1 into the properties  
not merely of names but of the things   
named4  ,although the meaning of every  
concrete general name resides in the    
attributes which it connotes1 the       
objects were named before the           
attributes2 as appears from the fact    
that in all languages1 abstract names   
are mostly compounds or other           
derivatives of the concrete names which 
correspond to them4 ,connotative names1 
therefore1 were1 after proper names1 the
 first which were used3 and in the      

simpler cases1 no doubt1 a distinct     
connotation was present to the minds of 
those who first used the name1 and was  
distinctly intended by them to be       
conveyed by it4 ,the first person who   
used the word white1 as applied to snow 
or to any other object1 knew1 no doubt1 
very well what quality he intended to   
predicate1 and had a perfectly distinct 
conception in his mind of the attribute 
signified by the name4  ,but where the  
resemblances and differences on which   
our classifications are founded are not 
of this palpable and easily determinable
 kind2 especially where they consist not
 in any one quality but in a number of  
qualities1 the effects of which being   
blended together are not very easily    
discriminated1 and referred each to its 
true source2 it often happens that names
 are applied to nameable objects1 with  
no distinct connotation present to the  
minds of those who apply them4 ,they are
 only influenced by a general           
resemblance between the new object and  

all or some of the old familiar objects 
which they have been accustomed to call 
by that name4 ,this1 as we have seen1 is
 the law which even the mind of the     
philosopher must follow1 in giving names
 to the simple elementary feelings of   
our nature3 but1 where the things to be 
named are complex wholes1 a philosopher 
is not content with noticing a general  
resemblance2 he examines what the       
resemblance consists in3 and he only    
gives the same name to things which     
resemble one another in the same        
definite particulars4 ,the philosopher1 
therefore1 habitually employs his       
general names with a definite           
connotation4 ,but language was not made1
 and can only in some small degree be   
mended1 by philosophers4 ,in the minds  
of the real arbiters of language1       
general names1 especially where the     
classes they denote cannot be brought   
before the tribunal of the outward      
senses to be identified and             
discriminated1 connote little more than 

a vague gross resemblance to the things 
which they were earliest1 or have been  
most1 accustomed to call by those names4
 ,when1 for instance1 ordinary persons  
predicate the words just or unjust of   
any action1 noble or mean of any        
sentiment1 expression1 or demeanour1    
statesman or charlatan of any personage 
figuring in politics1 do they mean to   
affirm of those various subjects any    
determinate attributes1 of whatever     
kind8 ,no3 they merely recognise1 as    
they think1 some likeness1 more or less 
vague and loose1 between these and some 
other things which they have been       
accustomed to denominate or to hear     
denominated by those appellations4      
,language1 as ,sir ,james ,mackintosh   
used to say of governments1 is not made1
 but grows4 ,a name is not imposed at   
once and by previous purpose upon a     
class of objects1 but is first applied  
to one thing1 and then extended by a    
series of transitions to another and    
another4 ,by this process 7as has been  

remarked by several writers1 and        
illustrated with great force and        
clearness by ,dugald ,stewart in his    
,philosophical ,essays7 a name not      
unfrequently passes by successive links 
of resemblance from one object to       
another1 until it becomes applied to    
things having nothing in common with the
 first things to which the name was     
given2 which1 however1 do not1 for that 
reason1 drop the name2 so that it at    
last denotes a confused huddle of       
objects1 having nothing whatever in     
common2 and connotes nothing1 not even a
 vague and general resemblance4 ,when a 
name has fallen into this state1 in     
which by predicating it of any object we
 assert literally nothing about the     
object1 it has become unfit for the     
purposes either of thought or of the    
communication of thought2 and can only  
be made serviceable by stripping it of  
some part of its multifarious           
denotation1 and confining it to objects 
possessed of some attributes in common1 

which it may be made to connote4 ,such  
are the inconveniences of a language    
which is not made1 but grows4 ,like the 
governments which are in a similar case1
 it may be compared to a road which is  
not made but has made itself3 it        
requires continual mending in order to  
be passable4  ,from this it is already  
evident1 why the question respecting the
 definition of an abstract name is often
 one of so much difficulty4 ,the        
question1 ,what is justice8 is1 in other
 words1 ,what is the attribute which    
mankind mean to predicate when they call
 an action just8 ,to which the first    
answer is1 that having come to no       
precise agreement on the point1 they do 
not mean to predicate distinctly any    
attribute at all4 ,nevertheless1 all    
believe that there is some common       
attribute belonging to all the actions  
which they are in the habit of calling  
just4 ,the question then must be1       
whether there is any such common        
attribute8 and1 in the first place1     

whether mankind agree sufficiently with 
one another as to the particular actions
 which they do or do not call just1 to  
render the inquiry1 what quality those  
actions have in common1 a possible one3 
if so1 whether the actions really have  
any quality in common2 and if they have1
 what it is4 ,of these three1 the first 
alone is an inquiry into usage and      
convention2 the other two are inquiries 
into matters of fact4 ,and if the second
 question 7whether the actions form a   
class at all7 has been answered         
negatively1 there remains a fourth1     
often more arduous than all the rest1   
namely1 how best to form a class        
artificially1 which the name may denote4
  ,and here it is fitting to remark1    
that the study of the spontaneous growth
 of languages is of the utmost          
importance to those who would logically 
remodel them4 ,the classifications      
rudely made by established language1    
when retouched1 as they almost all      
require to be1 by the hands of the      

logician1 are often in themselves       
excellently suited to his purposes4 ,as 
compared with the classifications of a  
philosopher1 they are like the customary
 law of a country1 which has grown up as
 it were spontaneously1 compared with   
laws methodized and digested into a     
code3 the former are a far less perfect 
instrument than the latter2 but being   
the result of a long1 though            
unscientific1 course of experience1 they
 contain a mass of materials which may  
be made very usefully available in the  
formation of the systematic body of     
written law4 ,in like manner1 the       
established grouping of objects under a 
common name1 even when founded only on a
 gross and general resemblance1 is      
evidence1 in the first place1 that the  
resemblance is obvious1 and therefore   
considerable2 and1 in the next place1   
that it is a resemblance which has      
struck great numbers of persons during a
 series of years and ages4 ,even when a 
name1 by successive extensions1 has come

 to be applied to things among which    
there does not exist this gross         
resemblance common to them all1 still at
 every step in its progress we shall    
find such a resemblance4 ,and these     
transitions of the meaning of words are 
often an index to real connexions       
between the things denoted by them1     
which might otherwise escape the notice 
of thinkers2 of those at least who1 from
 using a different language1 or from any
 difference in their habitual           
associations1 have fixed their attention
 in preference on some other aspect of  
the things4 ,the history of philosophy  
abounds in examples of such oversights1 
committed for want of perceiving the    
hidden link that connected together the 
seemingly disparate meanings of some    
ambiguous word4#bi  ,whenever the       
inquiry into the definition of the name 
of any real object consists of anything 
else than a mere comparison of          
authorities1 we tacitly assume that a   
meaning must be found for the name1     

compatible with its continuing to       
denote1 if possible all1 but at any rate
 the greater or the more important part1
 of the things of which it is commonly  
predicated4 ,the inquiry1 therefore1    
into the definition1 is an inquiry into 
the resemblances and differences among  
those things3 whether there be any      
resemblance running through them all2 if
 not1 through what portion of them such 
a general resemblance can be traced3 and
 finally1 what are the common           
attributes1 the possession of which     
gives to them all1 or to that portion of
 them1 the character of resemblance     
which has led to their being classed    
together4 ,when these common attributes 
have been ascertained and specified1 the
 name which belongs in common to the    
resembling objects acquires a distinct  
instead of a vague connotation2 and by  
possessing this distinct connotation1   
becomes susceptible of definition4  ,in 
giving a distinct connotation to the    
general name1 the philosopher will      

endeavour to fix upon such attributes   
as1 while they are common to all the    
things usually denoted by the name1 are 
also of greatest importance in          
themselves2 either directly1 or from the
 number1 the conspicuousness1 or the    
interesting character1 of the           
consequences to which they lead4 ,he    
will select1 as far as possible1 such   
differenti as lead to the greatest      
number of interesting propria4 ,for     
these1 rather than the more obscure and 
recondite qualities on which they often 
depend1 give that general character and 
aspect to a set of objects1 which       
determine the groups into which they    
naturally fall4 ,but to penetrate to the
 more hidden agreement on which these   
obvious and superficial agreements      
depend1 is often one of the most        
difficult of scientific problems4 ,as it
 is among the most difficult1 so it     
seldom fails to be among the most       
important4 ,and since upon the result of
 this inquiry respecting the causes of  

the properties of a class of things1    
there incidentally depends the question 
what shall be the meaning of a word2    
some of the most profound and most      
valuable investigations which philosophy
 presents to us1 have been introduced   
by1 and have offered themselves under   
the guise of1 inquiries into the        
definition of a name4  ,,footnotes3  #a 
,computation or ,logic1 chap4 ii4  #b   
,in the original had1 or had not4 ,these
 last words1 as involving a subtlety    
foreign to our present purpose1 ,i have 
forborne to quote4  #c ,vide infra1 note
 at the end of  #c1 book ii4 ch4 ii4  #d
 ,notare1 to mark2 connotare1 to mark   
along with2 to mark one thing with or in
 addition to another4  #e ,archbishop   
,whately1 who1 in the later editions of 
his ,elements of ,logic1 aided in       
reviving the important distinction      
treated of in the text1 proposes the    
term ,attributive as a substitute for   
,connotative 7p4 #bb1 #ith ed47 ,the    
expression is1 in itself1 appropriate2  

but as it has not the advantage of being
 connected with any verb1 of so markedly
 distinctive a character as to connote1 
it is not1 ,i think1 fitted to supply   
the place of the word ,connotative in   
scientific use4  #f ,a writer who       
entitles his book ,philosophy2 or1 the  
,science of ,truth1 charges me in his   
very first page 7referring at the foot  
of it to this passage7 with asserting   
that general names have properly no     
signification4 ,and he repeats this     
statement many times in the course of   
his volume1 with comments1 not at all   
flattering1 thereon4 ,it is well to be  
now and then reminded to how great a    
length perverse misquotation 7for1      
strange as it appears1 ,i do not believe
 that the writer is dishonest7 can      
sometimes go4 ,it is a warning to       
readers1 when they see an author        
accused1 with volume and page referred  
to1 and the apparent guarantee of       
inverted commas1 of maintaining         
something more than commonly absurd1 not

 to give implicit credence to the       
assertion without verifying the         
reference4  #g ,before quitting the     
subject of connotative names1 it is     
proper to observe1 that the first writer
 who1 in our times1 has adopted from the
 schoolmen the word to connote1 ,mr4    
,james ,mill1 in his ,analysis of the   
,phenomena of the ,human ,mind1 employs 
it in a signification different from    
that in which it is here used4 ,he uses 
the word in a sense coextensive with its
 etymology1 applying it to every case in
 which a name1 while pointing directly  
to one thing1 7which is consequently    
termed its signification17 includes also
 a tacit reference to some other thing4 
,in the case considered in the text1    
that of concrete general names1 his     
language and mine are the converse of   
one another4 ,considering 7very justly7 
the signification of the name to lie in 
the attribute1 he speaks of the word as 
noting the attribute1 and connoting the 
things possessing the attribute4 ,and he

 describes abstract names as being      
properly concrete names with their      
connotation dropped3 whereas1 in my     
view1 it is the denotation which would  
be said to be dropped1 what was         
previously connoted becoming the whole  
signification4  ,in adopting a          
phraseology at variance with that which 
so high an authority1 and one which ,i  
am less likely than any other person to 
undervalue1 has deliberately sanctioned1
 ,i have been influenced by the urgent  
necessity for a term exclusively        
appropriated to express the manner in   
which a concrete general name serves to 
mark the attributes which are involved  
in its signification4 ,this necessity   
can scarcely be felt in its full force  
by any one who has not found by         
experience how vain is the attempt to   
communicate clear ideas on the          
philosophy of language without such a   
word4 ,it is hardly an exaggeration to  
say1 that some of the most prevalent of 
the errors with which logic has been    

infected1 and a large part of the       
cloudiness and confusion of ideas which 
have enveloped it1 would1 in all        
probability1 have been avoided1 if a    
term had been in common use to express  
exactly what ,i have signified by the   
term to connote4 ,and the schoolmen1 to 
whom we are indebted for the greater    
part of our logical language1 gave us   
this also1 and in this very sense4 ,for 
though some of their general expressions
 countenance the use of the word in the 
more extensive and vague acceptation in 
which it is taken by ,mr4 ,mill1 yet    
when they had to define it specifically 
as a technical term1 and to fix its     
meaning as such1 with that admirable    
precision which always characterizes    
their definitions1 they clearly         
explained that nothing was said to be   
connoted except forms1 which word may   
generally1 in their writings1 be        
understood as synonymous with           
attributes4  ,now1 if the word to       
connote1 so well suited to the purpose  

to which they applied it1 be diverted   
from that purpose by being taken to     
fulfil another1 for which it does not   
seem to me to be at all required2 ,i am 
unable to find any expression to replace
 it1 but such as are commonly employed  
in a sense so much more general1 that it
 would be useless attempting to         
associate them peculiarly with this     
precise idea4 ,such are the words1 to   
involve1 to imply1 c4 ,by employing     
these1 ,i should fail of attaining the  
object for which alone the name is      
needed1 namely1 to distinguish this     
particular kind of involving and        
implying from all other kinds1 and to   
assure to it the degree of habitual     
attention which its importance demands4 
#h ,or rather1 all objects except itself
 and the percipient mind2 for1 as we    
shall see hereafter1 to ascribe any     
attribute to an object1 necessarily     
implies a mind to perceive it4  ,the    
simple and clear explanation given in   
the text1 of relation and relative      

names1 a subject so long the opprobrium 
of metaphysics1 was given 7as far as ,i 
know7 for the first time1 by ,mr4 ,james
 ,mill1 in his ,analysis of the         
,phenomena of the ,human ,mind4  #i     
,philosophy of the ,inductive ,sciences1
 vol4 i4 p4 #dj4  #aj ,discussions on   
,philosophy1 c4 ,appendix ,i4 pp4       
#fdc-d4  #aa ,it is to be regretted that
 ,sir ,william ,hamilton1 though he     
often strenuously insists on this       
doctrine1 and though1 in the passage    
quoted1 he states it with a             
comprehensiveness and force which leave 
nothing to be desired1 did not          
consistently adhere to his own doctrine1
 but maintained along with it opinions  
with which it is utterly                
irreconcileable4 ,see the third and     
other chapters of ,an ,examination of   
,sir ,william ,hamilton's ,philosophy4  
#ab ,nous savons qu'il existe quelque   
chose hors de nous1 parceque nous ne    
pouvons expliquer nos perceptions sans  
les rattacher  des causes distinctes de 

nous-mmes2 nous savons de plus que ces  
causes1 dont nous ne connaissons pas    
d'ailleurs l'essence1 produisent les    
effets les plus variables1 les plus     
divers1 et mme les plus contraires1     
selon qu'elles rencontrent telle nature 
ou telle disposition du sujet4 ,mais    
savons-nous quelque chose de plus8 et   
mme1 vu le caractre indtermin des causes
 que nous concevons dans les corps1 y   
a-t-il quelque chose de plus  savoir8 ,y
 a-t-il lieu de nous enqurir si nous    
percevons les choses telles qu'elles    
sont8 ,non videmment4444 ,je ne dis pas 
que le problme est insoluble1 je dis    
qu'il est absurde et enferme une        
contradiction4 ,nous ne savons pas ce   
que ces causes sont en elles-mmes1 et la
 raison nous dfend de chercher  le      
connatre3 mais il est bien vident       
priori1 qu'elles ne sont pas en         
elles-mmes ce qu'elles sont par rapport 
nous1 puisque la prsence du sujet       
modifie ncessairement leur action4      
,supprimez tout sujet sentant1 il est   

certain que ces causes agiraient encore 
puisqu'elles continueraient d'exister2  
mais elles agiraient autrement2 elles   
seraient encore des qualits et des      
proprits1 mais qui ne ressembleraient   
rien de ce que nous connaissons4 ,le feu
 ne manifesterait plus aucune des       
proprits que nous lui connaissons3 que  
serait-il8 ,c'est ce que nous ne saurons
 jamais4 ,c'est d'ailleurs peut-tre un  
problme qui ne rpugne pas seulement  la 
nature de notre esprit1 mais  l'essence 
mme des choses4 ,quand mme en effet on  
supprimerait par la pense tous les      
sujets sentants1 il faudrait encore     
admettre que nul corps ne manifesterait 
ses proprits autrement qu'en relation   
avec un sujet quelconque1 et dans ce cas
 ses proprits ne seraient encore que    
relatives3 en sorte qu'il me parat fort 
raisonnable d'admettre que les proprits 
dtermines des corps n'existent pas      
indpendamment d'un sujet quelconque1 et 
que quand on demande si les proprits de 
la matire sont telles que nous les      

percevons1 il faudrait voir auparavant  
si elles sont en tant que dtermines1 et 
dans quel sens il est vrai de dire      
qu'elles sont4--,cours d',histoire de la
 ,philosophie ,morale au #ahme sicle1   
#hme leon4  #ac ,an attempt1 indeed1 has
 been made by ,reid and others1 to      
establish that although some of the     
properties we ascribe to objects exist  
only in our sensations1 others exist in 
the things themselves1 being such as    
cannot possibly be copies of any        
impression upon the senses2 and they    
ask1 from what sensations our notions of
 extension and figure have been derived8
 ,the gauntlet thrown down by ,reid was 
taken up by ,brown1 who1 applying       
greater powers of analysis than had     
previously been applied to the notions  
of extension and figure1 pointed out    
that the sensations from which those    
notions are derived1 are sensations of  
touch1 combined with sensations of a    
class previously too little adverted to 
by metaphysicians1 those which have     

their seat in our muscular frame4 ,his  
analysis1 which was adopted and followed
 up by ,james ,mill1 has been further   
and greatly improved upon in ,professor 
,bain's profound work1 ,the ,senses and 
the ,intellect1 and in the chapters on  
,perception of a work of eminent        
analytic power1 ,mr4 ,herbert ,spencer's
 ,principles of ,psychology4  ,on this  
point ,m4 ,cousin may again be cited in 
favour of the better doctrine4 ,m4      
,cousin recognises1 in opposition to    
,reid1 the essential subjectivity of our
 conceptions of what are called the     
primary qualities of matter1 as         
extension1 solidity1 c41 equally with   
those of colour1 heat1 and the remainder
 of the so-called secondary             
qualities4--,cours1 ut supra1 #ime leon4
  #ad ,this doctrine1 which is the most 
complete form of the philosophical      
theory known as the ,relativity of      
,human ,knowledge1 has1 since the recent
 revival in this country of an active   
interest in metaphysical speculation1   

been the subject of a greatly increased 
amount of discussion and controversy2   
and dissentients have manifested        
themselves in considerably greater      
number than ,i had any knowledge of when
 the passage in the text was written4   
,the doctrine has been attacked from two
 sides4 ,some thinkers1 among whom are  
the late ,professor ,ferrier1 in his    
,institutes of ,metaphysic1 and         
,professor ,john ,grote in his          
,exploratio ,philosophica1 appear to    
deny altogether the reality of ,noumena1
 or ,things in themselves--of an        
unknowable substratum or support for the
 sensations which we experience1 and    
which1 according to the theory1         
constitute all our knowledge of an      
external world4 ,it seems to me1        
however1 that in ,professor ,grote's    
case at least1 the denial of ,noumena is
 only apparent1 and that he does not    
essentially differ from the other class 
of objectors1 including ,mr4 ,bailey in 
his valuable ,letters on the ,philosophy

 of the ,human ,mind1 and 7in spite of  
the striking passage quoted in the text7
 also ,sir ,william ,hamilton1 who      
contend for a direct knowledge by the   
human mind of more than the             
sensations--of certain attributes or    
properties as they exist not in us1 but 
in the ,things themselves4  ,with the   
first of these opinions1 that which     
denies ,noumena1 ,i have1 as a          
metaphysician1 no quarrel2 but1 whether 
it be true or false1 it is irrelevant to
 ,logic4 ,and since all the forms of    
language are in contradiction to it1    
nothing but confusion could result from 
its unnecessary introduction into a     
treatise1 every essential doctrine of   
which could stand equally well with the 
opposite and accredited opinion4 ,the   
other and rival doctrine1 that of a     
direct perception or intuitive knowledge
 of the outward object as it is in      
itself1 considered as distinct from the 
sensations we receive from it1 is of far
 greater practical moment4 ,but even    

this question1 depending on the nature  
and laws of ,intuitive ,knowledge1 is   
not within the province of ,logic4 ,for 
the grounds of my own opinion concerning
 it1 ,i must content myself with        
referring to a work already             
mentioned--,an ,examination of ,sir     
,william ,hamilton's ,philosophy2       
several chapters of which are devoted to
 a full discussion of the questions and 
theories relating to the supposed direct
 perception of external objects4  #ae   
,analysis of the ,human ,mind1 i4 #abf  
et seq4  #af ,it may1 however1 be       
considered as equivalent to an universal
 proposition with a different predicate1
 viz4 ,all wine is good qu wine1 or is  
good in respect of the qualities which  
constitute it wine4  #ag ,dr4 ,whewell  
7,philosophy of ,discovery1 p4 #bdb7    
questions this statement1 and asks1 ,are
 we to say that a mole cannot dig the   
ground1 except he has an idea of the    
ground1 and of the snout and paws with  
which he digs it8 ,i do not know what   

passes in a mole's mind1 nor what amount
 of mental apprehension may or may not  
accompany his instinctive actions4 ,but 
a human being does not use a spade by   
instinct2 and he certainly could not use
 it unless he had knowledge of a spade1 
and of the earth which he uses it upon4 
#ah ,from hence also this may be        
deduced1 that the first truths were     
arbitrarily made by those that first of 
all imposed names upon things1 or       
received them from the imposition of    
others4 ,for it is true 7for example7   
that man is a living creature1 but it is
 for this reason1 that it pleased men to
 impose both these names on the same    
thing4--,computation or ,logic1 ch4 iii4
 sect4 #h4  #ai ,men are subject to err 
not only in affirming and denying1 but  
also in perception1 and in silent       
cogitation4444 ,tacit errors1 or the    
errors of sense and cogitation1 are made
 by passing from one imagination to the 
imagination of another different thing2 
or by feigning that to be past1 or      

future1 which never was1 nor ever shall 
be2 as when by seeing the image of the  
sun in water1 we imagine the sun itself 
to be there2 or by seeing swords1 that  
there has been1 or shall be1 fighting1  
because it uses to be so for the most   
part2 or when from promises we feign the
 mind of the promiser to be such and    
such2 or1 lastly1 when from any sign we 
vainly imagine something to be signified
 which is not4 ,and errors of this sort 
are common to all things that have      
sense4--,computation or ,logic1 ch4 v4  
sect4 #a4  #bj ,ch4 iii4 sect4 #c4  #ba 
,to the preceding statement it has been 
objected1 that we naturally construe the
 subject of a proposition in its        
extension1 and the predicate 7which     
therefore may be an adjective7 in its   
intension1 7connotation73 and that      
consequently coexistence of attributes  
does not1 any more than the opposite    
theory of equation of groups1 correspond
 with the living processes of thought   
and language4 ,i acknowledge the        

distinction here drawn1 which1 indeed1  
,i had myself laid down and exemplified 
a few pages back 7p4 #ajd74 ,but though 
it is true that we naturally construe   
the subject of a proposition in its     
extension1 this extension1 or in other  
words1 the extent of the class denoted  
by the name1 is not apprehended or      
indicated directly4 ,it is both         
apprehended and indicated solely through
 the attributes4 ,in the living         
processes of thought and language the   
extension1 though in this case really   
thought of 7which in the case of the    
predicate it is not71 is thought of only
 through the medium of what my acute and
 courteous critic terms the intension4  
,for further illustrations of this      
subject1 see ,examination of ,sir       
,william ,hamilton's ,philosophy1 ch4   
xxii4  #bb ,book iv4 ch4 vii4  #bc ,the 
doctrines which prevented the real      
meaning of ,essences from being         
understood1 had not assumed so settled a
 shape in the time of ,aristotle and his

 immediate followers1 as was afterwards 
given to them by the ,realists of the   
middle ages4 ,aristotle himself 7in his 
,treatise on the ,categories7 expressly 
denies that the ,greek3 deuterai ousiai1
 or ,substanti ,secund1 inhere in a     
subject4 ,they are only1 he says1       
predicated of it4  #bd ,the always acute
 and often profound author of ,an       
,outline of ,sematology 7,mr4 ,b4 ,h4   
,smart7 justly says1 ,locke will be much
 more intelligible if1 in the majority  
of places1 we substitute 'the knowledge 
of' for what he calls 'the ,idea of' 7p4
 #aj74 ,among the many criticisms on    
,locke's use of the word ,idea1 this is 
the one which1 as it appears to me1 most
 nearly hits the mark2 and ,i quote it  
for the additional reason that it       
precisely expresses the point of        
difference respecting the import of     
,propositions1 between my view and what 
,i have spoken of as the ,conceptualist 
view of them4 ,where a ,conceptualist   
says that a name or a proposition       

expresses our ,idea of a thing1 ,i      
should generally say 7instead of our    
,idea7 our ,knowledge1 or ,belief1      
concerning the thing itself4  #be ,this 
distinction corresponds to that which is
 drawn by ,kant and other metaphysicians
 between what they term analytic1 and   
synthetic1 judgments2 the former being  
those which can be evolved from the     
meaning of the terms used4  #bf ,if we  
allow a differentia to what is not      
really a species4 ,for the distinction  
of ,kinds1 in the sense explained by us1
 not being in any way applicable to     
attributes1 it of course follows that   
although attributes may be put into     
classes1 those classes can be admitted  
to be genera or species only by         
courtesy4  #bg ,in the fuller discussion
 which ,archbishop ,whately has given to
 this subject in his later editions1 he 
almost ceases to regard the definitions 
of names and those of things as1 in any 
important sense1 distinct4 ,he seems    
7#ith ed4 p4 #ade7 to limit the notion  

of a ,real ,definition to one which     
explains anything more of the nature of 
the thing than is implied in the name2  
7including under the word implied1 not  
only what the name connotes1 but        
everything which can be deduced by      
reasoning from the attributes connoted74
 ,even this1 as he adds1 is usually     
called1 not a ,definition1 but a        
,description2 and 7as it seems to me7   
rightly so called4 ,a ,description1 ,i  
conceive1 can only be ranked among      
,definitions1 when taken 7as in the case
 of the zoological definition of man7 to
 fulfil the true office of a            
,definition1 by declaring the           
connotation given to a word in some     
special use1 as a term of science or    
art3 which special connotation of course
 would not be expressed by the proper   
definition of the word in its ordinary  
employment4  ,mr4 ,de ,morgan1 exactly  
reversing the doctrine of ,archbishop   
,whately1 understands by a ,real        
,definition one which contains less than

 the ,nominal ,definition1 provided only
 that what it contains is sufficient for
 distinction4 ,by real definition ,i    
mean such an explanation of the word1 be
 it the whole of the meaning or only    
part1 as will be sufficient to separate 
the things contained under that word    
from all others4 ,thus the following1 ,i
 believe1 is a complete definition of an
 elephant3 ,an animal which naturally   
drinks by drawing the water into its    
nose1 and then spurting it into its     
mouth4--,formal ,logic1 p4 #cf4 ,mr4 ,de
 ,morgan's general proposition and his  
example are at variance2 for the        
peculiar mode of drinking of the        
elephant certainly forms no part of the 
meaning of the word elephant4 ,it could 
not be said1 because a person happened  
to be ignorant of this property1 that he
 did not know what an elephant means4   
#bh ,in the only attempt which1 so far  
as ,i know1 has been made to refute the 
preceding argumentation1 it is          
maintained that in the first form of the

 syllogism1    ,a dragon is a thing     
which breathes flame1   ,a dragon is a  
serpent1   ,therefore some serpent or   
serpents breathe flame1  there is just  
as much truth in the conclusion as there
 is in the premises1 or rather1 no more 
in the latter than in the former4 ,if   
the general name serpent includes both  
real and imaginary serpents1 there is no
 falsity in the conclusion2 if not1     
there is falsity in the minor premise4  
,let us1 then1 try to set out the       
syllogism on the hypothesis that the    
name serpent includes imaginary         
serpents4 ,we shall find that it is now 
necessary to alter the predicates2 for  
it cannot be asserted that an imaginary 
creature breathes flame3 in predicating 
of it such a fact1 we assert by the most
 positive implication that it is real   
and not imaginary4 ,the conclusion must 
run thus1 ,some serpent or serpents     
either do or are imagined to breathe    
flame4 ,and to prove this conclusion by 
the instance of dragons1 the premises   

must be1 ,a dragon is imagined as       
breathing flame1 ,a dragon is a 7real or
 imaginary7 serpent3 from which it      
undoubtedly follows1 that there are     
serpents which are imagined to breathe  
flame2 but the major premise is not a   
definition1 nor part of a definition2   
which is all that ,i am concerned to    
prove4  ,let us now examine the other   
assertion--that if the word serpent     
stands for none but real serpents1 the  
minor premise 7a dragon is a serpent7 is
 false4 ,this is exactly what ,i have   
myself said of the premise1 considered  
as a statement of fact3 but it is not   
false as part of the definition of a    
dragon2 and since the premises1 or one  
of them1 must be false1 7the conclusion 
being so17 the real premise cannot be   
the definition1 which is true1 but the  
statement of fact1 which is false4  #bi 
,few people 7,i have said in another    
place7 have reflected how great a       
knowledge of ,things is required to     
enable a man to affirm that any given   

argument turns wholly upon words4 ,there
 is1 perhaps1 not one of the leading    
terms of philosophy which is not used in
 almost innumerable shades of meaning1  
to express ideas more or less widely    
different from one another4 ,between two
 of these ideas a sagacious and         
penetrating mind will discern1 as it    
were intuitively1 an unobvious link of  
connexion1 upon which1 though perhaps   
unable to give a logical account of it1 
he will found a perfectly valid         
argument1 which his critic1 not having  
so keen an insight into the ,things1    
will mistake for a fallacy turning on   
the double meaning of a term4 ,and the  
greater the genius of him who thus      
safely leaps over the chasm1 the greater
 will probably be the crowing and       
vain-glory of the mere logician1 who1   
hobbling after him1 evinces his own     
superior wisdom by pausing on its brink1
 and giving up as desperate his proper  
business of bridging it over4     ,,book
 ,,ii4  ,,of ,,reasoning4   ,greek3     

,dirismenn de toutn legmen d1 dia tinn1 
kai pote1 kai ps ginetai pas syllogismos
 hysteron de lekteon peri apodeixes4    
,proteron gar peri syllogismou lekteon1 
peri apodeixes1 dia to katholou mallon  
einai ton syllogismon4 ,h men gar       
apodeixis1 syllogismos tis2 ho          
syllogismos de ou pas1 apodeixis4       
,,arist4 ,analyt4 ,prior4 l4 i4 cap4 #d4
     ,,chapter ,i4  ,,of ,,inference1   
,,or ,,reasoning1 ,,in ,,general4    #a4
 ,in the preceding ,book1 we have been  
occupied not with the nature of ,proof1 
but with the nature of ,assertion3 the  
import conveyed by a ,proposition1      
whether that ,proposition be true or    
false2 not the means by which to        
discriminate true from false            
,propositions4 ,the proper subject1     
however1 of ,logic is ,proof4 ,before we
 could understand what ,proof is1 it was
 necessary to understand what that is to
 which proof is applicable2 what that is
 which can be a subject of belief or    
disbelief1 of affirmation or denial2    

what1 in short1 the different kinds of  
,propositions assert4  ,this preliminary
 inquiry we have prosecuted to a        
definite result4 ,assertion1 in the     
first place1 relates either to the      
meaning of words1 or to some property of
 the things which words signify4        
,assertions respecting the meaning of   
words1 among which definitions are the  
most important1 hold a place1 and an    
indispensable one1 in philosophy2 but as
 the meaning of words is essentially    
arbitrary1 this class of assertions are 
not susceptible of truth or falsity1 nor
 therefore of proof or disproof4        
,assertions respecting ,things1 or what 
may be called ,real ,propositions1 in   
contradistinction to verbal ones1 are of
 various sorts4 ,we have analysed the   
import of each sort1 and have           
ascertained the nature of the things    
they relate to1 and the nature of what  
they severally assert respecting those  
things4 ,we found that whatever be the  
form of the proposition1 and whatever   

its nominal subject or predicate1 the   
real subject of every proposition is    
some one or more facts or phenomena of  
consciousness1 or some one or more of   
the hidden causes or powers to which we 
ascribe those facts2 and that what is   
predicated or asserted1 either in the   
affirmative or negative1 of those       
phenomena or those powers1 is always    
either ,existence1 ,order in ,place1    
,order in ,time1 ,causation1 or         
,resemblance4 ,this1 then1 is the theory
 of the ,import of ,propositions1       
reduced to its ultimate elements3 but   
there is another and a less abstruse    
expression for it1 which1 though        
stopping short in an earlier stage of   
the analysis1 is sufficiently scientific
 for many of the purposes for which such
 a general expression is required4 ,this
 expression recognises the commonly     
received distinction between ,subject   
and ,attribute1 and gives the following 
as the analysis of the meaning of       
propositions3--,every ,proposition      

asserts1 that some given subject does or
 does not possess some attribute2 or    
that some attribute is or is not 7either
 in all or in some portion of the       
subjects in which it is met with7       
conjoined with some other attribute4    
,we shall now for the present take our  
leave of this portion of our inquiry1   
and proceed to the peculiar problem of  
the ,science of ,logic1 namely1 how the 
assertions1 of which we have analysed   
the import1 are proved or disproved2    
such of them1 at least1 as1 not being   
amenable to direct consciousness or     
intuition1 are appropriate subjects of  
proof4  ,we say of a fact or statement1 
that it is proved1 when we believe its  
truth by reason of some other fact or   
statement from which it is said to      
follow4 ,most of the propositions1      
whether affirmative or negative1        
universal1 particular1 or singular1     
which we believe1 are not believed on   
their own evidence1 but on the ground of
 something previously assented to1 from 

which they are said to be inferred4 ,to 
infer a proposition from a previous     
proposition or propositions2 to give    
credence to it1 or claim credence for   
it1 as a conclusion from something else2
 is to reason1 in the most extensive    
sense of the term4 ,there is a narrower 
sense1 in which the name reasoning is   
confined to the form of inference which 
is termed ratiocination1 and of which   
the syllogism is the general type4 ,the 
reasons for not conforming to this      
restricted use of the term were stated  
in an earlier stage of our inquiry1 and 
additional motives will be suggested by 
the considerations on which we are now  
about to enter4    #b4 ,in proceeding to
 take into consideration the cases in   
which inferences can legitimately be    
drawn1 we shall first mention some cases
 in which the inference is apparent1 not
 real2 and which require notice chiefly 
that they may not be confounded with    
cases of inference properly so called4  
,this occurs when the proposition       

ostensibly inferred from another1       
appears on analysis to be merely a      
repetition of the same1 or part of the  
same1 assertion1 which was contained in 
the first4 ,all the cases mentioned in  
books of ,logic as examples of          
quipollency or equivalence of           
propositions1 are of this nature4 ,thus1
 if we were to argue1 ,no man is        
incapable of reason1 for every man is   
rational2 or1 ,all men are mortal1 for  
no man is exempt from death2 it would be
 plain that we were not proving the     
proposition1 but only appealing to      
another mode of wording it1 which may or
 may not be more readily comprehensible 
by the hearer1 or better adapted to     
suggest the real proof1 but which       
contains in itself no shadow of proof4  
,another case is where1 from an         
universal proposition1 we affect to     
infer another which differs from it only
 in being particular3 as ,all ,a is ,b1 
therefore ,some ,a is ,b3 ,no ,a is ,b1 
therefore ,some ,a is not ,b4 ,this1    

too1 is not to conclude one proposition 
from another1 but to repeat a second    
time something which had been asserted  
at first2 with the difference1 that we  
do not here repeat the whole of the     
previous assertion1 but only an         
indefinite part of it4  ,a third case is
 where1 the antecedent having affirmed a
 predicate of a given subject1 the      
consequent affirms of the same subject  
something already connoted by the former
 predicate3 as1 ,socrates is a man1     
therefore ,socrates is a living         
creature2 where all that is connoted by 
living creature was affirmed of         
,socrates when he was asserted to be a  
man4 ,if the propositions are negative1 
we must invert their order1 thus3       
,socrates is not a living creature1     
therefore he is not a man2 for if we    
deny the less1 the greater1 which       
includes it1 is already denied by       
implication4 ,these1 therefore1 are not 
really cases of inference2 and yet the  
trivial examples by which1 in manuals of

 ,logic1 the rules of the syllogism are 
illustrated1 are often of this          
ill-chosen kind2 formal demonstrations  
of conclusions to which whoever         
understands the terms used in the       
statement of the data1 has already1 and 
consciously1 assented4  ,the most       
complex case of this sort of apparent   
inference is what is called the         
,conversion of propositions2 which      
consists in turning the predicate into a
 subject1 and the subject into a        
predicate1 and framing out of the same  
terms thus reversed1 another            
proposition1 which must be true if the  
former is true4 ,thus1 from the         
particular affirmative proposition1     
,some ,a is ,b1 we may infer that ,some 
,b is ,a4 ,from the universal negative1 
,no ,a is ,b1 we may conclude that ,no  
,b is ,a4 ,from the universal           
affirmative proposition1 ,all ,a is ,b1 
it cannot be inferred that all ,b is ,a2
 though all water is liquid1 it is not  
implied that all liquid is water2 but it

 is implied that some liquid is so2 and 
hence the proposition1 ,all ,a is ,b1 is
 legitimately convertible into ,some ,b 
is ,a4 ,this process1 which converts an 
universal proposition into a particular1
 is termed conversion per accidens4     
,from the proposition1 ,some ,a is not  
,b1 we cannot even infer that some ,b is
 not ,a2 though some men are not        
,englishmen1 it does not follow that    
some ,englishmen are not men4 ,the only 
mode usually recognised of converting a 
particular negative proposition1 is in  
the form1 ,some ,a is not ,b1 therefore1
 something which is not ,b is ,a2 and   
this is termed conversion by            
contraposition4 ,in this case1 however1 
the predicate and subject are not merely
 reversed1 but one of them is changed4  
,instead of ,a and ,b1 the terms of the 
new proposition are a thing which is not
 ,b1 and ,a4 ,the original proposition1 
,some ,a is not ,b1 is first changed    
into a proposition quipollent with it1  
,some ,a is a thing which is not ,b2 and

 the proposition1 being now no longer a 
particular negative1 but a particular   
affirmative1 admits of conversion in the
 first mode1 or as it is called1 simple 
conversion4#a  ,in all these cases there
 is not really any inference2 there is  
in the conclusion no new truth1 nothing 
but what was already asserted in the    
premises1 and obvious to whoever        
apprehends them4 ,the fact asserted in  
the conclusion is either the very same  
fact1 or part of the fact asserted in   
the original proposition4 ,this follows 
from our previous analysis of the       
,import of ,propositions4 ,when we say1 
for example1 that some lawful sovereigns
 are tyrants1 what is the meaning of the
 assertion8 ,that the attributes        
connoted by the term lawful sovereign1  
and the attributes connoted by the term 
tyrant1 sometimes coexist in the same   
individual4 ,now this is also precisely 
what we mean1 when we say that some     
tyrants are lawful sovereigns2 which1   
therefore1 is not a second proposition  

inferred from the first1 any more than  
the ,english translation of ,euclid's   
,elements is a collection of theorems   
different from1 and consequences of1    
those contained in the ,greek original4 
,again1 if we assert that no great      
general is a rash man1 we mean that the 
attributes connoted by great general1   
and those connoted by rash1 never       
coexist in the same subject2 which is   
also the exact meaning which would be   
expressed by saying1 that no rash man is
 a great general4 ,when we say that all 
quadrupeds are warm-blooded1 we assert1 
not only that the attributes connoted by
 quadruped and those connoted by        
warm-blooded sometimes coexist1 but that
 the former never exist without the     
latter3 now the proposition1 ,some      
warm-blooded creatures are quadrupeds1  
expresses the first half of this        
meaning1 dropping the latter half2 and  
therefore has been already affirmed in  
the antecedent proposition1 ,all        
quadrupeds are warm-blooded4 ,but that  

all warm-blooded creatures are          
quadrupeds1 or1 in other words1 that the
 attributes connoted by warm-blooded    
never exist without those connoted by   
quadruped1 has not been asserted1 and   
cannot be inferred4 ,in order to        
reassert1 in an inverted form1 the whole
 of what was affirmed in the            
proposition1 ,all quadrupeds are        
warm-blooded1 we must convert it by     
contraposition1 thus1 ,nothing which is 
not warm-blooded is a quadruped4 ,this  
proposition1 and the one from which it  
is derived1 are exactly equivalent1 and 
either of them may be substituted for   
the other2 for1 to say that when the    
attributes of a quadruped are present1  
those of a warm-blooded creature are    
present1 is to say that when the latter 
are absent the former are absent4  ,in a
 manual for young students1 it would be 
proper to dwell at greater length on the
 conversion and quipollency of          
propositions4 ,for1 though that cannot  
be called reasoning or inference which  

is a mere reassertion in different words
 of what had been asserted before1 there
 is no more important intellectual      
habit1 nor any the cultivation of which 
falls more strictly within the province 
of the art of logic1 than that of       
discerning rapidly and surely the       
identity of an assertion when disguised 
under diversity of language4 ,that      
important chapter in logical treatises  
which relates to the ,opposition of     
,propositions1 and the excellent        
technical language which logic provides 
for distinguishing the different kinds  
or modes of opposition1 are of use      
chiefly for this purpose4 ,such         
considerations as these1 that contrary  
propositions may both be false1 but     
cannot both be true2 that subcontrary   
propositions may both be true1 but      
cannot both be false2 that of two       
contradictory propositions one must be  
true and the other false2 that of two   
subalternate propositions the truth of  
the universal proves the truth of the   

particular1 and the falsity of the      
particular proves the falsity of the    
universal1 but not vice vers2#b are apt 
to appear1 at first sight1 very         
technical and mysterious1 but when      
explained1 seem almost too obvious to   
require so formal a statement1 since the
 same amount of explanation which is    
necessary to make the principles        
intelligible1 would enable the truths   
which they convey to be apprehended in  
any particular case which can occur4 ,in
 this respect1 however1 these axioms of 
logic are on a level with those of      
mathematics4 ,that things which are     
equal to the same thing are equal to one
 another1 is as obvious in any          
particular case as it is in the general 
statement3 and if no such general maxim 
had ever been laid down1 the            
demonstrations in ,euclid would never   
have halted for any difficulty in       
stepping across the gap which this axiom
 at present serves to bridge over4 ,yet 
no one has ever censured writers on     

geometry1 for placing a list of these   
elementary generalizations at the head  
of their treatises1 as a first exercise 
to the learner of the faculty which will
 be required in him at every step1 that 
of apprehending a general truth4 ,and   
the student of logic1 in the discussion 
even of such truths as we have cited    
above1 acquires habits of circumspect   
interpretation of words1 and of exactly 
measuring the length and breadth of his 
assertions1 which are among the most    
indispensable conditions of any         
considerable mental attainment1 and     
which it is one of the primary objects  
of logical discipline to cultivate4     
#c4 ,having noticed1 in order to exclude
 from the province of ,reasoning or     
,inference properly so called1 the cases
 in which the progression from one truth
 to another is only apparent1 the       
logical consequent being a mere         
repetition of the logical antecedent2 we
 now pass to those which are cases of   
inference in the proper acceptation of  

the term1 those in which we set out from
 known truths1 to arrive at others      
really distinct from them4  ,reasoning1 
in the extended sense in which ,i use   
the term1 and in which it is synonymous 
with ,inference1 is popularly said to be
 of two kinds3 reasoning from           
particulars to generals1 and reasoning  
from generals to particulars2 the former
 being called ,induction1 the latter    
,ratiocination or ,syllogism4 ,it will  
presently be shown that there is a third
 species of reasoning1 which falls under
 neither of these descriptions1 and     
which1 nevertheless1 is not only valid1 
but is the foundation of both the       
others4  ,it is necessary to observe1   
that the expressions1 reasoning from    
particulars to generals1 and reasoning  
from generals to particulars1 are       
recommended by brevity rather than by   
precision1 and do not adequately mark1  
without the aid of a commentary1 the    
distinction between ,induction 7in the  
sense now adverted to7 and              

,ratiocination4 ,the meaning intended by
 these expressions is1 that ,induction  
is inferring a proposition from         
propositions less general than itself1  
and ,ratiocination is inferring a       
proposition from propositions equally or
 more general4 ,when1 from the          
observation of a number of individual   
instances1 we ascend to a general       
proposition1 or when1 by combining a    
number of general propositions1 we      
conclude from them another proposition  
still more general1 the process1 which  
is substantially the same in both       
instances1 is called ,induction4 ,when  
from a general proposition1 not alone   
7for from a single proposition nothing  
can be concluded which is not involved  
in the terms71 but by combining it with 
other propositions1 we infer a          
proposition of the same degree of       
generality with itself1 or a less       
general proposition1 or a proposition   
merely individual1 the process is       
,ratiocination4 ,when1 in short1 the    

conclusion is more general than the     
largest of the premises1 the argument is
 commonly called ,induction2 when less  
general1 or equally general1 it is      
,ratiocination4  ,as all experience     
begins with individual cases1 and       
proceeds from them to generals1 it might
 seem most conformable to the natural   
order of thought that ,induction should 
be treated of before we touch upon      
,ratiocination4 ,it will1 however1 be   
advantageous1 in a science which aims at
 tracing our acquired knowledge to its  
sources1 that the inquirer should       
commence with the latter rather than    
with the earlier stages of the process  
of constructing our knowledge2 and      
should trace derivative truths backward 
to the truths from which they are       
deduced1 and on which they depend for   
their evidence1 before attempting to    
point out the original spring from which
 both ultimately take their rise4 ,the  
advantages of this order of proceeding  
in the present instance will manifest   

themselves as we advance1 in a manner   
superseding the necessity of any further
 justification or explanation4  ,of     
,induction1 therefore1 we shall say no  
more at present1 than that it at least  
is1 without doubt1 a process of real    
inference4 ,the conclusion in an        
induction embraces more than is         
contained in the premises4 ,the         
principle or law collected from         
particular instances1 the general       
proposition in which we embody the      
result of our experience1 covers a much 
larger extent of ground than the        
individual experiments which form its   
basis4 ,a principle ascertained by      
experience1 is more than a mere summing 
up of what has been specifically        
observed in the individual cases which  
have been examined2 it is a             
generalization grounded on those cases1 
and expressive of our belief1 that what 
we there found true is true in an       
indefinite number of cases which we have
 not examined1 and are never likely to  

examine4 ,the nature and grounds of this
 inference1 and the conditions necessary
 to make it legitimate1 will be the     
subject of discussion in the ,third     
,book3 but that such inference really   
takes place is not susceptible of       
question4 ,in every induction we proceed
 from truths which we knew1 to truths   
which we did not know2 from facts       
certified by observation1 to facts which
 we have not observed1 and even to facts
 not capable of being now observed2     
future facts1 for example2 but which we 
do not hesitate to believe on the sole  
evidence of the induction itself4       
,induction1 then1 is a real process of  
,reasoning or ,inference4 ,whether1 and 
in what sense1 as much can be said of   
the ,syllogism1 remains to be determined
 by the examination into which we are   
about to enter4     ,,chapter ,,ii4     
,,of ,,ratiocination1 ,,or ,,syllogism4 
#a4 ,the analysis of the ,syllogism has 
been so accurately and fully performed  
in the common manuals of ,logic1 that in

 the present work1 which is not designed
 as a manual1 it is sufficient to       
recapitulate1 memori caus1 the leading  
results of that analysis1 as a          
foundation for the remarks to be        
afterwards made on the functions of the 
syllogism1 and the place which it holds 
in science4  ,to a legitimate syllogism 
it is essential that there should be    
three1 and no more than three1          
propositions1 namely1 the conclusion1 or
 proposition to be proved1 and two other
 propositions which together prove it1  
and which are called the premises4 ,it  
is essential that there should be three1
 and no more than three1 terms1 namely1 
the subject and predicate of the        
conclusion1 and another called the      
middleterm1 which must be found in both 
premises1 since it is by means of it    
that the other two terms are to be      
connected together4 ,the predicate of   
the conclusion is called the major term 
of the syllogism2 the subject of the    
conclusion is called the minor term4 ,as

 there can be but three terms1 the major
 and minor terms must each be found in  
one1 and only one1 of the premises1     
together with the middleterm which is in
 them both4 ,the premise which contains 
the middleterm and the major term is    
called the major premise2 that which    
contains the middleterm and the minor   
term is called the minor premise4       
,syllogisms are divided by some         
logicians into three figures1 by others 
into four1 according to the position of 
the middleterm1 which may either be the 
subject in both premises1 the predicate 
in both1 or the subject in one and the  
predicate in the other4 ,the most common
 case is that in which the middleterm is
 the subject of the major premise and   
the predicate of the minor4 ,this is    
reckoned as the first figure4 ,when the 
middleterm is the predicate in both     
premises1 the syllogism belongs to the  
second figure2 when it is the subject in
 both1 to the third4 ,in the fourth     
figure the middleterm is the subject of 

the minor premise and the predicate of  
the major4 ,those writers who reckon no 
more than three figures1 include this   
case in the first4  ,each figure is     
divided into moods1 according to what   
are called the quantity and quality of  
the propositions1 that is1 according as 
they are universal or particular1       
affirmative or negative4 ,the following 
are examples of all the legitimate      
moods1 that is1 all those in which the  
conclusion correctly follows from the   
premises4 ,a is the minor term1 ,c the  
major1 ,b the middleterm4  ,,first      
,,figure4    ,all ,b is ,c    ,no ,b is 
,c     ,all ,b is ,c     ,no ,b is ,c   
,all ,a is ,b    ,all ,a is ,b    ,some 
,a is ,b    ,some ,a is ,b     therefore
     therefore     therefore            
therefore   ,all ,a is ,c    ,no ,a is  
,c     ,some ,a is ,c    ,some ,a is not
 ,c  ,,second ,,figure4    ,no ,c is ,b 
,all ,c is ,b    ,no ,c is ,b           
,all ,c is ,b   ,all ,a is ,b    ,no ,a 
is ,b     ,some ,a is ,b       ,some ,a 

is not ,b     therefore     therefore   
therefore         therefore   ,no ,a is 
,c     ,no ,a is ,c     ,some ,a is not 
,c   ,some ,a is not ,c  ,,third        
,,figure4    ,all ,b is ,c   ,no ,b is  
,c    ,some ,b is ,c  ,all ,b is ,c     
,some ,b      ,no ,b is ,c              
is not ,c   ,all ,b is ,a   ,all ,b is  
,a   ,all ,b is ,a   ,some ,b is ,a     
,all ,b is ,a  ,some ,b is ,a           
therefore    therefore    therefore     
therefore    therefore   therefore      
,some ,a is ,c  ,some ,a       ,some ,a 
is ,c  ,some ,a is ,c  ,some ,a         
,some ,a                  is not ,c     
is not ,c    is not ,c  ,,fourth        
,,figure4    ,all ,c is ,b   ,all ,c is 
,b       ,some ,c is ,b  ,no ,c is ,b   
,no ,c is ,b   ,all ,b is ,a   ,no ,b is
 ,a        ,all ,b is ,a   ,all ,b is ,a
       ,some ,b is ,a     therefore     
therefore        therefore    therefore 
therefore   ,some ,a is ,c  ,some ,a is 
not ,c  ,some ,a is ,c  ,some ,a is not 
,c  ,some ,a is not ,c  ,in these       

exemplars1 or blank forms for making    
syllogisms1 no place is assigned to     
singular propositions2 not1 of course1  
because such propositions are not used  
in ratiocination1 but because1 their    
predicate being affirmed or denied of   
the whole of the subject1 they are      
ranked1 for the purposes of the         
syllogism1 with universal propositions4 
,thus1 these two syllogisms--    ,all   
men are mortal1      ,all men are       
mortal1   ,all kings are men1           
,socrates is a man1     therefore       
therefore   ,all kings are mortal1      
,socrates is mortal1  are arguments     
precisely similar1 and are both ranked  
in the first mood of the first figure4  
,the reasons why syllogisms in any of   
the above forms are legitimate1 that is1
 why1 if the premises are true1 the     
conclusion must inevitably be so1 and   
why this is not the case in any other   
possible mood1 7that is1 in any other   
combination of universal and particular1
 affirmative and negative propositions17

 any person taking interest in these    
inquiries may be presumed to have either
 learned from the common school books of
 the syllogistic logic1 or to be capable
 of discovering for himself4 ,the reader
 may1 however1 be referred1 for every   
needful explanation1 to ,archbishop     
,whately's ,elements of ,logic1 where he
 will find stated with philosophical    
precision1 and explained with remarkable
 perspicuity1 the whole of the common   
doctrine of the syllogism4  ,all valid  
ratiocination2 all reasoning by which1  
from general propositions previously    
admitted1 other propositions equally or 
less general are inferred2 may be       
exhibited in some of the above forms4   
,the whole of ,euclid1 for example1     
might be thrown without difficulty into 
a series of syllogisms1 regular in mood 
and figure4  ,though a syllogism framed 
according to any of these formul is a   
valid argument1 all correct             
ratiocination admits of being stated in 
syllogisms of the first figure alone4   

,the rules for throwing an argument in  
any of the other figures into the first 
figure1 are called rules for the        
reduction of syllogisms4 ,it is done by 
the conversion of one or other1 or both1
 of the premises4 ,thus an argument in  
the first mood of the second figure1    
as--    ,no ,c is ,b   ,all ,a is ,b    
therefore   ,no ,a is ,c1  may be       
reduced as follows4 ,the proposition1   
,no ,c is ,b1 being an universal        
negative1 admits of simple conversion1  
and may be changed into ,no ,b is ,c1   
which1 as we showed1 is the very same   
assertion in other words--the same fact 
differently expressed4 ,this            
transformation having been effected1 the
 argument assumes the following form3-- 
,no ,b is ,c   ,all ,a is ,b            
therefore   ,no ,a is ,c1  which is a   
good syllogism in the second mood of the
 first figure4 ,again1 an argument in   
the first mood of the third figure must 
resemble the following3--    ,all ,b is 
,c   ,all ,b is ,a     therefore   ,some

 ,a is ,c1  where the minor premise1    
,all ,b is ,a1 conformably to what was  
laid down in the last chapter respecting
 universal affirmatives1 does not admit 
of simple conversion1 but may be        
converted per accidens1 thus1 ,some ,a  
is ,b2 which1 though it does not express
 the whole of what is asserted in the   
proposition ,all ,b is ,a1 expresses1 as
 was formerly shown1 part of it1 and    
must therefore be true if the whole is  
true4 ,we have1 then1 as the result of  
the reduction1 the following syllogism  
in the third mood of the first figure3--
    ,all ,b is ,c   ,some ,a is ,b1     
from which it obviously follows1 that   
,some ,a is ,c4  ,in the same manner1 or
 in a manner on which after these       
examples it is not necessary to enlarge1
 every mood of the second1 third1 and   
fourth figures may be reduced to some   
one of the four moods of the first4 ,in 
other words1 every conclusion which can 
be proved in any of the last three      
figures1 may be proved in the first     

figure from the same premises1 with a   
slight alteration in the mere manner of 
expressing them4 ,every valid           
ratiocination1 therefore1 may be stated 
in the first figure1 that is1 in one of 
the following forms3--    ,every ,b is  
,c            ,no ,b is ,c   ,all ,a    
is ,b1        ,all ,a    is ,b1   ,some 
,a                 ,some ,a             
therefore               therefore   ,all
 ,a     is ,c4        ,no ,a is         
,c4   ,some ,a                 ,some ,a 
is not    ,or if more significant       
symbols are preferred3--  ,to prove an  
affirmative1 the argument must admit of 
being stated in this form3--    ,all    
animals are mortal2   ,all men          
,some men    are animals2   ,socrates   
therefore   ,all men      ,some men     
are mortal4   ,socrates    ,to prove a  
negative1 the argument must be capable  
of being expressed in this form3--      
,no one who is capable of self-control  
is necessarily vicious2   ,all negroes  
,some negroes    are capable of         

self-control2   ,mr4 ,a's negro         
therefore   ,no negroes are             
,some negroes are not    necessarily    
vicious4   ,mr4 ,a's negro is not       
,though all ratiocination admits of     
being thrown into one or the other of   
these forms1 and sometimes gains        
considerably by the transformation1 both
 in clearness and in the obviousness of 
its consequence2 there are1 no doubt1   
cases in which the argument falls more  
naturally into one of the other three   
figures1 and in which its conclusiveness
 is more apparent at the first glance in
 those figures1 than when reduced to the
 first4 ,thus1 if the proposition were  
that pagans may be virtuous1 and the    
evidence to prove it were the example of
 ,aristides2 a syllogism in the third   
figure1    ,aristides was virtuous1     
,aristides was a pagan1        therefore
   ,some pagan was virtuous1  would be a
 more natural mode of stating the       
argument1 and would carry conviction    
more instantly home1 than the same      

ratiocination strained into the first   
figure1 thus--    ,aristides was        
virtuous1   ,some pagan was ,aristides1 
therefore   ,some pagan was virtuous4   
,a ,german philosopher1 ,lambert1 whose 
,neues ,organon 7published in the year  
#agfd7 contains among other things one  
of the most elaborate and complete      
expositions which had ever been made of 
the syllogistic doctrine1 has expressly 
examined what sort of arguments fall    
most naturally and suitably into each of
 the four figures2 and his investigation
 is characterized by great ingenuity and
 clearness of thought4#c ,the argument1 
however1 is one and the same1 in        
whichever figure it is expressed2 since1
 as we have already seen1 the premises  
of a syllogism in the second1 third1 or 
fourth figure1 and those of the         
syllogism in the first figure to which  
it may be reduced1 are the same premises
 in everything except language1 or1 at  
least1 as much of them as contributes to
 the proof of the conclusion is the     

same4 ,we are therefore at liberty1 in  
conformity with the general opinion of  
logicians1 to consider the two          
elementary forms of the first figure as 
the universal types of all correct      
ratiocination2 the one1 when the        
conclusion to be proved is affirmative1 
the other1 when it is negative2 even    
though certain arguments may have a     
tendency to clothe themselves in the    
forms of the second1 third1 and fourth  
figures2 which1 however1 cannot possibly
 happen with the only class of arguments
 which are of first-rate scientific     
importance1 those in which the          
conclusion is an universal affirmative1 
such conclusions being susceptible of   
proof in the first figure alone4#d      
#b4 ,on examining1 then1 these two      
general formul1 we find that in both of 
them1 one premise1 the major1 is an     
universal proposition2 and according as 
this is affirmative or negative1 the    
conclusion is so too4 ,all              
ratiocination1 therefore1 starts from a 

general proposition1 principle1 or      
assumption3 a proposition in which a    
predicate is affirmed or denied of an   
entire class2 that is1 in which some    
attribute1 or the negation of some      
attribute1 is asserted of an indefinite 
number of objects distinguished by a    
common characteristic1 and designated in
 consequence1 by a common name4  ,the   
other premise is always affirmative1 and
 asserts that something 7which may be   
either an individual1 a class1 or part  
of a class7 belongs to1 or is included  
in1 the class respecting which something
 was affirmed or denied in the major    
premise4 ,it follows that the attribute 
affirmed or denied of the entire class  
may 7if that affirmation or denial was  
correct7 be affirmed or denied of the   
object or objects alleged to be included
 in the class3 and this is precisely the
 assertion made in the conclusion4      
,whether or not the foregoing is an     
adequate account of the constituent     
parts of the syllogism1 will be         

presently considered2 but as far as it  
goes it is a true account4 ,it has      
accordingly been generalized1 and       
erected into a logical maxim1 on which  
all ratiocination is said to be founded1
 insomuch that to reason1 and to apply  
the maxim1 are supposed to be one and   
the same thing4 ,the maxim is1 ,that    
whatever can be affirmed 7or denied7 of 
a class1 may be affirmed 7or denied7 of 
everything included in the class4 ,this 
axiom1 supposed to be the basis of the  
syllogistic theory1 is termed by        
logicians the dictum de omni et nullo4  
,this maxim1 however1 when considered as
 a principle of reasoning1 appears      
suited to a system of metaphysics once  
indeed generally received1 but which for
 the last two centuries has been        
considered as finally abandoned1 though 
there have not been wanting in our own  
day attempts at its revival4 ,so long as
 what are termed ,universals were       
regarded as a peculiar kind of          
substances1 having an objective         

existence distinct from the individual  
objects classed under them1 the dictum  
de omni conveyed an important meaning2  
because it expressed the intercommunity 
of nature1 which it was necessary on    
that theory that we should suppose to   
exist between those general substances  
and the particular substances which were
 subordinated to them4 ,that everything 
predicable of the universal was         
predicable of the various individuals   
contained under it1 was then no         
identical proposition1 but a statement  
of what was conceived as a fundamental  
law of the universe4 ,the assertion that
 the entire nature and properties of the
 substantia secunda formed part of the  
nature and properties of each of the    
individual substances called by the same
 name2 that the properties of ,man1 for 
example1 were properties of all men2 was
 a proposition of real significance when
 man did not mean all men1 but something
 inherent in men1 and vastly superior to
 them in dignity4 ,now1 however1 when it

 is known that a class1 an universal1 a 
genus or species1 is not an entity per  
se1 but neither more nor less than the  
individual substances themselves which  
are placed in the class1 and that there 
is nothing real in the matter except    
those objects1 a common name given to   
them1 and common attributes indicated by
 the name2 what1 ,i should be glad to   
know1 do we learn by being told1 that   
whatever can be affirmed of a class1 may
 be affirmed of every object contained  
in the class8 ,the class is nothing but 
the objects contained in it3 and the    
dictum de omni merely amounts to the    
identical proposition1 that whatever is 
true of certain objects1 is true of each
 of those objects4 ,if all ratiocination
 were no more than the application of   
this maxim to particular cases1 the     
syllogism would indeed be1 what it has  
so often been declared to be1 solemn    
trifling4 ,the dictum de omni is on a   
par with another truth1 which in its    
time was also reckoned of great         

importance1 ,whatever is1 is4 ,to give  
any real meaning to the dictum de omni1 
we must consider it not as an axiom1 but
 as a definition2 we must look upon it  
as intended to explain1 in a circuitous 
and paraphrastic manner1 the meaning of 
the word1 class4  ,an error which seemed
 finally refuted and dislodged from     
thought1 often needs only put on a new  
suit of phrases1 to be welcomed back to 
its old quarters1 and allowed to repose 
unquestioned for another cycle of ages4 
,modern philosophers have not been      
sparing in their contempt for the       
scholastic dogma that genera and species
 are a peculiar kind of substances1     
which general substances being the only 
permanent things1 while the individual  
substances comprehended under them are  
in a perpetual flux1 knowledge1 which   
necessarily imports stability1 can only 
have relation to those general          
substances or universals1 and not to the
 facts or particulars included under    
them4 ,yet1 though nominally rejected1  

this very doctrine1 whether disguised   
under the ,abstract ,ideas of ,locke    
7whose speculations1 however1 it has    
less vitiated than those of perhaps any 
other writer who has been infected with 
it71 under the ultra-nominalism of      
,hobbes and ,condillac1 or the ontology 
of the later ,kantians1 has never ceased
 to poison philosophy4 ,once accustomed 
to consider scientific investigation as 
essentially consisting in the study of  
universals1 men did not drop this habit 
of thought when they ceased to regard   
universals as possessing an independent 
existence3 and even those who went the  
length of considering them as mere      
names1 could not free themselves from   
the notion that the investigation of    
truth consisted entirely or partly in   
some kind of conjuration or juggle with 
those names4 ,when a philosopher adopted
 fully the ,nominalist view of the      
signification of general language1      
retaining along with it the dictum de   
omni as the foundation of all reasoning1

 two such premises fairly put together  
were likely1 if he was a consistent     
thinker1 to land him in rather startling
 conclusions4 ,accordingly it has been  
seriously held1 by writers of deserved  
celebrity1 that the process of arriving 
at new truths by reasoning consists in  
the mere substitution of one set of     
arbitrary signs for another2 a doctrine 
which they suppose to derive            
irresistible confirmation from the      
example of algebra4 ,if there were any  
process in sorcery or necromancy more   
preternatural than this1 ,i should be   
much surprised4 ,the culminating point  
of this philosophy is the noted aphorism
 of ,condillac1 that a science is       
nothing1 or scarcely anything1 but une  
langue bien faite2 in other words1 that 
the one sufficient rule for discovering 
the nature and properties of objects is 
to name them properly3 as if the reverse
 were not the truth1 that it is         
impossible to name them properly except 
in proportion as we are already         

acquainted with their nature and        
properties4 ,can it be necessary to say1
 that none1 not even the most trivial   
knowledge with respect to ,things1 ever 
was or could be originally got at by any
 conceivable manipulation of mere names1
 as such2 and that what can be learned  
from names1 is only what somebody who   
used the names knew before8             
,philosophical analysis confirms the    
indication of common sense1 that the    
function of names is but that of        
enabling us to remember and to          
communicate our thoughts4 ,that they    
also strengthen1 even to an incalculable
 extent1 the power of thought itself1 is
 most true3 but they do this by no      
intrinsic and peculiar virtue2 they do  
it by the power inherent in an          
artificial memory1 an instrument of     
which few have adequately considered the
 immense potency4 ,as an artificial     
memory1 language truly is1 what it has  
so often been called1 an instrument of  
thought2 but it is one thing to be the  

instrument1 and another to be the       
exclusive subject upon which the        
instrument is exercised4 ,we think1     
indeed1 to a considerable extent1 by    
means of names1 but what we think of1   
are the things called by those names2   
and there cannot be a greater error than
 to imagine that thought can be carried 
on with nothing in our mind but names1  
or that we can make the names think for 
us4    #c4 ,those who considered the    
dictum de omni as the foundation of the 
syllogism1 looked upon arguments in a   
manner corresponding to the erroneous   
view which ,hobbes took of propositions4
 ,because there are some propositions   
which are merely verbal1 ,hobbes1 in    
order apparently that his definition    
might be rigorously universal1 defined a
 proposition as if no propositions      
declared anything except the meaning of 
words4 ,if ,hobbes was right2 if no     
further account than this could be given
 of the import of propositions2 no      
theory could be given but the commonly  

received one1 of the combination of     
propositions in a syllogism4 ,if the    
minor premise asserted nothing more than
 that something belongs to a class1 and 
if the major premise asserted nothing of
 that class except that it is included  
in another class1 the conclusion would  
only be that what was included in the   
lower class is included in the higher1  
and the result1 therefore1 nothing      
except that the classification is       
consistent with itself4 ,but we have    
seen that it is no sufficient account of
 the meaning of a proposition1 to say   
that it refers something to1 or excludes
 something from1 a class4 ,every        
proposition which conveys real          
information asserts a matter of fact1   
dependent on the laws of nature1 and not
 on classification4 ,it asserts that a  
given object does or does not possess a 
given attribute2 or it asserts that two 
attributes1 or sets of attributes1 do or
 do not 7constantly or occasionally7    
coexist4 ,since such is the purport of  

all propositions which convey any real  
knowledge1 and since ratiocination is a 
mode of acquiring real knowledge1 any   
theory of ratiocination which does not  
recognise this import of propositions1  
cannot1 we may be sure1 be the true one4
  ,applying this view of propositions to
 the two premises of a syllogism1 we    
obtain the following results4 ,the major
 premise1 which1 as already remarked1 is
 always universal1 asserts1 that all    
things which have a certain attribute   
7or attributes7 have or have not along  
with it1 a certain other attribute 7or  
attributes74 ,the minor premise asserts 
that the thing or set of things which   
are the subject of that premise1 have   
the first-mentioned attribute2 and the  
conclusion is1 that they have 7or that  
they have not7 the second4 ,thus in our 
former example1    ,all men are mortal1 
,socrates is a man1         therefore   
,socrates is mortal1  the subject and   
predicate of the major premise are      
connotative terms1 denoting objects and 

connoting attributes4 ,the assertion in 
the major premise is1 that along with   
one of the two sets of attributes1 we   
always find the other3 that the         
attributes connoted by man never exist  
unless conjoined with the attribute     
called mortality4 ,the assertion in the 
minor premise is that the individual    
named ,socrates possesses the former    
attributes2 and it is concluded that he 
possesses also the attribute mortality4 
,or if both the premises are general    
propositions1 as    ,all men are mortal1
   ,all kings are men1         therefore
   ,all kings are mortal1  the minor    
premise asserts that the attributes     
denoted by kingship only exist in       
conjunction with those signified by the 
word man4 ,the major asserts as before1 
that the last-mentioned attributes are  
never found without the attribute of    
mortality4 ,the conclusion is1 that     
wherever the attributes of kingship are 
found1 that of mortality is found also4 
,if the major premise were negative1 as1

 ,no men are omnipotent1 it would       
assert1 not that the attributes connoted
 by man never exist without1 but that   
they never exist with1 those connoted by
 omnipotent3 from which1 together with  
the minor premise1 it is concluded1 that
 the same incompatibility exists between
 the attribute omnipotence and those    
constituting a king4 ,in a similar      
manner we might analyse any other       
example of the syllogism4  ,if we       
generalize this process1 and look out   
for the principle or law involved in    
every such inference1 and presupposed in
 every syllogism1 the propositions of   
which are anything more than merely     
verbal2 we find1 not the unmeaning      
dictum de omni et nullo1 but a          
fundamental principle1 or rather two    
principles1 strikingly resembling the   
axioms of mathematics4 ,the first1 which
 is the principle of affirmative        
syllogisms1 is1 that things which       
coexist with the same thing1 coexist    
with one another4 ,the second is the    

principle of negative syllogisms1 and is
 to this effect3 that a thing which     
coexists with another thing1 with which 
other a third thing does not coexist1 is
 not coexistent with that third thing4  
,these axioms manifestly relate to      
facts1 and not to conventions2 and one  
or other of them is the ground of the   
legitimacy of every argument in which   
facts and not conventions are the matter
 treated of4#e    #d4 ,it remains to    
translate this exposition of the        
syllogism from the one into the other of
 the two languages in which we formerly 
remarked#f that all propositions1 and of
 course therefore all combinations of   
propositions1 might be expressed4 ,we   
observed that a proposition might be    
considered in two different lights2 as a
 portion of our knowledge of nature1 or 
as a memorandum for our guidance4 ,under
 the former1 or speculative aspect1 an  
affirmative general proposition is an   
assertion of a speculative truth1 viz4  
that whatever has a certain attribute   

has a certain other attribute4 ,under   
the other aspect1 it is to be regarded  
not as a part of our knowledge1 but as  
an aid for our practical exigencies1 by 
enabling us1 when we see or learn that  
an object possesses one of the two      
attributes1 to infer that it possesses  
the other2 thus employing the first     
attribute as a mark or evidence of the  
second4 ,thus regarded1 every syllogism 
comes within the following general      
formula3--    ,attribute ,a is a mark of
 attribute ,b1   ,the given object has  
the mark ,a1               therefore    
,the given object has the attribute ,b4 
,referred to this type1 the arguments   
which we have lately cited as specimens 
of the syllogism1 will express          
themselves in the following manner3--   
,the attributes of man are a mark of the
 attribute mortality1   ,socrates has   
the attributes of man1                  
therefore   ,socrates has the attribute 
mortality4  ,and again1    ,the         
attributes of man are a mark of the     

attribute mortality1   ,the attributes  
of a king are a mark of the attributes  
of man1                                 
therefore   ,the attributes of a king   
are a mark of the attribute mortality4  
,and1 lastly1    ,the attributes of man 
are a mark of the absence of     the    
attribute omnipotence1   ,the attributes
 of a king are a mark of the attributes 
of man1                                 
therefore   ,the attributes of a king   
are a mark of the absence of     the    
attribute signified by the word         
omnipotent     7or1 are evidence of the 
absence of that attribute74  ,to        
correspond with this alteration in the  
form of the syllogisms1 the axioms on   
which the syllogistic process is founded
 must undergo a corresponding           
transformation4 ,in this altered        
phraseology1 both those axioms may be   
brought under one general expression2   
namely1 that whatever has any mark1 has 
that which it is a mark of4 ,or1 when   
the minor premise as well as the major  

is universal1 we may state it thus3     
,whatever is a mark of any mark1 is a   
mark of that which this last is a mark  
of4 ,to trace the identity of these     
axioms with those previously laid down1 
may be left to the intelligent reader4  
,we shall find1 as we proceed1 the great
 convenience of the phraseology into    
which we have last thrown them1 and     
which is better adapted than any ,i am  
acquainted with1 to express with        
precision and force what is aimed at1   
and actually accomplished1 in every case
 of the ascertainment of a truth by     
ratiocination4     ,,chapter ,,iii4     
,,of ,,the ,,functions ,,and ,,logical  
,,value ,,of ,,the ,,syllogism4    #a4  
,we have shown what is the real nature  
of the truths with which the ,syllogism 
is conversant1 in contradistinction to  
the more superficial manner in which    
their import is conceived in the common 
theory2 and what are the fundamental    
axioms on which its probative force or  
conclusiveness depends4 ,we have now to 

inquire1 whether the syllogistic        
process1 that of reasoning from generals
 to particulars1 is1 or is not1 a       
process of inference2 a progress from   
the known to the unknown3 a means of    
coming to a knowledge of something which
 we did not know before4  ,logicians    
have been remarkably unanimous in their 
mode of answering this question4 ,it is 
universally allowed that a syllogism is 
vicious if there be anything more in the
 conclusion than was assumed in the     
premises4 ,but this is1 in fact1 to say1
 that nothing ever was1 or can be1      
proved by syllogism1 which was not      
known1 or assumed to be known1 before4  
,is ratiocination1 then1 not a process  
of inference8 ,and is the syllogism1 to 
which the word reasoning has so often   
been represented to be exclusively      
appropriate1 not really entitled to be  
called reasoning at all8 ,this seems an 
inevitable consequence of the doctrine1 
admitted by all writers on the subject1 
that a syllogism can prove no more than 

is involved in the premises4 ,yet the   
acknowledgment so explicitly made1 has  
not prevented one set of writers from   
continuing to represent the syllogism as
 the correct analysis of what the mind  
actually performs in discovering and    
proving the larger half of the truths1  
whether of science or of daily life1    
which we believe2 while those who have  
avoided this inconsistency1 and followed
 out the general theorem respecting the 
logical value of the syllogism to its   
legitimate corollary1 have been led to  
impute uselessness and frivolity to the 
syllogistic theory itself1 on the ground
 of the petitio principii which they    
allege to be inherent in every          
syllogism4 ,as ,i believe both these    
opinions to be fundamentally erroneous1 
,i must request the attention of the    
reader to certain considerations1       
without which any just appreciation of  
the true character of the syllogism1 and
 the functions it performs in           
philosophy1 appears to me impossible2   

but which seem to have been either      
overlooked1 or insufficiently adverted  
to1 both by the defenders of the        
syllogistic theory and by its           
assailants4    #b4 ,it must be granted  
that in every syllogism1 considered as  
an argument to prove the conclusion1    
there is a petitio principii4 ,when we  
say1    ,all men are mortal1   ,socrates
 is a man1       therefore   ,socrates  
is mortal2  it is unanswerably urged by 
the adversaries of the syllogistic      
theory1 that the proposition1 ,socrates 
is mortal1 is presupposed in the more   
general assumption1 ,all men are mortal3
 that we cannot be assured of the       
mortality of all men1 unless we are     
already certain of the mortality of     
every individual man3 that if it be     
still doubtful whether ,socrates1 or any
 other individual we choose to name1 be 
mortal or not1 the same degree of       
uncertainty must hang over the          
assertion1 ,all men are mortal3 that the
 general principle1 instead of being    

given as evidence of the particular     
case1 cannot itself be taken for true   
without exception1 until every shadow of
 doubt which could affect any case      
comprised with it1 is dispelled by      
evidence aliund2 and then what remains  
for the syllogism to prove8 ,that1 in   
short1 no reasoning from generals to    
particulars can1 as such1 prove         
anything3 since from a general principle
 we cannot infer any particulars1 but   
those which the principle itself assumes
 as known4  ,this doctrine appears to me
 irrefragable2 and if logicians1 though 
unable to dispute it1 have usually      
exhibited a strong disposition to       
explain it away1 this was not because   
they could discover any flaw in the     
argument itself1 but because the        
contrary opinion seemed to rest on      
arguments equally indisputable4 ,in the 
syllogism last referred to1 for example1
 or in any of those which we previously 
constructed1 is it not evident that the 
conclusion may1 to the person to whom   

the syllogism is presented1 be actually 
and bon fide a new truth8 ,is it not    
matter of daily experience that truths  
previously unthought of1 facts which    
have not been1 and cannot be1 directly  
observed1 are arrived at by way of      
general reasoning8 ,we believe that the 
,duke of ,wellington is mortal4 ,we do  
not know this by direct observation1 so 
long as he is not yet dead4 ,if we were 
asked how1 this being the case1 we know 
the duke to be mortal1 we should        
probably answer1 ,because all men are   
so4 ,here1 therefore1 we arrive at the  
knowledge of a truth not 7as yet7       
susceptible of observation1 by a        
reasoning which admits of being         
exhibited in the following syllogism3-- 
,all men are mortal1   ,the ,duke of    
,wellington is a man1                   
therefore   ,the ,duke of ,wellington is
 mortal4  ,and since a large portion of 
our knowledge is thus acquired1         
logicians have persisted in representing
 the syllogism as a process of inference

 or proof2 though none of them has      
cleared up the difficulty which arises  
from the inconsistency between that     
assertion1 and the principle1 that if   
there be anything in the conclusion     
which was not already asserted in the   
premises1 the argument is vicious4 ,for 
it is impossible to attach any serious  
scientific value to such a mere salvo1  
as the distinction drawn between being  
involved by implication in the premises1
 and being directly asserted in them4   
,when ,archbishop ,whately says#g that  
the object of reasoning is merely to    
expand and unfold the assertions wrapt  
up1 as it were1 and implied in those    
with which we set out1 and to bring a   
person to perceive and acknowledge the  
full force of that which he has         
admitted1 he does not1 ,i think1 meet   
the real difficulty requiring to be     
explained1 namely1 how it happens that a
 science1 like geometry1 can be all     
wrapt up in a few definitions and       
axioms4 ,nor does this defence of the   

syllogism differ much from what its     
assailants urge against it as an        
accusation1 when they charge it with    
being of no use except to those who seek
 to press the consequences of an        
admission into which a person has been  
entrapped without having considered and 
understood its full force4 ,when you    
admitted the major premise1 you asserted
 the conclusion2 but1 says ,archbishop  
,whately1 you asserted it by implication
 merely3 this1 however1 can here only   
mean that you asserted it unconsciously2
 that you did not know you were         
asserting it2 but1 if so1 the difficulty
 revives in this shape--,ought you not  
to have known8 ,were you warranted in   
asserting the general proposition       
without having satisfied yourself of the
 truth of everything which it fairly    
includes8 ,and if not1 is not the       
syllogistic art prim facie what its     
assailants affirm it to be1 a           
contrivance for catching you in a trap1 
and holding you fast in it8#h    #c4    

,from this difficulty there appears to  
be but one issue4 ,the proposition that 
the ,duke of ,wellington is mortal1 is  
evidently an inference2 it is got at as 
a conclusion from something else2 but do
 we1 in reality1 conclude it from the   
proposition1 ,all men are mortal8 ,i    
answer1 no4  ,the error committed is1 ,i
 conceive1 that of overlooking the      
distinction between two parts of the    
process of philosophizing1 the inferring
 part1 and the registering part2 and    
ascribing to the latter the functions of
 the former4 ,the mistake is that of    
referring a person to his own notes for 
the origin of his knowledge4 ,if a      
person is asked a question1 and is at   
the moment unable to answer it1 he may  
refresh his memory by turning to a      
memorandum which he carries about with  
him4 ,but if he were asked1 how the fact
 came to his knowledge1 he would        
scarcely answer1 because it was set down
 in his note-book3 unless the book was  
written1 like the ,koran1 with a quill  

from the wing of the angel ,gabriel4    
,assuming that the proposition1 ,the    
,duke of ,wellington is mortal1 is      
immediately an inference from the       
proposition1 ,all men are mortal2 whence
 do we derive our knowledge of that     
general truth8 ,of course from          
observation4 ,now1 all which man can    
observe are individual cases4 ,from     
these all general truths must be drawn1 
and into these they may be again        
resolved2 for a general truth is but an 
aggregate of particular truths2 a       
comprehensive expression1 by which an   
indefinite number of individual facts   
are affirmed or denied at once4 ,but a  
general proposition is not merely a     
compendious form for recording and      
preserving in the memory a number of    
particular facts1 all of which have been
 observed4 ,generalization is not a     
process of mere naming1 it is also a    
process of inference4 ,from instances   
which we have observed1 we feel         
warranted in concluding1 that what we   

found true in those instances1 holds in 
all similar ones1 past1 present1 and    
future1 however numerous they may be4   
,we then1 by that valuable contrivance  
of language which enables us to speak of
 many as if they were one1 record all   
that we have observed1 together with all
 that we infer from our observations1 in
 one concise expression2 and have thus  
only one proposition1 instead of an     
endless number1 to remember or to       
communicate4 ,the results of many       
observations and inferences1 and        
instructions for making innumerable     
inferences in unforeseen cases1 are     
compressed into one short sentence4     
,when1 therefore1 we conclude from the  
death of ,john and ,thomas1 and every   
other person we ever heard of in whose  
case the experiment had been fairly     
tried1 that the ,duke of ,wellington is 
mortal like the rest2 we may1 indeed1   
pass through the generalization1 ,all   
men are mortal1 as an intermediate      
stage2 but it is not in the latter half 

of the process1 the descent from all men
 to the ,duke of ,wellington1 that the  
inference resides4 ,the inference is    
finished when we have asserted that all 
men are mortal4 ,what remains to be     
performed afterwards is merely          
decyphering our own notes4  ,archbishop 
,whately has contended that syllogizing1
 or reasoning from generals to          
particulars1 is not1 agreeably to the   
vulgar idea1 a peculiar mode of         
reasoning1 but the philosophical        
analysis of the mode in which all men   
reason1 and must do so if they reason at
 all4 ,with the deference due to so high
 an authority1 ,i cannot help thinking  
that the vulgar notion is1 in this case1
 the more correct4 ,if1 from our        
experience of ,john1 ,thomas1 c41 who   
once were living1 but are now dead1 we  
are entitled to conclude that all human 
beings are mortal1 we might surely      
without any logical inconsequence have  
concluded at once from those instances1 
that the ,duke of ,wellington is mortal4

 ,the mortality of ,john1 ,thomas1 and  
company is1 after all1 the whole        
evidence we have for the mortality of   
the ,duke of ,wellington4 ,not one iota 
is added to the proof by interpolating a
 general proposition4 ,since the        
individual cases are all the evidence we
 can possess1 evidence which no logical 
form into which we choose to throw it   
can make greater than it is2 and since  
that evidence is either sufficient in   
itself1 or1 if insufficient for the one 
purpose1 cannot be sufficient for the   
other2 ,i am unable to see why we should
 be forbidden to take the shortest cut  
from these sufficient premises to the   
conclusion1 and constrained to travel   
the high priori road1 by the arbitrary  
fiat of logicians4 ,i cannot perceive   
why it should be impossible to journey  
from one place to another unless we     
march up a hill1 and then march down    
again4 ,it may be the safest road1 and  
there may be a resting-place at the top 
of the hill1 affording a commanding view

 of the surrounding country2 but for the
 mere purpose of arriving at our        
journey's end1 our taking that road is  
perfectly optional2 it is a question of 
time1 trouble1 and danger4  ,not only   
may we reason from particulars to       
particulars without passing through     
generals1 but we perpetually do so      
reason4 ,all our earliest inferences are
 of this nature4 ,from the first dawn of
 intelligence we draw inferences1 but   
years elapse before we learn the use of 
general language4 ,the child1 who1      
having burnt his fingers1 avoids to     
thrust them again into the fire1 has    
reasoned or inferred1 though he has     
never thought of the general maxim1     
,fire burns4 ,he knows from memory that 
he has been burnt1 and on this evidence 
believes1 when he sees a candle1 that if
 he puts his finger into the flame of   
it1 he will be burnt again4 ,he believes
 this in every case which happens to    
arise2 but without looking1 in each     
instance1 beyond the present case4 ,he  

is not generalizing2 he is inferring a  
particular from particulars4 ,in the    
same way1 also1 brutes reason4 ,there is
 no ground for attributing to any of the
 lower animals the use of signs1 of such
 a nature as to render general          
propositions possible4 ,but those       
animals profit by experience1 and avoid 
what they have found to cause them pain1
 in the same manner1 though not always  
with the same skill1 as a human         
creature4 ,not only the burnt child1 but
 the burnt dog1 dreads the fire4  ,i    
believe that1 in point of fact1 when    
drawing inferences from our personal    
experience1 and not from maxims handed  
down to us by books or tradition1 we    
much oftener conclude from particulars  
to particulars directly1 than through   
the intermediate agency of any general  
proposition4 ,we are constantly         
reasoning from ourselves to other       
people1 or from one person to another1  
without giving ourselves the trouble to 
erect our observations into general     

maxims of human or external nature4     
,when we conclude that some person will1
 on some given occasion1 feel or act so 
and so1 we sometimes judge from an      
enlarged consideration of the manner in 
which human beings in general1 or       
persons of some particular character1   
are accustomed to feel and act3 but much
 oftener from merely recollecting the   
feelings and conduct of the same person 
in some previous instance1 or from      
considering how we should feel or act   
ourselves4 ,it is not only the village  
matron1 who1 when called to a           
consultation upon the case of a         
neighbour's child1 pronounces on the    
evil and its remedy simply on the       
recollection and authority of what she  
accounts the similar case of her ,lucy4 
,we all1 where we have no definite      
maxims to steer by1 guide ourselves in  
the same way3 and if we have an         
extensive experience1 and retain its    
impressions strongly1 we may acquire in 
this manner a very considerable power of

 accurate judgment1 which we may be     
utterly incapable of justifying or of   
communicating to others4 ,among the     
higher order of practical intellects    
there have been many of whom it was     
remarked how admirably they suited their
 means to their ends1 without being able
 to give any sufficient reasons for what
 they did2 and applied1 or seemed to    
apply1 recondite principles which they  
were wholly unable to state4 ,this is a 
natural consequence of having a mind    
stored with appropriate particulars1 and
 having been long accustomed to reason  
at once from these to fresh particulars1
 without practising the habit of stating
 to oneself or to others the            
corresponding general propositions4 ,an 
old warrior1 on a rapid glance at the   
outlines of the ground1 is able at once 
to give the necessary orders for a      
skilful arrangement of his troops2      
though if he has received little        
theoretical instruction1 and has seldom 
been called upon to answer to other     

people for his conduct1 he may never    
have had in his mind a single general   
theorem respecting the relation between 
ground and array4 ,but his experience of
 encampments1 in circumstances more or  
less similar1 has left a number of      
vivid1 unexpressed1 ungeneralized       
analogies in his mind1 the most         
appropriate of which1 instantly         
suggesting itself1 determines him to a  
judicious arrangement4  ,the skill of an
 uneducated person in the use of        
weapons1 or of tools1 is of a precisely 
similar nature4 ,the savage who executes
 unerringly the exact throw which brings
 down his game1 or his enemy1 in the    
manner most suited to his purpose1 under
 the operation of all the conditions    
necessarily involved1 the weight and    
form of the weapon1 the direction and   
distance of the object1 the action of   
the wind1 c41 owes this power to a long 
series of previous experiments1 the     
results of which he certainly never     
framed into any verbal theorems or      

rules4 ,the same thing may generally be 
said of any other extraordinary manual  
dexterity4 ,not long ago a ,scotch      
manufacturer procured from ,england1 at 
a high rate of wages1 a working dyer1   
famous for producing very fine colours1 
with the view of teaching to his other  
workmen the same skill4 ,the workman    
came2 but his mode of proportioning the 
ingredients1 in which lay the secret of 
the effects he produced1 was by taking  
them up in handfuls1 while the common   
method was to weigh them4 ,the          
manufacturer sought to make him turn his
 handling system into an equivalent     
weighing system1 that the general       
principle of his peculiar mode of       
proceeding might be ascertained4 ,this1 
however1 the man found himself quite    
unable to do1 and therefore could impart
 his skill to nobody4 ,he had1 from the 
individual cases of his own experience1 
established a connexion in his mind     
between fine effects of colour1 and     
tactual perceptions in handling his     

dyeing materials2 and from these        
perceptions he could1 in any particular 
case1 infer the means to be employed1   
and the effects which would be produced1
 but could not put others in possession 
of the grounds on which he proceeded1   
from having never generalized them in   
his own mind1 or expressed them in      
language4  ,almost every one knows ,lord
 ,mansfield's advice to a man of        
practical good sense1 who1 being        
appointed governor of a colony1 had to  
preside in its court of justice1 without
 previous judicial practice or legal    
education4 ,the advice was to give his  
decision boldly1 for it would probably  
be right2 but never to venture on       
assigning reasons1 for they would almost
 infallibly be wrong4 ,in cases like    
this1 which are of no uncommon          
occurrence1 it would be absurd to       
suppose that the bad reason was the     
source of the good decision4 ,lord      
,mansfield knew that if any reason were 
assigned it would be necessarily an     

afterthought1 the judge being in fact   
guided by impressions from past         
experience1 without the circuitous      
process of framing general principles   
from them1 and that if he attempted to  
frame any such he would assuredly fail4 
,lord ,mansfield1 however1 would not    
have doubted that a man of equal        
experience who had also a mind stored   
with general propositions derived by    
legitimate induction from that          
experience1 would have been greatly     
preferable as a judge1 to one1 however  
sagacious1 who could not be trusted with
 the explanation and justification of   
his own judgments4 ,the cases of men of 
talent performing wonderful things they 
know not how1 are examples of the rudest
 and most spontaneous form of the       
operations of superior minds4 ,it is a  
defect in them1 and often a source of   
errors1 not to have generalized as they 
went on2 but generalization1 though a   
help1 the most important indeed of all  
helps1 is not an essential4  ,even the  

scientifically instructed1 who possess1 
in the form of general propositions1 a  
systematic record of the results of the 
experience of mankind1 need not always  
revert to those general propositions in 
order to apply that experience to a new 
case4 ,it is justly remarked by ,dugald 
,stewart1 that though the reasonings in 
mathematics depend entirely on the      
axioms1 it is by no means necessary to  
our seeing the conclusiveness of the    
proof1 that the axioms should be        
expressly adverted to4 ,when it is      
inferred that ,,ab is equal to ,,cd     
because each of them is equal to ,,ef1  
the most uncultivated understanding1 as 
soon as the propositions were           
understood1 would assent to the         
inference1 without having ever heard of 
the general truth that things which are 
equal to the same thing are equal to one
 another4 ,this remark of ,stewart1     
consistently followed out1 goes to the  
root1 as ,i conceive1 of the philosophy 
of ratiocination2 and it is to be       

regretted that he himself stopt short at
 a much more limited application of it4 
,he saw that the general propositions on
 which a reasoning is said to depend1   
may1 in certain cases1 be altogether    
omitted1 without impairing its probative
 force4 ,but he imagined this to be a   
peculiarity belonging to axioms2 and    
argued from it1 that axioms are not the 
foundations or first principles of      
geometry1 from which all the other      
truths of the science are synthetically 
deduced 7as the laws of motion and of   
the composition of forces in dynamics1  
the equal mobility of fluids in         
hydrostatics1 the laws of reflection and
 refraction in optics1 are the first    
principles of those sciences72 but are  
merely necessary assumptions1           
self-evident indeed1 and the denial of  
which would annihilate all              
demonstration1 but from which1 as       
premises1 nothing can be demonstrated4  
,in the present1 as in many other       
instances1 this thoughtful and elegant  

writer has perceived an important truth1
 but only by halves4 ,finding1 in the   
case of geometrical axioms1 that general
 names have not any talismanic virtue   
for conjuring new truths out of the well
 where they lie hid1 and not seeing that
 this is equally true in every other    
case of generalization1 he contended    
that axioms are in their nature barren  
of consequences1 and that the really    
fruitful truths1 the real first         
principles of geometry1 are the         
definitions2 that the definition1 for   
example1 of the circle is to the        
properties of the circle1 what the laws 
of equilibrium and of the pressure of   
the atmosphere are to the rise of the   
mercury in the ,torricellian tube4 ,yet 
all that he had asserted respecting the 
function to which the axioms are        
confined in the demonstrations of       
geometry1 holds equally true of the     
definitions4 ,every demonstration in    
,euclid might be carried on without     
them4 ,this is apparent from the        

ordinary process of proving a           
proposition of geometry by means of a   
diagram4 ,what assumption1 in fact1 do  
we set out from1 to demonstrate by a    
diagram any of the properties of the    
circle8 ,not that in all circles the    
radii are equal1 but only that they are 
so in the circle ,,abc4 ,as our warrant 
for assuming this1 we appeal1 it is     
true1 to the definition of a circle in  
general2 but it is only necessary that  
the assumption be granted in the case of
 the particular circle supposed4 ,from  
this1 which is not a general but a      
singular proposition1 combined with     
other propositions of a similar kind1   
some of which when generalized are      
called definitions1 and others axioms1  
we prove that a certain conclusion is   
true1 not of all circles1 but of the    
particular circle ,,abc2 or at least    
would be so1 if the facts precisely     
accorded with our assumptions4 ,the     
enunciation1 as it is called1 that is1  
the general theorem which stands at the 

head of the demonstration1 is not the   
proposition actually demonstrated4 ,one 
instance only is demonstrated3 but the  
process by which this is done1 is a     
process which1 when we consider its     
nature1 we perceive might be exactly    
copied in an indefinite number of other 
instances2 in every instance which      
conforms to certain conditions4 ,the    
contrivance of general language         
furnishing us with terms which connote  
these conditions1 we are able to assert 
this indefinite multitude of truths in a
 single expression1 and this expression 
is the general theorem4 ,by dropping the
 use of diagrams1 and substituting1 in  
the demonstrations1 general phrases for 
the letters of the alphabet1 we might   
prove the general theorem directly1 that
 is1 we might demonstrate all the cases 
at once2 and to do this we must1 of     
course1 employ as our premises1 the     
axioms and definitions in their general 
form4 ,but this only means1 that if we  
can prove an individual conclusion by   

assuming an individual fact1 then in    
whatever case we are warranted in making
 an exactly similar assumption1 we may  
draw an exactly similar conclusion4 ,the
 definition is a sort of notice to      
ourselves and others1 what assumptions  
we think ourselves entitled to make4    
,and so in all cases1 the general       
propositions1 whether called            
definitions1 axioms1 or laws of nature1 
which we lay down at the beginning of   
our reasonings1 are merely abridged     
statements1 in a kind of short-hand1 of 
the particular facts1 which1 as occasion
 arises1 we either think we may proceed 
on as proved1 or intend to assume4 ,in  
any one demonstration it is enough if we
 assume for a particular case suitably  
selected1 what by the statement of the  
definition or principle we announce that
 we intend to assume in all cases which 
may arise4 ,the definition of the       
circle1 therefore1 is to one of         
,euclid's demonstrations1 exactly what1 
according to ,stewart1 the axioms are2  

that is1 the demonstration does not     
depend on it1 but yet if we deny it the 
demonstration fails4 ,the proof does not
 rest on the general assumption1 but on 
a similar assumption confined to the    
particular case3 that case1 however1    
being chosen as a specimen or paradigm  
of the whole class of cases included in 
the theorem1 there can be no ground for 
making the assumption in that case which
 does not exist in every other2 and to  
deny the assumption as a general truth1 
is to deny the right of making it in the
 particular instance4  ,there are1      
undoubtedly1 the most ample reasons for 
stating both the principles and the     
theorems in their general form1 and     
these will be explained presently1 so   
far as explanation is requisite4 ,but1  
that unpractised learners1 even in      
making use of one theorem to demonstrate
 another1 reason rather from particular 
to particular than from the general     
proposition1 is manifest from the       
difficulty they find in applying a      

theorem to a case in which the          
configuration of the diagram is         
extremely unlike that of the diagram by 
which the original theorem was          
demonstrated4 ,a difficulty which1      
except in cases of unusual mental power1
 long practice can alone remove1 and    
removes chiefly by rendering us familiar
 with all the configurations consistent 
with the general conditions of the      
theorem4    #d4 ,from the considerations
 now adduced1 the following conclusions 
seem to be established4 ,all inference  
is from particulars to particulars3     
,general propositions are merely        
registers of such inferences already    
made1 and short formul for making more3 
,the major premise of a syllogism1      
consequently1 is a formula of this      
description3 and the conclusion is not  
an inference drawn from the formula1 but
 an inference drawn according to the    
formula3 the real logical antecedent1 or
 premise1 being the particular facts    
from which the general proposition was  

collected by induction4 ,those facts1   
and the individual instances which      
supplied them1 may have been forgotten3 
but a record remains1 not indeed        
descriptive of the facts themselves1 but
 showing how those cases may be         
distinguished1 respecting which the     
facts1 when known1 were considered to   
warrant a given inference4 ,according to
 the indications of this record we draw 
our conclusion2 which is1 to all intents
 and purposes1 a conclusion from the    
forgotten facts4 ,for this it is        
essential that we should read the record
 correctly3 and the rules of the        
syllogism are a set of precautions to   
ensure our doing so4  ,this view of the 
functions of the syllogism is confirmed 
by the consideration of precisely those 
cases which might be expected to be     
least favourable to it1 namely1 those in
 which ratiocination is independent of  
any previous induction4 ,we have already
 observed that the syllogism1 in the    
ordinary course of our reasoning1 is    

only the latter half of the process of  
travelling from premises to a           
conclusion4 ,there are1 however1 some   
peculiar cases in which it is the whole 
process4 ,particulars alone are capable 
of being subjected to observation2 and  
all knowledge which is derived from     
observation1 begins1 therefore1 of      
necessity1 in particulars2 but our      
knowledge may1 in cases of certain      
descriptions1 be conceived as coming to 
us from other sources than observation4 
,it may present itself as coming from   
testimony1 which1 on the occasion and   
for the purpose in hand1 is accepted as 
of an authoritative character3 and the  
information thus communicated1 may be   
conceived to comprise not only          
particular facts but general            
propositions1 as when a scientific      
doctrine is accepted without examination
 on the authority of writers1 or a      
theological doctrine on that of         
,scripture4 ,or the generalization may  
not be1 in the ordinary sense1 an       

assertion at all1 but a command2 a law1 
not in the philosophical1 but in the    
moral and political sense of the term3  
an expression of the desire of a        
superior1 that we1 or any number of     
other persons1 shall conform our conduct
 to certain general instructions4 ,so   
far as this asserts a fact1 namely1 a   
volition of the legislator1 that fact is
 an individual fact1 and the            
proposition1 therefore1 is not a general
 proposition4 ,but the description      
therein contained of the conduct which  
it is the will of the legislator that   
his subjects should observe1 is general4
 ,the proposition asserts1 not that all 
men are anything1 but that all men shall
 do something4  ,in both these cases the
 generalities are the original data1 and
 the particulars are elicited from them 
by a process which correctly resolves   
itself into a series of syllogisms4 ,the
 real nature1 however1 of the supposed  
deductive process1 is evident enough4   
,the only point to be determined is1    

whether the authority which declared the
 general proposition1 intended to       
include this case in it2 and whether the
 legislator intended his command to     
apply to the present case among others1 
or not4 ,this is ascertained by         
examining whether the case possesses the
 marks by which1 as those authorities   
have signified1 the cases which they    
meant to certify or to influence may be 
known4 ,the object of the inquiry is to 
make out the witness's or the           
legislator's intention1 through the     
indication given by their words4 ,this  
is a question1 as the ,germans express  
it1 of hermeneutics4 ,the operation is  
not a process of inference1 but a       
process of interpretation4  ,in this    
last phrase we have obtained an         
expression which appears to me to       
characterize1 more aptly than any other1
 the functions of the syllogism in all  
cases4 ,when the premises are given by  
authority1 the function of ,reasoning is
 to ascertain the testimony of a        

witness1 or the will of a legislator1 by
 interpreting the signs in which the one
 has intimated his assertion and the    
other his command4 ,in like manner1 when
 the premises are derived from          
observation1 the function of ,reasoning 
is to ascertain what we 7or our         
predecessors7 formerly thought might be 
inferred from the observed facts1 and to
 do this by interpreting a memorandum of
 ours1 or of theirs4 ,the memorandum    
reminds us1 that from evidence1 more or 
less carefully weighed1 it formerly     
appeared that a certain attribute might 
be inferred wherever we perceive a      
certain mark4 ,the proposition1 ,all men
 are mortal 7for instance7 shows that we
 have had experience from which we      
thought it followed that the attributes 
connoted by the term man1 are a mark of 
mortality4 ,but when we conclude that   
the ,duke of ,wellington is mortal1 we  
do not infer this from the memorandum1  
but from the former experience4 ,all    
that we infer from the memorandum is our

 own previous belief1 7or that of those 
who transmitted to us the proposition71 
concerning the inferences which that    
former experience would warrant4  ,this 
view of the nature of the syllogism     
renders consistent and intelligible what
 otherwise remains obscure and confused 
in the theory of ,archbishop ,whately   
and other enlightened defenders of the  
syllogistic doctrine1 respecting the    
limits to which its functions are       
confined4 ,they affirm in as explicit   
terms as can be used1 that the sole     
office of general reasoning is to       
prevent inconsistency in our opinions2  
to prevent us from assenting to         
anything1 the truth of which would      
contradict something to which we had    
previously on good grounds given our    
assent4 ,and they tell us1 that the sole
 ground which a syllogism affords for   
assenting to the conclusion1 is that the
 supposition of its being false1        
combined with the supposition that the  
premises are true1 would lead to a      

contradiction in terms4 ,now this would 
be but a lame account of the real       
grounds which we have for believing the 
facts which we learn from reasoning1 in 
contradistinction to observation4 ,the  
true reason why we believe that the     
,duke of ,wellington will die1 is that  
his fathers1 and our fathers1 and all   
other persons who were cotemporary with 
them1 have died4 ,those facts are the   
real premises of the reasoning4 ,but we 
are not led to infer the conclusion from
 those premises1 by the necessity of    
avoiding any verbal inconsistency4      
,there is no contradiction in supposing 
that all those persons have died1 and   
that the ,duke of ,wellington may1      
notwithstanding1 live for ever4 ,but    
there would be a contradiction if we    
first1 on the ground of those same      
premises1 made a general assertion      
including and covering the case of the  
,duke of ,wellington1 and then refused  
to stand to it in the individual case4  
,there is an inconsistency to be avoided

 between the memorandum we make of the  
inferences which may be justly drawn in 
future cases1 and the inferences we     
actually draw in those cases when they  
arise4 ,with this view we interpret our 
own formula1 precisely as a judge       
interprets a law3 in order that we may  
avoid drawing any inferences not        
conformable to our former intention1 as 
a judge avoids giving any decision not  
conformable to the legislator's         
intention4 ,the rules for this          
interpretation are the rules of the     
syllogism3 and its sole purpose is to   
maintain consistency between the        
conclusions we draw in every particular 
case1 and the previous general          
directions for drawing them2 whether    
those general directions were framed by 
ourselves as the result of induction1 or
 were received by us from an authority  
competent to give them4    #e4 ,in the  
above observations it has1 ,i think1    
been shown1 that1 though there is always
 a process of reasoning or inference    

where a syllogism is used1 the syllogism
 is not a correct analysis of that      
process of reasoning or inference2 which
 is1 on the contrary1 7when not a mere  
inference from testimony7 an inference  
from particulars to particulars2        
authorized by a previous inference from 
particulars to generals1 and            
substantially the same with it2 of the  
nature1 therefore1 of ,induction4 ,but  
while these conclusions appear to me    
undeniable1 ,i must yet enter a protest1
 as strong as that of ,archbishop       
,whately himself1 against the doctrine  
that the syllogistic art is useless for 
the purposes of reasoning4 ,the         
reasoning lies in the act of            
generalization1 not in interpreting the 
record of that act2 but the syllogistic 
form is an indispensable collateral     
security for the correctness of the     
generalization itself4  ,it has already 
been seen1 that if we have a collection 
of particulars sufficient for grounding 
an induction1 we need not frame a       

general proposition2 we may reason at   
once from those particulars to other    
particulars4 ,but it is to be remarked  
withal1 that whenever1 from a set of    
particular cases1 we can legitimately   
draw any inference1 we may legitimately 
make our inference a general one4 ,if1  
from observation and experiment1 we can 
conclude to one new case1 so may we to  
an indefinite number4 ,if that which has
 held true in our past experience will  
therefore hold in time to come1 it will 
hold not merely in some individual case1
 but in all cases of some given         
description4 ,every induction1          
therefore1 which suffices to prove one  
fact1 proves an indefinite multitude of 
facts3 the experience which justifies a 
single prediction must be such as will  
suffice to bear out a general theorem4  
,this theorem it is extremely important 
to ascertain and declare1 in its        
broadest form of generality2 and thus to
 place before our minds1 in its full    
extent1 the whole of what our evidence  

must prove if it proves anything4  ,this
 throwing of the whole body of possible 
inferences from a given set of          
particulars1 into one general           
expression1 operates as a security for  
their being just inferences1 in more    
ways than one4 ,first1 the general      
principle presents a larger object to   
the imagination than any of the singular
 propositions which it contains4 ,a     
process of thought which leads to a     
comprehensive generality1 is felt as of 
greater importance than one which       
terminates in an insulated fact2 and the
 mind is1 even unconsciously1 led to    
bestow greater attention upon the       
process1 and to weigh more carefully the
 sufficiency of the experience appealed 
to1 for supporting the inference        
grounded upon it4 ,there is another1 and
 a more important1 advantage4 ,in       
reasoning from a course of individual   
observations to some new and unobserved 
case1 which we are but imperfectly      
acquainted with 7or we should not be    

inquiring into it71 and in which1 since 
we are inquiring into it1 we probably   
feel a peculiar interest2 there is very 
little to prevent us from giving way to 
negligence1 or to any bias which may    
affect our wishes or our imagination1   
and1 under that influence1 accepting    
insufficient evidence as sufficient4    
,but if1 instead of concluding straight 
to the particular case1 we place before 
ourselves an entire class of facts--the 
whole contents of a general proposition1
 every tittle of which is legitimately  
inferrible from our premises1 if that   
one particular conclusion is so2 there  
is then a considerable likelihood that  
if the premises are insufficient1 and   
the general inference1 therefore1       
groundless1 it will comprise within it  
some fact or facts the reverse of which 
we already know to be true2 and we shall
 thus discover the error in our         
generalization by a reductio ad         
impossibile4  ,thus if1 during the reign
 of ,marcus ,aurelius1 a subject of the 

,roman empire1 under the bias naturally 
given to the imagination and            
expectations by the lives and characters
 of the ,antonines1 had been disposed to
 expect that ,commodus would be a just  
ruler2 supposing him to stop there1 he  
might only have been undeceived by sad  
experience4 ,but if he reflected that   
this expectation could not be           
justifiable unless from the same        
evidence he was warranted in concluding 
some general proposition1 as1 for       
instance1 that all ,roman emperors are  
just rulers2 he would immediately have  
thought of ,nero1 ,domitian1 and other  
instances1 which1 showing the falsity of
 the general conclusion1 and therefore  
the insufficiency of the premises1 would
 have warned him that those premises    
could not prove in the instance of      
,commodus1 what they were inadequate to 
prove in any collection of cases in     
which his was included4  ,the advantage1
 in judging whether any controverted    
inference is legitimate1 of referring to

 a parallel case1 is universally        
acknowledged4 ,but by ascending to the  
general proposition1 we bring under our 
view not one parallel case only1 but all
 possible parallel cases at once2 all   
cases to which the same set of          
evidentiary considerations are          
applicable4  ,when1 therefore1 we argue 
from a number of known cases to another 
case supposed to be analogous1 it is    
always possible1 and generally          
advantageous1 to divert our argument    
into the circuitous channel of an       
induction from those known cases to a   
general proposition1 and a subsequent   
application of that general proposition 
to the unknown case4 ,this second part  
of the operation1 which1 as before      
observed1 is essentially a process of   
interpretation1 will be resolvable into 
a syllogism or a series of syllogisms1  
the majors of which will be general     
propositions embracing whole classes of 
cases2 every one of which propositions  
must be true in all its extent1 if the  

argument is maintainable4 ,if1          
therefore1 any fact fairly coming within
 the range of one of these general      
propositions1 and consequently asserted 
by it1 is known or suspected to be other
 than the proposition asserts it to be1 
this mode of stating the argument causes
 us to know or to suspect that the      
original observations1 which are the    
real grounds of our conclusion1 are not 
sufficient to support it4 ,and in       
proportion to the greater chance of our 
detecting the inconclusiveness of our   
evidence1 will be the increased reliance
 we are entitled to place in it if no   
such evidence of defect shall appear4   
,the value1 therefore1 of the           
syllogistic form1 and of the rules for  
using it correctly1 does not consist in 
their being the form and the rules      
according to which our reasonings are   
necessarily1 or even usually1 made2 but 
in their furnishing us with a mode in   
which those reasonings may always be    
represented1 and which is admirably     

calculated1 if they are inconclusive1 to
 bring their inconclusiveness to light4 
,an induction from particulars to       
generals1 followed by a syllogistic     
process from those generals to other    
particulars1 is a form in which we may  
always state our reasonings if we       
please4 ,it is not a form in which we   
must reason1 but it is a form in which  
we may reason1 and into which it is     
indispensable to throw our reasoning1   
when there is any doubt of its validity3
 though when the case is familiar and   
little complicated1 and there is no     
suspicion of error1 we may1 and do1     
reason at once from the known particular
 cases to unknown ones4#i  ,these are   
the uses of syllogism1 as a mode of     
verifying any given argument4 ,its      
ulterior uses1 as respects the general  
course of our intellectual operations1  
hardly require illustration1 being in   
fact the acknowledged uses of general   
language4 ,they amount substantially to 
this1 that the inductions may be made   

once for all3 a single careful          
interrogation of experience may suffice1
 and the result may be registered in the
 form of a general proposition1 which is
 committed to memory or to writing1 and 
from which afterwards we have only to   
syllogize4 ,the particulars of our      
experiments may then be dismissed from  
the memory1 in which it would be        
impossible to retain so great a         
multitude of details2 while the         
knowledge which those details afforded  
for future use1 and which would         
otherwise be lost as soon as the        
observations were forgotten1 or as their
 record became too bulky for reference1 
is retained in a commodious and         
immediately available shape by means of 
general language4  ,against this        
advantage is to be set the              
countervailing inconvenience1 that      
inferences originally made on           
insufficient evidence1 become           
consecrated1 and1 as it were1 hardened  
into general maxims2 and the mind       

cleaves to them from habit1 after it has
 outgrown any liability to be misled by 
similar fallacious appearances if they  
were now for the first time presented2  
but having forgotten the particulars1 it
 does not think of revising its own     
former decision4 ,an inevitable         
drawback1 which1 however considerable in
 itself1 forms evidently but a small    
set-off against the immense benefits of 
general language4  ,the use of the      
syllogism is in truth no other than the 
use of general propositions in          
reasoning4 ,we can reason without them2 
in simple and obvious cases we          
habitually do so2 minds of great        
sagacity can do it in cases not simple  
and obvious1 provided their experience  
supplies them with instances essentially
 similar to every combination of        
circumstances likely to arise4 ,but     
other minds1 and the same minds where   
they have not the same pre-eminent      
advantages of personal experience1 are  
quite helpless without the aid of       

general propositions1 wherever the case 
presents the smallest complication2 and 
if we made no general propositions1 few 
persons would get much beyond those     
simple inferences which are drawn by the
 more intelligent of the brutes4 ,though
 not necessary to reasoning1 general    
propositions are necessary to any       
considerable progress in reasoning4 ,it 
is1 therefore1 natural and indispensable
 to separate the process of             
investigation into two parts2 and obtain
 general formul for determining what    
inferences may be drawn1 before the     
occasion arises for drawing the         
inferences4 ,the work of drawing them is
 then that of applying the formul2 and  
the rules of syllogism are a system of  
securities for the correctness of the   
application4    #f4 ,to complete the    
series of considerations connected with 
the philosophical character of the      
syllogism1 it is requisite to consider1 
since the syllogism is not the universal
 type of the reasoning process1 what is 

the real type4 ,this resolves itself    
into the question1 what is the nature of
 the minor premise1 and in what manner  
it contributes to establish the         
conclusion3 for as to the major1 we now 
fully understand1 that the place which  
it nominally occupies in our reasonings1
 properly belongs to the individual     
facts or observations of which it       
expresses the general result2 the major 
itself being no real part of the        
argument1 but an intermediate           
halting-place for the mind1 interposed  
by an artifice of language between the  
real premises and the conclusion1 by way
 of a security1 which it is in a most   
material degree1 for the correctness of 
the process4 ,the minor1 however1 being 
an indispensable part of the syllogistic
 expression of an argument1 without     
doubt either is1 or corresponds to1 an  
equally indispensable part of the       
argument itself1 and we have only to    
inquire what part4  ,it is perhaps worth
 while to notice here a speculation of a

 philosopher to whom mental science is  
much indebted1 but who1 though a very   
penetrating1 was a very hasty thinker1  
and whose want of due circumspection    
rendered him fully as remarkable for    
what he did not see1 as for what he saw4
 ,i allude to ,dr4 ,thomas ,brown1 whose
 theory of ratiocination is peculiar4   
,he saw the petitio principii which is  
inherent in every syllogism1 if we      
consider the major to be itself the     
evidence by which the conclusion is     
proved1 instead of being1 what in fact  
it is1 an assertion of the existence of 
evidence sufficient to prove any        
conclusion of a given description4      
,seeing this1 ,dr4 ,brown not only      
failed to see the immense advantage1 in 
point of security for correctness1 which
 is gained by interposing this step     
between the real evidence and the       
conclusion2 but he thought it incumbent 
on him to strike out the major          
altogether from the reasoning process1  
without substituting anything else1 and 

maintained that our reasonings consist  
only of the minor premise and the       
conclusion1 ,socrates is a man1         
therefore ,socrates is mortal3 thus     
actually suppressing1 as an unnecessary 
step in the argument1 the appeal to     
former experience4 ,the absurdity of    
this was disguised from him by the      
opinion he adopted1 that reasoning is   
merely analysing our own general        
notions1 or abstract ideas2 and that the
 proposition1 ,socrates is mortal1 is   
evolved from the proposition1 ,socrates 
is a man1 simply by recognising the     
notion of mortality as already contained
 in the notion we form of a man4  ,after
 the explanations so fully entered into 
on the subject of propositions1 much    
further discussion cannot be necessary  
to make the radical error of this view  
of ratiocination apparent4 ,if the word 
man connoted mortality2 if the meaning  
of mortal were involved in the meaning  
of man2 we might1 undoubtedly1 evolve   
the conclusion from the minor alone1    

because the minor would have already    
asserted it4 ,but if1 as is in fact the 
case1 the word man does not connote     
mortality1 how does it appear that in   
the mind of every person who admits     
,socrates to be a man1 the idea of man  
must include the idea of mortality8 ,dr4
 ,brown could not help seeing this      
difficulty1 and in order to avoid it1   
was led1 contrary to his intention1 to  
re-establish1 under another name1 that  
step in the argument which corresponds  
to the major1 by affirming the necessity
 of previously perceiving the relation  
between the idea of man and the idea of 
mortal4 ,if the reasoner has not        
previously perceived this relation1 he  
will not1 says ,dr4 ,brown1 infer       
because ,socrates is a man1 that        
,socrates is mortal4 ,but even this     
admission1 though amounting to a        
surrender of the doctrine that an       
argument consists of the minor and the  
conclusion alone1 will not save the     
remainder of ,dr4 ,brown's theory4 ,the 

failure of assent to the argument does  
not take place merely because the       
reasoner1 for want of due analysis1 does
 not perceive that his idea of man      
includes the idea of mortality2 it takes
 place1 much more commonly1 because in  
his mind that relation between the two  
ideas has never existed4 ,and in truth  
it never does exist1 except as the      
result of experience4 ,consenting1 for  
the sake of the argument1 to discuss the
 question on a supposition of which we  
have recognised the radical             
incorrectness1 namely1 that the meaning 
of a proposition relates to the ideas of
 the things spoken of1 and not to the   
things themselves2 ,i must yet observe1 
that the idea of man1 as an universal   
idea1 the common property of all        
rational creatures1 cannot involve      
anything but what is strictly implied in
 the name4 ,if any one includes in his  
own private idea of man1 as no doubt is 
always the case1 some other attributes1 
such for instance as mortality1 he does 

so only as the consequence of           
experience1 after having satisfied      
himself that all men possess that       
attribute3 so that whatever the idea    
contains1 in any person's mind1 beyond  
what is included in the conventional    
signification of the word1 has been     
added to it as the result of assent to a
 proposition2 while ,dr4 ,brown's theory
 requires us to suppose1 on the         
contrary1 that assent to the proposition
 is produced by evolving1 through an    
analytic process1 this very element out 
of the idea4 ,this theory1 therefore1   
may be considered as sufficiently       
refuted2 and the minor premise must be  
regarded as totally insufficient to     
prove the conclusion1 except with the   
assistance of the major1 or of that     
which the major represents1 namely1 the 
various singular propositions expressive
 of the series of observations1 of which
 the generalization called the major    
premise is the result4  ,in the         
argument1 then1 which proves that       

,socrates is mortal1 one indispensable  
part of the premises will be as follows3
 ,my father1 and my father's father1 ,a1
 ,b1 ,c1 and an indefinite number of    
other persons1 were mortal2 which is    
only an expression in different words of
 the observed fact that they have died4 
,this is the major premise divested of  
the petitio principii1 and cut down to  
as much as is really known by direct    
evidence4  ,in order to connect this    
proposition with the conclusion         
,socrates is mortal1 the additional link
 necessary is such a proposition as the 
following3 ,socrates resembles my       
father1 and my father's father1 and the 
other individuals specified4 ,this      
proposition we assert when we say that  
,socrates is a man4 ,by saying so we    
likewise assert in what respect he      
resembles them1 namely1 in the          
attributes connoted by the word man4    
,and we conclude that he further        
resembles them in the attribute         
mortality4    #g4 ,we have thus obtained

 what we were seeking1 an universal type
 of the reasoning process4 ,we find it  
resolvable in all cases into the        
following elements3 ,certain individuals
 have a given attribute2 an individual  
or individuals resemble the former in   
certain other attributes2 therefore they
 resemble them also in the given        
attribute4 ,this type of ratiocination  
does not claim1 like the syllogism1 to  
be conclusive1 from the mere form of the
 expression2 nor can it possibly be so4 
,that one proposition does or does not  
assert the very fact which was already  
asserted in another1 may appear from the
 form of the expression1 that is1 from a
 comparison of the language2 but when   
the two propositions assert facts which 
are bon fide different1 whether the one 
fact proves the other or not can never  
appear from the language1 but must      
depend on other considerations4         
,whether1 from the attributes in which  
,socrates resembles those men who have  
heretofore died1 it is allowable to     

infer that he resembles them also in    
being mortal1 is a question of          
,induction2 and is to be decided by the 
principles or canons which we shall     
hereafter recognise as tests of the     
correct performance of that great mental
 operation4  ,meanwhile1 however1 it is 
certain1 as before remarked1 that if    
this inference can be drawn as to       
,socrates1 it can be drawn as to all    
others who resemble the observed        
individuals in the same attributes in   
which he resembles them2 that is 7to    
express the thing concisely7 of all     
mankind4 ,if1 therefore1 the argument be
 admissible in the case of ,socrates1 we
 are at liberty1 once for all1 to treat 
the possession of the attributes of man 
as a mark1 or satisfactory evidence1 of 
the attribute of mortality4 ,this we do 
by laying down the universal            
proposition1 ,all men are mortal1 and   
interpreting this1 as occasion arises1  
in its application to ,socrates and     
others4 ,by this means we establish a   

very convenient division of the entire  
logical operation into two steps2 first1
 that of ascertaining what attributes   
are marks of mortality2 and1 secondly1  
whether any given individuals possess   
those marks4 ,and it will generally be  
advisable1 in our speculations on the   
reasoning process1 to consider this     
double operation as in fact taking      
place1 and all reasoning as carried on  
in the form into which it must          
necessarily be thrown to enable us to   
apply to it any test of its correct     
performance4  ,although1 therefore1 all 
processes of thought in which the       
ultimate premises are particulars1      
whether we conclude from particulars to 
a general formula1 or from particulars  
to other particulars according to that  
formula1 are equally ,induction3 we     
shall yet1 conformably to usage1        
consider the name ,induction as more    
peculiarly belonging to the process of  
establishing the general proposition1   
and the remaining operation1 which is   

substantially that of interpreting the  
general proposition1 we shall call by   
its usual name1 ,deduction4 ,and we     
shall consider every process by which   
anything is inferred respecting an      
unobserved case1 as consisting of an    
,induction followed by a ,deduction2    
because1 although the process needs not 
necessarily be carried on in this form1 
it is always susceptible of the form1   
and must be thrown into it when         
assurance of scientific accuracy is     
needed and desired4    #h4 ,the theory  
of the syllogism1 laid down in the      
preceding pages1 has obtained1 among    
other important adhesions1 three of     
peculiar value2 those of ,sir ,john     
,herschel1#aj ,dr4 ,whewell#aa and ,mr4 
,bailey2#ab ,sir ,john ,herschel        
considering the doctrine1 though not    
strictly a discovery1#ac to be one of   
the greatest steps which have yet been  
made in the philosophy of ,logic4 ,when 
we consider 7to quote the further words 
of the same authority7 the inveteracy of

 the habits and prejudices which it has 
cast to the winds1 there is no cause for
 misgiving in the fact that other       
thinkers1 no less entitled to           
consideration1 have formed a very       
different estimate of it4 ,their        
principal objection cannot be better or 
more succinctly stated than by borrowing
 a sentence from ,archbishop            
,whately4#ad ,in every case where an    
inference is drawn from ,induction      
7unless that name is to be given to a   
mere random guess without any grounds at
 all7 we must form a judgment that the  
instance or instances adduced are       
sufficient to authorize the conclusion2 
that it is allowable to take these      
instances as a sample warranting an     
inference respecting the whole class2   
and the expression of this judgment in  
words 7it has been said by several of my
 critics7 is the major premise4  ,i     
quite admit that the major is an        
affirmation of the sufficiency of the   
evidence on which the conclusion rests4 

,that it is so1 is the very essence of  
my own theory4 ,and whoever admits that 
the major premise is only this1 adopts  
the theory in its essentials4  ,but ,i  
cannot concede that this recognition of 
the sufficiency of the evidence--that   
is1 of the correctness of the           
induction--is a part of the induction   
itself2 unless we ought to say that it  
is a part of everything we do1 to       
satisfy ourselves that it has been done 
rightly4 ,we conclude from known        
instances to unknown by the impulse of  
the generalizing propensity2 and 7until 
after a considerable amount of practice 
and mental discipline7 the question of  
the sufficiency of the evidence is only 
raised by a retrospective act1 turning  
back upon our own footsteps1 and        
examining whether we were warranted in  
doing what we have already done4 ,to    
speak of this reflex operation as part  
of the original one1 requiring to be    
expressed in words in order that the    
verbal formula may correctly represent  

the psychological process1 appears to me
 false psychology4#ae ,we review our    
syllogistic as well as our inductive    
processes1 and recognise that they have 
been correctly performed2 but logicians 
do not add a third premise to the       
syllogism1 to express this act of       
recognition4 ,a careful copyist verifies
 his transcript by collating it with the
 original2 and if no error appears1 he  
recognises that the transcript has been 
correctly made4 ,but we do not call the 
examination of the copy a part of the   
act of copying4  ,the conclusion in an  
induction is inferred from the evidence 
itself1 and not from a recognition of   
the sufficiency of the evidence2 as ,i  
infer that my friend is walking towards 
me because ,i see him1 and not because  
,i recognise that my eyes are open1 and 
that eyesight is a means of knowledge4  
,in all operations which require care1  
it is good to assure ourselves that the 
process has been performed accurately2  
but the testing of the process is not   

the process itself2 and1 besides1 may   
have been omitted altogether1 and yet   
the process be correct4 ,it is precisely
 because that operation is omitted in   
ordinary unscientific reasoning1 that   
there is anything gained in certainty by
 throwing reasoning into the syllogistic
 form4 ,to make sure1 as far as         
possible1 that it shall not be omitted1 
we make the testing operation a part of 
the reasoning process itself4 ,we insist
 that the inference from particulars to 
particulars shall pass through a general
 proposition4 ,but this is a security   
for good reasoning1 not a condition of  
all reasoning2 and in some cases not    
even a security4 ,our most familiar     
inferences are all made before we learn 
the use of general propositions2 and a  
person of untutored sagacity will       
skilfully apply his acquired experience 
to adjacent cases1 though he would      
bungle grievously in fixing the limits  
of the appropriate general theorem4 ,but
 though he may conclude rightly1 he     

never1 properly speaking1 knows whether 
he has done so or not2 he has not tested
 his reasoning4 ,now1 this is precisely 
what forms of reasoning do for us4 ,we  
do not need them to enable us to reason1
 but to enable us to know whether we    
reason correctly4  ,in still further    
answer to the objection1 it may be added
 that1 even when the test has been      
applied1 and the sufficiency of the     
evidence recognised1--if it is          
sufficient to support the general       
proposition1 it is sufficient also to   
support an inference from particulars to
 particulars without passing through the
 general proposition4 ,the inquirer who 
has logically satisfied himself that the
 conditions of legitimate induction were
 realized in the cases ,a1 ,b1 ,c1 would
 be as much justified in concluding     
directly to the ,duke of ,wellington as 
in concluding to all men4 ,the general  
conclusion is never legitimate1 unless  
the particular one would be so too2 and 
in no sense1 intelligible to me1 can the

 particular conclusion be said to be    
drawn from the general one4 ,whenever   
there is ground for drawing any         
conclusion at all from particular       
instances1 there is ground for a general
 conclusion2 but that this general      
conclusion should be actually drawn1    
however useful1 cannot be an            
indispensable condition of the validity 
of the inference in the particular case4
 ,a man gives away sixpence by the same 
power by which he disposes of his whole 
fortune2 but it is not necessary to the 
legality of the smaller act1 that he    
should make a formal assertion of his   
right to the greater one4  ,some        
additional remarks1 in reply to minor   
objections1 are appended4#af    #i4 ,the
 preceding considerations enable us to  
understand the true nature of what is   
termed1 by recent writers1 ,formal      
,logic1 and the relation between it and 
,logic in the widest sense4 ,logic1 as  
,i conceive it1 is the entire theory of 
the ascertainment of reasoned or        

inferred truth4 ,formal ,logic1         
therefore1 which ,sir ,william ,hamilton
 from his own point of view1 and        
,archbishop ,whately from his1 have     
represented as the whole of ,logic      
properly so called1 is really a very    
subordinate part of it1 not being       
directly concerned with the process of  
,reasoning or ,inference in the sense in
 which that process is a part of the    
,investigation of ,truth4 ,what1 then1  
is ,formal ,logic8 ,the name seems to be
 properly applied to all that portion of
 doctrine which relates to the          
equivalence of different modes of       
expression2 the rules for determining   
when assertions in a given form imply or
 suppose the truth or falsity of other  
assertions4 ,this includes the theory of
 the ,import of ,propositions1 and of   
their ,conversion1 quipollence1 and     
,opposition2 of those falsely called    
,inductions 7to be hereafter spoken     
of#ag71 in which the apparent           
generalization is a mere abridged       

statement of cases known individually2  
and finally1 of the syllogism3 while the
 theory of ,naming1 and of 7what is     
inseparably connected with it7          
,definition1 though belonging still more
 to the other and larger kind of logic  
than to this1 is a necessary preliminary
 to this4 ,the end aimed at by ,formal  
,logic1 and attained by the observance  
of its precepts1 is not truth1 but      
consistency4 ,it has been seen that this
 is the only direct purpose of the rules
 of the syllogism2 the intention and    
effect of which is simply to keep our   
inferences or conclusions in complete   
consistency with our general formul or  
directions for drawing them4 ,the ,logic
 of ,consistency is a necessary         
auxiliary to the logic of truth1 not    
only because what is inconsistent with  
itself or with other truths cannot be   
true1 but also because truth can only be
 successfully pursued by drawing        
inferences from experience1 which1 if   
warrantable at all1 admit of being      

generalized1 and1 to test their         
warrantableness1 require to be exhibited
 in a generalized form2 after which the 
correctness of their application to     
particular cases is a question which    
specially concerns the ,logic of        
,consistency4 ,this ,logic1 not         
requiring any preliminary knowledge of  
the processes or conclusions of the     
various sciences1 may be studied with   
benefit in a much earlier stage of      
education than the ,logic of ,truth3 and
 the practice which has empirically     
obtained of teaching it apart1 through  
elementary treatises which do not       
attempt to include anything else1 though
 the reasons assigned for the practice  
are in general very far from            
philosophical1 admits of a philosophical
 justification4     ,,chapter ,,iv4     
,,of ,,trains ,,of ,,reasoning1 ,,and   
,,deductive ,,sciences4    #a4 ,in our  
analysis of the syllogism1 it appeared  
that the minor premise always affirms a 
resemblance between a new case and some 

cases previously known2 while the major 
premise asserts something which1 having 
been found true of those known cases1 we
 consider ourselves warranted in holding
 true of any other case resembling the  
former in certain given particulars4    
,if all ratiocinations resembled1 as to 
the minor premise1 the examples which   
were exclusively employed in the        
preceding chapter2 if the resemblance1  
which that premise asserts1 were obvious
 to the senses1 as in the proposition   
,socrates is a man1 or were at once     
ascertainable by direct observation2    
there would be no necessity for trains  
of reasoning1 and ,deductive or         
,ratiocinative ,sciences would not      
exist4 ,trains of reasoning exist only  
for the sake of extending an induction  
founded1 as all inductions must be1 on  
observed cases1 to other cases in which 
we not only cannot directly observe what
 is to be proved1 but cannot directly   
observe even the mark which is to prove 
it4    #b4 ,suppose the syllogism to be1

 ,all cows ruminate1 the animal which is
 before me is a cow1 therefore it       
ruminates4 ,the minor1 if true at all1  
is obviously so3 the only premise the   
establishment of which requires any     
anterior process of inquiry1 is the     
major2 and provided the induction of    
which that premise is the expression was
 correctly performed1 the conclusion    
respecting the animal now present will  
be instantly drawn2 because1 as soon as 
she is compared with the formula1 she   
will be identified as being included in 
it4 ,but suppose the syllogism to be the
 following3--,all arsenic is poisonous1 
the substance which is before me is     
arsenic1 therefore it is poisonous4 ,the
 truth of the minor may not here be     
obvious at first sight2 it may not be   
intuitively evident1 but may itself be  
known only by inference4 ,it may be the 
conclusion of another argument1 which1  
thrown into the syllogistic form1 would 
stand thus3--,whatever when lighted     
produces a dark spot on a piece of white

 porcelain held in the flame1 which spot
 is soluble in hypochlorite of calcium1 
is arsenic2 the substance before me     
conforms to this condition2 therefore it
 is arsenic4 ,to establish1 therefore1  
the ultimate conclusion1 ,the substance 
before me is poisonous1 requires a      
process1 which1 in order to be          
syllogistically expressed1 stands in    
need of two syllogisms2 and we have a   
,train of ,reasoning4  ,when1 however1  
we thus add syllogism to syllogism1 we  
are really adding induction to          
induction4 ,two separate inductions must
 have taken place to render this chain  
of inference possible2 inductions       
founded1 probably1 on different sets of 
individual instances1 but which converge
 in their results1 so that the instance 
which is the subject of inquiry comes   
within the range of them both4 ,the     
record of these inductions is contained 
in the majors of the two syllogisms4    
,first1 we1 or others for us1 have      
examined various objects which yielded  

under the given circumstances a dark    
spot with the given property1 and found 
that they possessed the properties      
connoted by the word arsenic2 they were 
metallic1 volatile1 their vapour had a  
smell of garlic1 and so forth4 ,next1   
we1 or others for us1 have examined     
various specimens which possessed this  
metallic and volatile character1 whose  
vapour had this smell1 c41 and have     
invariably found that they were         
poisonous4 ,the first observation we    
judge that we may extend to all         
substances whatever which yield that    
particular kind of dark spot2 the       
second1 to all metallic and volatile    
substances resembling those we examined2
 and consequently1 not to those only    
which are seen to be such1 but to those 
which are concluded to be such by the   
prior induction4 ,the substance before  
us is only seen to come within one of   
these inductions2 but by means of this  
one1 it is brought within the other4 ,we
 are still1 as before1 concluding from  

particulars to particulars2 but we are  
now concluding from particulars         
observed1 to other particulars which are
 not1 as in the simple case1 seen to    
resemble them in the material points1   
but inferred to do so1 because          
resembling them in something else1 which
 we have been led by quite a different  
set of instances to consider as a mark  
of the former resemblance4  ,this first 
example of a train of reasoning is still
 extremely simple1 the series consisting
 of only two syllogisms4 ,the following 
is somewhat more complicated3--,no      
government1 which earnestly seeks the   
good of its subjects1 is likely to be   
overthrown2 some particular government  
earnestly seeks the good of its         
subjects1 therefore it is not likely to 
be overthrown4 ,the major premise in    
this argument we shall suppose not to be
 derived from considerations  priori1   
but to be a generalization from history1
 which1 whether correct or erroneous1   
must have been founded on observation of

 governments concerning whose desire of 
the good of their subjects there was no 
doubt4 ,it has been found1 or thought to
 be found1 that these were not easily   
overthrown1 and it has been deemed that 
those instances warranted an extension  
of the same predicate to any and every  
government which resembles them in the  
attribute of desiring earnestly the good
 of its subjects4 ,but does the         
government in question thus resemble    
them8 ,this may be debated pro and con  
by many arguments1 and must1 in any     
case1 be proved by another induction2   
for we cannot directly observe the      
sentiments and desires of the persons   
who carry on the government4 ,to prove  
the minor1 therefore1 we require an     
argument in this form3 ,every government
 which acts in a certain manner1 desires
 the good of its subjects2 the supposed 
government acts in that particular      
manner1 therefore it desires the good of
 its subjects4 ,but is it true that the 
government acts in the manner supposed8 

,this minor also may require proof2     
still another induction1 as thus3--,what
 is asserted by intelligent and         
disinterested witnesses1 may be believed
 to be true2 that the government acts in
 this manner1 is asserted by such       
witnesses1 therefore it may be believed 
to be true4 ,the argument hence consists
 of three steps4 ,having the evidence of
 our senses that the case of the        
government under consideration resembles
 a number of former cases1 in the       
circumstance of having something        
asserted respecting it by intelligent   
and disinterested witnesses1 we infer1  
first1 that1 as in those former         
instances1 so in this instance1 the     
assertion is true4 ,secondly1 what was  
asserted of the government being that it
 acts in a particular manner1 and other 
governments or persons having been      
observed to act in the same manner1 the 
government in question is brought into  
known resemblance with those other      
governments or persons2 and since they  

were known to desire the good of the    
people1 it is thereupon1 by a second    
induction1 inferred that the particular 
government spoken of1 desires the good  
of the people4 ,this brings that        
government into known resemblance with  
the other governments which were thought
 likely to escape revolution1 and       
thence1 by a third induction1 it is     
concluded that this particular          
government is also likely to escape4    
,this is still reasoning from           
particulars to particulars1 but we now  
reason to the new instance from three   
distinct sets of former instances3 to   
one only of those sets of instances do  
we directly perceive the new one to be  
similar2 but from that similarity we    
inductively infer that it has the       
attribute by which it is assimilated to 
the next set1 and brought within the    
corresponding induction2 after which by 
a repetition of the same operation we   
infer it to be similar to the third set1
 and hence a third induction conducts us

 to the ultimate conclusion4    #c4     
,notwithstanding the superior           
complication of these examples1 compared
 with those by which in the preceding   
chapter we illustrated the general      
theory of reasoning1 every doctrine     
which we then laid down holds equally   
true in these more intricate cases4 ,the
 successive general propositions are not
 steps in the reasoning1 are not        
intermediate links in the chain of      
inference1 between the particulars      
observed and those to which we apply the
 observation4 ,if we had sufficiently   
capacious memories1 and a sufficient    
power of maintaining order among a huge 
mass of details1 the reasoning could go 
on without any general propositions2    
they are mere formul for inferring      
particulars from particulars4 ,the      
principle of general reasoning is 7as   
before explained71 that if from         
observation of certain known            
particulars1 what was seen to be true of
 them can be inferred to be true of any 

others1 it may be inferred of all others
 which are of a certain description4    
,and in order that we may never fail to 
draw this conclusion in a new case when 
it can be drawn correctly1 and may avoid
 drawing it when it cannot1 we determine
 once for all what are the              
distinguishing marks by which such cases
 may be recognised4 ,the subsequent     
process is merely that of identifying an
 object1 and ascertaining it to have    
those marks2 whether we identify it by  
the very marks themselves1 or by others 
which we have ascertained 7through      
another and a similar process7 to be    
marks of those marks4 ,the real         
inference is always from particulars to 
particulars1 from the observed instances
 to an unobserved one3 but in drawing   
this inference1 we conform to a formula 
which we have adopted for our guidance  
in such operations1 and which is a      
record of the criteria by which we      
thought we had ascertained that we might
 distinguish when the inference could1  

and when it could not1 be drawn4 ,the   
real premises are the individual        
observations1 even though they may have 
been forgotten1 or1 being the           
observations of others and not of       
ourselves1 may1 to us1 never have been  
known3 but we have before us proof that 
we or others once thought them          
sufficient for an induction1 and we have
 marks to show whether any new case is  
one of those to which1 if then known1   
the induction would have been deemed to 
extend4 ,these marks we either recognise
 at once1 or by the aid of other marks1 
which by another previous induction we  
collected to be marks of the first4     
,even these marks of marks may only be  
recognised through a third set of marks2
 and we may have a train of reasoning1  
of any length1 to bring a new case      
within the scope of an induction        
grounded on particulars its similarity  
to which is only ascertained in this    
indirect manner4  ,thus1 in the         
preceding example1 the ultimate         

inductive inference was1 that a certain 
government was not likely to be         
overthrown2 this inference was drawn    
according to a formula in which desire  
of the public good was set down as a    
mark of not being likely to be          
overthrown2 a mark of this mark was1    
acting in a particular manner2 and a    
mark of acting in that manner was1 being
 asserted to do so by intelligent and   
disinterested witnesses3 this mark1 the 
government under discussion was         
recognised by the senses as possessing4 
,hence that government fell within the  
last induction1 and by it was brought   
within all the others4 ,the perceived   
resemblance of the case to one set of   
observed particular cases1 brought it   
into known resemblance with another set1
 and that with a third4  ,in the more   
complex branches of knowledge1 the      
deductions seldom consist1 as in the    
examples hitherto exhibited1 of a single
 chain1 a a mark of b1 b of c1 c of d1  
therefore a a mark of d4 ,they consist  

7to carry on the same metaphor7 of      
several chains united at the extremity1 
as thus3 a a mark of d1 b of e1 c of f1 
d e f of n1 therefore a b c a mark of n4
 ,suppose1 for example1 the following   
combination of circumstances2 #ast1 rays
 of light impinging on a reflecting     
surface2 #bnd1 that surface parabolic2  
#crd1 those rays parallel to each other 
and to the axis of the surface4 ,it is  
to be proved that the concourse of these
 three circumstances is a mark that the 
reflected rays will pass through the    
focus of the parabolic surface4 ,now1   
each of the three circumstances is      
singly a mark of something material to  
the case4 ,rays of light impinging on a 
reflecting surface1 are a mark that     
those rays will be reflected at an angle
 equal to the angle of incidence4 ,the  
parabolic form of the surface is a mark 
that1 from any point of it1 a line drawn
 to the focus and a line parallel to the
 axis will make equal angles with the   
surface4 ,and finally1 the parallelism  

of the rays to the axis is a mark that  
their angle of incidence coincides with 
one of these equal angles4 ,the three   
marks taken together are therefore a    
mark of all these three things united4  
,but the three united are evidently a   
mark that the angle of reflection must  
coincide with the other of the two equal
 angles1 that formed by a line drawn to 
the focus2 and this again1 by the       
fundamental axiom concerning straight   
lines1 is a mark that the reflected rays
 pass through the focus4 ,most chains of
 physical deduction are of this more    
complicated type2 and even in           
mathematics such are abundant1 as in all
 propositions where the hypothesis      
includes numerous conditions3 ,if a     
circle be taken1 and if within that     
circle a point be taken1 not the centre1
 and if straight lines be drawn from    
that point to the circumference1 then1  
c4    #d4 ,the considerations now stated
 remove a serious difficulty from the   
view we have taken of reasoning2 which  

view might otherwise have seemed not    
easily reconcileable with the fact that 
there are ,deductive or ,ratiocinative  
,sciences4 ,it might seem to follow1 if 
all reasoning be induction1 that the    
difficulties of philosophical           
investigation must lie in the inductions
 exclusively1 and that when these were  
easy1 and susceptible of no doubt or    
hesitation1 there could be no science1  
or1 at least1 no difficulties in        
science4 ,the existence1 for example1 of
 an extensive ,science of ,mathematics1 
requiring the highest scientific genius 
in those who contributed to its         
creation1 and calling for a most        
continued and vigorous exertion of      
intellect in order to appropriate it    
when created1 may seem hard to be       
accounted for on the foregoing theory4  
,but the considerations more recently   
adduced remove the mystery1 by showing1 
that even when the inductions themselves
 are obvious1 there may be much         
difficulty in finding whether the       

particular case which is the subject of 
inquiry comes within them2 and ample    
room for scientific ingenuity in so     
combining various inductions1 as1 by    
means of one within which the case      
evidently falls1 to bring it within     
others in which it cannot be directly   
seen to be included4  ,when the more    
obvious of the inductions which can be  
made in any science from direct         
observations1 have been made1 and       
general formulas have been framed1      
determining the limits within which     
these inductions are applicable2 as     
often as a new case can be at once seen 
to come within one of the formulas1 the 
induction is applied to the new case1   
and the business is ended4 ,but new     
cases are continually arising1 which do 
not obviously come within any formula   
whereby the question we want solved in  
respect of them could be answered4 ,let 
us take an instance from geometry3 and  
as it is taken only for illustration1   
let the reader concede to us for the    

present1 what we shall endeavour to     
prove in the next chapter1 that the     
first principles of geometry are results
 of induction4 ,our example shall be the
 fifth proposition of the first book of 
,euclid4 ,the inquiry is1 ,are the      
angles at the base of an isosceles      
triangle equal or unequal8 ,the first   
thing to be considered is1 what         
inductions we have1 from which we can   
infer equality or inequality4 ,for      
inferring equality we have the following
 formul3--,things which being applied to
 each other coincide1 are equals4       
,things which are equal to the same     
thing are equals4 ,a whole and the sum  
of its parts are equals4 ,the sums of   
equal things are equals4 ,the           
differences of equal things are equals4 
,there are no other original formul to  
prove equality4 ,for inferring          
inequality we have the following3--,a   
whole and its parts are unequals4 ,the  
sums of equal things and unequal things 
are unequals4 ,the differences of equal 

things and unequal things are unequals4 
,in all1 eight formul4 ,the angles at   
the base of an isosceles triangle do not
 obviously come within any of these4    
,the formul specify certain marks of    
equality and of inequality1 but the     
angles cannot be perceived intuitively  
to have any of those marks4 ,on         
examination it appears that they have2  
and we ultimately succeed in bringing   
them within the formula1 ,the           
differences of equal things are equal4  
,whence comes the difficulty of         
recognising these angles as the         
differences of equal things8 ,because   
each of them is the difference not of   
one pair only1 but of innumerable pairs 
of angles2 and out of these we had to   
imagine and select two1 which could     
either be intuitively perceived to be   
equals1 or possessed some of the marks  
of equality set down in the various     
formul4 ,by an exercise of ingenuity1   
which1 on the part of the first         
inventor1 deserves to be regarded as    

considerable1 two pairs of angles were  
hit upon1 which united these requisites4
 ,first1 it could be perceived          
intuitively that their differences were 
the angles at the base2 and1 secondly1  
they possessed one of the marks of      
equality1 namely1 coincidence when      
applied to one another4 ,this           
coincidence1 however1 was not perceived 
intuitively1 but inferred1 in conformity
 to another formula4  ,for greater      
clearness1 ,i subjoin an analysis of the
 demonstration4 ,euclid1 it will be     
remembered1 demonstrates his fifth      
proposition by means of the fourth4     
,this it is not allowable for us to do1 
because we are undertaking to trace     
deductive truths not to prior           
deductions1 but to their original       
inductive foundation4 ,we must therefore
 use the premises of the fourth         
proposition instead of its conclusion1  
and prove the fifth directly from first 
principles4 ,to do so requires six      
formulas4 7,we must begin1 as in        

,euclid1 by prolonging the equal sides  
,,ab1 ,,ac1 to equal distances1 and     
joining the extremities ,,be1 ,,dc47    
,illustration  ,,first ,,formula4 ,the  
sums of equals are equal4  ,,ad and ,,ae
 are sums of equals by the supposition4 
,having that mark of equality1 they are 
concluded by this formula to be equal4  
,,second ,,formula4 ,equal straight     
lines being applied to one another      
coincide4  ,,ac1 ,,ab1 are within this  
formula by supposition2 ,,ad1 ,,ae1 have
 been brought within it by the preceding
 step4 ,both these pairs of straight    
lines have the property of equality2    
which1 according to the second formula1 
is a mark that1 if applied to each      
other1 they will coincide4 ,coinciding  
altogether means coinciding in every    
part1 and of course at their            
extremities1 ,d1 ,e1 and ,b1 ,c4        
,,third ,,formula4 ,straight lines1     
having their extremities coincident1    
coincide4  ,,be and ,,cd have been      
brought within this formula by the      

preceding induction2 they will1         
therefore1 coincide4  ,,fourth          
,,formula4 ,angles1 having their sides  
coincident1 coincide4  ,the third       
induction having shown that ,,be and    
,,cd coincide1 and the second that ,,ab1
 ,,ac1 coincide1 the angles ,,abe and   
,,acd are thereby brought within the    
fourth formula1 and accordingly         
coincide4  ,,fifth ,,formula4 ,things   
which coincide are equal4  ,the angles  
,,abe and ,,acd are brought within this 
formula by the induction immediately    
preceding4 ,this train of reasoning     
being also applicable1 mutatis mutandis1
 to the angles ,,ebc1 ,,dcb1 these also 
are brought within the fifth formula4   
,and1 finally1  ,,sixth ,,formula4 ,the 
differences of equals are equal4  ,the  
angle ,,abc being the difference of     
,,abe1 ,,cbe1 and the angle ,,acb being 
the difference of ,,acd1 ,,dcb2 which   
have been proved to be equals2 ,,abc and
 ,,acb are brought within the last      
formula by the whole of the previous    

process4  ,the difficulty here          
encountered is chiefly that of figuring 
to ourselves the two angles at the base 
of the triangle ,,abc as remainders made
 by cutting one pair of angles out of   
another1 while each pair shall be       
corresponding angles of triangles which 
have two sides and the intervening angle
 equal4 ,it is by this happy contrivance
 that so many different inductions are  
brought to bear upon the same particular
 case4 ,and this not being at all an    
obvious thought1 it may be seen from an 
example so near the threshold of        
mathematics1 how much scope there may   
well be for scientific dexterity in the 
higher branches of that and other       
sciences1 in order so to combine a few  
simple inductions1 as to bring within   
each of them innumerable cases which are
 not obviously included in it2 and how  
long1 and numerous1 and complicated may 
be the processes necessary for bringing 
the inductions together1 even when each 
induction may itself be very easy and   

simple4 ,all the inductions involved in 
all geometry are comprised in those     
simple ones1 the formul of which are the
 ,axioms1 and a few of the so-called    
,definitions4 ,the remainder of the     
science is made up of the processes     
employed for bringing unforeseen cases  
within these inductions2 or 7in         
syllogistic language7 for proving the   
minors necessary to complete the        
syllogisms2 the majors being the        
definitions and axioms4 ,in those       
definitions and axioms are laid down the
 whole of the marks1 by an artful       
combination of which it has been found  
possible to discover and prove all that 
is proved in geometry4 ,the marks being 
so few1 and the inductions which furnish
 them being so obvious and familiar2 the
 connecting of several of them together1
 which constitutes ,deductions1 or      
,trains of ,reasoning1 forms the whole  
difficulty of the science1 and with a   
trifling exception1 its whole bulk2 and 
hence ,geometry is a ,deductive         

,science4    #e4 ,it will be seen       
hereafter#ah that there are weighty     
scientific reasons for giving to every  
science as much of the character of a   
,deductive ,science as possible2 for    
endeavouring to construct the science   
from the fewest and the simplest        
possible inductions1 and to make these1 
by any combinations however complicated1
 suffice for proving even such truths1  
relating to complex cases1 as could be  
proved1 if we chose1 by inductions from 
specific experience4 ,every branch of   
natural philosophy was originally       
experimental2 each generalization rested
 on a special induction1 and was derived
 from its own distinct set of           
observations and experiments4 ,from     
being sciences of pure experiment1 as   
the phrase is1 or1 to speak more        
correctly1 sciences in which the        
reasonings mostly consist of no more    
than one step1 and are expressed by     
single syllogisms1 all these sciences   
have become to some extent1 and some of 

them in nearly the whole of their       
extent1 sciences of pure reasoning2     
whereby multitudes of truths1 already   
known by induction from as many         
different sets of experiments1 have come
 to be exhibited as deductions or       
corollaries from inductive propositions 
of a simpler and more universal         
character4 ,thus mechanics1             
hydrostatics1 optics1 acoustics1        
thermology1 have successively been      
rendered mathematical2 and astronomy was
 brought by ,newton within the laws of  
general mechanics4 ,why it is that the  
substitution of this circuitous mode of 
proceeding for a process apparently much
 easier and more natural1 is held1 and  
justly1 to be the greatest triumph of   
the investigation of nature1 we are not1
 in this stage of our inquiry1 prepared 
to examine4 ,but it is necessary to     
remark1 that although1 by this          
progressive transformation1 all sciences
 tend to become more and more           
,deductive1 they are not1 therefore1 the

 less ,inductive2 every step in the     
,deduction is still an ,induction4 ,the 
opposition is not between the terms     
,deductive and ,inductive1 but between  
,deductive and ,experimental4 ,a science
 is experimental1 in proportion as every
 new case1 which presents any peculiar  
features1 stands in need of a new set of
 observations and experiments--a fresh  
induction4 ,it is deductive1 in         
proportion as it can draw conclusions1  
respecting cases of a new kind1 by      
processes which bring those cases under 
old inductions2 by ascertaining that    
cases which cannot be observed to have  
the requisite marks1 have1 however1     
marks of those marks4  ,we can now1     
therefore1 perceive what is the generic 
distinction between sciences which can  
be made ,deductive1 and those which must
 as yet remain ,experimental4 ,the      
difference consists in our having been  
able1 or not yet able1 to discover marks
 of marks4 ,if by our various inductions
 we have been able to proceed no further

 than to such propositions as these1 a a
 mark of b1 or a and b marks of one     
another1 c a mark of d1 or c and d marks
 of one another1 without anything to    
connect a or b with c or d2 we have a   
science of detached and mutually        
independent generalizations1 such as    
these1 that acids redden vegetable      
blues1 and that alkalies colour them    
green2 from neither of which            
propositions could we1 directly or      
indirectly1 infer the other3 and a      
science1 so far as it is composed of    
such propositions1 is purely            
experimental4 ,chemistry1 in the present
 state of our knowledge1 has not yet    
thrown off this character4 ,there are   
other sciences1 however1 of which the   
propositions are of this kind3 a a mark 
of b1 b a mark of c1 c of d1 d of e1 c4 
,in these sciences we can mount the     
ladder from a to e by a process of      
ratiocination2 we can conclude that a is
 a mark of e1 and that every object     
which has the mark a has the property e1

 although1 perhaps1 we never were able  
to observe a and e together1 and        
although even d1 our only direct mark of
 e1 may not be perceptible in those     
objects1 but only inferrible4 ,or1      
varying the first metaphor1 we may be   
said to get from a to e underground3 the
 marks b1 c1 d1 which indicate the      
route1 must all be possessed somewhere  
by the objects concerning which we are  
inquiring2 but they are below the       
surface3 a is the only mark that is     
visible1 and by it we are able to trace 
in succession all the rest4    #f4 ,we  
can now understand how an experimental  
may transform itself into a deductive   
science by the mere progress of         
experiment4 ,in an experimental science1
 the inductions1 as we have said1 lie   
detached1 as1 a a mark of b1 c a mark of
 d1 e a mark of f1 and so on3 now1 a new
 set of instances1 and a consequent new 
induction1 may at any time bridge over  
the interval between two of these       
unconnected arches2 b1 for example1 may 

be ascertained to be a mark of c1 which 
enables us thenceforth to prove         
deductively that a is a mark of c4 ,or1 
as sometimes happens1 some comprehensive
 induction may raise an arch high in the
 air1 which bridges over hosts of them  
at once3 b1 d1 f1 and all the rest1     
turning out to be marks of some one     
thing1 or of things between which a     
connexion has already been traced4 ,as  
when ,newton discovered that the        
motions1 whether regular or apparently  
anomalous1 of all the bodies of the     
solar system1 7each of which motions had
 been inferred by a separate logical    
operation1 from separate marks17 were   
all marks of moving round a common      
centre1 with a centripetal force varying
 directly as the mass1 and inversely as 
the square of the distance from that    
centre4 ,this is the greatest example   
which has yet occurred of the           
transformation1 at one stroke1 of a     
science which was still to a great      
degree merely experimental1 into a      

deductive science4  ,transformations of 
the same nature1 but on a smaller scale1
 continually take place in the less     
advanced branches of physical knowledge1
 without enabling them to throw off the 
character of experimental sciences4     
,thus with regard to the two unconnected
 propositions before cited1 namely1     
,acids redden vegetable blues1 ,alkalies
 make them green2 it is remarked by     
,liebig1 that all blue colouring matters
 which are reddened by acids 7as well   
as1 reciprocally1 all red colouring     
matters which are rendered blue by      
alkalies7 contain nitrogen3 and it is   
quite possible that this circumstance   
may one day furnish a bond of connexion 
between the two propositions in         
question1 by showing that the           
antagonistic action of acids and        
alkalies in producing or destroying the 
colour blue1 is the result of some one1 
more general1 law4 ,although this       
connecting of detached generalizations  
is so much gain1 it tends but little to 

give a deductive character to any       
science as a whole2 because the new     
courses of observation and experiment1  
which thus enable us to connect together
 a few general truths1 usually make     
known to us a still greater number of   
unconnected new ones4 ,hence chemistry1 
though similar extensions and           
simplifications of its generalizations  
are continually taking place1 is still  
in the main an experimental science2 and
 is likely so to continue unless some   
comprehensive induction should be       
hereafter arrived at1 which1 like       
,newton's1 shall connect a vast number  
of the smaller known inductions         
together1 and change the whole method of
 the science at once4 ,chemistry has    
already one great generalization1 which1
 though relating to one of the          
subordinate aspects of chemical         
phenomena1 possesses within its limited 
sphere this comprehensive character2 the
 principle of ,dalton1 called the atomic
 theory1 or the doctrine of chemical    

equivalents3 which by enabling us to a  
certain extent to foresee the           
proportions in which two substances will
 combine1 before the experiment has been
 tried1 constitutes undoubtedly a source
 of new chemical truths obtainable by   
deduction1 as well as a connecting      
principle for all truths of the same    
description previously obtained by      
experiment4    #g4 ,the discoveries     
which change the method of a science    
from experimental to deductive1 mostly  
consist in establishing1 either by      
deduction or by direct experiment1 that 
the varieties of a particular phenomenon
 uniformly accompany the varieties of   
some other phenomenon better known4     
,thus the science of sound1 which       
previously stood in the lowest rank of  
merely experimental science1 became     
deductive when it was proved by         
experiment that every variety of sound  
was consequent on1 and therefore a mark 
of1 a distinct and definable variety of 
oscillatory motion among the particles  

of the transmitting medium4 ,when this  
was ascertained1 it followed that every 
relation of succession or coexistence   
which obtained between phenomena of the 
more known class1 obtained also between 
the phenomena which corresponded to them
 in the other class4 ,every sound1 being
 a mark of a particular oscillatory     
motion1 became a mark of everything     
which1 by the laws of dynamics1 was     
known to be inferrible from that motion2
 and everything which by those same laws
 was a mark of any oscillatory motion   
among the particles of an elastic       
medium1 became a mark of the            
corresponding sound4 ,and thus many     
truths1 not before suspected1 concerning
 sound1 become deducible from the known 
laws of the propagation of motion       
through an elastic medium2 while facts  
already empirically known respecting    
sound1 become an indication of          
corresponding properties of vibrating   
bodies1 previously undiscovered4  ,but  
the grand agent for transforming        

experimental into deductive sciences1 is
 the science of number4 ,the properties 
of numbers1 alone among all known       
phenomena1 are1 in the most rigorous    
sense1 properties of all things         
whatever4 ,all things are not coloured1 
or ponderable1 or even extended2 but all
 things are numerable4 ,and if we       
consider this science in its whole      
extent1 from common arithmetic up to the
 calculus of variations1 the truths     
already ascertained seem all but        
infinite1 and admit of indefinite       
extension4  ,these truths1 though       
affirmable of all things whatever1 of   
course apply to them only in respect of 
their quantity4 ,but if it comes to be  
discovered that variations of quality in
 any class of phenomena1 correspond     
regularly to variations of quantity     
either in those same or in some other   
phenomena2 every formula of mathematics 
applicable to quantities which vary in  
that particular manner1 becomes a mark  
of a corresponding general truth        

respecting the variations in quality    
which accompany them3 and the science of
 quantity being 7as far as any science  
can be7 altogether deductive1 the theory
 of that particular kind of qualities   
becomes1 to this extent1 deductive      
likewise4  ,the most striking instance  
in point which history affords 7though  
not an example of an experimental       
science rendered deductive1 but of an   
unparalleled extension given to the     
deductive process in a science which was
 deductive already71 is the revolution  
in geometry which originated with       
,descartes1 and was completed by        
,clairaut4 ,these great mathematicians  
pointed out the importance of the fact1 
that to every variety of position in    
points1 direction in lines1 or form in  
curves or surfaces 7all of which are    
,qualities71 there corresponds a        
peculiar relation of quantity between   
either two or three rectilineal         
co-ordinates2 insomuch that if the law  
were known according to which those     

co-ordinates vary relatively to one     
another1 every other geometrical        
property of the line or surface in      
question1 whether relating to quantity  
or quality1 would be capable of being   
inferred4 ,hence it followed that every 
geometrical question could be solved1 if
 the corresponding algebraical one      
could2 and geometry received an         
accession 7actual or potential7 of new  
truths1 corresponding to every property 
of numbers which the progress of the    
calculus had brought1 or might in future
 bring1 to light4 ,in the same general  
manner1 mechanics1 astronomy1 and in a  
less degree1 every branch of natural    
philosophy commonly so called1 have been
 made algebraical4 ,the varieties of    
physical phenomena with which those     
sciences are conversant1 have been found
 to answer to determinable varieties in 
the quantity of some circumstance or    
other2 or at least to varieties of form 
or position1 for which corresponding    
equations of quantity had already been1 

or were susceptible of being1 discovered
 by geometers4  ,in these various       
transformations1 the propositions of the
 science of number do but fulfil the    
function proper to all propositions     
forming a train of reasoning1 viz4 that 
of enabling us to arrive in an indirect 
method1 by marks of marks1 at such of   
the properties of objects as we cannot  
directly ascertain 7or not so           
conveniently7 by experiment4 ,we travel 
from a given visible or tangible fact1  
through the truths of numbers1 to the   
facts sought4 ,the given fact is a mark 
that a certain relation subsists between
 the quantities of some of the elements 
concerned2 while the fact sought        
presupposes a certain relation between  
the quantities of some other elements3  
now1 if these last quantities are       
dependent in some known manner upon the 
former1 or vice vers1 we can argue from 
the numerical relation between the one  
set of quantities1 to determine that    
which subsists between the other set2   

the theorems of the calculus affording  
the intermediate links4 ,and thus one of
 the two physical facts becomes a mark  
of the other1 by being a mark of a mark 
of a mark of it4     ,,chapter ,v4  ,,of
 ,,demonstration1 ,,and ,,necessary     
,,truths4    #a4 ,if1 as laid down in   
the two preceding chapters1 the         
foundation of all sciences1 even        
deductive or demonstrative sciences1 is 
,induction2 if every step in the        
ratiocinations even of geometry is an   
act of induction2 and if a train of     
reasoning is but bringing many          
inductions to bear upon the same subject
 of inquiry1 and drawing a case within  
one induction by means of another2      
wherein lies the peculiar certainty     
always ascribed to the sciences which   
are entirely1 or almost entirely1       
deductive8 ,why are they called the     
,exact ,sciences8 ,why are mathematical 
certainty1 and the evidence of          
demonstration1 common phrases to express
 the very highest degree of assurance   

attainable by reason8 ,why are          
mathematics by almost all philosophers1 
and 7by some7 even those branches of    
natural philosophy which1 through the   
medium of mathematics1 have been        
converted into deductive sciences1      
considered to be independent of the     
evidence of experience and observation1 
and characterized as systems of         
,necessary ,truth8  ,the answer ,i      
conceive to be1 that this character of  
necessity1 ascribed to the truths of    
mathematics1 and even 7with some        
reservations to be hereafter made7 the  
peculiar certainty attributed to them1  
is an illusion2 in order to sustain     
which1 it is necessary to suppose that  
those truths relate to1 and express the 
properties of1 purely imaginary objects4
 ,it is acknowledged that the           
conclusions of geometry are deduced1    
partly at least1 from the so-called     
,definitions1 and that those definitions
 are assumed to be correct              
representations1 as far as they go1 of  

the objects with which geometry is      
conversant4 ,now we have pointed out    
that1 from a definition as such1 no     
proposition1 unless it be one concerning
 the meaning of a word1 can ever follow2
 and that what apparently follows from a
 definition1 follows in reality from an 
implied assumption that there exists a  
real thing conformable thereto4 ,this   
assumption1 in the case of the          
definitions of geometry1 is false3 there
 exist no real things exactly           
conformable to the definitions4 ,there  
exist no points without magnitude2 no   
lines without breadth1 nor perfectly    
straight2 no circles with all their     
radii exactly equal1 nor squares with   
all their angles perfectly right4 ,it   
will perhaps be said that the assumption
 does not extend to the actual1 but only
 to the possible1 existence of such     
things4 ,i answer that1 according to any
 test we have of possibility1 they are  
not even possible4 ,their existence1 so 
far as we can form any judgment1 would  

seem to be inconsistent with the        
physical constitution of our planet at  
least1 if not of the universe4 ,to get  
rid of this difficulty1 and at the same 
time to save the credit of the supposed 
system of necessary truth1 it is        
customary to say that the points1 lines1
 circles1 and squares which are the     
subject of geometry1 exist in our       
conceptions merely1 and are part of our 
minds2 which minds1 by working on their 
own materials1 construct an  priori     
science1 the evidence of which is purely
 mental1 and has nothing whatever to do 
with outward experience4 ,by howsoever  
high authorities this doctrine may have 
been sanctioned1 it appears to me       
psychologically incorrect4 ,the points1 
lines1 circles1 and squares1 which any  
one has in his mind1 are 7,i apprehend7 
simply copies of the points1 lines1     
circles1 and squares which he has known 
in his experience4 ,our idea of a point1
 ,i apprehend to be simply our idea of  
the minimum visibile1 the smallest      

portion of surface which we can see4 ,a 
line1 as defined by geometers1 is wholly
 inconceivable4 ,we can reason about a  
line as if it had no breadth2 because we
 have a power1 which is the foundation  
of all the control we can exercise over 
the operations of our minds2 the power1 
when a perception is present to our     
senses1 or a conception to our          
intellects1 of attending to a part only 
of that perception or conception1       
instead of the whole4 ,but we cannot    
conceive a line without breadth2 we can 
form no mental picture of such a line3  
all the lines which we have in our minds
 are lines possessing breadth4 ,if any  
one doubts this1 we may refer him to his
 own experience4 ,i much question if any
 one who fancies that he can conceive   
what is called a mathematical line1     
thinks so from the evidence of his      
consciousness3 ,i suspect it is rather  
because he supposes that unless such a  
conception were possible1 mathematics   
could not exist as a science3 a         

supposition which there will be no      
difficulty in showing to be entirely    
groundless4  ,since1 then1 neither in   
nature1 nor in the human mind1 do there 
exist any objects exactly corresponding 
to the definitions of geometry1 while   
yet that science cannot be supposed to  
be conversant about non-entities2       
nothing remains but to consider geometry
 as conversant with such lines1 angles1 
and figures1 as really exist2 and the   
definitions1 as they are called1 must be
 regarded as some of our first and most 
obvious generalizations concerning those
 natural objects4 ,the correctness of   
those generalizations1 as               
generalizations1 is without a flaw3 the 
equality of all the radii of a circle is
 true of all circles1 so far as it is   
true of any one3 but it is not exactly  
true of any circle2 it is only nearly   
true2 so nearly that no error of any    
importance in practice will be incurred 
by feigning it to be exactly true4 ,when
 we have occasion to extend these       

inductions1 or their consequences1 to   
cases in which the error would be       
appreciable--to lines of perceptible    
breadth or thickness1 parallels which   
deviate sensibly from equidistance1 and 
the like--we correct our conclusions1 by
 combining with them a fresh set of     
propositions relating to the aberration2
 just as we also take in propositions   
relating to the physical or chemical    
properties of the material1 if those    
properties happen to introduce any      
modification into the result2 which they
 easily may1 even with respect to figure
 and magnitude1 as in the case1 for     
instance1 of expansion by heat4 ,so     
long1 however1 as there exists no       
practical necessity for attending to any
 of the properties of the object except 
its geometrical properties1 or to any of
 the natural irregularities in those1 it
 is convenient to neglect the           
consideration of the other properties   
and of the irregularities1 and to reason
 as if these did not exist3 accordingly1

 we formally announce in the            
definitions1 that we intend to proceed  
on this plan4 ,but it is an error to    
suppose1 because we resolve to confine  
our attention to a certain number of the
 properties of an object1 that we       
therefore conceive1 or have an idea of1 
the object1 denuded of its other        
properties4 ,we are thinking1 all the   
time1 of precisely such objects as we   
have seen and touched1 and with all the 
properties which naturally belong to    
them2 but1 for scientific convenience1  
we feign them to be divested of all     
properties1 except those which are      
material to our purpose1 and in regard  
to which we design to consider them4    
,the peculiar accuracy1 supposed to be  
characteristic of the first principles  
of geometry1 thus appears to be         
fictitious4 ,the assertions on which the
 reasonings of the science are founded1 
do not1 any more than in other sciences1
 exactly correspond with the fact2 but  
we suppose that they do so1 for the sake

 of tracing the consequences which      
follow from the supposition4 ,the       
opinion of ,dugald ,stewart respecting  
the foundations of geometry1 is1 ,i     
conceive1 substantially correct2 that it
 is built on hypotheses2 that it owes to
 this alone the peculiar certainty      
supposed to distinguish it2 and that in 
any science whatever1 by reasoning from 
a set of hypotheses1 we may obtain a    
body of conclusions as certain as those 
of geometry1 that is1 as strictly in    
accordance with the hypotheses1 and as  
irresistibly compelling assent1 on      
condition that those hypotheses are     
true4  ,when1 therefore1 it is affirmed 
that the conclusions of geometry are    
necessary truths1 the necessity consists
 in reality only in this1 that they     
correctly follow from the suppositions  
from which they are deduced4 ,those     
suppositions are so far from being      
necessary1 that they are not even true2 
they purposely depart1 more or less     
widely1 from the truth4 ,the only sense 

in which necessity can be ascribed to   
the conclusions of any scientific       
investigation1 is that of legitimately  
following from some assumption1 which1  
by the conditions of the inquiry1 is not
 to be questioned4 ,in this relation1 of
 course1 the derivative truths of every 
deductive science must stand to the     
inductions1 or assumptions1 on which the
 science is founded1 and which1 whether 
true or untrue1 certain or doubtful in  
themselves1 are always supposed certain 
for the purposes of the particular      
science4 ,and therefore the conclusions 
of all deductive sciences were said by  
the ancients to be necessary            
propositions4 ,we have observed already 
that to be predicated necessarily was   
characteristic of the predicable        
,proprium1 and that a proprium was any  
property of a thing which could be      
deduced from its essence1 that is1 from 
the properties included in its          
definition4    #b4 ,the important       
doctrine of ,dugald ,stewart1 which ,i  

have endeavoured to enforce1 has been   
contested by ,dr4 ,whewell1 both in the 
dissertation appended to his excellent  
,mechanical ,euclid1 and in his         
elaborate work on the ,philosophy of the
 ,inductive ,sciences2 in which last he 
also replies to an article in the       
,edinburgh ,review1 7ascribed to a      
writer of great scientific eminence71 in
 which ,stewart's opinion was defended  
against his former strictures4 ,the     
supposed refutation of ,stewart consists
 in proving against him 7as has also    
been done in this work7 that the        
premises of geometry are not            
definitions1 but assumptions of the real
 existence of things corresponding to   
those definitions4 ,this1 however1 is   
doing little for ,dr4 ,whewell's        
purpose2 for it is these very           
assumptions which are asserted to be    
hypotheses1 and which he1 if he denies  
that geometry is founded on hypotheses1 
must show to be absolute truths4 ,all he
 does1 however1 is to observe1 that they

 at any rate1 are not arbitrary         
hypotheses2 that we should not be at    
liberty to substitute other hypotheses  
for them2 that not only a definition1 to
 be admissible1 must necessarily refer  
to and agree with some conception which 
we can distinctly frame in our thoughts1
 but that the straight lines1 for       
instance1 which we define1 must be those
 by which angles are contained1 those by
 which triangles are bounded1 those of  
which parallelism may be predicated1 and
 the like4#ai ,and this is true2 but    
this has never been contradicted4 ,those
 who say that the premises of geometry  
are hypotheses1 are not bound to        
maintain them to be hypotheses which    
have no relation whatever to fact4      
,since an hypothesis framed for the     
purpose of scientific inquiry must      
relate to something which has real      
existence1 7for there can be no science 
respecting non-entities17 it follows    
that any hypothesis we make respecting  
an object1 to facilitate our study of   

it1 must not involve anything which is  
distinctly false1 and repugnant to its  
real nature3 we must not ascribe to the 
thing any property which it has not2 our
 liberty extends only to slightly       
exaggerating some of those which it has1
 7by assuming it to be completely what  
it really is very nearly17 and          
suppressing others1 under the           
indispensable obligation of restoring   
them whenever1 and in as far as1 their  
presence or absence would make any      
material difference in the truth of our 
conclusions4 ,of this nature1           
accordingly1 are the first principles   
involved in the definitions of geometry4
 ,that the hypotheses should be of this 
particular character1 is however no     
further necessary1 than inasmuch as no  
others could enable us to deduce        
conclusions which1 with due corrections1
 would be true of real objects3 and in  
fact1 when our aim is only to illustrate
 truths1 and not to investigate them1 we
 are not under any such restriction4 ,we

 might suppose an imaginary animal1 and 
work out by deduction1 from the known   
laws of physiology1 its natural history2
 or an imaginary commonwealth1 and from 
the elements composing it1 might argue  
what would be its fate4 ,and the        
conclusions which we might thus draw    
from purely arbitrary hypotheses1 might 
form a highly useful intellectual       
exercise3 but as they could only teach  
us what would be the properties of      
objects which do not really exist1 they 
would not constitute any addition to our
 knowledge of nature3 while on the      
contrary1 if the hypothesis merely      
divests a real object of some portion of
 its properties1 without clothing it in 
false ones1 the conclusions will always 
express1 under known liability to       
correction1 actual truth4    #c4 ,but   
though ,dr4 ,whewell has not shaken     
,stewart's doctrine as to the           
hypothetical character of that portion  
of the first principles of geometry     
which are involved in the so-called     

definitions1 he has1 ,i conceive1       
greatly the advantage of ,stewart on    
another important point in the theory of
 geometrical reasoning2 the necessity of
 admitting1 among those first           
principles1 axioms as well as           
definitions4 ,some of the axioms of     
,euclid might1 no doubt1 be exhibited in
 the form of definitions1 or might be   
deduced1 by reasoning1 from propositions
 similar to what are so called4 ,thus1  
if instead of the axiom1 ,magnitudes    
which can be made to coincide are equal1
 we introduce a definition1 ,equal      
magnitudes are those which may be so    
applied to one another as to coincide2  
the three axioms which follow           
7,magnitudes which are equal to the same
 are equal to one another--,if equals   
are added to equals the sums are        
equal--,if equals are taken from equals 
the remainders are equal17 may be proved
 by an imaginary superposition1         
resembling that by which the fourth     
proposition of the first book of ,euclid

 is demonstrated4 ,but though these and 
several others may be struck out of the 
list of first principles1 because1      
though not requiring demonstration1 they
 are susceptible of it2 there will be   
found in the list of axioms two or three
 fundamental truths1 not capable of     
being demonstrated3 among which must be 
reckoned the proposition that two       
straight lines cannot inclose a space1  
7or its equivalent1 ,straight lines     
which coincide in two points coincide   
altogether17 and some property of       
parallel lines1 other than that which   
constitutes their definition3 one of the
 most suitable for the purpose being    
that selected by ,professor ,playfair3  
,two straight lines which intersect each
 other cannot both of them be parallel  
to a third straight line4#bj  ,the      
axioms1 as well those which are         
indemonstrable as those which admit of  
being demonstrated1 differ from that    
other class of fundamental principles   
which are involved in the definitions1  

in this1 that they are true without any 
mixture of hypothesis4 ,that things     
which are equal to the same thing are   
equal to one another1 is as true of the 
lines and figures in nature1 as it would
 be of the imaginary ones assumed in the
 definitions4 ,in this respect1 however1
 mathematics are only on a par with most
 other sciences4 ,in almost all sciences
 there are some general propositions    
which are exactly true1 while the       
greater part are only more or less      
distant approximations to the truth4    
,thus in mechanics1 the first law of    
motion 7the continuance of a movement   
once impressed1 until stopped or        
slackened by some resisting force7 is   
true without qualification or error4    
,the rotation of the earth in           
twenty-four hours1 of the same length as
 in our time1 has gone on since the     
first accurate observations1 without the
 increase or diminution of one second in
 all that period4 ,these are inductions 
which require no fiction to make them be

 received as accurately true3 but along 
with them there are others1 as for      
instance the propositions respecting the
 figure of the earth1 which are but     
approximations to the truth2 and in     
order to use them for the further       
advancement of our knowledge1 we must   
feign that they are exactly true1 though
 they really want something of being so4
    #d4 ,it remains to inquire1 what is 
the ground of our belief in axioms--what
 is the evidence on which they rest8 ,i 
answer1 they are experimental truths2   
generalizations from observation4 ,the  
proposition1 ,two straight lines cannot 
inclose a space--or in other words1 ,two
 straight lines which have once met1 do 
not meet again1 but continue to         
diverge--is an induction from the       
evidence of our senses4  ,this opinion  
runs counter to a scientific prejudice  
of long standing and great strength1 and
 there is probably no proposition       
enunciated in this work for which a more
 unfavourable reception is to be        

expected4 ,it is1 however1 no new       
opinion2 and even if it were so1 would  
be entitled to be judged1 not by its    
novelty1 but by the strength of the     
arguments by which it can be supported4 
,i consider it very fortunate that so   
eminent a champion of the contrary      
opinion as ,dr4 ,whewell1 has found     
occasion for a most elaborate treatment 
of the whole theory of axioms1 in       
attempting to construct the philosophy  
of the mathematical and physical        
sciences on the basis of the doctrine   
against which ,i now contend4 ,whoever  
is anxious that a discussion should go  
to the bottom of the subject1 must      
rejoice to see the opposite side of the 
question worthily represented4 ,if what 
is said by ,dr4 ,whewell1 in support of 
an opinion which he has made the        
foundation of a systematic work1 can be 
shown not to be conclusive1 enough will 
have been done1 without going further in
 quest of stronger arguments and a more 
powerful adversary4  ,it is not         

necessary to show that the truths which 
we call axioms are originally suggested 
by observation1 and that we should never
 have known that two straight lines     
cannot inclose a space if we had never  
seen a straight line3 thus much being   
admitted by ,dr4 ,whewell1 and by all1  
in recent times1 who have taken his view
 of the subject4 ,but they contend1 that
 it is not experience which proves the  
axiom2 but that its truth is perceived  
priori1 by the constitution of the mind 
itself1 from the first moment when the  
meaning of the proposition is           
apprehended2 and without any necessity  
for verifying it by repeated trials1 as 
is requisite in the case of truths      
really ascertained by observation4      
,they cannot1 however1 but allow that   
the truth of the axiom1 ,two straight   
lines cannot inclose a space1 even if   
evident independently of experience1 is 
also evident from experience4 ,whether  
the axiom needs confirmation or not1 it 
receives confirmation in almost every   

instant of our lives2 since we cannot   
look at any two straight lines which    
intersect one another1 without seeing   
that from that point they continue to   
diverge more and more4 ,experimental    
proof crowds in upon us in such endless 
profusion1 and without one instance in  
which there can be even a suspicion of  
an exception to the rule1 that we should
 soon have stronger ground for believing
 the axiom1 even as an experimental     
truth1 than we have for almost any of   
the general truths which we confessedly 
learn from the evidence of our senses4  
,independently of  priori evidence1 we  
should certainly believe it with an     
intensity of conviction far greater than
 we accord to any ordinary physical     
truth3 and this too at a time of life   
much earlier than that from which we    
date almost any part of our acquired    
knowledge1 and much too early to admit  
of our retaining any recollection of the
 history of our intellectual operations 
at that period4 ,where then is the      

necessity for assuming that our         
recognition of these truths has a       
different origin from the rest of our   
knowledge1 when its existence is        
perfectly accounted for by supposing its
 origin to be the same8 when the causes 
which produce belief in all other       
instances1 exist in this instance1 and  
in a degree of strength as much superior
 to what exists in other cases1 as the  
intensity of the belief itself is       
superior8 ,the burden of proof lies on  
the advocates of the contrary opinion3  
it is for them to point out some fact1  
inconsistent with the supposition that  
this part of our knowledge of nature is 
derived from the same sources as every  
other part4#ba  ,this1 for instance1    
they would be able to do1 if they could 
prove chronologically that we had the   
conviction 7at least practically7 so    
early in infancy as to be anterior to   
those impressions on the senses1 upon   
which1 on the other theory1 the         
conviction is founded4 ,this1 however1  

cannot be proved3 the point being too   
far back to be within the reach of      
memory1 and too obscure for external    
observation4 ,the advocates of the      
priori theory are obliged to have       
recourse to other arguments4 ,these are 
reducible to two1 which ,i shall        
endeavour to state as clearly and as    
forcibly as possible4    #e4 ,in the    
first place it is said that if our      
assent to the proposition that two      
straight lines cannot inclose a space1  
were derived from the senses1 we could  
only be convinced of its truth by actual
 trial1 that is1 by seeing or feeling   
the straight lines2 whereas in fact it  
is seen to be true by merely thinking of
 them4 ,that a stone thrown into water  
goes to the bottom1 may be perceived by 
our senses1 but mere thinking of a stone
 thrown into the water would never have 
led us to that conclusion3 not so1      
however1 with the axioms relating to    
straight lines3 if ,i could be made to  
conceive what a straight line is1       

without having seen one1 ,i should at   
once recognise that two such lines      
cannot inclose a space4 ,intuition is   
imaginary looking2#bb but experience    
must be real looking3 if we see a       
property of straight lines to be true by
 merely fancying ourselves to be looking
 at them1 the ground of our belief      
cannot be the senses1 or experience2 it 
must be something mental4  ,to this     
argument it might be added in the case  
of this particular axiom1 7for the      
assertion would not be true of all      
axioms17 that the evidence of it from   
actual ocular inspection is not only    
unnecessary1 but unattainable4 ,what    
says the axiom8 ,that two straight lines
 cannot inclose a space2 that after     
having once intersected1 if they are    
prolonged to infinity they do not meet1 
but continue to diverge from one        
another4 ,how can this1 in any single   
case1 be proved by actual observation8  
,we may follow the lines to any distance
 we please2 but we cannot follow them to

 infinity3 for aught our senses can     
testify1 they may1 immediately beyond   
the farthest point to which we have     
traced them1 begin to approach1 and at  
last meet4 ,unless1 therefore1 we had   
some other proof of the impossibility   
than observation affords us1 we should  
have no ground for believing the axiom  
at all4  ,to these arguments1 which ,i  
trust ,i cannot be accused of           
understating1 a satisfactory answer     
will1 ,i conceive1 be found1 if we      
advert to one of the characteristic     
properties of geometrical forms--their  
capacity of being painted in the        
imagination with a distinctness equal to
 reality3 in other words1 the exact     
resemblance of our ideas of form to the 
sensations which suggest them4 ,this1 in
 the first place1 enables us to make 7at
 least with a little practice7 mental   
pictures of all possible combinations of
 lines and angles1 which resemble the   
realities quite as well as any which we 
could make on paper2 and in the next    

place1 make those pictures just as fit  
subjects of geometrical experimentation 
as the realities themselves2 inasmuch as
 pictures1 if sufficiently accurate1    
exhibit of course all the properties    
which would be manifested by the        
realities at one given instant1 and on  
simple inspection3 and in geometry we   
are concerned only with such properties1
 and not with that which pictures could 
not exhibit1 the mutual action of bodies
 one upon another4 ,the foundations of  
geometry would therefore be laid in     
direct experience1 even if the          
experiments 7which in this case consist 
merely in attentive contemplation7 were 
practised solely upon what we call our  
ideas1 that is1 upon the diagrams in our
 minds1 and not upon outward objects4   
,for in all systems of experimentation  
we take some objects to serve as        
representatives of all which resemble   
them2 and in the present case the       
conditions which qualify a real object  
to be the representative of its class1  

are completely fulfilled by an object   
existing only in our fancy4 ,without    
denying1 therefore1 the possibility of  
satisfying ourselves that two straight  
lines cannot inclose a space1 by merely 
thinking of straight lines without      
actually looking at them2 ,i contend1   
that we do not believe this truth on the
 ground of the imaginary intuition      
simply1 but because we know that the    
imaginary lines exactly resemble real   
ones1 and that we may conclude from them
 to real ones with quite as much        
certainty as we could conclude from one 
real line to another4 ,the conclusion1  
therefore1 is still an induction from   
observation4 ,and we should not be      
authorized to substitute observation of 
the image in our mind1 for observation  
of the reality1 if we had not learnt by 
long-continued experience that the      
properties of the reality are faithfully
 represented in the image2 just as we   
should be scientifically warranted in   
describing an animal which we have never

 seen1 from a picture made of it with a 
daguerreotype2 but not until we had     
learnt by ample experience1 that        
observation of such a picture is        
precisely equivalent to observation of  
the original4  ,these considerations    
also remove the objection arising from  
the impossibility of ocularly following 
the lines in their prolongation to      
infinity4 ,for though1 in order actually
 to see that two given lines never meet1
 it would be necessary to follow them to
 infinity2 yet without doing so we may  
know that if they ever do meet1 or if1  
after diverging from one another1 they  
begin again to approach1 this must take 
place not at an infinite1 but at a      
finite distance4 ,supposing1 therefore1 
such to be the case1 we can transport   
ourselves thither in imagination1 and   
can frame a mental image of the         
appearance which one or both of the     
lines must present at that point1 which 
we may rely on as being precisely       
similar to the reality4 ,now1 whether we

 fix our contemplation upon this        
imaginary picture1 or call to mind the  
generalizations we have had occasion to 
make from former ocular observation1 we 
learn by the evidence of experience1    
that a line which1 after diverging from 
another straight line1 begins to        
approach to it1 produces the impression 
on our senses which we describe by the  
expression1 a bent line1 not by the     
expression1 a straight line4#bc    #f4  
,the first of the two arguments in      
support of the theory that axioms are   
priori truths1 having1 ,i think1 been   
sufficiently answered2 ,i proceed to the
 second1 which is usually the most      
relied on4 ,axioms 7it is asserted7 are 
conceived by us not only as true1 but as
 universally and necessarily true4 ,now1
 experience cannot possibly give to any 
proposition this character4 ,i may have 
seen snow a hundred times1 and may have 
seen that it was white1 but this cannot 
give me entire assurance even that all  
snow is white2 much less that snow must 

be white4 ,however many instances we may
 have observed of the truth of a        
proposition1 there is nothing to assure 
us that the next case shall not be an   
exception to the rule4 ,if it be        
strictly true that every ruminant animal
 yet known has cloven hoofs1 we still   
cannot be sure that some creature will  
not hereafter be discovered which has   
the first of these attributes1 without  
having the other4444 ,experience must   
always consist of a limited number of   
observations2 and1 however numerous     
these may be1 they can show nothing with
 regard to the infinite number of cases 
in which the experiment has not been    
made4 ,besides1 ,axioms are not only    
universal1 they are also necessary4 ,now
 experience cannot offer the smallest   
ground for the necessity of a           
proposition4 ,she can observe and record
 what has happened2 but she cannot find1
 in any case1 or in any accumulation of 
cases1 any reason for what must happen4 
,she may see objects side by side2 but  

she cannot see a reason why they must   
ever be side by side4 ,she finds certain
 events to occur in succession2 but the 
succession supplies1 in its occurrence1 
no reason for its recurrence4 ,she      
contemplates external objects2 but she  
cannot detect any internal bond1 which  
indissolubly connects the future with   
the past1 the possible with the real4   
,to learn a proposition by experience1  
and to see it to be necessarily true1   
are two altogether different processes  
of thought4#bd ,and ,dr4 ,whewell adds1 
,if any one does not clearly comprehend 
this distinction of necessary and       
contingent truths1 he will not be able  
to go along with us in our researches   
into the foundations of human knowledge2
 nor1 indeed1 to pursue with success any
 speculation on the subject4#be  ,in the
 following passage1 we are told what the
 distinction is1 the non-recognition of 
which incurs this denunciation4         
,necessary truths are those in which we 
not only learn that the proposition is  

true1 but see that it must be true2 in  
which the negation of the truth is not  
only false1 but impossible2 in which we 
cannot1 even by an effort of            
imagination1 or in a supposition1       
conceive the reverse of that which is   
asserted4 ,that there are such truths   
cannot be doubted4 ,we may take1 for    
example1 all relations of number4 ,three
 and ,two added together make ,five4 ,we
 cannot conceive it to be otherwise4 ,we
 cannot1 by any freak of thought1       
imagine ,three and ,two to make         
,seven4#bf  ,although ,dr4 ,whewell has 
naturally and properly employed a       
variety of phrases to bring his meaning 
more forcibly home1 he would1 ,i        
presume1 allow that they are all        
equivalent2 and that what he means by a 
necessary truth1 would be sufficiently  
defined1 a proposition the negation of  
which is not only false but             
inconceivable4 ,i am unable to find in  
any of his expressions1 turn them what  
way you will1 a meaning beyond this1 and

 ,i do not believe he would contend that
 they mean anything more4  ,this1       
therefore1 is the principle asserted3   
that propositions1 the negation of which
 is inconceivable1 or in other words1   
which we cannot figure to ourselves as  
being false1 must rest on evidence of a 
higher and more cogent description than 
any which experience can afford4  ,now  
,i cannot but wonder that so much stress
 should be laid on the circumstance of  
inconceivableness1 when there is such   
ample experience to show1 that our      
capacity or incapacity of conceiving a  
thing has very little to do with the    
possibility of the thing in itself2 but 
is in truth very much an affair of      
accident1 and depends on the past       
history and habits of our own minds4    
,there is no more generally acknowledged
 fact in human nature1 than the extreme 
difficulty at first felt in conceiving  
anything as possible1 which is in       
contradiction to long established and   
familiar experience2 or even to old     

familiar habits of thought4 ,and this   
difficulty is a necessary result of the 
fundamental laws of the human mind4     
,when we have often seen and thought of 
two things together1 and have never in  
any one instance either seen or thought 
of them separately1 there is by the     
primary law of association an increasing
 difficulty1 which may in the end become
 insuperable1 of conceiving the two     
things apart4 ,this is most of all      
conspicuous in uneducated persons1 who  
are in general utterly unable to        
separate any two ideas which have once  
become firmly associated in their minds2
 and if persons of cultivated intellect 
have any advantage on the point1 it is  
only because1 having seen and heard and 
read more1 and being more accustomed to 
exercise their imagination1 they have   
experienced their sensations and        
thoughts in more varied combinations1   
and have been prevented from forming    
many of these inseparable associations4 
,but this advantage has necessarily its 

limits4 ,the most practised intellect is
 not exempt from the universal laws of  
our conceptive faculty4 ,if daily habit 
presents to any one for a long period   
two facts in combination1 and if he is  
not led during that period either by    
accident or by his voluntary mental     
operations to think of them apart1 he   
will probably in time become incapable  
of doing so even by the strongest       
effort2 and the supposition that the two
 facts can be separated in nature1 will 
at last present itself to his mind with 
all the characters of an inconceivable  
phenomenon4#bg ,there are remarkable    
instances of this in the history of     
science3 instances in which the most    
instructed men rejected as impossible1  
because inconceivable1 things which     
their posterity1 by earlier practice and
 longer perseverance in the attempt1    
found it quite easy to conceive1 and    
which everybody now knows to be true4   
,there was a time when men of the most  
cultivated intellects1 and the most     

emancipated from the dominion of early  
prejudice1 could not credit the         
existence of antipodes2 were unable to  
conceive1 in opposition to old          
association1 the force of gravity acting
 upwards instead of downwards4 ,the     
,cartesians long rejected the ,newtonian
 doctrine of the gravitation of all     
bodies towards one another1 on the faith
 of a general proposition1 the reverse  
of which seemed to them to be           
inconceivable--the proposition that a   
body cannot act where it is not4 ,all   
the cumbrous machinery of imaginary     
vortices1 assumed without the smallest  
particle of evidence1 appeared to these 
philosophers a more rational mode of    
explaining the heavenly motions1 than   
one which involved what seemed to them  
so great an absurdity4#bh ,and they no  
doubt found it as impossible to conceive
 that a body should act upon the earth  
at the distance of the sun or moon1 as  
we find it to conceive an end to space  
or time1 or two straight lines inclosing

 a space4 ,newton himself had not been  
able to realize the conception1 or we   
should not have had his hypothesis of a 
subtle ether1 the occult cause of       
gravitation2 and his writings prove1    
that though he deemed the particular    
nature of the intermediate agency a     
matter of conjecture1 the necessity of  
some such agency appeared to him        
indubitable4 ,it would seem that even   
now the majority of scientific men have 
not completely got over this very       
difficulty2 for though they have at last
 learnt to conceive the sun attracting  
the earth without any intervening fluid1
 they cannot yet conceive the sun       
illuminating the earth without some such
 medium4  ,if1 then1 it be so natural to
 the human mind1 even in a high state of
 culture1 to be incapable of conceiving1
 and on that ground to believe          
impossible1 what is afterwards not only 
found to be conceivable but proved to be
 true2 what wonder if in cases where the
 association is still older1 more       

confirmed1 and more familiar1 and in    
which nothing ever occurs to shake our  
conviction1 or even suggest to us any   
conception at variance with the         
association1 the acquired incapacity    
should continue1 and be mistaken for a  
natural incapacity8 ,it is true1 our    
experience of the varieties in nature   
enables us1 within certain limits1 to   
conceive other varieties analogous to   
them4 ,we can conceive the sun or moon  
falling2 for though we never saw them   
fall1 nor ever perhaps imagined them    
falling1 we have seen so many other     
things fall1 that we have innumerable   
familiar analogies to assist the        
conception2 which1 after all1 we should 
probably have some difficulty in        
framing1 were we not well accustomed to 
see the sun and moon move 7or appear to 
move17 so that we are only called upon  
to conceive a slight change in the      
direction of motion1 a circumstance     
familiar to our experience4 ,but when   
experience affords no model on which to 

shape the new conception1 how is it     
possible for us to form it8 ,how1 for   
example1 can we imagine an end to space 
or time8 ,we never saw any object       
without something beyond it1 nor        
experienced any feeling without         
something following it4 ,when1          
therefore1 we attempt to conceive the   
last point of space1 we have the idea   
irresistibly raised of other points     
beyond it4 ,when we try to imagine the  
last instant of time1 we cannot help    
conceiving another instant after it4    
,nor is there any necessity to assume1  
as is done by a modern school of        
metaphysicians1 a peculiar fundamental  
law of the mind to account for the      
feeling of infinity inherent in our     
conceptions of space and time2 that     
apparent infinity is sufficiently       
accounted for by simpler and universally
 acknowledged laws4  ,now1 in the case  
of a geometrical axiom1 such1 for       
example1 as that two straight lines     
cannot inclose a space1--a truth which  

is testified to us by our very earliest 
impressions of the external world1--how 
is it possible 7whether those external  
impressions be or be not the ground of  
our belief7 that the reverse of the     
proposition could be otherwise than     
inconceivable to us8 ,what analogy have 
we1 what similar order of facts in any  
other branch of our experience1 to      
facilitate to us the conception of two  
straight lines inclosing a space8 ,nor  
is even this all4 ,i have already called
 attention to the peculiar property of  
our impressions of form1 that the ideas 
or mental images exactly resemble their 
prototypes1 and adequately represent    
them for the purposes of scientific     
observation4 ,from this1 and from the   
intuitive character of the observation1 
which in this case reduces itself to    
simple inspection1 we cannot so much as 
call up in our imagination two straight 
lines1 in order to attempt to conceive  
them inclosing a space1 without by that 
very act repeating the scientific       

experiment which establishes the        
contrary4 ,will it really be contended  
that the inconceivableness of the thing1
 in such circumstances1 proves anything 
against the experimental origin of the  
conviction8 ,is it not clear that in    
whichever mode our belief in the        
proposition may have originated1 the    
impossibility of our conceiving the     
negative of it must1 on either          
hypothesis1 be the same8 ,as1 then1 ,dr4
 ,whewell exhorts those who have any    
difficulty in recognising the           
distinction held by him between         
necessary and contingent truths1 to     
study geometry1--a condition which ,i   
can assure him ,i have conscientiously  
fulfilled1--,i1 in return1 with equal   
confidence1 exhort those who agree with 
him1 to study the general laws of       
association2 being convinced that       
nothing more is requisite than a        
moderate familiarity with those laws1 to
 dispel the illusion which ascribes a   
peculiar necessity to our earliest      

inductions from experience1 and measures
 the possibility of things in           
themselves1 by the human capacity of    
conceiving them4  ,i hope to be pardoned
 for adding1 that ,dr4 ,whewell himself 
has both confirmed by his testimony the 
effect of habitual association in giving
 to an experimental truth the appearance
 of a necessary one1 and afforded a     
striking instance of that remarkable law
 in his own person4 ,in his ,philosophy 
of the ,inductive ,sciences he          
continually asserts1 that propositions  
which not only are not self-evident1 but
 which we know to have been discovered  
gradually1 and by great efforts of      
genius and patience1 have1 when once    
established1 appeared so self-evident   
that1 but for historical proof1 it would
 have been impossible to conceive that  
they had not been recognised from the   
first by all persons in a sound state of
 their faculties4 ,we now despise those 
who1 in the ,copernican controversy1    
could not conceive the apparent motion  

of the sun on the heliocentric          
hypothesis2 or those who1 in opposition 
to ,galileo1 thought that a uniform     
force might be that which generated a   
velocity proportional to the space2 or  
those who held there was something      
absurd in ,newton's doctrine of the     
different refrangibility of differently 
coloured rays2 or those who imagined    
that when elements combine1 their       
sensible qualities must be manifest in  
the compound2 or those who were         
reluctant to give up the distinction of 
vegetables into herbs1 shrubs1 and      
trees4 ,we cannot help thinking that men
 must have been singularly dull of      
comprehension1 to find a difficulty in  
admitting what is to us so plain and    
simple4 ,we have a latent persuasion    
that we in their place should have been 
wiser and more clear-sighted2 that we   
should have taken the right side1 and   
given our assent at once to the truth4  
,yet in reality such a persuasion is a  
mere delusion4 ,the persons who1 in such

 instances as the above1 were on the    
losing side1 were very far1 in most     
cases1 from being persons more          
prejudiced1 or stupid1 or narrow-minded1
 than the greater part of mankind now   
are2 and the cause for which they fought
 was far from being a manifestly bad    
one1 till it had been so decided by the 
result of the war4444 ,so complete has  
been the victory of truth in most of    
these instances1 that at present we can 
hardly imagine the struggle to have been
 necessary4 ,the very essence of these  
triumphs is1 that they lead us to regard
 the views we reject as not only false  
but inconceivable4#bi  ,this last       
proposition is precisely what ,i contend
 for2 and ,i ask no more1 in order to   
overthrow the whole theory of its author
 on the nature of the evidence of       
axioms4 ,for what is that theory8 ,that 
the truth of axioms cannot have been    
learnt from experience1 because their   
falsity is inconceivable4 ,but ,dr4     
,whewell himself says1 that we are      

continually led1 by the natural progress
 of thought1 to regard as inconceivable 
what our forefathers not only conceived 
but believed1 nay even 7he might have   
added7 were unable to conceive the      
reverse of4 ,he cannot intend to justify
 this mode of thought3 he cannot mean to
 say1 that we can be right in regarding 
as inconceivable what others have       
conceived1 and as self-evident what to  
others did not appear evident at all4   
,after so complete an admission that    
inconceivableness is an accidental      
thing1 not inherent in the phenomenon   
itself1 but dependent on the mental     
history of the person who tries to      
conceive it1 how can he ever call upon  
us to reject a proposition as impossible
 on no other ground than its            
inconceivableness8 ,yet he not only does
 so1 but has unintentionally afforded   
some of the most remarkable examples    
which can be cited of the very illusion 
which he has himself so clearly pointed 
out4 ,i select as specimens1 his remarks

 on the evidence of the three laws of   
motion1 and of the atomic theory4  ,with
 respect to the laws of motion1 ,dr4    
,whewell says3 ,no one can doubt that1  
in historical fact1 these laws were     
collected from experience4 ,that such is
 the case1 is no matter of conjecture4  
,we know the time1 the persons1 the     
circumstances1 belonging to each step of
 each discovery4#cj ,after this         
testimony1 to adduce evidence of the    
fact would be superfluous4 ,and not only
 were these laws by no means intuitively
 evident1 but some of them were         
originally paradoxes4 ,the first law was
 especially so4 ,that a body1 once in   
motion1 would continue for ever to move 
in the same direction with undiminished 
velocity unless acted upon by some new  
force1 was a proposition which mankind  
found for a long time the greatest      
difficulty in crediting4 ,it stood      
opposed to apparent experience of the   
most familiar kind1 which taught that it
 was the nature of motion to abate      

gradually1 and at last terminate of     
itself4 ,yet when once the contrary     
doctrine was firmly established1        
mathematicians1 as ,dr4 ,whewell        
observes1 speedily began to believe that
 laws1 thus contradictory to first      
appearances1 and which1 even after full 
proof had been obtained1 it had required
 generations to render familiar to the  
minds of the scientific world1 were     
under a demonstrable necessity1         
compelling them to be such as they are  
and no other2 and he himself1 though not
 venturing absolutely to pronounce that 
all these laws can be rigorously traced 
to an absolute necessity in the nature  
of things1#ca does actually so think of 
the law just mentioned2 of which he     
says3 ,though the discovery of the first
 law of motion was made1 historically   
speaking1 by means of experiment1 we    
have now attained a point of view in    
which we see that it might have been    
certainly known to be true1             
independently of experience4#cb ,can    

there be a more striking exemplification
 than is here afforded1 of the effect of
 association which we have described8   
,philosophers1 for generations1 have the
 most extraordinary difficulty in       
putting certain ideas together2 they at 
last succeed in doing so2 and after a   
sufficient repetition of the process1   
they first fancy a natural bond between 
the ideas1 then experience a growing    
difficulty1 which at last1 by the       
continuation of the same progress1      
becomes an impossibility1 of severing   
them from one another4 ,if such be the  
progress of an experimental conviction  
of which the date is of yesterday1 and  
which is in opposition to first         
appearances1 how must it fare with those
 which are conformable to appearances   
familiar from the first dawn of         
intelligence1 and of the conclusiveness 
of which1 from the earliest records of  
human thought1 no sceptic has suggested 
even a momentary doubt8  ,the other     
instance which ,i shall quote is a truly

 astonishing one1 and may be called the 
reductio ad absurdum of the theory of   
inconceivableness4 ,speaking of the laws
 of chemical composition1 ,dr4 ,whewell 
says3#cc ,that they could never have    
been clearly understood1 and therefore  
never firmly established1 without       
laborious and exact experiments1 is     
certain2 but yet we may venture to say1 
that being once known1 they possess an  
evidence beyond that of mere experiment4
 ,for how in fact can we conceive       
combinations1 otherwise than as definite
 in kind and quality8 ,if we were to    
suppose each element ready to combine   
with any other indifferently1 and       
indifferently in any quantity1 we should
 have a world in which all would be     
confusion and indefiniteness4 ,there    
would be no fixed kinds of bodies4      
,salts1 and stones1 and ores1 would     
approach to and graduate into each other
 by insensible degrees4 ,instead of     
this1 we know that the world consists of
 bodies distinguishable from each other 

by definite differences1 capable of     
being classified and named1 and of      
having general propositions asserted    
concerning them4 ,and as we cannot      
conceive a world in which this should   
not be the case1 it would appear that we
 cannot conceive a state of things in   
which the laws of the combination of    
elements should not be of that definite 
and measured kind which we have above   
asserted4  ,that a philosopher of ,dr4  
,whewell's eminence should gravely      
assert that we cannot conceive a world  
in which the simple elements should     
combine in other than definite          
proportions2 that by dint of meditating 
on a scientific truth1 the original     
discoverer of which was still living1 he
 should have rendered the association in
 his own mind between the idea of       
combination and that of constant        
proportions so familiar and intimate as 
to be unable to conceive the one fact   
without the other2 is so signal an      
instance of the mental law for which ,i 

am contending1 that one word more in    
illustration must be superfluous4  ,in  
the latest and most complete elaboration
 of his metaphysical system 7the        
,philosophy of ,discovery71 as well as  
in the earlier discourse on the         
,fundamental ,antithesis of ,philosophy1
 reprinted as an appendix to that work1 
,dr4 ,whewell1 while very candidly      
admitting that his language was open to 
misconception1 disclaims having intended
 to say that mankind in general can now 
perceive the law of definite proportions
 in chemical combination to be a        
necessary truth4 ,all he meant was that 
philosophical chemists in a future      
generation may possibly see this4 ,some 
truths may be seen by intuition1 but yet
 the intuition of them may be a rare and
 a difficult attainment4#cd ,and he     
explains that the inconceivableness     
which1 according to his theory1 is the  
test of axioms1 depends entirely upon   
the clearness of the ,ideas which the   
axioms involve4 ,so long as those ,ideas

 are vague and indistinct1 the contrary 
of an ,axiom may be assented to1 though 
it cannot be distinctly conceived4 ,it  
may be assented to1 not because it is   
possible1 but because we do not see     
clearly what is possible4 ,to a person  
who is only beginning to think          
geometrically1 there may appear nothing 
absurd in the assertion1 that two       
straight lines may inclose a space4 ,and
 in the same manner1 to a person who is 
only beginning to think of mechanical   
truths1 it may not appear to be absurd1 
that in mechanical processes1 ,reaction 
should be greater or less than ,action2 
and so1 again1 to a person who has not  
thought steadily about ,substance1 it   
may not appear inconceivable1 that by   
chemical operations1 we should generate 
new matter1 or destroy matter which     
already exists4#ce ,necessary truths1   
therefore1 are not those of which we    
cannot conceive1 but those of which we  
cannot distinctly conceive1 the         
contrary4#cf ,so long as our ideas are  

indistinct altogether1 we do not know   
what is or is not capable of being      
distinctly conceived2 but1 by the ever  
increasing distinctness with which      
scientific men apprehend the general    
conceptions of science1 they in time    
come to perceive that there are certain 
laws of nature1 which1 though           
historically and as a matter of fact    
they were learnt from experience1 we    
cannot1 now that we know them1          
distinctly conceive to be other than    
they are4  ,the account which ,i should 
give of this progress of the scientific 
mind is somewhat different4 ,after a    
general law of nature has been          
ascertained1 men's minds do not at first
 acquire a complete facility of         
familiarly representing to themselves   
the phenomena of nature in the character
 which that law assigns to them4 ,the   
habit which constitutes the scientific  
cast of mind1 that of conceiving facts  
of all descriptions conformably to the  
laws which regulate them--phenomena of  

all descriptions according to the       
relations which have been ascertained   
really to exist between them2 this      
habit1 in the case of newly discovered  
relations1 comes only by degrees4 ,so   
long as it is not thoroughly formed1 no 
necessary character is ascribed to the  
new truth4 ,but in time1 the philosopher
 attains a state of mind in which his   
mental picture of nature spontaneously  
represents to him all the phenomena with
 which the new theory is concerned1 in  
the exact light in which the theory     
regards them3 all images or conceptions 
derived from any other theory1 or from  
the confused view of the facts which is 
anterior to any theory1 having entirely 
disappeared from his mind4 ,the mode of 
representing facts which results from   
the theory1 has now become1 to his      
faculties1 the only natural mode of     
conceiving them4 ,it is a known truth1  
that a prolonged habit of arranging     
phenomena in certain groups1 and        
explaining them by means of certain     

principles1 makes any other arrangement 
or explanation of these facts be felt as
 unnatural3 and it may at last become as
 difficult to him to represent the facts
 to himself in any other mode1 as it    
often was1 originally1 to represent them
 in that mode4  ,but1 further1 if the   
theory is true1 as we are supposing it  
to be1 any other mode in which he tries1
 or in which he was formerly accustomed1
 to represent the phenomena1 will be    
seen by him to be inconsistent with the 
facts that suggested the new            
theory--facts which now form a part of  
his mental picture of nature4 ,and since
 a contradiction is always              
inconceivable1 his imagination rejects  
these false theories1 and declares      
itself incapable of conceiving them4    
,their inconceivableness to him does    
not1 however1 result from anything in   
the theories themselves1 intrinsically  
and  priori repugnant to the human      
faculties2 it results from the          
repugnance between them and a portion of

 the facts2 which facts as long as he   
did not know1 or did not distinctly     
realize in his mental representations1  
the false theory did not appear other   
than conceivable2 it becomes            
inconceivable1 merely from the fact that
 contradictory elements cannot be       
combined in the same conception4        
,although1 then1 his real reason for    
rejecting theories at variance with the 
true one1 is no other than that they    
clash with his experience1 he easily    
falls into the belief1 that he rejects  
them because they are inconceivable1 and
 that he adopts the true theory because 
it is self-evident1 and does not need   
the evidence of experience at all4      
,this ,i take to be the real and        
sufficient explanation of the           
paradoxical truth1 on which so much     
stress is laid by ,dr4 ,whewell1 that a 
scientifically cultivated mind is       
actually1 in virtue of that cultivation1
 unable to conceive suppositions which a
 common man conceives without the       

smallest difficulty4 ,for there is      
nothing inconceivable in the            
suppositions themselves2 the            
impossibility is in combining them with 
facts inconsistent with them1 as part of
 the same mental picture2 an obstacle of
 course only felt by those who know the 
facts1 and are able to perceive the     
inconsistency4 ,as far as the           
suppositions themselves are concerned1  
in the case of many of ,dr4 ,whewell's  
necessary truths the negative of the    
axiom is1 and probably will be as long  
as the human race lasts1 as easily      
conceivable as the affirmative4 ,there  
is no axiom 7for example7 to which ,dr4 
,whewell ascribes a more thorough       
character of necessity and              
self-evidence1 than that of the         
indestructibility of matter4 ,that this 
is a true law of nature ,i fully admit2 
but ,i imagine there is no human being  
to whom the opposite supposition is     
inconceivable--who has any difficulty in
 imagining a portion of matter          

annihilated3 inasmuch as its apparent   
annihilation1 in no respect             
distinguishable from real by our        
unassisted senses1 takes place every    
time that water dries up1 or fuel is    
consumed4 ,again1 the law that bodies   
combine chemically in definite          
proportions is undeniably true2 but few 
besides ,dr4 ,whewell have reached the  
point which he seems personally to have 
arrived at1 7though he only dares       
prophesy similar success to the         
multitude after the lapse of            
generations17 that of being unable to   
conceive a world in which the elements  
are ready to combine with one another   
indifferently in any quantity2 nor is it
 likely that we shall ever rise to this 
sublime height of inability1 so long as 
all the mechanical mixtures in our      
planet1 whether solid1 liquid1 or       
ariform1 exhibit to our daily           
observation the very phenomenon declared
 to be inconceivable4  ,according to    
,dr4 ,whewell1 these and similar laws of

 nature cannot be drawn from experience1
 inasmuch as they are1 on the contrary1 
assumed in the interpretation of        
experience4 ,our inability to add to or 
diminish the quantity of matter in the  
world1 is a truth which neither is nor  
can be derived from experience2 for the 
experiments which we make to verify it  
presuppose its truth4444 ,when men began
 to use the balance in chemical         
analysis1 they did not prove by trial1  
but took for granted1 as self-evident1  
that the weight of the whole must be    
found in the aggregate weight of the    
elements4#cg ,true1 it is assumed2 but1 
,i apprehend1 no otherwise than as all  
experimental inquiry assumes            
provisionally some theory or hypothesis1
 which is to be finally held true or    
not1 according as the experiments       
decide4 ,the hypothesis chosen for this 
purpose will naturally be one which     
groups together some considerable number
 of facts already known4 ,the           
proposition that the material of the    

world1 as estimated by weight1 is       
neither increased nor diminished by any 
of the processes of nature or art1 had  
many appearances in its favour to begin 
with4 ,it expressed truly a great number
 of familiar facts4 ,there were other   
facts which it had the appearance of    
conflicting with1 and which made its    
truth1 as an universal law of nature1 at
 first doubtful4 ,because it was        
doubtful1 experiments were devised to   
verify it4 ,men assumed its truth       
hypothetically1 and proceeded to try    
whether1 on more careful examination1   
the phenomena which apparently pointed  
to a different conclusion1 would not be 
found to be consistent with it4 ,this   
turned out to be the case2 and from that
 time the doctrine took its place as an 
universal truth1 but as one proved to be
 such by experience4 ,that the theory   
itself preceded the proof of its        
truth--that it had to be conceived      
before it could be proved1 and in order 
that it might be proved--does not imply 

that it was self-evident1 and did not   
need proof4 ,otherwise all the true     
theories in the sciences are necessary  
and self-evident2 for no one knows      
better than ,dr4 ,whewell that they all 
began by being assumed1 for the purpose 
of connecting them by deductions with   
those facts of experience on which1 as  
evidence1 they now confessedly rest4#ch 
,,chapter ,,vi4  ,,the ,,same ,,subject 
,,continued4    #a4 ,in the examination 
which formed the subject of the last    
chapter1 into the nature of the evidence
 of those deductive sciences which are  
commonly represented to be systems of   
necessary truth1 we have been led to the
 following conclusions4 ,the results of 
those sciences are indeed necessary1 in 
the sense of necessarily following from 
certain first principles1 commonly      
called axioms and definitions2 that is1 
of being certainly true if those axioms 
and definitions are so2 for the word    
necessity1 even in this acceptation of  
it1 means no more than certainty4 ,but  

their claim to the character of         
necessity in any sense beyond this1 as  
implying an evidence independent of and 
superior to observation and experience1 
must depend on the previous             
establishment of such a claim in favour 
of the definitions and axioms           
themselves4 ,with regard to axioms1 we  
found that1 considered as experimental  
truths1 they rest on superabundant and  
obvious evidence4 ,we inquired1 whether1
 since this is the case1 it be          
imperative to suppose any other evidence
 of those truths than experimental      
evidence1 any other origin for our      
belief of them than an experimental     
origin4 ,we decided1 that the burden of 
proof lies with those who maintain the  
affirmative1 and we examined1 at        
considerable length1 such arguments as  
they have produced4 ,the examination    
having led to the rejection of those    
arguments1 we have thought ourselves    
warranted in concluding that axioms are 
but a class1 the most universal class1  

of inductions from experience2 the      
simplest and easiest cases of           
generalization from the facts furnished 
to us by our senses or by our internal  
consciousness4  ,while the axioms of    
demonstrative sciences thus appeared to 
be experimental truths1 the definitions1
 as they are incorrectly called1 in     
those sciences1 were found by us to be  
generalizations from experience which   
are not even1 accurately speaking1      
truths2 being propositions in which1    
while we assert of some kind of object1 
some property or properties which       
observation shows to belong to it1 we at
 the same time deny that it possesses   
any other properties1 though in truth   
other properties do in every individual 
instance accompany1 and in almost all   
instances modify1 the property thus     
exclusively predicated4 ,the denial1    
therefore1 is a mere fiction1 or        
supposition1 made for the purpose of    
excluding the consideration of those    
modifying circumstances1 when their     

influence is of too trifling amount to  
be worth considering1 or adjourning it1 
when important1 to a more convenient    
moment4  ,from these considerations it  
would appear that ,deductive or         
,demonstrative ,sciences are all1       
without exception1 ,inductive ,sciences2
 that their evidence is that of         
experience2 but that they are also1 in  
virtue of the peculiar character of one 
indispensable portion of the general    
formul according to which their         
inductions are made1 ,hypothetical      
,sciences4 ,their conclusions are only  
true on certain suppositions1 which are1
 or ought to be1 approximations to the  
truth1 but are seldom1 if ever1 exactly 
true2 and to this hypothetical character
 is to be ascribed the peculiar         
certainty1 which is supposed to be      
inherent in demonstration4  ,what we    
have now asserted1 however1 cannot be   
received as universally true of         
,deductive or ,demonstrative ,sciences1 
until verified by being applied to the  

most remarkable of all those sciences1  
that of ,numbers2 the theory of the     
,calculus2 ,arithmetic and ,algebra4 ,it
 is harder to believe of the doctrines  
of this science than of any other1      
either that they are not truths  priori1
 but experimental truths1 or that their 
peculiar certainty is owing to their    
being not absolute but only conditional 
truths4 ,this1 therefore1 is a case     
which merits examination apart2 and the 
more so1 because on this subject we have
 a double set of doctrines to contend   
with2 that of the  priori philosophers  
on one side2 and on the other1 a theory 
the most opposite to theirs1 which was  
at one time very generally received1 and
 is still far from being altogether     
exploded1 among metaphysicians4    #b4  
,this theory attempts to solve the      
difficulty apparently inherent in the   
case1 by representing the propositions  
of the science of numbers as merely     
verbal1 and its processes as simple     
transformations of language1            

substitutions of one expression for     
another4 ,the proposition1 ,two and one 
are equal to three1 according to these  
writers1 is not a truth1 is not the     
assertion of a really existing fact1 but
 a definition of the word three2 a      
statement that mankind have agreed to   
use the name three as a sign exactly    
equivalent to two and one2 to call by   
the former name whatever is called by   
the other more clumsy phrase4 ,according
 to this doctrine1 the longest process  
in algebra is but a succession of       
changes in terminology1 by which        
equivalent expressions are substituted  
one for another2 a series of            
translations of the same fact1 from one 
into another language2 though how1 after
 such a series of translations1 the fact
 itself comes out changed 7as when we   
demonstrate a new geometrical theorem by
 algebra17 they have not explained2 and 
it is a difficulty which is fatal to    
their theory4  ,it must be acknowledged 
that there are peculiarities in the     

processes of arithmetic and algebra     
which render the theory in question very
 plausible1 and have not unnaturally    
made those sciences the stronghold of   
,nominalism4 ,the doctrine that we can  
discover facts1 detect the hidden       
processes of nature1 by an artful       
manipulation of language1 is so contrary
 to common sense1 that a person must    
have made some advances in philosophy to
 believe it3 men fly to so paradoxical a
 belief to avoid1 as they think1 some   
even greater difficulty1 which the      
vulgar do not see4 ,what has led many to
 believe that reasoning is a mere verbal
 process1 is1 that no other theory      
seemed reconcileable with the nature of 
the ,science of ,numbers4 ,for we do not
 carry any ideas along with us when we  
use the symbols of arithmetic or of     
algebra4 ,in a geometrical demonstration
 we have a mental diagram1 if not one on
 paper2 ,,ab1 ,,ac1 are present to our  
imagination as lines1 intersecting other
 lines1 forming an angle with one       

another1 and the like2 but not so a and 
b4 ,these may represent lines or any    
other magnitudes1 but those magnitudes  
are never thought of2 nothing is        
realized in our imagination but a and b4
 ,the ideas which1 on the particular    
occasion1 they happen to represent1 are 
banished from the mind during every     
intermediate part of the process1       
between the beginning1 when the premises
 are translated from things into signs1 
and the end1 when the conclusion is     
translated back from signs into things4 
,nothing1 then1 being in the reasoner's 
mind but the symbols1 what can seem more
 inadmissible than to contend that the  
reasoning process has to do with        
anything more8 ,we seem to have come to 
one of ,bacon's ,prerogative ,instances2
 an experimentum crucis on the nature of
 reasoning itself4  ,nevertheless1 it   
will appear on consideration1 that this 
apparently so decisive instance is no   
instance at all2 that there is in every 
step of an arithmetical or algebraical  

calculation a real induction1 a real    
inference of facts from facts2 and that 
what disguises the induction is simply  
its comprehensive nature1 and the       
consequent extreme generality of the    
language4 ,all numbers must be numbers  
of something3 there are no such things  
as numbers in the abstract4 ,ten must   
mean ten bodies1 or ten sounds1 or ten  
beatings of the pulse4 ,but though      
numbers must be numbers of something1   
they may be numbers of anything4        
,propositions1 therefore1 concerning    
numbers1 have the remarkable peculiarity
 that they are propositions concerning  
all things whatever2 all objects1 all   
existences of every kind1 known to our  
experience4 ,all things possess         
quantity2 consist of parts which can be 
numbered2 and in that character possess 
all the properties which are called     
properties of numbers4 ,that half of    
four is two1 must be true whatever the  
word four represents1 whether four      
hours1 four miles1 or four pounds       

weight4 ,we need only conceive a thing  
divided into four equal parts1 7and all 
things may be conceived as so divided17 
to be able to predicate of it every     
property of the number four1 that is1   
every arithmetical proposition in which 
the number four stands on one side of   
the equation4 ,algebra extends the      
generalization still farther3 every     
number represents that particular number
 of all things without distinction1 but 
every algebraical symbol does more1 it  
represents all numbers without          
distinction4 ,as soon as we conceive a  
thing divided into equal parts1 without 
knowing into what number of parts1 we   
may call it a or x1 and apply to it1    
without danger of error1 every          
algebraical formula in the books4 ,the  
proposition1 #b7;a  b7  #b;a  #b;b1 is a
 truth co-extensive with all nature4    
,since then algebraical truths are true 
of all things whatever1 and not1 like   
those of geometry1 true of lines only or
 angles only1 it is no wonder that the  

symbols should not excite in our minds  
ideas of any things in particular4 ,when
 we demonstrate the forty-seventh       
proposition of ,euclid1 it is not       
necessary that the words should raise in
 us an image of all right-angled        
triangles1 but only of some one         
right-angled triangle3 so in algebra we 
need not1 under the symbol a1 picture to
 ourselves all things whatever1 but only
 some one thing2 why not1 then1 the     
letter itself8 ,the mere written        
characters1 a1 b1 x1 y1 z1 serve as well
 for representatives of ,things in      
general1 as any more complex and        
apparently more concrete conception4    
,that we are conscious of them however  
in their character of things1 and not of
 mere signs1 is evident from the fact   
that our whole process of reasoning is  
carried on by predicating of them the   
properties of things4 ,in resolving an  
algebraic equation1 by what rules do we 
proceed8 ,by applying at each step to a1
 b1 and x1 the proposition that equals  

added to equals make equals2 that equals
 taken from equals leave equals2 and    
other propositions founded on these two4
 ,these are not properties of language1 
or of signs as such1 but of magnitudes1 
which is as much as to say1 of all      
things4 ,the inferences1 therefore1     
which are successively drawn1 are       
inferences concerning things1 not       
symbols2 though as any ,things whatever 
will serve the turn1 there is no        
necessity for keeping the idea of the   
,thing at all distinct1 and consequently
 the process of thought may1 in this    
case1 be allowed without danger to do   
what all processes of thought1 when they
 have been performed often1 will do if  
permitted1 namely1 to become entirely   
mechanical4 ,hence the general language 
of algebra comes to be used familiarly  
without exciting ideas1 as all other    
general language is prone to do from    
mere habit1 though in no other case than
 this can it be done with complete      
safety4 ,but when we look back to see   

from whence the probative force of the  
process is derived1 we find that at     
every single step1 unless we suppose    
ourselves to be thinking and talking of 
the things1 and not the mere symbols1   
the evidence fails4  ,there is another  
circumstance1 which1 still more than    
that which we have now mentioned1 gives 
plausibility to the notion that the     
propositions of arithmetic and algebra  
are merely verbal4 ,that is1 that when  
considered as propositions respecting   
,things1 they all have the appearance of
 being identical propositions4 ,the     
assertion1 ,two and one are equal to    
three1 considered as an assertion       
respecting objects1 as for instance ,two
 pebbles and one pebble are equal to    
three pebbles1 does not affirm equality 
between two collections of pebbles1 but 
absolute identity4 ,it affirms that if  
we put one pebble to two pebbles1 those 
very pebbles are three4 ,the objects1   
therefore1 being the very same1 and the 
mere assertion that objects are         

themselves being insignificant1 it seems
 but natural to consider the            
proposition1 ,two and one are equal to  
three1 as asserting mere identity of    
signification between the two names4    
,this1 however1 though it looks so      
plausible1 will not bear examination4   
,the expression two pebbles and one     
pebble1 and the expression1 three       
pebbles1 stand indeed for the same      
aggregation of objects1 but they by no  
means stand for the same physical fact4 
,they are names of the same objects1 but
 of those objects in two different      
states3 though they denote the same     
things1 their connotation is different4 
,three pebbles in two separate parcels1 
and three pebbles in one parcel1 do not 
make the same impression on our senses2 
and the assertion that the very same    
pebbles may by an alteration of place   
and arrangement be made to produce      
either the one set of sensations or the 
other1 though a very familiar           
proposition1 is not an identical one4   

,it is a truth known to us by early and 
constant experience3 an inductive truth2
 and such truths are the foundation of  
the science of ,number4 ,the fundamental
 truths of that science all rest on the 
evidence of sense2 they are proved by   
showing to our eyes and our fingers that
 any given number of objects1 ten balls 
for example1 may by separation and      
re-arrangement exhibit to our senses all
 the different sets of numbers the sum  
of which is equal to ten4 ,all the      
improved methods of teaching arithmetic 
to children proceed on a knowledge of   
this fact4 ,all who wish to carry the   
child's mind along with them in learning
 arithmetic2 all who wish to teach      
numbers1 and not mere ciphers--now teach
 it through the evidence of the senses1 
in the manner we have described4  ,we   
may1 if we please1 call the proposition1
 ,three is two and one1 a definition of 
the number three1 and assert that       
arithmetic1 as it has been asserted that
 geometry1 is a science founded on      

definitions4 ,but they are definitions  
in the geometrical sense1 not the       
logical2 asserting not the meaning of a 
term only1 but along with it an observed
 matter of fact4 ,the proposition1 ,a   
circle is a figure bounded by a line    
which has all its points equally distant
 from a point within it1 is called the  
definition of a circle2 but the         
proposition from which so many          
consequences follow1 and which is really
 a first principle in geometry1 is1 that
 figures answering to this description  
exist4 ,and thus we may call ,three is  
two and one a definition of three2 but  
the calculations which depend on that   
proposition do not follow from the      
definition itself1 but from an          
arithmetical theorem presupposed in it1 
namely1 that collections of objects     
exist1 which while they impress the     
senses thus1    o o    o1  may be       
separated into two parts1 thus1    o o  
o4  ,this proposition being granted1 we 
term all such parcels ,threes1 after    

which the enunciation of the above      
mentioned physical fact will serve also 
for a definition of the word ,three4    
,the ,science of ,number is thus no     
exception to the conclusion we          
previously arrived at1 that the         
processes even of deductive sciences are
 altogether inductive1 and that their   
first principles are generalizations    
from experience4 ,it remains to be      
examined whether this science resembles 
geometry in the further circumstance1   
that some of its inductions are not     
exactly true2 and that the peculiar     
certainty ascribed to it1 on account of 
which its propositions are called       
,necessary ,truths1 is fictitious and   
hypothetical1 being true in no other    
sense than that those propositions      
legitimately follow from the hypothesis 
of the truth of premises which are      
avowedly mere approximations to truth4  
#c4 ,the inductions of arithmetic are of
 two sorts3 first1 those which we have  
just expounded1 such as ,one and one are

 two1 ,two and one are three1 c41 which 
may be called the definitions of the    
various numbers1 in the improper or     
geometrical sense of the word           
,definition2 and secondly1 the two      
following axioms3 ,the sums of equals   
are equal1 ,the differences of equals   
are equal4 ,these two are sufficient2   
for the corresponding propositions      
respecting unequals may be proved from  
these1 by a reductio ad absurdum4       
,these axioms1 and likewise the         
so-called definitions1 are1 as has      
already been said1 results of induction2
 true of all objects whatever1 and1 as  
it may seem1 exactly true1 without the  
hypothetical assumption of unqualified  
truth where an approximation to it is   
all that exists4 ,the conclusions1      
therefore1 it will naturally be         
inferred1 are exactly true1 and the     
science of number is an exception to    
other demonstrative sciences in this1   
that the categorical certainty which is 
predicable of its demonstrations is     

independent of all hypothesis4  ,on more
 accurate investigation1 however1 it    
will be found that1 even in this case1  
there is one hypothetical element in the
 ratiocination4 ,in all propositions    
concerning numbers1 a condition is      
implied1 without which none of them     
would be true2 and that condition is an 
assumption which maybe false4 ,the      
condition1 is that #a  #a2 that all the 
numbers are numbers of the same or of   
equal units4 ,let this be doubtful1 and 
not one of the propositions of          
arithmetic will hold true4 ,how can we  
know that one pound and one pound make  
two pounds1 if one of the pounds may be 
troy1 and the other avoirdupois8 ,they  
may not make two pounds of either1 or of
 any weight4 ,how can we know that a    
forty-horse power is always equal to    
itself1 unless we assume that all horses
 are of equal strength8 ,it is certain  
that #a is always equal in number to #a2
 and where the mere number of objects1  
or of the parts of an object1 without   

supposing them to be equivalent in any  
other respect1 is all that is material1 
the conclusions of arithmetic1 so far as
 they go to that alone1 are true without
 mixture of hypothesis4 ,there are a few
 such cases2 as1 for instance1 an       
inquiry into the amount of the          
population of any country4 ,it is       
indifferent to that inquiry whether they
 are grown people or children1 strong or
 weak1 tall or short2 the only thing we 
want to ascertain is their number4 ,but 
whenever1 from equality or inequality of
 number1 equality or inequality in any  
other respect is to be inferred1        
arithmetic carried into such inquiries  
becomes as hypothetical a science as    
geometry4 ,all units must be assumed to 
be equal in that other respect2 and this
 is never accurately true1 for one      
actual pound weight is not exactly equal
 to another1 nor one measured mile's    
length to another2 a nicer balance1 or  
more accurate measuring instruments1    
would always detect some difference4    

,what is commonly called mathematical   
certainty1 therefore1 which comprises   
the twofold conception of unconditional 
truth and perfect accuracy1 is not an   
attribute of all mathematical truths1   
but of those only which relate to pure  
,number1 as distinguished from ,quantity
 in the more enlarged sense2 and only so
 long as we abstain from supposing that 
the numbers are a precise index to      
actual quantities4 ,the certainty       
usually ascribed to the conclusions of  
geometry1 and even to those of          
mechanics1 is nothing whatever but      
certainty of inference4 ,we can have    
full assurance of particular results    
under particular suppositions1 but we   
cannot have the same assurance that     
these suppositions are accurately true1 
nor that they include all the data which
 may exercise an influence over the     
result in any given instance4    #d4 ,it
 appears1 therefore1 that the method of 
all ,deductive ,sciences is             
hypothetical4 ,they proceed by tracing  

the consequences of certain assumptions2
 leaving for separate consideration     
whether the assumptions are true or not1
 and if not exactly true1 whether they  
are a sufficiently near approximation to
 the truth4 ,the reason is obvious4     
,since it is only in questions of pure  
number that the assumptions are exactly 
true1 and even there1 only so long as no
 conclusions except purely numerical    
ones are to be founded on them2 it must1
 in all other cases of deductive        
investigation1 form a part of the       
inquiry1 to determine how much the      
assumptions want of being exactly true  
in the case in hand4 ,this is generally 
a matter of observation1 to be repeated 
in every fresh case2 or if it has to be 
settled by argument instead of          
observation1 may require in every       
different case different evidence1 and  
present every degree of difficulty from 
the lowest to the highest4 ,but the     
other part of the process--namely1 to   
determine what else may be concluded if 

we find1 and in proportion as we find1  
the assumptions to be true--may be      
performed once for all1 and the results 
held ready to be employed as the        
occasions turn up for use4 ,we thus do  
all beforehand that can be so done1 and 
leave the least possible work to be     
performed when cases arise and press for
 a decision4 ,this inquiry into the     
inferences which can be drawn from      
assumptions1 is what properly           
constitutes ,demonstrative ,science4    
,it is of course quite as practicable to
 arrive at new conclusions from facts   
assumed1 as from facts observed2 from   
fictitious1 as from real1 inductions4   
,deduction1 as we have seen1 consists of
 a series of inferences in this form--a 
is a mark of b1 b of c1 c of d1         
therefore a is a mark of d1 which last  
may be a truth inaccessible to direct   
observation4 ,in like manner it is      
allowable to say1 suppose that a were a 
mark of b1 b of c1 and c of d1 a would  
be a mark of d1 which last conclusion   

was not thought of by those who laid    
down the premises4 ,a system of         
propositions as complicated as geometry 
might be deduced from assumptions which 
are false2 as was done by ,ptolemy1     
,descartes1 and others1 in their        
attempts to explain synthetically the   
phenomena of the solar system on the    
supposition that the apparent motions of
 the heavenly bodies were the real      
motions1 or were produced in some way   
more or less different from the true    
one4 ,sometimes the same thing is       
knowingly done1 for the purpose of      
showing the falsity of the assumption2  
which is called a reductio ad absurdum4 
,in such cases1 the reasoning is as     
follows3 a is a mark of b1 and b of c2  
now if c were also a mark of d1 a would 
be a mark of d2 but d is known to be a  
mark of the absence of a2 consequently a
 would be a mark of its own absence1    
which is a contradiction2 therefore c is
 not a mark of d4    #e4 ,it has even   
been held by some writers1 that all     

ratiocination rests in the last resort  
on a reductio ad absurdum2 since the way
 to enforce assent to it1 in case of    
obscurity1 would be to show that if the 
conclusion be denied we must deny some  
one at least of the premises1 which1 as 
they are all supposed true1 would be a  
contradiction4 ,and in accordance with  
this1 many have thought that the        
peculiar nature of the evidence of      
ratiocination consisted in the          
impossibility of admitting the premises 
and rejecting the conclusion without a  
contradiction in terms4 ,this theory1   
however1 is inadmissible as an          
explanation of the grounds on which     
ratiocination itself rests4 ,if any one 
denies the conclusion notwithstanding   
his admission of the premises1 he is not
 involved in any direct and express     
contradiction until he is compelled to  
deny some premise2 and he can only be   
forced to do this by a reductio ad      
absurdum1 that is1 by another           
ratiocination3 now1 if he denies the    

validity of the reasoning process       
itself1 he can no more be forced to     
assent to the second syllogism than to  
the first4 ,in truth1 therefore1 no one 
is ever forced to a contradiction in    
terms3 he can only be forced to a       
contradiction 7or rather an             
infringement7 of the fundamental maxim  
of ratiocination1 namely1 that whatever 
has a mark1 has what it is a mark of2   
or1 7in the case of universal           
propositions17 that whatever is a mark  
of anything1 is a mark of whatever else 
that thing is a mark of4 ,for in the    
case of every correct argument1 as soon 
as thrown into the syllogistic form1 it 
is evident without the aid of any other 
syllogism1 that he who1 admitting the   
premises1 fails to draw the conclusion1 
does not conform to the above axiom4    
,we have now proceeded as far in the    
theory of ,deduction as we can advance  
in the present stage of our inquiry4    
,any further insight into the subject   
requires that the foundation shall have 

been laid of the philosophic theory of  
,induction itself2 in which theory that 
of deduction1 as a mode of induction1   
which we have now shown it to be1 will  
assume spontaneously the place which    
belongs to it1 and will receive its     
share of whatever light may be thrown   
upon the great intellectual operation of
 which it forms so important a part4    
,,chapter ,,vii4  ,,examination ,,of    
,,some ,,opinions ,,opposed ,,to ,,the  
,,preceding ,,doctrines4    #a4         
,polemical discussion is foreign to the 
plan of this work4 ,but an opinion which
 stands in need of much illustration1   
can often receive it most effectually1  
and least tediously1 in the form of a   
defence against objections4 ,and on     
subjects concerning which speculative   
minds are still divided1 a writer does  
but half his duty by stating his own    
doctrine1 if he does not also examine1  
and to the best of his ability judge1   
those of other thinkers4  ,in the       
dissertation which ,mr4 ,herbert        

,spencer has prefixed to his1 in many   
respects1 highly philosophical treatise 
on the ,mind1#ci he criticises some of  
the doctrines of the two preceding      
chapters1 and propounds a theory of his 
own on the subject of first principles4 
,mr4 ,spencer agrees with me in         
considering axioms to be simply our     
earliest inductions from experience4    
,but he differs from me widely as to the
 worth of the test of inconceivableness4
 ,he thinks that it is the ultimate test
 of all beliefs4 ,he arrives at this    
conclusion by two steps4 ,first1 we     
never can have any stronger ground for  
believing anything1 than that the belief
 of it invariably exists4 ,whenever any 
fact or proposition is invariably       
believed2 that is1 if ,i understand ,mr4
 ,spencer rightly1 believed by all      
persons1 and by oneself at all times2 it
 is entitled to be received as one of   
the primitive truths1 or original       
premises of our knowledge4 ,secondly1   
the criterion by which we decide whether

 anything is invariably believed to be  
true1 is our inability to conceive it as
 false4 ,the inconceivability of its    
negation is the test by which we        
ascertain whether a given belief        
invariably exists or not4 ,for our      
primary beliefs1 the fact of invariable 
existence1 tested by an abortive effort 
to cause their non-existence1 is the    
only reason assignable4 ,he thinks this 
the sole ground of our belief in our own
 sensations4 ,if ,i believe that ,i feel
 cold1 ,i only receive this as true     
because ,i cannot conceive that ,i am   
not feeling cold4 ,while the proposition
 remains true1 the negation of it       
remains inconceivable4 ,there are       
numerous other beliefs which ,mr4       
,spencer considers to rest on the same  
basis2 being chiefly those1 or a part of
 those1 which the metaphysicians of the 
,reid and ,stewart school consider as   
truths of immediate intuition4 ,that    
there exists a material world2 that this
 is the very world which we directly and

 immediately perceive1 and not merely   
the hidden cause of our perceptions2    
that ,space1 ,time1 ,force1 ,extension1 
,figure1 are not modes of our           
consciousness1 but objective realities2 
are regarded by ,mr4 ,spencer as truths 
known by the inconceivableness of their 
negatives4 ,we cannot1 he says1 by any  
effort1 conceive these objects of       
thought as mere states of our mind2 as  
not having an existence external to us4 
,their real existence is1 therefore1 as 
certain as our sensations themselves4   
,the truths which are the subject of    
direct knowledge1 being1 according to   
this doctrine1 known to be truths only  
by the inconceivability of their        
negation2 and the truths which are not  
the object of direct knowledge1 being   
known as inferences from those which    
are2 and those inferences being believed
 to follow from the premises1 only      
because we cannot conceive them not to  
follow2 inconceivability is thus the    
ultimate ground of all assured beliefs4 

,thus far1 there is no very wide        
difference between ,mr4 ,spencer's      
doctrine and the ordinary one of        
philosophers of the intuitive school1   
from ,descartes to ,dr4 ,whewell2 but at
 this point ,mr4 ,spencer diverges from 
them4 ,for he does not1 like them1 set  
up the test of inconceivability as      
infallible4 ,on the contrary1 he holds  
that it may be fallacious1 not from any 
fault in the test itself1 but because   
men have mistaken for inconceivable     
things1 some things which were not      
inconceivable4 ,and he himself1 in this 
very book1 denies not a few propositions
 usually regarded as among the most     
marked examples of truths whose         
negations are inconceivable4 ,but       
occasional failure1 he says1 is incident
 to all tests4 ,if such failure vitiates
 the test of inconceivableness1 it must 
similarly vitiate all tests whatever4   
,we consider an inference logically     
drawn from established premises to be   
true4 ,yet in millions of cases men have

 been wrong in the inferences they have 
thought thus drawn4 ,do we therefore    
argue that it is absurd to consider an  
inference true on no other ground than  
that it is logically drawn from         
established premises8 ,no3 we say that  
though men may have taken for logical   
inferences1 inferences that were not    
logical1 there nevertheless are logical 
inferences1 and that we are justified in
 assuming the truth of what seem to us  
such1 until better instructed4          
,similarly1 though men may have thought 
some things inconceivable which were not
 so1 there may still be inconceivable   
things2 and the inability to conceive   
the negation of a thing1 may still be   
our best warrant for believing it4444   
,though occasionally it may prove an    
imperfect test1 yet1 as our most certain
 beliefs are capable of no better1 to   
doubt any one belief because we have no 
higher guarantee for it1 is really to   
doubt all beliefs4 ,mr4 ,spencer's      
doctrine1 therefore1 does not erect the 

curable1 but only the incurable         
limitations of the human conceptive     
faculty1 into laws of the outward       
universe4    #b4 ,the doctrine1 that a  
belief which is proved by the           
inconceivableness of its negation to    
invariably exist1 is true1 ,mr4 ,spencer
 enforces by two arguments1 one of which
 may be distinguished as positive1 and  
the other as negative4  ,the positive   
argument is1 that every such belief     
represents the aggregate of all past    
experience4 ,conceding the entire truth 
of the position1 that during any phase  
of human progress1 the ability or       
inability to form a specific conception 
wholly depends on the experiences men   
have had2 and that1 by a widening of    
their experiences1 they may1 by and by1 
be enabled to conceive things before    
inconceivable to them2 it may still be  
argued that as1 at any time1 the best   
warrant men can have for a belief is the
 perfect agreement of all pre-existing  
experience in support of it1 it follows 

that1 at any time1 the inconceivableness
 of its negation is the deepest test any
 belief admits of4444 ,objective facts  
are ever impressing themselves upon us2 
our experience is a register of these   
objective facts2 and the                
inconceivableness of a thing implies    
that it is wholly at variance with the  
register4 ,even were this all1 it is not
 clear how1 if every truth is primarily 
inductive1 any better test of truth     
could exist4 ,but it must be remembered 
that whilst many of these facts1        
impressing themselves upon us1 are      
occasional2 whilst others again are very
 general2 some are universal and        
unchanging4 ,these universal and        
unchanging facts are1 by the hypothesis1
 certain to establish beliefs of which  
the negations are inconceivable2 whilst 
the others are not certain to do this2  
and if they do1 subsequent facts will   
reverse their action4 ,hence if1 after  
an immense accumulation of experiences1 
there remain beliefs of which the       

negations are still inconceivable1 most1
 if not all of them1 must correspond to 
universal objective facts4 ,if there be 
444 certain absolute uniformities in    
nature2 if these uniformities produce1  
as they must1 absolute uniformities in  
our experience2 and if 444 these        
absolute uniformities in our experience 
disable us from conceiving the negations
 of them2 then answering to each        
absolute uniformity in nature which we  
can cognize1 there must exist in us a   
belief of which the negation is         
inconceivable1 and which is absolutely  
true4 ,in this wide range of cases      
subjective inconceivableness must       
correspond to objective impossibility4  
,further experience will produce        
correspondence where it may not yet     
exist2 and we may expect the            
correspondence to become ultimately     
complete4 ,in nearly all cases this test
 of inconceivableness must be valid now2
 7,i wish ,i could think we were so     
nearly arrived at omniscience7 and where

 it is not1 it still expresses the net  
result of our experience up to the      
present time2 which is the most that any
 test can do4  ,to this ,i answer3 ,even
 if it were true that inconceivableness 
represents the net result of all past   
experience1 why should we stop at the   
representative when we can get at the   
thing represented8 ,if our incapacity to
 conceive the negation of a given       
supposition is proof of its truth1      
because proving that our experience has 
hitherto been uniform in its favour1 the
 real evidence for the supposition is   
not the inconceivableness1 but the      
uniformity of experience4 ,now this1    
which is the substantial and only proof1
 is directly accessible4 ,we are not    
obliged to presume it from an incidental
 consequence4 ,if all past experience is
 in favour of a belief1 let this be     
stated1 and the belief openly rested on 
that ground3 after which the question   
arises1 what that fact may be worth as  
evidence of its truth8 ,for uniformity  

of experience is evidence in very       
different degrees3 in some cases it is  
strong evidence1 in others weak1 in     
others it scarcely amounts to evidence  
at all4 ,that all metals sink in water1 
was an uniform experience1 from the     
origin of the human race to the         
discovery of potassium in the present   
century by ,sir ,humphry ,davy4 ,that   
all swans are white1 was an uniform     
experience down to the discovery of     
,australia4 ,in the few cases in which  
uniformity of experience does amount to 
the strongest possible proof1 as with   
such propositions as these1 ,two        
straight lines cannot inclose a space1  
,every event has a cause1 it is not     
because their negations are             
inconceivable1 which is not always the  
fact2 but because the experience1 which 
has been thus uniform1 pervades all     
nature4 ,it will be shown in the        
following ,book that none of the        
conclusions either of induction or of   
deduction can be considered certain1    

except as far as their truth is shown to
 be inseparably bound up with truths of 
this class4  ,i maintain then1 first1   
that uniformity of past experience is   
very far from being universally a       
criterion of truth4 ,but secondly1      
inconceivableness is still farther from 
being a test even of that test4         
,uniformity of contrary experience is   
only one of many causes of              
inconceivability4 ,tradition handed down
 from a period of more limited          
knowledge1 is one of the commonest4 ,the
 mere familiarity of one mode of        
production of a phenomenon1 often       
suffices to make every other mode appear
 inconceivable4 ,whatever connects two  
ideas by a strong association may1 and  
continually does1 render their          
separation in thought impossible2 as    
,mr4 ,spencer1 in other parts of his    
speculations1 frequently recognises4 ,it
 was not for want of experience that the
 ,cartesians were unable to conceive    
that one body could produce motion in   

another without contact4 ,they had as   
much experience of other modes of       
producing motion1 as they had of that   
mode4 ,the planets had revolved1 and    
heavy bodies had fallen1 every hour of  
their lives4 ,but they fancied these    
phenomena to be produced by a hidden    
machinery which they did not see1       
because without it they were unable to  
conceive what they did see4 ,the        
inconceivableness1 instead of           
representing their experience1 dominated
 and overrode their experience4 ,it is  
needless to dwell farther on what ,i    
have termed the positive argument of    
,mr4 ,spencer in support of his         
criterion of truth4 ,i pass to his      
negative argument1 on which he lays more
 stress4    #c4 ,the negative argument  
is1 that1 whether inconceivability be   
good evidence or bad1 no stronger       
evidence is to be obtained4 ,that what  
is inconceivable cannot be true1 is     
postulated in every act of thought4 ,it 
is the foundation of all our original   

premises4 ,still more it is assumed in  
all conclusions from those premises4    
,the invariability of belief1 tested by 
the inconceivableness of its negation1  
is our sole warrant for every           
demonstration4 ,logic is simply a       
systematization of the process by which 
we indirectly obtain this warrant for   
beliefs that do not directly possess it4
 ,to gain the strongest conviction      
possible respecting any complex fact1 we
 either analytically descend from it by 
successive steps1 each of which we      
unconsciously test by the               
inconceivableness of its negation1 until
 we reach some axiom or truth which we  
have similarly tested2 or we            
synthetically ascend from such axiom or 
truth by such steps4 ,in either case we 
connect some isolated belief1 with a    
belief which invariably exists1 by a    
series of intermediate beliefs which    
invariably exist4 ,the following passage
 sums up the whole theory3 ,when we     
perceive that the negation of the belief

 is inconceivable1 we have all possible 
warrant for asserting the invariability 
of its existence3 and in asserting this1
 we express alike our logical           
justification of it1 and the inexorable 
necessity we are under of holding it4444
 ,we have seen that this is the         
assumption on which every conclusion    
whatever ultimately rests4 ,we have no  
other guarantee for the reality of      
consciousness1 of sensations1 of        
personal existence2 we have no other    
guarantee for any axiom2 we have no     
other guarantee for any step in a       
demonstration4 ,hence1 as being taken   
for granted in every act of the         
understanding1 it must be regarded as   
the ,universal ,postulate4 ,but as this 
postulate which we are under an         
inexorable necessity of holding true1 is
 sometimes false2 as beliefs that once  
were shown by the inconceivableness of  
their negations to invariably exist1    
have since been found untrue1 and as    
beliefs that now possess this character 

may some day share the same fate2 the   
canon of belief laid down by ,mr4       
,spencer is1 that the most certain      
conclusion is that which involves the   
postulate the fewest times4 ,reasoning1 
therefore1 never ought to prevail       
against one of the immediate beliefs    
7the belief in ,matter1 in the outward  
reality of ,extension1 ,space1 and the  
like71 because each of these involves   
the postulate only once2 while an       
argument1 besides involving it in the   
premises1 involves it again in every    
step of the ratiocination1 no one of the
 successive acts of inference being     
recognised as valid except because we   
cannot conceive the conclusion not to   
follow from the premises4  ,it will be  
convenient to take the last part of this
 argument first4 ,in every reasoning1   
according to ,mr4 ,spencer1 the         
assumption of the postulate is renewed  
at every step4 ,at each inference we    
judge that the conclusion follows from  
the premises1 our sole warrant for that 

judgment being that we cannot conceive  
it not to follow4 ,consequently if the  
postulate is fallible1 the conclusions  
of reasoning are more vitiated by that  
uncertainty than direct intuitions2 and 
the disproportion is greater1 the more  
numerous the steps of the argument4  ,to
 test this doctrine1 let us first       
suppose an argument consisting only of a
 single step1 which would be represented
 by one syllogism4 ,this argument does  
rest on an assumption1 and we have seen 
in the preceding chapters what the      
assumption is4 ,it is1 that whatever has
 a mark1 has what it is a mark of4 ,the 
evidence of this axiom ,i shall not     
consider at present2#dj let us suppose  
it 7with ,mr4 ,spencer7 to be the       
inconceivableness of its reverse4  ,let 
us now add a second step to the         
argument3 we require1 what8 ,another    
assumption8 ,no3 the same assumption a  
second time2 and so on to a third1 and a
 fourth4 ,i confess ,i do not see how1  
on ,mr4 ,spencer's own principles1 the  

repetition of the assumption at all     
weakens the force of the argument4 ,if  
it were necessary the second time to    
assume some other axiom1 the argument   
would no doubt be weakened1 since it    
would be necessary to its validity that 
both axioms should be true1 and it might
 happen that one was true and not the   
other3 making two chances of error      
instead of one4 ,but since it is the    
same axiom1 if it is true once it is    
true every time2 and if the argument1   
being of a hundred links1 assumed the   
axiom a hundred times1 these hundred    
assumptions would make but one chance of
 error among them all4 ,it is           
satisfactory that we are not obliged to 
suppose the deductions of pure          
mathematics to be among the most        
uncertain of argumentative processes1   
which on ,mr4 ,spencer's theory they    
could hardly fail to be1 since they are 
the longest4 ,but the number of steps in
 an argument does not subtract from its 
reliableness1 if no new premises1 of an 

uncertain character1 are taken up by the
 way4  ,to speak next of the premises4  
,our assurance of their truth1 whether  
they be generalities or individual      
facts1 is grounded1 in ,mr4 ,spencer's  
opinion1 on the inconceivableness of    
their being false4 ,it is necessary to  
advert to a double meaning of the word  
inconceivable1 which ,mr4 ,spencer is   
aware of1 and would sincerely disclaim  
founding an argument upon1 but from     
which his case derives no little        
advantage notwithstanding4 ,by          
inconceivableness is sometimes meant1   
inability to form or get rid of an idea2
 sometimes1 inability to form or get rid
 of a belief4 ,the former meaning is the
 most conformable to the analogy of     
language2 for a conception always means 
an idea1 and never a belief4 ,the wrong 
meaning of inconceivable is1 however1   
fully as frequent in philosophical      
discussion as the right meaning1 and the
 intuitive school of metaphysicians     
could not well do without either4 ,to   

illustrate the difference1 we will take 
two contrasted examples4 ,the early     
physical speculators considered         
antipodes incredible1 because           
inconceivable4 ,but antipodes were not  
inconceivable in the primitive sense of 
the word4 ,an idea of them could be     
formed without difficulty3 they could be
 completely pictured to the mental eye4 
,what was difficult1 and as it then     
seemed1 impossible1 was to apprehend    
them as believable4 ,the idea could be  
put together1 of men sticking on by     
their feet to the under side of the     
earth2 but the belief would follow1 that
 they must fall off4 ,antipodes were not
 unimaginable1 but they were            
unbelievable4  ,on the other hand1 when 
,i endeavour to conceive an end to      
extension1 the two ideas refuse to come 
together4 ,when ,i attempt to form a    
conception of the last point of space1  
,i cannot help figuring to myself a vast
 space beyond that last point4 ,the     
combination is1 under the conditions of 

our experience1 unimaginable4 ,this     
double meaning of inconceivable it is   
very important to bear in mind1 for the 
argument from inconceivableness almost  
always turns on the alternate           
substitution of each of those meanings  
for the other4  ,in which of these two  
senses does ,mr4 ,spencer employ the    
term1 when he makes it a test of the    
truth of a proposition that its negation
 is inconceivable8 ,until ,mr4 ,spencer 
expressly stated the contrary1 ,i       
inferred from the course of his         
argument1 that he meant unbelievable4   
,he has1 however1 in a paper published  
in the fifth number of the ,fortnightly 
,review1 disclaimed this meaning1 and   
declared that by an inconceivable       
proposition he means1 now and always1   
one of which the terms cannot1 by any   
effort1 be brought before consciousness 
in that relation which the proposition  
asserts between them--a proposition of  
which the subject and predicate offer an
 insurmountable resistance to union in  

thought4 ,we now1 therefore1 know       
positively that ,mr4 ,spencer always    
endeavours to use the word inconceivable
 in this1 its proper1 sense3 but it may 
yet be questioned whether his endeavour 
is always successful2 whether the other1
 and popular use of the word does not   
sometimes creep in with its             
associations1 and prevent him from      
maintaining a clear separation between  
the two4 ,when1 for example1 he says1   
that when ,i feel cold1 ,i cannot       
conceive that ,i am not feeling cold1   
this expression cannot be translated    
into1 ,i cannot conceive myself not     
feeling cold1 for it is evident that ,i 
can3 the word conceive1 therefore1 is   
here used to express the recognition of 
a matter of fact--the perception of     
truth or falsehood2 which ,i apprehend  
to be exactly the meaning of an act of  
belief1 as distinguished from simple    
conception4 ,again1 ,mr4 ,spencer calls 
the attempt to conceive something which 
is inconceivable1 an abortive effort to 

cause the non-existence not of a        
conception or mental representation1 but
 of a belief4 ,there is need1 therefore1
 to revise a considerable part of ,mr4  
,spencer's language1 if it is to be kept
 always consistent with his definition  
of inconceivability4 ,but in truth the  
point is of little importance2 since    
inconceivability1 in ,mr4 ,spencer's    
theory1 is only a test of truth1        
inasmuch as it is a test of             
believability4 ,the inconceivableness of
 a supposition is the extreme case of   
its unbelievability4 ,this is the very  
foundation of ,mr4 ,spencer's doctrine4 
,the invariability of the belief is with
 him the real guarantee4 ,the attempt to
 conceive the negative1 is made in order
 to test the inevitableness of the      
belief4 ,it should be called1 an attempt
 to believe the negative4 ,when ,mr4    
,spencer says that while looking at the 
sun a man cannot conceive that he is    
looking into darkness1 he should have   
said that a man cannot believe that he  

is doing so4 ,for it is surely possible1
 in broad daylight1 to imagine oneself  
looking into darkness4#da ,as ,mr4      
,spencer himself says1 speaking of the  
belief of our own existence3 ,that he   
might not exist1 he can conceive well   
enough2 but that he does not exist1 he  
finds it impossible to conceive1 i4e4 to
 believe4 ,so that the statement        
resolves itself into this3 ,that ,i     
exist1 and that ,i have sensations1 ,i  
believe1 because ,i cannot believe      
otherwise4 ,and in this case every one  
will admit that the necessity is real4  
,any one's present sensations1 or other 
states of subjective consciousness1 that
 one person inevitably believes4 ,they  
are facts known per se3 it is impossible
 to ascend beyond them4 ,their negative 
is really unbelievable1 and therefore   
there is never any question about       
believing it4 ,mr4 ,spencer's theory is 
not needed for these truths4  ,but      
according to ,mr4 ,spencer there are    
other beliefs1 relating to other things 

than our own subjective feelings1 for   
which we have the same guarantee--which 
are1 in a similar manner1 invariable and
 necessary4 ,with regard to these other 
beliefs1 they cannot be necessary1 since
 they do not always exist4 ,there have  
been1 and are1 many persons who do not  
believe the reality of an external      
world1 still less the reality of        
extension and figure as the forms of    
that external world2 who do not believe 
that space and time have an existence   
independent of the mind--nor any other  
of ,mr4 ,spencer's objective intuitions4
 ,the negations of these alleged        
invariable beliefs are not unbelievable1
 for they are believed4 ,it may be      
maintained1 without obvious error1 that 
we cannot imagine tangible objects as   
mere states of our own and other        
people's consciousness2 that the        
perception of them irresistibly suggests
 to us the idea of something external to
 ourselves3 and ,i am not in a condition
 to say that this is not the fact       

7though ,i do not think any one is      
entitled to affirm it of any person     
besides himself74 ,but many thinkers    
have believed1 whether they could       
conceive it or not1 that what we        
represent to ourselves as material      
objects1 are mere modifications of      
consciousness2 complex feelings of touch
 and of muscular action4 ,mr4 ,spencer  
may think the inference correct from the
 unimaginable to the unbelievable1      
because he holds that belief itself is  
but the persistence of an idea1 and that
 what we can succeed in imagining1 we   
cannot at the moment help apprehending  
as believable4 ,but of what consequence 
is it what we apprehend at the moment1  
if the moment is in contradiction to the
 permanent state of our mind8 ,a person 
who has been frightened when an infant  
by stories of ghosts1 though he         
disbelieves them in after years 7and    
perhaps disbelieved them at first71 may 
be unable all his life to be in a dark  
place1 in circumstances stimulating to  

the imagination1 without mental         
discomposure4 ,the idea of ghosts1 with 
all its attendant terrors1 is           
irresistibly called up in his mind by   
the outward circumstances4 ,mr4 ,spencer
 may say1 that while he is under the    
influence of this terror he does not    
disbelieve in ghosts1 but has a         
temporary and uncontrollable belief in  
them4 ,be it so2 but allowing it to be  
so1 which would it be truest to say of  
this man on the whole--that he believes 
in ghosts1 or that he does not believe  
in them8 ,assuredly that he does not    
believe in them4 ,the case is similar   
with those who disbelieve a material    
world4 ,though they cannot get rid of   
the idea2 though while looking at a     
solid object they cannot help having the
 conception1 and therefore1 according to
 ,mr4 ,spencer's metaphysics1 the       
momentary belief1 of its externality2   
even at that moment they would sincerely
 deny holding that belief3 and it would 
be incorrect to call them other than    

disbelievers of the doctrine4 ,the      
belief therefore is not invariable2 and 
the test of inconceivableness fails in  
the only cases to which there could ever
 be any occasion to apply it4  ,that a  
thing may be perfectly believable1 and  
yet may not have become conceivable1 and
 that we may habitually believe one side
 of an alternative1 and conceive only in
 the other1 is familiarly exemplified in
 the state of mind of educated persons  
respecting sunrise and sunset4 ,all     
educated persons either know by         
investigation1 or believe on the        
authority of science1 that it is the    
earth and not the sun which moves3 but  
there are probably few who habitually   
conceive the phenomenon otherwise than  
as the ascent or descent of the sun4    
,assuredly no one can do so without a   
prolonged trial2 and it is probably not 
easier now than in the first generation 
after ,copernicus4 ,mr4 ,spencer does   
not say1 ,in looking at sunrise it is   
impossible not to conceive that it is   

the sun which moves1 therefore this is  
what everybody believes1 and we have all
 the evidence for it that we can have   
for any truth4 ,yet this would be an    
exact parallel to his doctrine about the
 belief in matter4  ,the existence of   
matter1 and other ,noumena1 as          
distinguished from the phenomenal world1
 remains a question of argument1 as it  
was before2 and the very general1 but   
neither necessary nor universal1 belief 
in them1 stands as a psychological      
phenomenon to be explained1 either on   
the hypothesis of its truth1 or on some 
other4 ,the belief is not a conclusive  
proof of its own truth1 unless there are
 no such things as idola tribs2 but1    
being a fact1 it calls on antagonists to
 show1 from what except the real        
existence of the thing believed1 so     
general and apparently spontaneous a    
belief can have originated4 ,and its    
opponents have never hesitated to accept
 this challenge4#db ,the amount of their
 success in meeting it will probably    

determine the ultimate verdict of       
philosophers on the question4    #d4    
,sir ,william ,hamilton holds as ,i do1 
that inconceivability is no criterion of
 impossibility4 ,there is no ground for 
inferring a certain fact to be          
impossible1 merely from our inability to
 conceive its possibility4 ,things there
 are which may1 nay must1 be true1 of   
which the understanding is wholly unable
 to construe to itself the              
possibility4#dc ,sir ,william ,hamilton 
is however a firm believer in the       
priori character of many axioms1 and of 
the sciences deduced from them2 and is  
so far from considering those axioms to 
rest on the evidence of experience1 that
 he declares certain of them to be true 
even of ,noumena--of the                
,unconditioned--of which it is one of   
the principal aims of his philosophy to 
prove that the nature of our faculties  
debars us from having any knowledge4    
,the axioms to which he attributes this 
exceptional emancipation from the limits

 which confine all our other            
possibilities of knowledge2 the chinks  
through which1 as he represents1 one ray
 of light finds its way to us from      
behind the curtain which veils from us  
the mysterious world of ,things in      
themselves1--are the two principles1    
which he terms1 after the schoolmen1 the
 ,principle of ,contradiction1 and the  
,principle of ,excluded ,middle3 the    
first1 that two contradictory           
propositions cannot both be true2 the   
second1 that they cannot both be false4 
,armed with these logical weapons1 we   
may boldly face ,things in themselves1  
and tender to them the double           
alternative1 sure that they must        
absolutely elect one or the other side1 
though we may be for ever precluded from
 discovering which4 ,to take his        
favourite example1 we cannot conceive   
the infinite divisibility of matter1 and
 we cannot conceive a minimum1 or end to
 divisibility3 yet one or the other must
 be true4  ,as ,i have hitherto said    

nothing of the two axioms in question1  
those of ,contradiction and of ,excluded
 ,middle1 it is not unseasonable to     
consider them here4 ,the former asserts 
that an affirmative proposition and the 
corresponding negative proposition      
cannot both be true2 which has generally
 been held to be intuitively evident4   
,sir ,william ,hamilton and the ,germans
 consider it to be the statement in     
words of a form or law of our thinking  
faculty4 ,other philosophers1 not less  
deserving of consideration1 deem it to  
be an identical proposition2 an         
assertion involved in the meaning of    
terms2 a mode of defining ,negation1 and
 the word ,not4  ,i am able to go one   
step with these last4 ,an affirmative   
assertion and its negative are not two  
independent assertions1 connected with  
each other only as mutually             
incompatible4 ,that if the negative be  
true1 the affirmative must be false1    
really is a mere identical proposition2 
for the negative proposition asserts    

nothing but the falsity of the          
affirmative1 and has no other sense or  
meaning whatever4 ,the ,principium      
,contradictionis should therefore put   
off the ambitious phraseology which     
gives it the air of a fundamental       
antithesis pervading nature1 and should 
be enunciated in the simpler form1 that 
the same proposition cannot at the same 
time be false and true4 ,but ,i can go  
no farther with the ,nominalists2 for ,i
 cannot look upon this last as a merely 
verbal proposition4 ,i consider it to   
be1 like other axioms1 one of our first 
and most familiar generalizations from  
experience4 ,the original foundation of 
it ,i take to be1 that ,belief and      
,disbelief are two different mental     
states1 excluding one another4 ,this we 
know by the simplest observation of our 
own minds4 ,and if we carry our         
observation outwards1 we also find that 
light and darkness1 sound and silence1  
motion and quiescence1 equality and     
inequality1 preceding and following1    

succession and simultaneousness1 any    
positive phenomenon whatever and its    
negative1 are distinct phenomena1       
pointedly contrasted1 and the one always
 absent where the other is present4 ,i  
consider the maxim in question to be a  
generalization from all these facts4    
,in like manner as the ,principle of    
,contradiction 7that one of two         
contradictories must be false7 means    
that an assertion cannot be both true   
and false1 so the ,principle of         
,excluded ,middle1 or that one of two   
contradictories must be true1 means that
 an assertion must be either true or    
false3 either the affirmative is true1  
or otherwise the negative is true1 which
 means that the affirmative is false4 ,i
 cannot help thinking this principle a  
surprising specimen of a so-called      
necessity of ,thought1 since it is not  
even true1 unless with a large          
qualification4 ,a proposition must be   
either true or false1 provided that the 
predicate be one which can in any       

intelligible sense be attributed to the 
subject2 7and as this is always assumed 
to be the case in treatises on logic1   
the axiom is always laid down there as  
of absolute truth74 ,abracadabra is a   
second intention is neither true nor    
false4 ,between the true and the false  
there is a third possibility1 the       
,unmeaning3 and this alternative is     
fatal to ,sir ,william ,hamilton's      
extension of the maxim to ,noumena4     
,that ,matter must either have a minimum
 of divisibility or be infinitely       
divisible1 is more than we can ever     
know4 ,for in the first place1 ,matter1 
in any other than the phenomenal sense  
of the term1 may not exist3 and it will 
scarcely be said that a non-entity must 
be either infinitely or finitely        
divisible4#dd ,in the second place1     
though matter1 considered as the occult 
cause of our sensations1 do really      
exist1 yet what we call divisibility may
 be an attribute only of our sensations 
of sight and touch1 and not of their    

uncognizable cause4 ,divisibility may   
not be predicable at all1 in any        
intelligible sense1 of ,things in       
themselves1 nor therefore of ,matter in 
itself2 and the assumed necessity of    
being either infinitely or finitely     
divisible1 may be an inapplicable       
alternative4  ,on this question ,i am   
happy to have the full concurrence of   
,mr4 ,herbert ,spencer1 from whose paper
 in the ,fortnightly ,review ,i extract 
the following passage4 ,the germ of an  
idea identical with that of ,mr4        
,spencer may be found in the present    
chapter1 about a page back1 but in ,mr4 
,spencer it is not an undeveloped       
thought1 but a philosophical theory4    
,when remembering a certain thing as in 
a certain place1 the place and the thing
 are mentally represented together2     
while to think of the non-existence of  
the thing in that place1 implies a      
consciousness in which the place is     
represented1 but not the thing4         
,similarly1 if instead of thinking of an

 object as colourless1 we think of its  
having colour1 the change consists in   
the addition to the concept of an       
element that was before absent from     
it--the object cannot be thought of     
first as red and then as not red1       
without one component of the thought    
being totally expelled from the mind by 
another4 ,the law of the ,excluded      
,middle1 then1 is simply a              
generalization of the universal         
experience that some mental states are  
directly destructive of other states4   
,it formulates a certain absolutely     
constant law1 that the appearance of any
 positive mode of consciousness cannot  
occur without excluding a correlative   
negative mode2 and that the negative    
mode cannot occur without excluding the 
correlative positive mode3 the          
antithesis of positive and negative     
being1 indeed1 merely an expression of  
this experience4 ,hence it follows that 
if consciousness is not in one of the   
two modes it must be in the other4#de   

,i must here close this supplementary   
chapter1 and with it the ,second ,book4 
,the theory of ,induction1 in the most  
comprehensive sense of the term1 will   
form the subject of the ,third4         
,,footnotes3  #a ,as ,sir ,william      
,hamilton has pointed out1 ,some ,a is  
not ,b may also be converted in the     
following form3 ,no ,b is some ,a4 ,some
 men are not negroes2 therefore1 ,no    
negroes are some men 7e4g4 ,europeans74 
#b   ,all ,a is ,b  contraries4   ,no   
,a is ,b     ,some ,a is ,b             
subcontraries4   ,some ,a is not ,b     
,all  ,a is ,b      contradictories4    
,some ,a is not ,b     ,no   ,a is ,b   
also contradictories4   ,some ,a is ,b  
,all  ,a is ,b  and  ,no   ,a is ,b     
respectively subalternate4   ,some ,a is
 ,b       ,some ,a is not ,b   #c ,his  
conclusions are1 ,the first figure is   
suited to the discovery or proof of the 
properties of a thing2 the second to the
 discovery or proof of the distinctions 
between things2 the third to the        

discovery or proof of instances and     
exceptions2 the fourth to the discovery1
 or exclusion1 of the different species 
of a genus4 ,the reference of syllogisms
 in the last three figures to the dictum
 de omni et nullo is1 in ,lambert's     
opinion1 strained and unnatural3 to each
 of the three belongs1 according to him1
 a separate axiom1 co-ordinate and of   
equal authority with that dictum1 and to
 which he gives the names of dictum de  
diverso for the second figure1 dictum de
 exemplo for the third1 and dictum de   
reciproco for the fourth4 ,see part i4  
or ,dianoiologie1 chap4 iv4  #bbi et    
seqq4 ,mr4 ,bailey1 7,theory of         
,reasoning1 #bnd ed4 pp4 #gj-gd7 takes a
 similar view of the subject4  #d ,since
 this chapter was written1 two treatises
 have appeared 7or rather a treatise and
 a fragment of a treatise71 which aim at
 a further improvement in the theory of 
the forms of ratiocination3 ,mr4 ,de    
,morgan's ,formal ,logic2 or1 the       
,calculus of ,inference1 ,necessary and 

,probable2 and the ,new ,analytic of    
,logical ,forms1 attached as an         
,appendix to ,sir ,william ,hamilton's  
,discussions on ,philosophy1 and at     
greater length1 to his posthumous       
,lectures on ,logic4  ,in ,mr4 ,de      
,morgan's volume--abounding1 in its more
 popular parts1 with valuable           
observations felicitously expressed--the
 principal feature of originality is an 
attempt to bring within strict technical
 rules the cases in which a conclusion  
can be drawn from premises of a form    
usually classed as particular4 ,mr4 ,de 
,morgan observes1 very justly1 that from
 the premises ,most ,bs are ,cs1 most   
,bs are ,as1 it may be concluded with   
certainty that some ,as are ,cs1 since  
two portions of the class ,b1 each of   
them comprising more than half1 must    
necessarily in part consist of the same 
individuals4 ,following out this line of
 thought1 it is equally evident that if 
we knew exactly what proportion the most
 in each of the premises bear to the    

entire class ,b1 we could increase in a 
corresponding degree the definiteness of
 the conclusion4 ,thus if #fj per cent  
of ,b are included in ,c1 and #gj per   
cent in ,a1 #cj per cent at least must  
be common to both2 in other words1 the  
number of ,as which are ,cs1 and of ,cs 
which are ,as1 must be at least equal to
 #cj per cent of the class ,b4          
,proceeding on this conception of       
numerically definite propositions1 and  
extending it to such forms as           
these3--#de ,xs 7or more7 are each of   
them one of #gj ,ys1 or #de ,xs 7or     
more7 are no one of them to be found    
among #gj ,ys1 and examining what       
inferences admit of being drawn from the
 various combinations which may be made 
of premises of this description1 ,mr4   
,de ,morgan establishes universal formul
 for such inferences2 creating for that 
purpose not only a new technical        
language1 but a formidable array of     
symbols analogous to those of algebra4  
,since it is undeniable that inferences1

 in the cases examined by ,mr4 ,de      
,morgan1 can legitimately be drawn1 and 
that the ordinary theory takes no       
account of them1 ,i will not say that it
 was not worth while to show in detail  
how these also could be reduced to      
formul as rigorous as those of          
,aristotle4 ,what ,mr4 ,de ,morgan has  
done was worth doing once 7perhaps more 
than once1 as a school exercise72 but ,i
 question if its results are worth      
studying and mastering for any practical
 purpose4 ,the practical use of         
technical forms of reasoning is to bar  
out fallacies3 but the fallacies which  
require to be guarded against in        
ratiocination properly so called1 arise 
from the incautious use of the common   
forms of language2 and the logician must
 track the fallacy into that territory1 
instead of waiting for it on a territory
 of his own4 ,while he remains among    
propositions which have acquired the    
numerical precision of the ,calculus of 
,probabilities1 the enemy is left in    

possession of the only ground on which  
he can be formidable4 ,and since the    
propositions 7short of universal7 on    
which a thinker has to depend1 either   
for purposes of speculation or of       
practice1 do not1 except in a few       
peculiar cases1 admit of any numerical  
precision2 common reasoning cannot be   
translated into ,mr4 ,de ,morgan's      
forms1 which therefore cannot serve any 
purpose as a test of it4  ,sir ,william 
,hamilton's theory of the quantification
 of the predicate 7concerning the       
originality of which in his case there  
can be no doubt1 however ,mr4 ,de       
,morgan may have also1 and              
independently1 originated an equivalent 
doctrine7 may be briefly described as   
follows3--  ,logically 7,i quote his own
 words7 we ought to take into account   
the quantity1 always understood in      
thought1 but usually1 for manifest      
reasons1 elided in its expression1 not  
only of the subject1 but also of the    
predicate of a judgment4 ,all ,a is ,b1 

is equivalent to all ,a is some ,b4 ,no 
,a is ,b1 to ,no ,a is any ,b4 ,some ,a 
is ,b1 is tantamount to some ,a is some 
,b4 ,some ,a is not ,b1 to ,some ,a is  
not any ,b4 ,as in these forms of       
assertion the predicate is exactly      
coextensive with the subject1 they all  
admit of simple conversion2 and by this 
we obtain two additional forms--,some ,b
 is all ,a1 and ,no ,b is some ,a4 ,we  
may also make the assertion ,all ,a is  
all ,b1 which will be true if the       
classes ,a and ,b are exactly           
coextensive4 ,the last three forms1     
though conveying real assertions1 have  
no place in the ordinary classification 
of ,propositions4 ,all propositions1    
then1 being supposed to be translated   
into this language1 and written each in 
that one of the preceding forms which   
answers to its signification1 there     
emerges a new set of syllogistic rules1 
materially different from the common    
ones4 ,a general view of the points of  
difference may be given in the words of 

,sir ,w4 ,hamilton 7,discussions1 #bnd  
ed4 p4 #fea73--  ,the revocation of the 
two terms of a ,proposition to their    
true relation2 a proposition being      
always an equation of its subject and   
its predicate4  ,the consequent         
reduction of the ,conversion of         
,propositions from three species to     
one--that of ,simple ,conversion4  ,the 
reduction of all the ,general ,laws of  
,categorical ,syllogisms to a single    
,canon4  ,the evolution from that one   
canon of all the ,species and varieties 
of ,syllogisms4  ,the abrogation of all 
the ,special ,laws of ,syllogism4  ,a   
demonstration of the exclusive          
possibility of ,three syllogistic       
,figures2 and 7on new grounds7 the      
scientific and final abolition of the   
,fourth4  ,a manifestation that ,figure 
is an unessential variation in          
syllogistic form2 and the consequent    
absurdity of ,reducing the syllogisms of
 the other figures to the first4  ,an   
enouncement of one ,organic ,principle  

for each ,figure4  ,a determination of  
the true number of the ,legitimate      
,moods2 with  ,their amplification in   
number 7thirty-six72  ,their numerical  
equality under all the figures2 and     
,their relative equivalence1 or virtual 
identity1 throughout every schematic    
difference4  ,that1 in the second and   
third figures1 the extremes holding both
 the same relation to the middle term1  
there is not1 as in the first1 an       
opposition and subordination between a  
term major and a term minor1 mutually   
containing and contained1 in the counter
 wholes of ,extension and               
,comprehension4  ,consequently1 in the  
second and third figures1 there is no   
determinate major and minor premise1 and
 there are two indifferent conclusions3 
whereas in the first the premises are   
determinate1 and there is a single      
proximate conclusion4  ,this doctrine1  
like that of ,mr4 ,de ,morgan previously
 noticed1 is a real addition to the     
syllogistic theory2 and has moreover    

this advantage over ,mr4 ,de ,morgan's  
numerically definite ,syllogism1 that   
the forms it supplies are really        
available as a test of the correctness  
of ratiocination2 since propositions in 
the common form may always have their   
predicates quantified1 and so be made   
amenable to ,sir ,w4 ,hamilton's rules4 
,considered however as a contribution to
 the ,science of ,logic1 that is1 to the
 analysis of the mental processes       
concerned in reasoning1 the new doctrine
 appears to me1 ,i confess1 not merely  
superfluous1 but erroneous2 since the   
form in which it clothes propositions   
does not1 like the ordinary form1       
express what is in the mind of the      
speaker when he enunciates the          
proposition4 ,i cannot think ,sir       
,william ,hamilton right in maintaining 
that the quantity of the predicate is   
always understood in thought4 ,it is    
implied1 but is not present to the mind 
of the person who asserts the           
proposition4 ,the quantification of the 

predicate1 instead of being a means of  
bringing out more clearly the meaning of
 the proposition1 actually leads the    
mind out of the proposition1 into       
another order of ideas4 ,for when we    
say1 ,all men are mortal1 we simply mean
 to affirm the attribute mortality of   
all men2 without thinking at all of the 
class mortal in the concrete1 or        
troubling ourselves about whether it    
contains any other beings or not4 ,it is
 only for some artificial purpose that  
we ever look at the proposition in the  
aspect in which the predicate also is   
thought of as a class-name1 either      
including the subject only1 or the      
subject and something more4 7,see above1
 p4 #ajd47  ,for a fuller discussion of 
this subject1 see the twenty-second     
chapter of a work already referred to1  
,an ,examination of ,sir ,william       
,hamilton's ,philosophy4  #e ,mr4       
,herbert ,spencer 7,principles of       
,psychology1 pp4 #abe-g71 though his    
theory of the syllogism coincides with  

all that is essential of mine1 thinks it
 a logical fallacy to present the two   
axioms in the text1 as the regulating   
principles of syllogism4 ,he charges me 
with falling into the error pointed out 
by ,archbishop ,whately and myself1 of  
confounding exact likeness with literal 
identity2 and maintains1 that we ought  
not to say that ,socrates possesses the 
same attributes which are connoted by   
the word ,man1 but only that he         
possesses attributes exactly like them3 
according to which phraseology1         
,socrates1 and the attribute mortality1 
are not two things coexisting with the  
same thing1 as the axiom asserts1 but   
two things coexisting with two different
 things4  ,the question between ,mr4    
,spencer and me is merely one of        
language2 for neither of us 7if ,i      
understand ,mr4 ,spencer's opinions     
rightly7 believes an attribute to be a  
real thing1 possessed of objective      
existence2 we believe it to be a        
particular mode of naming our           

sensations1 or our expectations of      
sensation1 when looked at in their      
relation to an external object which    
excites them4 ,the question raised by   
,mr4 ,spencer does not1 therefore1      
concern the properties of any really    
existing thing1 but the comparative     
appropriateness1 for philosophical      
purposes1 of two different modes of     
using a name4 ,considered in this point 
of view1 the phraseology ,i have        
employed1 which is that commonly used by
 philosophers1 seems to me to be the    
best4 ,mr4 ,spencer is of opinion that  
because ,socrates and ,alcibiades are   
not the same man1 the attribute which   
constitutes them men should not be      
called the same attribute2 that because 
the humanity of one man and that of     
another express themselves to our senses
 not by the same individual sensations  
but by sensations exactly alike1        
humanity ought to be regarded as a      
different attribute in every different  
man4 ,but on this showing1 the humanity 

even of any one man should be considered
 as different attributes now and        
half-an-hour hence2 for the sensations  
by which it will then manifest itself to
 my organs will not be a continuation of
 my present sensations1 but a repetition
 of them2 fresh sensations1 not         
identical with1 but only exactly like   
the present4 ,if every general          
conception1 instead of being the ,one in
 the ,many1 were considered to be as    
many different conceptions as there are 
things to which it is applicable1 there 
would be no such thing as general       
language4 ,a name would have no general 
meaning if man connoted one thing when  
predicated of ,john1 and another1 though
 closely resembling1 thing when         
predicated of ,william4 ,accordingly a  
recent pamphlet asserts the             
impossibility of general knowledge on   
this precise ground4  ,the meaning of   
any general name is some outward or     
inward phenomenon1 consisting1 in the   
last resort1 of feelings2 and these     

feelings1 if their continuity is for an 
instant broken1 are no longer the same  
feelings1 in the sense of individual    
identity4 ,what1 then1 is the common    
something which gives a meaning to the  
general name8 ,mr4 ,spencer can only    
say1 it is the similarity of the        
feelings2 and ,i rejoin1 the attribute  
is precisely that similarity4 ,the names
 of attributes are in their ultimate    
analysis names for the resemblances of  
our sensations 7or other feelings74     
,every general name1 whether abstract or
 concrete1 denotes or connotes one or   
more of those resemblances4 ,it will    
not1 probably1 be denied1 that if a     
hundred sensations are undistinguishably
 alike1 their resemblance ought to be   
spoken of as one resemblance1 and not a 
hundred resemblances which merely       
resemble one another4 ,the things       
compared are many1 but the something    
common to all of them must be conceived 
as one1 just as the name is conceived as
 one1 though corresponding to           

numerically different sensations of     
sound each time it is pronounced4 ,the  
general term man does not connote the   
sensations derived once from one man1   
which1 once gone1 can no more occur     
again than the same flash of lightning4 
,it connotes the general type of the    
sensations derived always from all men1 
and the power 7always thought of as one7
 of producing sensations of that type4  
,and the axiom might be thus worded3    
,two types of sensation each of which   
coexists with a third type1 coexist with
 another2 or ,two powers each of which  
coexists with a third power coexist with
 one another4  ,mr4 ,spencer has        
misunderstood me in another particular4 
,he supposes that the coexistence spoken
 of in the axiom1 of two things with the
 same third thing1 means                
simultaneousness in time4 ,the          
coexistence meant is that of being      
jointly attributes of the same subject4 
,the attribute of being born without    
teeth1 and the attribute of having      

thirty-two teeth in mature age1 are in  
this sense coexistent1 both being       
attributes of man1 though ex vi termini 
never of the same man at the same time4 
#f ,supra1 p4 #abh4  #g ,logic1 p4 #bci 
7#ith ed474  #h ,it is hardly necessary 
to say1 that ,i am not contending for   
any such absurdity as that we actually  
ought to have known and considered the  
case of every individual man1 past1     
present1 and future1 before affirming   
that all men are mortal3 although this  
interpretation has been1 strangely      
enough1 put upon the preceding          
observations4 ,there is no difference   
between me and ,archbishop ,whately1 or 
any other defender of the syllogism1 on 
the practical part of the matter2 ,i am 
only pointing out an inconsistency in   
the logical theory of it1 as conceived  
by almost all writers4 ,i do not say    
that a person who affirmed1 before the  
,duke of ,wellington was born1 that all 
men are mortal1 knew that the ,duke of  
,wellington was mortal2 but ,i do say   

that he asserted it2 and ,i ask for an  
explanation of the apparent logical     
fallacy1 of adducing in proof of the    
,duke of ,wellington's mortality1 a     
general statement which presupposes it4 
,finding no sufficient resolution of    
this difficulty in any of the writers on
 ,logic1 ,i have attempted to supply    
one4  #i ,the language of ratiocination 
would1 ,i think1 be brought into closer 
agreement with the real nature of the   
process1 if the general propositions    
employed in reasoning1 instead of being 
in the form ,all men are mortal1 or     
,every man is mortal1 were expressed in 
the form ,any man is mortal4 ,this mode 
of expression1 exhibiting as the type of
 all reasoning from experience ,the men 
,a1 ,b1 ,c1 c4 are so and so1 therefore 
any man is so and so1 would much better 
manifest the true idea--that inductive  
reasoning is always1 at bottom1         
inference from particulars to           
particulars1 and that the whole function
 of general propositions in reasoning1  

is to vouch for the legitimacy of such  
inferences4  #aj ,review of ,quetelet on
 ,probabilities1 ,essays1 p4 #cfg4  #aa 
,philosophy of ,discovery1 p4 #bhi4  #ab
 ,theory of ,reasoning1 ch4 iv4 to which
 ,i may refer for an able statement and 
enforcement of the grounds of the       
doctrine4  #ac ,it is very probable that
 the doctrine is not new1 and that it   
was1 as ,sir ,john ,herschel thinks1    
substantially anticipated by ,berkeley4 
,but ,i certainly am not aware that it  
is 7as has been affirmed by one of my   
ablest and most candid critics7 among   
the standing marks of what is called the
 empirical philosophy4  #ad ,logic1 book
 iv4 ch4 i4 sect4 #a4  #ae ,see the     
important chapter on ,belief1 in        
,professor ,bain's great treatise1 ,the 
,emotions and the ,will1 pp4 #eha-d4    
#af ,a writer in the ,british ,quarterly
 ,review 7,august #ahdf71 in a review of
 this treatise1 endeavours to show that 
there is no petitio principii in the    
syllogism1 by denying that the          

proposition1 ,all men are mortal1       
asserts or assumes that ,socrates is    
mortal4 ,in support of this denial1 he  
argues that we may1 and in fact do1     
admit the general proposition that all  
men are mortal1 without having          
particularly examined the case of       
,socrates1 and even without knowing     
whether the individual so named is a man
 or something else4 ,but this of course 
was never denied4 ,that we can and do   
draw conclusions concerning cases       
specifically unknown to us1 is the datum
 from which all who discuss this subject
 must set out4 ,the question is1 in what
 terms the evidence1 or ground1 on which
 we draw these conclusions1 may best be 
designated--whether it is most correct  
to say1 that the unknown case is proved 
by known cases1 or that it is proved by 
a general proposition including both    
sets of cases1 the unknown and the      
known8 ,i contend for the former mode of
 expression4 ,i hold it an abuse of     
language to say1 that the proof that    

,socrates is mortal1 is that all men are
 mortal4 ,turn it in what way we will1  
this seems to me to be asserting that a 
thing is the proof of itself4 ,whoever  
pronounces the words1 ,all men are      
mortal1 has affirmed that ,socrates is  
mortal1 though he may never have heard  
of ,socrates2 for since ,socrates1      
whether known to be so or not1 really is
 a man1 he is included in the words1    
,all men1 and in every assertion of     
which they are the subject4 ,if the     
reviewer does not see that there is a   
difficulty here1 ,i can only advise him 
to reconsider the subject until he does3
 after which he will be a better judge  
of the success or failure of an attempt 
to remove the difficulty4 ,that he had  
reflected very little on the point when 
he wrote his remarks1 is shown by his   
oversight respecting the dictum de omni 
et nullo4 ,he acknowledges that this    
maxim as commonly expressed1--,whatever 
is true of a class1 is true of          
everything included in the class1 is a  

mere identical proposition1 since the   
class is nothing but the things included
 in it4 ,but he thinks this defect would
 be cured by wording the maxim          
thus1--,whatever is true of a class1 is 
true of everything which can be shown to
 be a member of the class3 as if a thing
 could be shown to be a member of the   
class without being one4 ,if a class    
means the sum of all the things included
 in the class1 the things which can be  
shown to be included in it are part of  
the sum1 and the dictum is as much an   
identical proposition with respect to   
them as to the rest4 ,one would almost  
imagine that1 in the reviewer's opinion1
 things are not members of a class until
 they are called up publicly to take    
their place in it--that so long1 in     
fact1 as ,socrates is not known to be a 
man1 he is not a man1 and any assertion 
which can be made concerning men does   
not at all regard him1 nor is affected  
as to its truth or falsity by anything  
in which he is concerned4  ,the         

difference between the reviewer's theory
 and mine may be thus stated4 ,both     
admit that when we say1 ,all men are    
mortal1 we make an assertion reaching   
beyond the sphere of our knowledge of   
individual cases2 and that when a new   
individual1 ,socrates1 is brought within
 the field of our knowledge by means of 
the minor premise1 we learn that we have
 already made an assertion respecting   
,socrates without knowing it3 our own   
general formula being1 to that extent1  
for the first time interpreted to us4   
,but according to the reviewer's theory1
 the smaller assertion is proved by the 
larger3 while ,i contend1 that both     
assertions are proved together1 by the  
same evidence1 namely1 the grounds of   
experience on which the general         
assertion was made1 and by which it must
 be justified4  ,the reviewer says1 that
 if the major premise included the      
conclusion1 we should be able to affirm 
the conclusion without the intervention 
of the minor premise2 but every one sees

 that that is impossible4 ,a similar    
argument is urged by ,mr4 ,de ,morgan   
7,formal ,logic1 p4 #bei73 ,the whole   
objection tacitly assumes the           
superfluity of the minor2 that is1      
tacitly assumes we know ,socrates#df to 
be a man as soon as we know him to be   
,socrates4 ,the objection would be well 
grounded if the assertion that the major
 premise includes the conclusion1 meant 
that it individually specifies all it   
includes4 ,as however the only          
indication it gives is a description by 
marks1 we have still to compare any new 
individual with the marks2 and to show  
that this comparison has been made1 is  
the office of the minor4 ,but since1 by 
supposition1 the new individual has the 
marks1 whether we have ascertained him  
to have them or not2 if we have affirmed
 the major premise1 we have asserted him
 to be mortal4 ,now my position is that 
this assertion cannot be a necessary    
part of the argument4 ,it cannot be a   
necessary condition of reasoning that we

 should begin by making an assertion1   
which is afterwards to be employed in   
proving a part of itself4 ,i can        
conceive only one way out of this       
difficulty1 viz4 that what really forms 
the proof is the other part of the      
assertion2 the portion of it1 the truth 
of which has been ascertained           
previously3 and that the unproved part  
is bound up in one formula with the     
proved part in mere anticipation1 and as
 a memorandum of the nature of the      
conclusions which we are prepared to    
prove4  ,with respect to the minor      
premise in its formal shape1 the minor  
as it stands in the syllogism1          
predicating of ,socrates a definite     
class name1 ,i readily admit that it is 
no more a necessary part of reasoning   
than the major4 ,when there is a major1 
doing its work by means of a class name1
 minors are needed to interpret it3 but 
reasoning can be carried on without     
either the one or the other4 ,they are  
not the conditions of reasoning1 but a  

precaution against erroneous reasoning4 
,the only minor premise necessary to    
reasoning in the example under          
consideration1 is1 ,socrates is like ,a1
 ,b1 ,c1 and the other individuals who  
are known to have died4 ,and this is the
 only universal type of that step in the
 reasoning process which is represented 
by the minor4 ,experience1 however1 of  
the uncertainty of this loose mode of   
inference1 teaches the expediency of    
determining beforehand what kind of     
likeness to the cases observed1 is      
necessary to bring an unobserved case   
within the same predicate2 and the      
answer to this question is the major4   
,thus the syllogistic major and the     
syllogistic minor start into existence  
together1 and are called forth by the   
same exigency4 ,when we conclude from   
personal experience without referring to
 any record--to any general theorems1   
either written1 or traditional1 or      
mentally registered by ourselves as     
conclusions of our own drawing1 we do   

not use1 in our thoughts1 either a major
 or a minor1 such as the syllogism puts 
into words4 ,when1 however1 we revise   
this rough inference from particulars to
 particulars1 and substitute a careful  
one1 the revision consists in selecting 
two syllogistic premises4 ,but this     
neither alters nor adds to the evidence 
we had before2 it only puts us in a     
better position for judging whether our 
inference from particulars to           
particulars is well grounded4  #ag      
,infra1 book iii4 ch4 ii4  #ah ,infra1  
book iii4 ch4 iv4  #c1 and elsewhere4   
#ai ,mechanical ,euclid1 pp4 #adi et    
seqq4  #bj ,we might1 it is true1 insert
 this property into the definition of   
parallel lines1 framing the definition  
so as to require1 both that when        
produced indefinitely they shall never  
meet1 and also that any straight line   
which intersects one of them shall1 if  
prolonged1 meet the other4 ,but by doing
 this we by no means get rid of the     
assumption2 we are still obliged to take

 for granted the geometrical truth1 that
 all straight lines in the same plane1  
which have the former of these          
properties1 have also the latter4 ,for  
if it were possible that they should    
not1 that is1 if any straight lines     
other than those which are parallel     
according to the definition1 had the    
property of never meeting although      
indefinitely produced1 the              
demonstrations of the subsequent        
portions of the theory of parallels     
could not be maintained4  #ba ,some     
persons find themselves prevented from  
believing that the axiom1 ,two straight 
lines cannot inclose a space1 could ever
 become known to us through experience1 
by a difficulty which may be stated as  
follows4 ,if the straight lines spoken  
of are those contemplated in the        
definition--lines absolutely without    
breadth and absolutely straight2--that  
such are incapable of inclosing a space 
is not proved by experience1 for lines  
such as these do not present themselves 

in our experience4 ,if1 on the other    
hand1 the lines meant are such straight 
lines as we do meet with in experience1 
lines straight enough for practical     
purposes1 but in reality slightly       
zigzag1 and with some1 however trifling1
 breadth2 as applied to these lines the 
axiom is not true1 for two of them may1 
and sometimes do1 inclose a small       
portion of space4 ,in neither case1     
therefore1 does experience prove the    
axiom4  ,those who employ this argument 
to show that geometrical axioms cannot  
be proved by induction1 show themselves 
unfamiliar with a common and perfectly  
valid mode of inductive proof2 proof by 
approximation4 ,though experience       
furnishes us with no lines so           
unimpeachably straight that two of them 
are incapable of inclosing the smallest 
space1 it presents us with gradations of
 lines possessing less and less either  
of breadth or of flexure1 of which      
series the straight line of the         
definition is the ideal limit4 ,and     

observation shows that just as much1 and
 as nearly1 as the straight lines of    
experience approximate to having no     
breadth or flexure1 so much and so      
nearly does the space-inclosing power of
 any two of them approach to zero4 ,the 
inference that if they had no breadth or
 flexure at all1 they would inclose no  
space at all1 is a correct inductive    
inference from these facts1 conformable 
to one of the four ,inductive ,methods  
hereinafter characterized1 the ,method  
of ,concomitant ,variations2 of which   
the mathematical ,doctrine of ,limits   
presents the extreme case4  #bb         
,whewell's ,history of ,scientific      
,ideas1 i4 #adj4  #bc ,dr4 ,whewell     
7,philosophy of ,discovery1 p4 #bhi7    
thinks it unreasonable to contend that  
we know by experience1 that our idea of 
a line exactly resembles a real line4   
,it does not appear1 he says1 how we can
 compare our ideas with the realities1  
since we know the realities only by our 
ideas4 ,we know the realities 7,i       

conceive7 by our senses4 ,dr4 ,whewell  
surely does not hold the doctrine of    
perception by means of ideas1 which     
,reid gave himself so much trouble to   
refute4  ,if ,dr4 ,whewell doubts       
whether we compare our ideas with the   
corresponding sensations1 and assume    
that they resemble1 let me ask on what  
evidence do we judge that a portrait of 
a person not present is like the        
original4 ,surely because it is like our
 idea1 or mental image of the person1   
and because our idea is like the man    
himself4  ,dr4 ,whewell also says1 that 
it does not appear why this resemblance 
of ideas to the sensations of which they
 are copies1 should be spoken of as if  
it were a peculiarity of one class of   
ideas1 those of space4 ,my reply is1    
that ,i do not so speak of it4 ,the     
peculiarity ,i contend for is only one  
of degree4 ,all our ideas of sensation  
of course resemble the corresponding    
sensations1 but they do so with very    
different degrees of exactness and of   

reliability4 ,no one1 ,i presume1 can   
recal in imagination a colour or an     
odour with the same distinctness and    
accuracy with which almost every one can
 mentally reproduce an image of a       
straight line or a triangle4 ,to the    
extent1 however1 of their capabilities  
of accuracy1 our recollections of       
colours or of odours may serve as       
subjects of experimentation1 as well as 
those of lines and spaces1 and may yield
 conclusions which will be true of their
 external prototypes4 ,a person in whom1
 either from natural gift or from       
cultivation1 the impressions of colour  
were peculiarly vivid and distinct1 if  
asked which of two blue flowers was of  
the darkest tinge1 though he might never
 have compared the two1 or even looked  
at them together1 might be able to give 
a confident answer on the faith of his  
distinct recollection of the colours2   
that is1 he might examine his mental    
pictures1 and find there a property of  
the outward objects4 ,but in hardly any 

case except that of simple geometrical  
forms1 could this be done by mankind    
generally1 with a degree of assurance   
equal to that which is given by a       
contemplation of the objects themselves4
 ,persons differ most widely in the     
precision of their recollection1 even of
 forms3 one person1 when he has looked  
any one in the face for half a minute1  
can draw an accurate likeness of him    
from memory2 another may have seen him  
every day for six months1 and hardly    
know whether his nose is long or short4 
,but everybody has a perfectly distinct 
mental image of a straight line1 a      
circle1 or a rectangle4 ,and every one  
concludes confidently from these mental 
images to the corresponding outward     
things4 ,the truth is1 that we may1 and 
continually do1 study nature in our     
recollections1 when the objects         
themselves are absent2 and in the case  
of geometrical forms we can perfectly1  
but in most other cases only            
imperfectly1 trust our recollections4   

#bd ,history of ,scientific ,ideas1 i4  
#fe-fg4  #be ,ibid4 #fj4  #bf ,history  
of ,scientific ,ideas1 i4 #eh1 #ei4  #bg
 ,if all mankind had spoken one         
language1 we cannot doubt that there    
would have been a powerful1 perhaps a   
universal1 school of philosophers1 who  
would have believed in the inherent     
connexion between names and things1 who 
would have taken the sound man to be the
 mode of agitating the air which is     
essentially communicative of the ideas  
of reason1 cookery1 bipedality1 c4--,de 
,morgan1 ,formal ,logic1 p4 #bdf4  #bh  
,it would be difficult to name a man    
more remarkable at once for the         
greatness and the wide range of his     
mental accomplishments1 than ,leibnitz4 
,yet this eminent man gave as a reason  
for rejecting ,newton's scheme of the   
solar system1 that ,god could not make a
 body revolve round a distant centre1   
unless either by some impelling         
mechanism1 or by miracle3--,tout ce qui 
n'est pas explicable says he in a letter

 to the ,abb ,conti1 par la nature des  
cratures1 est miraculeux4 ,il ne suffit 
pas de dire3 ,dieu a fait une telle loi 
de nature2 donc la chose est naturelle4 
,il faut que la loi soit excutable par  
les natures des cratures4 ,si ,dieu     
donnait cette loi1 par exemple1  un     
corps libre1 de tourner  l'entour d'un  
certain centre1 il faudrait ou qu'il y  
joignt d'autres corps qui par leur      
impulsion l'obligeassent de rester      
toujours dans son orbite circulaire1 ou 
qu'il mt un ange  ses trousses1 ou enfin
 il faudrait qu'il y concourt           
extraordinairement2 car naturellement il
 s'cartera par la tangente4--,works of  
,leibnitz1 ed4 ,dutens1 iii4 #ddf4  #bi 
,novum ,organum ,renovatum1 pp4 #cb1    
#cc4  #cj ,history of ,scientific       
,ideas1 i4 #bfd4  #ca ,hist4 ,sc4 ,id41 
i4 #bfc4  #cb ,ibid4 #bdj4  #cc ,hist4  
,sc4 ,id41 ii4 #be1 #bf4  #cd ,phil4 of 
,disc41 p4 #cci4  #ce ,phil4 of ,disc41 
p4 #cch4  #cf ,ib4 p4 #dfc4  #cg ,phil4 
of ,disc41 pp4 #dgb1 #dgc4  #ch ,the    

,quarterly ,review for ,june #ahda1     
contained an article of great ability on
 ,dr4 ,whewell's two great works 7since 
acknowledged and reprinted in ,sir ,john
 ,herschel's ,essays7 which maintains1  
on the subject of axioms1 the doctrine  
advanced in the text1 that they are     
generalizations from experience1 and    
supports that opinion by a line of      
argument strikingly coinciding with     
mine4 ,when ,i state that the whole of  
the present chapter 7except the last    
four pages1 added in the fifth edition7 
was written before ,i had seen the      
article1 7the greater part1 indeed1     
before it was published17 it is not my  
object to occupy the reader's attention 
with a matter so unimportant as the     
degree of originality which may or may  
not belong to any portion of my own     
speculations1 but to obtain for an      
opinion which is opposed to reigning    
doctrines1 the recommendation derived   
from a striking concurrence of sentiment
 between two inquirers entirely         

independent of one another4 ,i embrace  
the opportunity of citing from a writer 
of the extensive acquirements in        
physical and metaphysical knowledge and 
the capacity of systematic thought which
 the article evinces1 passages so       
remarkably in unison with my own views  
as the following3--  ,the truths of     
geometry are summed up and embodied in  
its definitions and axioms4444 ,let us  
turn to the axioms1 and what do we find8
 ,a string of propositions concerning   
magnitude in the abstract1 which are    
equally true of space1 time1 force1     
number1 and every other magnitude       
susceptible of aggregation and          
subdivision4 ,such propositions1 where  
they are not mere definitions1 as some  
of them are1 carry their inductive      
origin on the face of their             
enunciation4444 ,those which declare    
that two straight lines cannot inclose a
 space1 and that two straight lines     
which cut one another cannot both be    
parallel to a third1 are in reality the 

only ones which express characteristic  
properties of space1 and these it will  
be worth while to consider more nearly4 
,now the only clear notion we can form  
of straightness is uniformity of        
direction1 for space in its ultimate    
analysis is nothing but an assemblage of
 distances and directions4 ,and 7not to 
dwell on the notion of continued        
contemplation1 i4e41 mental experience1 
as included in the very idea of         
uniformity2 nor on that of transfer of  
the contemplating being from point to   
point1 and of experience1 during such   
transfer1 of the homogeneity of the     
interval passed over7 we cannot even    
propose the proposition in an           
intelligible form to any one whose      
experience ever since he was born has   
not assured him of the fact4 ,the unity 
of direction1 or that we cannot march   
from a given point by more than one path
 direct to the same object1 is matter of
 practical experience long before it can
 by possibility become matter of        

abstract thought4 ,we cannot attempt    
mentally to exemplify the conditions of 
the assertion in an imaginary case      
opposed to it1 without violating our    
habitual recollection of this           
experience1 and defacing our mental     
picture of space as grounded on it4     
,what but experience1 we may ask1 can   
possibly assure us of the homogeneity of
 the parts of distance1 time1 force1 and
 measurable aggregates in general1 on   
which the truth of the other axioms     
depends8 ,as regards the latter axiom1  
after what has been said it must be     
clear that the very same course of      
remarks equally applies to its case1 and
 that its truth is quite as much forced 
on the mind as that of the former by    
daily and hourly experience1 444        
including always1 be it observed1 in our
 notion of experience1 that which is    
gained by contemplation of the inward   
picture which the mind forms to itself  
in any proposed case1 or which it       
arbitrarily selects as an example--such 

picture1 in virtue of the extreme       
simplicity of these primary relations1  
being called up by the imagination with 
as much vividness and clearness as could
 be done by any external impression1    
which is the only meaning we can attach 
to the word intuition1 as applied to    
such relations4  ,and again1 of the     
axioms of mechanics3--,as we admit no   
such propositions1 other than as truths 
inductively collected from observation1 
even in geometry itself1 it can hardly  
be expected that1 in a science of       
obviously contingent relations1 we      
should acquiesce in a contrary view4    
,let us take one of these axioms and    
examine its evidence3 for instance1 that
 equal forces perpendicularly applied at
 the opposite ends of equal arms of a   
straight lever will balance each other4 
,what but experience1 we may ask1 in the
 first place1 can possibly inform us    
that a force so applied will have any   
tendency to turn the lever on its centre
 at all8 or that force can be so        

transmitted along a rigid line          
perpendicular to its direction1 as to   
act elsewhere in space than along its   
own line of action8 ,surely this is so  
far from being self-evident that it has 
even a paradoxical appearance1 which is 
only to be removed by giving our lever  
thickness1 material composition1 and    
molecular powers4 ,again1 we conclude1  
that the two forces1 being equal and    
applied under precisely similar         
circumstances1 must1 if they exert any  
effort at all to turn the lever1 exert  
equal and opposite efforts3 but what    
priori reasoning can possibly assure us 
that they do act under precisely similar
 circumstances8 that points which differ
 in place are similarly circumstanced as
 regards the exertion of force8 that    
universal space may not have relations  
to universal force--or1 at all events1  
that the organization of the material   
universe may not be such as to place    
that portion of space occupied by it in 
such relations to the forces exerted in 

it1 as may invalidate the absolute      
similarity of circumstances assumed8 ,or
 we may argue1 what have we to do with  
the notion of angular movement in the   
lever at all8 ,the case is one of rest1 
and of quiescent destruction of force by
 force4 ,now how is this destruction    
effected8 ,assuredly by the             
counter-pressure which supports the     
fulcrum4 ,but would not this destruction
 equally arise1 and by the same amount  
of counter-acting force1 if each force  
simply pressed its own half of the lever
 against the fulcrum8 ,and what can     
assure us that it is not so1 except     
removal of one or other force1 and      
consequent tilting of the lever8 ,the   
other fundamental axiom of statics1 that
 the pressure on the point of support is
 the sum of the weights 444 is merely a 
scientific transformation and more      
refined mode of stating a coarse and    
obvious result of universal experience1 
viz4 that the weight of a rigid body is 
the same1 handle it or suspend it in    

what position or by what point we will1 
and that whatever sustains it sustains  
its total weight4 ,assuredly1 as ,mr4   
,whewell justly remarks1 ',no one       
probably ever made a trial for the      
purpose of showing that the pressure on 
the support is equal to the sum of the  
weights4' 444 ,but it is precisely      
because in every action of his life from
 earliest infancy he has been           
continually making the trial1 and seeing
 it made by every other living being    
about him1 that he never dreams of      
staking its result on one additional    
attempt made with scientific accuracy4  
,this would be as if a man should       
resolve to decide by experiment whether 
his eyes were useful for the purpose of 
seeing1 by hermetically sealing himself 
up for half an hour in a metal case4    
,on the paradox of universal            
propositions obtained by experience1 the
 same writer says3 ,if there be         
necessary and universal truths          
expressible in propositions of axiomatic

 simplicity and obviousness1 and having 
for their subject-matter the elements of
 all our experience and all our         
knowledge1 surely these are the truths  
which1 if experience suggest to us any  
truths at all1 it ought to suggest most 
readily1 clearly1 and unceasingly4 ,if  
it were a truth1 universal and          
necessary1 that a net is spread over the
 whole surface of every planetary globe1
 we should not travel far on our own    
without getting entangled in its meshes1
 and making the necessity of some means 
of extrication an axiom of              
locomotion4444 ,there is1 therefore1    
nothing paradoxical1 but the reverse1 in
 our being led by observation to a      
recognition of such truths1 as general  
propositions1 coextensive at least with 
all human experience4 ,that they pervade
 all the objects of experience1 must    
ensure their continual suggestion by    
experience2 that they are true1 must    
ensure that consistency of suggestion1  
that iteration of uncontradicted        

assertion1 which commands implicit      
assent1 and removes all occasion of     
exception2 that they are simple1 and    
admit of no misunderstanding1 must      
secure their admission by every mind4   
,a truth1 necessary and universal1      
relative to any object of our knowledge1
 must verify itself in every instance   
where that object is before our         
contemplation1 and if at the same time  
it be simple and intelligible1 its      
verification must be obvious4 ,the      
sentiment of such a truth cannot1       
therefore1 but be present to our minds  
whenever that object is contemplated1   
and must therefore make a part of the   
mental picture or idea of that object   
which we may on any occasion summon     
before our imagination4444 ,all         
propositions1 therefore1 become not only
 untrue but inconceivable1 if 444 axioms
 be violated in their enunciation4      
,another eminent mathematician had      
previously sanctioned by his authority  
the doctrine of the origin of           

geometrical axioms in experience4       
,geometry is thus founded likewise on   
observation2 but of a kind so familiar  
and obvious1 that the primary notions   
which it furnishes might seem           
intuitive4--,sir ,john ,leslie1 quoted  
by ,sir ,william ,hamilton1 ,discourses1
 c4 p4 #bgb4  #ci ,principles of        
,psychology4  #dj ,mr4 ,spencer is      
mistaken in supposing me to claim any   
peculiar necessity for this axiom as    
compared with others4 ,i have corrected 
the expressions which led him into that 
misapprehension of my meaning4  #da ,mr4
 ,spencer makes a distinction between   
conceiving myself looking into darkness1
 and conceiving that ,i am then and     
there looking into darkness4 ,to me it  
seems that this change of the expression
 to the form ,i am1 just marks the      
transition from conception to belief1   
and that the phrase to conceive that ,i 
am1 or that anything is1 is not         
consistent with using the word conceive 
in its rigorous sense4  #db ,i have     

myself accepted the contest1 and fought 
it out on this battleground1 in the     
eleventh chapter of ,an ,examination of 
,sir ,william ,hamilton's ,philosophy4  
#dc ,discussions1 c41 #bnd ed4 p4 #fbd4 
#dd ,if it be said that the existence of
 matter is among the things proved by   
the principle of ,excluded ,middle1 that
 principle must prove also the existence
 of dragons and hippogriffs1 because    
they must be either scaly or not scaly1 
creeping or not creeping1 and so forth4 
#de ,for further considerations         
respecting the axioms of ,contradiction 
and ,excluded ,middle1 see the          
twenty-first chapter of ,an ,examination
 of ,sir ,william ,hamilton's           
,philosophy4  #df ,mr4 ,de ,morgan says 
,plato1 but to prevent confusion ,i have
 kept to my own exemplum4     ,,book    
,,iii4  ,,of ,,induction4   ,according  
to the doctrine now stated1 the highest1
 or rather the only proper object of    
physics1 is to ascertain those          
established conjunctions of successive  

events1 which constitute the order of   
the universe2 to record the phenomena   
which it exhibits to our observations1  
or which it discloses to our            
experiments2 and to refer these         
phenomena to their general laws4--,d4   
,,stewart1 ,elements of the ,philosophy 
of the ,human ,mind1 vol4 ii4 chap4 iv4 
sect4 #a4     ,,chapter ,i4             
,,preliminary ,,observations ,,on       
,,induction ,,in ,,general4    #a4 ,the 
portion of the present inquiry upon     
which we are now about to enter1 may be 
considered as the principal1 both from  
its surpassing in intricacy all the     
other branches1 and because it relates  
to a process which has been shown in the
 preceding ,book to be that in which the
 investigation of nature essentially    
consists4 ,we have found that all       
,inference1 consequently all ,proof1 and
 all discovery of truths not            
self-evident1 consists of inductions1   
and the interpretation of inductions3   
that all our knowledge1 not intuitive1  

comes to us exclusively from that       
source4 ,what ,induction is1 therefore1 
and what conditions render it           
legitimate1 cannot but be deemed the    
main question of the science of         
logic--the question which includes all  
others4 ,it is1 however1 one which      
professed writers on logic have almost  
entirely passed over4 ,the generalities 
of the subject have not been altogether 
neglected by metaphysicians2 but1 for   
want of sufficient acquaintance with the
 processes by which science has actually
 succeeded in establishing general      
truths1 their analysis of the inductive 
operation1 even when unexceptionable as 
to correctness1 has not been specific   
enough to be made the foundation of     
practical rules1 which might be for     
induction itself what the rules of the  
syllogism are for the interpretation of 
induction3 while those by whom physical 
science has been carried to its present 
state of improvement--and who1 to arrive
 at a complete theory of the process1   

needed only to generalize1 and adapt to 
all varieties of problems1 the methods  
which they themselves employed in their 
habitual pursuits--never until very     
lately made any serious attempt to      
philosophize on the subject1 nor        
regarded the mode in which they arrived 
at their conclusions as deserving of    
study1 independently of the conclusions 
themselves4    #b4 ,for the purposes of 
the present inquiry1 ,induction may be  
defined1 the operation of discovering   
and proving general propositions4 ,it is
 true that 7as already shown7 the       
process of indirectly ascertaining      
individual facts1 is as truly inductive 
as that by which we establish general   
truths4 ,but it is not a different kind 
of induction2 it is a form of the very  
same process3 since1 on the one hand1   
generals are but collections of         
particulars1 definite in kind but       
indefinite in number2 and on the other  
hand1 whenever the evidence which we    
derive from observation of known cases  

justifies us in drawing an inference    
respecting even one unknown case1 we    
should on the same evidence be justified
 in drawing a similar inference with    
respect to a whole class of cases4 ,the 
inference either does not hold at all1  
or it holds in all cases of a certain   
description2 in all cases which1 in     
certain definable respects1 resemble    
those we have observed4  ,if these      
remarks are just2 if the principles and 
rules of inference are the same whether 
we infer general propositions or        
individual facts2 it follows that a     
complete logic of the sciences would be 
also a complete logic of practical      
business and common life4 ,since there  
is no case of legitimate inference from 
experience1 in which the conclusion may 
not legitimately be a general           
proposition2 an analysis of the process 
by which general truths are arrived at1 
is virtually an analysis of all         
induction whatever4 ,whether we are     
inquiring into a scientific principle or

 into an individual fact1 and whether we
 proceed by experiment or by            
ratiocination1 every step in the train  
of inferences is essentially inductive1 
and the legitimacy of the induction     
depends in both cases on the same       
conditions4  ,true it is that in the    
case of the practical inquirer1 who is  
endeavouring to ascertain facts not for 
the purposes of science but for those of
 business1 such for instance as the     
advocate or the judge1 the chief        
difficulty is one in which the          
principles of induction will afford him 
no assistance4 ,it lies not in making   
his inductions1 but in the selection of 
them2 in choosing from among all general
 propositions ascertained to be true1   
those which furnish marks by which he   
may trace whether the given subject     
possesses or not the predicate in       
question4 ,in arguing a doubtful        
question of fact before a jury1 the     
general propositions or principles to   
which the advocate appeals are mostly1  

in themselves1 sufficiently trite1 and  
assented to as soon as stated3 his skill
 lies in bringing his case under those  
propositions or principles2 in calling  
to mind such of the known or received   
maxims of probability as admit of       
application to the case in hand1 and    
selecting from among them those best    
adapted to his object4 ,success is here 
dependent on natural or acquired        
sagacity1 aided by knowledge of the     
particular subject1 and of subjects     
allied with it4 ,invention1 though it   
can be cultivated1 cannot be reduced to 
rule2 there is no science which will    
enable a man to bethink himself of that 
which will suit his purpose4  ,but when 
he has thought of something1 science can
 tell him whether that which he has     
thought of will suit his purpose or not4
 ,the inquirer or arguer must be guided 
by his own knowledge and sagacity in the
 choice of the inductions out of which  
he will construct his argument4 ,but the
 validity of the argument when          

constructed1 depends on principles and  
must be tried by tests which are the    
same for all descriptions of inquiries1 
whether the result be to give ,a an     
estate1 or to enrich science with a new 
general truth4 ,in the one case and in  
the other1 the senses1 or testimony1    
must decide on the individual facts2 the
 rules of the syllogism will determine  
whether1 those facts being supposed     
correct1 the case really falls within   
the formul of the different inductions  
under which it has been successively    
brought2 and finally1 the legitimacy of 
the inductions themselves must be       
decided by other rules1 and these it is 
now our purpose to investigate4 ,if this
 third part of the operation be1 in many
 of the questions of practical life1 not
 the most1 but the least arduous portion
 of it1 we have seen that this is also  
the case in some great departments of   
the field of science2 in all those which
 are principally deductive1 and most of 
all in mathematics2 where the inductions

 themselves are few in number1 and so   
obvious and elementary that they seem to
 stand in no need of the evidence of    
experience1 while to combine them so as 
to prove a given theorem or solve a     
problem1 may call for the utmost powers 
of invention and contrivance with which 
our species is gifted4  ,if the identity
 of the logical processes which prove   
particular facts and those which        
establish general scientific truths1    
required any additional confirmation1 it
 would be sufficient to consider that in
 many branches of science1 single facts 
have to be proved1 as well as           
principles2 facts as completely         
individual as any that are debated in a 
court of justice2 but which are proved  
in the same manner as the other truths  
of the science1 and without disturbing  
in any degree the homogeneity of its    
method4 ,a remarkable example of this is
 afforded by astronomy4 ,the individual 
facts on which that science grounds its 
most important deductions1 such facts as

 the magnitudes of the bodies of the    
solar system1 their distances from one  
another1 the figure of the earth1 and   
its rotation1 are scarcely any of them  
accessible to our means of direct       
observation3 they are proved indirectly1
 by the aid of inductions founded on    
other facts which we can more easily    
reach4 ,for example1 the distance of the
 moon from the earth was determined by a
 very circuitous process4 ,the share    
which direct observation had in the work
 consisted in ascertaining1 at one and  
the same instant1 the zenith distances  
of the moon1 as seen from two points    
very remote from one another on the     
earth's surface4 ,the ascertainment of  
these angular distances ascertained     
their supplements2 and since the angle  
at the earth's centre subtended by the  
distance between the two places of      
observation was deducible by spherical  
trigonometry from the latitude and      
longitude of those places1 the angle at 
the moon subtended by the same line     

became the fourth angle of a            
quadrilateral of which the other three  
angles were known4 ,the four angles     
being thus ascertained1 and two sides of
 the quadrilateral being radii of the   
earth2 the two remaining sides and the  
diagonal1 or in other words1 the moon's 
distance from the two places of         
observation and from the centre of the  
earth1 could be ascertained1 at least in
 terms of the earth's radius1 from      
elementary theorems of geometry4 ,at    
each step in this demonstration we take 
in a new induction1 represented1 in the 
aggregate of its results1 by a general  
proposition4  ,not only is the process  
by which an individual astronomical fact
 was thus ascertained1 exactly similar  
to those by which the same science      
establishes its general truths1 but also
 7as we have shown to be the case in all
 legitimate reasoning7 a general        
proposition might have been concluded   
instead of a single fact4 ,in           
strictness1 indeed1 the result of the   

reasoning is a general proposition2 a   
theorem respecting the distance1 not of 
the moon in particular1 but of any      
inaccessible object3 showing in what    
relation that distance stands to certain
 other quantities4 ,and although the    
moon is almost the only heavenly body   
the distance of which from the earth can
 really be thus ascertained1 this is    
merely owing to the accidental          
circumstances of the other heavenly     
bodies1 which render them incapable of  
affording such data as the application  
of the theorem requires2 for the theorem
 itself is as true of them as it is of  
the moon4#a  ,we shall fall into no     
error1 then1 if in treating of          
,induction1 we limit our attention to   
the establishment of general            
propositions4 ,the principles and rules 
of ,induction as directed to this end1  
are the principles and rules of all     
,induction2 and the logic of ,science is
 the universal ,logic1 applicable to all
 inquiries in which man can engage4     

,,chapter ,,ii4  ,,of ,,inductions      
,,improperly ,,so ,,called4    #a4      
,induction1 then1 is that operation of  
the mind1 by which we infer that what we
 know to be true in a particular case or
 cases1 will be true in all cases which 
resemble the former in certain          
assignable respects4 ,in other words1   
,induction is the process by which we   
conclude that what is true of certain   
individuals of a class is true of the   
whole class1 or that what is true at    
certain times will be true in similar   
circumstances at all times4  ,this      
definition excludes from the meaning of 
the term ,induction1 various logical    
operations1 to which it is not unusual  
to apply that name4  ,induction1 as     
above defined1 is a process of          
inference2 it proceeds from the known to
 the unknown2 and any operation         
involving no inference1 any process in  
which what seems the conclusion is no   
wider than the premises from which it is
 drawn1 does not fall within the meaning

 of the term4 ,yet in the common books  
of ,logic we find this laid down as the 
most perfect1 indeed the only quite     
perfect1 form of induction4 ,in those   
books1 every process which sets out from
 a less general and terminates in a more
 general expression1--which admits of   
being stated in the form1 ,this and that
 ,a are ,b1 therefore every ,a is       
,b1--is called an induction1 whether    
anything be really concluded or not3 and
 the induction is asserted not to be    
perfect1 unless every single individual 
of the class ,a is included in the      
antecedent1 or premise3 that is1 unless 
what we affirm of the class has already 
been ascertained to be true of every    
individual in it1 so that the nominal   
conclusion is not really a conclusion1  
but a mere reassertion of the premises4 
,if we were to say1 ,all the planets    
shine by the sun's light1 from          
observation of each separate planet1 or 
,all the ,apostles were ,jews1 because  
this is true of ,peter1 ,paul1 ,john1   

and every other apostle1--these1 and    
such as these1 would1 in the phraseology
 in question1 be called perfect1 and the
 only perfect1 ,inductions4 ,this1      
however1 is a totally different kind of 
induction from ours2 it is not an       
inference from facts known to facts     
unknown1 but a mere short-hand          
registration of facts known4 ,the two   
simulated arguments which we have       
quoted1 are not generalizations2 the    
propositions purporting to be           
conclusions from them1 are not really   
general propositions4 ,a general        
proposition is one in which the         
predicate is affirmed or denied of an   
unlimited number of individuals2 namely1
 all1 whether few or many1 existing or  
capable of existing1 which possess the  
properties connoted by the subject of   
the proposition4 ,all men are mortal    
does not mean all now living1 but all   
men past1 present1 and to come4 ,when   
the signification of the term is limited
 so as to render it a name not for any  

and every individual falling under a    
certain general description1 but only   
for each of a number of individuals     
designated as such1 and as it were      
counted off individually1 the           
proposition1 though it may be general in
 its language1 is no general            
proposition1 but merely that number of  
singular propositions1 written in an    
abridged character4 ,the operation may  
be very useful1 as most forms of        
abridged notation are2 but it is no part
 of the investigation of truth1 though  
often bearing an important part in the  
preparation of the materials for that   
investigation4  ,as we may sum up a     
definite number of singular propositions
 in one proposition1 which will be      
apparently1 but not really1 general1 so 
we may sum up a definite number of      
general propositions in one proposition1
 which will be apparently1 but not      
really1 more general4 ,if by a separate 
induction applied to every distinct     
species of animals1 it has been         

established that each possesses a       
nervous system1 and we affirm thereupon 
that all animals have a nervous system2 
this looks like a generalization1 though
 as the conclusion merely affirms of all
 what has already been affirmed of each1
 it seems to tell us nothing but what we
 knew before4 ,a distinction however    
must be made4 ,if in concluding that all
 animals have a nervous system1 we mean 
the same thing and no more as if we had 
said all known animals1 the proposition 
is not general1 and the process by which
 it is arrived at is not induction4 ,but
 if our meaning is that the observations
 made of the various species of animals 
have discovered to us a law of animal   
nature1 and that we are in a condition  
to say that a nervous system will be    
found even in animals yet undiscovered1 
this indeed is an induction2 but in this
 case the general proposition contains  
more than the sum of the special        
propositions from which it is inferred4 
,the distinction is still more forcibly 

brought out when we consider1 that if   
this real generalization be legitimate  
at all1 its legitimacy probably does not
 require that we should have examined   
without exception every known species4  
,it is the number and nature of the     
instances1 and not their being the whole
 of those which happen to be known1 that
 makes them sufficient evidence to prove
 a general law3 while the more limited  
assertion1 which stops at all known     
animals1 cannot be made unless we have  
rigorously verified it in every species4
 ,in like manner 7to return to a former 
example7 we might have inferred1 not    
that all the planets1 but that all      
planets1 shine by reflected light3 the  
former is no induction2 the latter is an
 induction1 and a bad one1 being        
disproved by the case of double         
stars--self-luminous bodies which are   
properly planets1 since they revolve    
round a centre4    #b4 ,there are       
several processes used in mathematics   
which require to be distinguished from  

,induction1 being not unfrequently      
called by that name1 and being so far   
similar to ,induction properly so       
called1 that the propositions they lead 
to are really general propositions4 ,for
 example1 when we have proved with      
respect to the circle1 that a straight  
line cannot meet it in more than two    
points1 and when the same thing has been
 successively proved of the ellipse1 the
 parabola1 and the hyperbola1 it may be 
laid down as an universal property of   
the sections of the cone4 ,the          
distinction drawn in the two previous   
examples can have no place here1 there  
being no difference between all known   
sections of the cone and all sections1  
since a cone demonstrably cannot be     
intersected by a plane except in one of 
these four lines4 ,it would be          
difficult1 therefore1 to refuse to the  
proposition arrived at1 the name of a   
generalization1 since there is no room  
for any generalization beyond it4 ,but  
there is no induction1 because there is 

no inference3 the conclusion is a mere  
summing up of what was asserted in the  
various propositions from which it is   
drawn4 ,a case somewhat1 though not     
altogether1 similar1 is the proof of a  
geometrical theorem by means of a       
diagram4 ,whether the diagram be on     
paper or only in the imagination1 the   
demonstration 7as formerly observed#b7  
does not prove directly the general     
theorem2 it proves only that the        
conclusion1 which the theorem asserts   
generally1 is true of the particular    
triangle or circle exhibited in the     
diagram2 but since we perceive that in  
the same way in which we have proved it 
of that circle1 it might also be proved 
of any other circle1 we gather up into  
one general expression all the singular 
propositions susceptible of being thus  
proved1 and embody them in an universal 
proposition4 ,having shown that the     
three angles of the triangle ,,abc are  
together equal to two right angles1 we  
conclude that this is true of every     

other triangle1 not because it is true  
of ,,abc1 but for the same reason which 
proved it to be true of ,,abc4 ,if this 
were to be called ,induction1 an        
appropriate name for it would be1       
induction by parity of reasoning4 ,but  
the term cannot properly belong to it2  
the characteristic quality of ,induction
 is wanting1 since the truth obtained1  
though really general1 is not believed  
on the evidence of particular instances4
 ,we do not conclude that all triangles 
have the property because some triangles
 have1 but from the ulterior            
demonstrative evidence which was the    
ground of our conviction in the         
particular instances4  ,there are       
nevertheless1 in mathematics1 some      
examples of so-called ,induction1 in    
which the conclusion does bear the      
appearance of a generalization grounded 
on some of the particular cases included
 in it4 ,a mathematician1 when he has   
calculated a sufficient number of the   
terms of an algebraical or arithmetical 

series to have ascertained what is      
called the law of the series1 does not  
hesitate to fill up any number of the   
succeeding terms without repeating the  
calculations4 ,but ,i apprehend he only 
does so when it is apparent from  priori
 considerations 7which might be         
exhibited in the form of demonstration7 
that the mode of formation of the       
subsequent terms1 each from that which  
preceded it1 must be similar to the     
formation of the terms which have been  
already calculated4 ,and when the       
attempt has been hazarded without the   
sanction of such general considerations1
 there are instances on record in which 
it has led to false results4  ,it is    
said that ,newton discovered the        
binomial theorem by induction2 by       
raising a binomial successively to a    
certain number of powers1 and comparing 
those powers with one another until he  
detected the relation in which the      
algebraic formula of each power stands  
to the exponent of that power1 and to   

the two terms of the binomial4 ,the fact
 is not improbable3 but a mathematician 
like ,newton1 who seemed to arrive per  
saltum at principles and conclusions    
that ordinary mathematicians only       
reached by a succession of steps1       
certainly could not have performed the  
comparison in question without being led
 by it to the  priori ground of the law2
 since any one who understands          
sufficiently the nature of              
multiplication to venture upon          
multiplying several lines of symbols at 
one operation1 cannot but perceive that 
in raising a binomial to a power1 the   
coefficients must depend on the laws of 
permutation and combination3 and as soon
 as this is recognised1 the theorem is  
demonstrated4 ,indeed1 when once it was 
seen that the law prevailed in a few of 
the lower powers1 its identity with the 
law of permutation would at once suggest
 the considerations which prove it to   
obtain universally4 ,even1 therefore1   
such cases as these1 are but examples of

 what ,i have called ,induction by      
parity of reasoning1 that is1 not really
 ,induction1 because not involving      
inference of a general proposition from 
particular instances4    #c4 ,there     
remains a third improper use of the term
 ,induction1 which it is of real        
importance to clear up1 because the     
theory of ,induction has been1 in no    
ordinary degree1 confused by it1 and    
because the confusion is exemplified in 
the most recent and elaborate treatise  
on the inductive philosophy which exists
 in our language4 ,the error in question
 is that of confounding a mere          
description1 by general terms1 of a set 
of observed phenomena1 with an induction
 from them4  ,suppose that a phenomenon 
consists of parts1 and that these parts 
are only capable of being observed      
separately1 and as it were piecemeal4   
,when the observations have been made1  
there is a convenience 7amounting for   
many purposes to a necessity7 in        
obtaining a representation of the       

phenomenon as a whole1 by combining1 or 
as we may say1 piecing these detached   
fragments together4 ,a navigator sailing
 in the midst of the ocean discovers    
land3 he cannot at first1 or by any one 
observation1 determine whether it is a  
continent or an island2 but he coasts   
along it1 and after a few days finds    
himself to have sailed completely round 
it3 he then pronounces it an island4    
,now there was no particular time or    
place of observation at which he could  
perceive that this land was entirely    
surrounded by water3 he ascertained the 
fact by a succession of partial         
observations1 and then selected a       
general expression which summed up in   
two or three words the whole of what he 
so observed4 ,but is there anything of  
the nature of an induction in this      
process8 ,did he infer anything that had
 not been observed1 from something else 
which had8 ,certainly not4 ,he had      
observed the whole of what the          
proposition asserts4 ,that the land in  

question is an island1 is not an        
inference from the partial facts which  
the navigator saw in the course of his  
circumnavigation2 it is the facts       
themselves2 it is a summary of those    
facts2 the description of a complex     
fact1 to which those simpler ones are as
 the parts of a whole4  ,now there is1  
,i conceive1 no difference in kind      
between this simple operation1 and that 
by which ,kepler ascertained the nature 
of the planetary orbits3 and ,kepler's  
operation1 all at least that was        
characteristic in it1 was not more an   
inductive act than that of our supposed 
navigator4  ,the object of ,kepler was  
to determine the real path described by 
each of the planets1 or let us say by   
the planet ,mars 7since it was of that  
body that he first established the two  
of his three laws which did not require 
a comparison of planets74 ,to do this   
there was no other mode than that of    
direct observation3 and all which       
observation could do was to ascertain a 

great number of the successive places of
 the planet2 or rather1 of its apparent 
places4 ,that the planet occupied       
successively all these positions1 or at 
all events1 positions which produced the
 same impressions on the eye1 and that  
it passed from one of these to another  
insensibly1 and without any apparent    
breach of continuity2 thus much the     
senses1 with the aid of the proper      
instruments1 could ascertain4 ,what     
,kepler did more than this1 was to find 
what sort of a curve these different    
points would make1 supposing them to be 
all joined together4 ,he expressed the  
whole series of the observed places of  
,mars by what ,dr4 ,whewell calls the   
general conception of an ellipse4 ,this 
operation was far from being as easy as 
that of the navigator who expressed the 
series of his observations on successive
 points of the coast by the general     
conception of an island4 ,but it is the 
very same sort of operation2 and if the 
one is not an induction but a           

description1 this must also be true of  
the other4  ,the only real induction    
concerned in the case1 consisted in     
inferring that because the observed     
places of ,mars were correctly          
represented by points in an imaginary   
ellipse1 therefore ,mars would continue 
to revolve in that same ellipse2 and in 
concluding 7before the gap had been     
filled up by further observations7 that 
the positions of the planet during the  
time which intervened between two       
observations1 must have coincided with  
the intermediate points of the curve4   
,for these were facts which had not been
 directly observed4 ,they were          
inferences from the observations2 facts 
inferred1 as distinguished from facts   
seen4 ,but these inferences were so far 
from being a part of ,kepler's          
philosophical operation1 that they had  
been drawn long before he was born4     
,astronomers had long known that the    
planets periodically returned to the    
same places4 ,when this had been        

ascertained1 there was no induction left
 for ,kepler to make1 nor did he make   
any further induction4 ,he merely       
applied his new conception to the facts 
inferred1 as he did to the facts        
observed4 ,knowing already that the     
planets continued to move in the same   
paths2 when he found that an ellipse    
correctly represented the past path1 he 
knew that it would represent the future 
path4 ,in finding a compendious         
expression for the one set of facts1 he 
found one for the other3 but he found   
the expression only1 not the inference2 
nor did he 7which is the true test of a 
general truth7 add anything to the power
 of prediction already possessed4    #d4
 ,the descriptive operation which       
enables a number of details to be summed
 up in a single proposition1 ,dr4       
,whewell1 by an aptly chosen expression1
 has termed the ,colligation of ,facts4 
,in most of his observations concerning 
that mental process ,i fully agree1 and 
would gladly transfer all that portion  

of his book into my own pages4 ,i only  
think him mistaken in setting up this   
kind of operation1 which according to   
the old and received meaning of the     
term1 is not induction at all1 as the   
type of induction generally2 and laying 
down1 throughout his work1 as principles
 of induction1 the principles of mere   
colligation4  ,dr4 ,whewell maintains   
that the general proposition which binds
 together the particular facts1 and     
makes them1 as it were1 one fact1 is not
 the mere sum of those facts1 but       
something more1 since there is          
introduced a conception of the mind1    
which did not exist in the facts        
themselves4 ,the particular facts1 says 
he1#c are not merely brought together1  
but there is a new element added to the 
combination by the very act of thought  
by which they are combined4444 ,when the
 ,greeks1 after long observing the      
motions of the planets1 saw that these  
motions might be rightly considered as  
produced by the motion of one wheel     

revolving in the inside of another      
wheel1 these wheels were creations of   
their minds1 added to the facts which   
they perceived by sense4 ,and even if   
the wheels were no longer supposed to be
 material1 but were reduced to mere     
geometrical spheres or circles1 they    
were not the less products of the mind  
alone1--something additional to the     
facts observed4 ,the same is the case in
 all other discoveries4 ,the facts are  
known1 but they are insulated and       
unconnected1 till the discoverer        
supplies from his own store a principle 
of connexion4 ,the pearls are there1 but
 they will not hang together till some  
one provides the string4  ,let me first 
remark that ,dr4 ,whewell1 in this      
passage1 blends together1               
indiscriminately1 examples of both the  
processes which ,i am endeavouring to   
distinguish from one another4 ,when the 
,greeks abandoned the supposition that  
the planetary motions were produced by  
the revolution of material wheels1 and  

fell back upon the idea of mere         
geometrical spheres or circles1 there   
was more in this change of opinion than 
the mere substitution of an ideal curve 
for a physical one4 ,there was the      
abandonment of a theory1 and the        
replacement of it by a mere description4
 ,no one would think of calling the     
doctrine of material wheels a mere      
description4 ,that doctrine was an      
attempt to point out the force by which 
the planets were acted upon1 and        
compelled to move in their orbits4 ,but 
when1 by a great step in philosophy1 the
 materiality of the wheels was          
discarded1 and the geometrical forms    
alone retained1 the attempt to account  
for the motions was given up1 and what  
was left of the theory was a mere       
description of the orbits4 ,the         
assertion that the planets were carried 
round by wheels revolving in the inside 
of other wheels1 gave place to the      
proposition1 that they moved in the same
 lines which would be traced by bodies  

so carried3 which was a mere mode of    
representing the sum of the observed    
facts2 as ,kepler's was another and a   
better mode of representing the same    
observations4  ,it is true that for     
these simply descriptive operations1 as 
well as for the erroneous inductive one1
 a conception of the mind was required4 
,the conception of an ellipse must have 
presented itself to ,kepler's mind1     
before he could identify the planetary  
orbits with it4 ,according to ,dr4      
,whewell1 the conception was something  
added to the facts4 ,he expresses       
himself as if ,kepler had put something 
into the facts by his mode of conceiving
 them4 ,but ,kepler did no such thing4  
,the ellipse was in the facts before    
,kepler recognised it2 just as the      
island was an island before it had been 
sailed round4 ,kepler did not put what  
he had conceived into the facts1 but saw
 it in them4 ,a conception implies1 and 
corresponds to1 something conceived3 and
 though the conception itself is not in 

the facts1 but in our mind1 yet if it is
 to convey any knowledge relating to    
them1 it must be a conception of        
something which really is in the facts1 
some property which they actually       
possess1 and which they would manifest  
to our senses1 if our senses were able  
to take cognizance of it4 ,if1 for      
instance1 the planet left behind it in  
space a visible track1 and if the       
observer were in a fixed position at    
such a distance from the plane of the   
orbit as would enable him to see the    
whole of it at once1 he would see it to 
be an ellipse2 and if gifted with       
appropriate instruments and powers of   
locomotion1 he could prove it to be such
 by measuring its different dimensions4 
,nay1 further3 if the track were        
visible1 and he were so placed that he  
could see all parts of it in succession1
 but not all of them at once1 he might  
be able1 by piecing together his        
successive observations1 to discover    
both that it was an ellipse and that the

 planet moved in it4 ,the case would    
then exactly resemble that of the       
navigator who discovers the land to be  
an island by sailing round it4 ,if the  
path was visible1 no one ,i think would 
dispute that to identify it with an     
ellipse is to describe it3 and ,i cannot
 see why any difference should be made  
by its not being directly an object of  
sense1 when every point in it is as     
exactly ascertained as if it were so4   
,subject to the indispensable condition 
which has just been stated1 ,i cannot   
conceive that the part which conceptions
 have in the operation of studying      
facts1 has ever been overlooked or      
undervalued4 ,no one ever disputed that 
in order to reason about anything we    
must have a conception of it2 or that   
when we include a multitude of things   
under a general expression1 there is    
implied in the expression a conception  
of something common to those things4    
,but it by no means follows that the    
conception is necessarily pre-existent1 

or constructed by the mind out of its   
own materials4 ,if the facts are rightly
 classed under the conception1 it is    
because there is in the facts themselves
 something of which the conception is   
itself a copy2 and which if we cannot   
directly perceive1 it is because of the 
limited power of our organs1 and not    
because the thing itself is not there4  
,the conception itself is often obtained
 by abstraction from the very facts     
which1 in ,dr4 ,whewell's language1 it  
is afterwards called in to connect4     
,this he himself admits1 when he        
observes1 7which he does on several     
occasions17 how great a service would be
 rendered to the science of physiology  
by the philosopher who should establish 
a precise1 tenable1 and consistent      
conception of life4#d ,such a conception
 can only be abstracted from the        
phenomena of life itself2 from the very 
facts which it is put in requisition to 
connect4 ,in other cases1 no doubt1     
instead of collecting the conception    

from the very phenomena which we are    
attempting to colligate1 we select it   
from among those which have been        
previously collected by abstraction from
 other facts4 ,in the instance of       
,kepler's laws1 the latter was the case4
 ,the facts being out of the reach of   
being observed1 in any such manner as   
would have enabled the senses to        
identify directly the path of the       
planet1 the conception requisite for    
framing a general description of that   
path could not be collected by          
abstraction from the observations       
themselves2 the mind had to supply      
hypothetically1 from among the          
conceptions it had obtained from other  
portions of its experience1 some one    
which would correctly represent the     
series of the observed facts4 ,it had to
 frame a supposition respecting the     
general course of the phenomenon1 and   
ask itself1 ,if this be the general     
description1 what will the details be8  
and then compare these with the details 

actually observed4 ,if they agreed1 the 
hypothesis would serve for a description
 of the phenomenon3 if not1 it was      
necessarily abandoned1 and another      
tried4 ,it is such a case as this which 
gives rise to the doctrine that the     
mind1 in framing the descriptions1 adds 
something of its own which it does not  
find in the facts4  ,yet it is a fact   
surely1 that the planet does describe an
 ellipse2 and a fact which we could see1
 if we had adequate visual organs and a 
suitable position4 ,not having these    
advantages1 but possessing the          
conception of an ellipse1 or 7to express
 the meaning in less technical language7
 knowing what an ellipse was1 ,kepler   
tried whether the observed places of the
 planet were consistent with such a     
path4 ,he found they were so2 and he1   
consequently1 asserted as a fact that   
the planet moved in an ellipse4 ,but    
this fact1 which ,kepler did not add to1
 but found in1 the motions of the       
planet1 namely1 that it occupied in     

succession the various points in the    
circumference of a given ellipse1 was   
the very fact1 the separate parts of    
which had been separately observed2 it  
was the sum of the different            
observations4  ,having stated this      
fundamental difference between my       
opinion and that of ,dr4 ,whewell1 ,i   
must add1 that his account of the manner
 in which a conception is selected1     
suitable to express the facts1 appears  
to me perfectly just4 ,the experience of
 all thinkers will1 ,i believe1 testify 
that the process is tentative2 that it  
consists of a succession of guesses2    
many being rejected1 until one at last  
occurs fit to be chosen4 ,we know from  
,kepler himself that before hitting upon
 the conception of an ellipse1 he tried 
nineteen other imaginary paths1 which1  
finding them inconsistent with the      
observations1 he was obliged to reject4 
,but as ,dr4 ,whewell truly says1 the   
successful hypothesis1 though a guess1  
ought generally to be called1 not a     

lucky1 but a skilful guess4 ,the guesses
 which serve to give mental unity and   
wholeness to a chaos of scattered       
particulars1 are accidents which rarely 
occur to any minds but those abounding  
in knowledge and disciplined in         
intellectual combinations4  ,how far    
this tentative method1 so indispensable 
as a means to the colligation of facts  
for purposes of description1 admits of  
application to ,induction itself1 and   
what functions belong to it in that     
department1 will be considered in the   
chapter of the present ,book which      
relates to ,hypotheses4 ,on the present 
occasion we have chiefly to distinguish 
this process of ,colligation from       
,induction properly so called2 and that 
the distinction may be made clearer1 it 
is well to advert to a curious and      
interesting remark1 which is as         
strikingly true of the former operation1
 as it appears to me unequivocally false
 of the latter4  ,in different stages of
 the progress of knowledge1 philosophers

 have employed1 for the colligation of  
the same order of facts1 different      
conceptions4 ,the early rude            
observations of the heavenly bodies1 in 
which minute precision was neither      
attained nor sought1 presented nothing  
inconsistent with the representation of 
the path of a planet as an exact circle1
 having the earth for its centre4 ,as   
observations increased in accuracy1 and 
facts were disclosed which were not     
reconcileable with this simple          
supposition2 for the colligation of     
those additional facts1 the supposition 
was varied2 and varied again and again  
as facts became more numerous and       
precise4 ,the earth was removed from the
 centre to some other point within the  
circle2 the planet was supposed to      
revolve in a smaller circle called an   
epicycle1 round an imaginary point which
 revolved in a circle round the earth3  
in proportion as observation elicited   
fresh facts contradictory to these      
representations1 other epicycles and    

other excentrics were added1 producing  
additional complication2 until at last  
,kepler swept all these circles away1   
and substituted the conception of an    
exact ellipse4 ,even this is found not  
to represent with complete correctness  
the accurate observations of the present
 day1 which disclose many slight        
deviations from an orbit exactly        
elliptical4 ,now ,dr4 ,whewell has      
remarked that these successive general  
expressions1 though apparently so       
conflicting1 were all correct3 they all 
answered the purpose of colligation2    
they all enabled the mind to represent  
to itself with facility1 and by a       
simultaneous glance1 the whole body of  
facts at the time ascertained3 each in  
its turn served as a correct description
 of the phenomena1 so far as the senses 
had up to that time taken cognizance of 
them4 ,if a necessity afterwards arose  
for discarding one of these general     
descriptions of the planet's orbit1 and 
framing a different imaginary line1 by  

which to express the series of observed 
positions1 it was because a number of   
new facts had now been added1 which it  
was necessary to combine with the old   
facts into one general description4 ,but
 this did not affect the correctness of 
the former expression1 considered as a  
general statement of the only facts     
which it was intended to represent4 ,and
 so true is this1 that1 as is well      
remarked by ,m4 ,comte1 these ancient   
generalizations1 even the rudest and    
most imperfect of them1 that of uniform 
movement in a circle1 are so far from   
being entirely false1 that they are even
 now habitually employed by astronomers 
when only a rough approximation to      
correctness is required4 ,l'astronomie  
moderne1 en dtruisant sans retour les   
hypothses primitives1 envisages comme   
lois relles du monde1 a soigneusement   
maintenu leur valeur positive et        
permanente1 la proprit de reprsenter    
commodment les phnomnes quand il s'agit 
d'une premire bauche4 ,nos ressources   

cet gard sont mme bien plus tendues1    
prcisment  cause que nous ne nous       
faisons aucune illusion sur la ralit des
 hypothses2 ce qui nous permet          
d'employer sans scrupule1 en chaque cas1
 celle que nous jugeons la plus         
avantageuse4#e  ,dr4 ,whewell's remark1 
therefore1 is philosophically correct4  
,successive expressions for the         
colligation of observed facts1 or in    
other words1 successive descriptions of 
a phenomenon as a whole1 which has been 
observed only in parts1 may1 though     
conflicting1 be all correct as far as   
they go4 ,but it would surely be absurd 
to assert this of conflicting           
inductions4  ,the scientific study of   
facts may be undertaken for three       
different purposes3 the simple          
description of the facts2 their         
explanation2 or their prediction3       
meaning by prediction1 the determination
 of the conditions under which similar  
facts may be expected again to occur4   
,to the first of these three operations 

the name of ,induction does not properly
 belong3 to the other two it does4 ,now1
 ,dr4 ,whewell's observation is true of 
the first alone4 ,considered as a mere  
description1 the circular theory of the 
heavenly motions represents perfectly   
well their general features3 and by     
adding epicycles without limit1 those   
motions1 even as now known to us1 might 
be expressed with any degree of accuracy
 that might be required4 ,the elliptical
 theory1 as a mere description1 would   
have a great advantage in point of      
simplicity1 and in the consequent       
facility of conceiving it and reasoning 
about it2 but it would not really be    
more true than the other4 ,different    
descriptions1 therefore1 may be all     
true3 but not1 surely1 different        
explanations4 ,the doctrine that the    
heavenly bodies moved by a virtue       
inherent in their celestial nature2 the 
doctrine that they were moved by impact1
 7which led to the hypothesis of        
vortices as the only impelling force    

capable of whirling bodies in circles17 
and the ,newtonian doctrine1 that they  
are moved by the composition of a       
centripetal with an original projectile 
force2 all these are explanations1      
collected by real induction from        
supposed parallel cases2 and they were  
all successively received by            
philosophers1 as scientific truths on   
the subject of the heavenly bodies4 ,can
 it be said of these1 as was said of the
 different descriptions1 that they are  
all true as far as they go8 ,is it not  
clear that only one can be true in any  
degree1 and the other two must be       
altogether false8 ,so much for          
explanations3 let us now compare        
different predictions3 the first1 that  
eclipses will occur when one planet or  
satellite is so situated as to cast its 
shadow upon another2 the second1 that   
they will occur when some great calamity
 is impending over mankind4 ,do these   
two doctrines only differ in the degree 
of their truth1 as expressing real facts

 with unequal degrees of accuracy8      
,assuredly the one is true1 and the     
other absolutely false4#f  ,in every    
way1 therefore1 it is evident that to   
explain induction as the colligation of 
facts by means of appropriate           
conceptions1 that is1 conceptions which 
will really express them1 is to confound
 mere description of the observed facts 
with inference from those facts1 and    
ascribe to the latter what is a         
characteristic property of the former4  
,there is1 however1 between ,colligation
 and ,induction1 a real correlation1    
which it is important to conceive       
correctly4 ,colligation is not always   
induction2 but induction is always      
colligation4 ,the assertion that the    
planets move in ellipses1 was but a mode
 of representing observed facts2 it was 
but a colligation2 while the assertion  
that they are drawn1 or tend1 towards   
the sun1 was the statement of a new     
fact1 inferred by induction4 ,but the   
induction1 once made1 accomplishes the  

purposes of colligation likewise4 ,it   
brings the same facts1 which ,kepler had
 connected by his conception of an      
ellipse1 under the additional conception
 of bodies acted upon by a central      
force1 and serves therefore as a new    
bond of connexion for those facts2 a new
 principle for their classification4    
,further1 the descriptions which are    
improperly confounded with induction1   
are nevertheless a necessary preparation
 for induction2 no less necessary than  
correct observation of the facts        
themselves4 ,without the previous       
colligation of detached observations by 
means of one general conception1 we     
could never have obtained any basis for 
an induction1 except in the case of     
phenomena of very limited compass4 ,we  
should not be able to affirm any        
predicates at all1 of a subject         
incapable of being observed otherwise   
than piecemeal3 much less could we      
extend those predicates by induction to 
other similar subjects4 ,induction1     

therefore1 always presupposes1 not only 
that the necessary observations are made
 with the necessary accuracy1 but also  
that the results of these observations  
are1 so far as practicable1 connected   
together by general descriptions1       
enabling the mind to represent to itself
 as wholes whatever phenomena are       
capable of being so represented4    #e4 
,dr4 ,whewell has replied at some length
 to the preceding observations1         
re-stating his opinions1 but without 7as
 far as ,i can perceive7 adding anything
 material to his former arguments4      
,since1 however1 mine have not had the  
good fortune to make any impression upon
 him1 ,i will subjoin a few remarks1    
tending to show more clearly in what our
 difference of opinion consists1 as well
 as1 in some measure1 to account for it4
  ,nearly all the definitions of        
induction1 by writers of authority1 make
 it consist in drawing inferences from  
known cases to unknown2 affirming of a  
class1 a predicate which has been found 

true of some cases belonging to the     
class2 concluding1 because some things  
have a certain property1 that other     
things which resemble them have the same
 property--or because a thing has       
manifested a property at a certain time1
 that it has and will have that property
 at other times4  ,it will scarcely be  
contended that ,kepler's operation was  
an ,induction in this sense of the term4
 ,the statement1 that ,mars moves in an 
elliptical orbit1 was no generalization 
from individual cases to a class of     
cases4 ,neither was it an extension to  
all time1 of what had been found true at
 some particular time4 ,the whole amount
 of generalization which the case       
admitted of1 was already completed1 or  
might have been so4 ,long before the    
elliptic theory was thought of1 it had  
been ascertained that the planets       
returned periodically to the same       
apparent places2 the series of these    
places was1 or might have been1         
completely determined1 and the apparent 

course of each planet marked out on the 
celestial globe in an uninterrupted     
line4 ,kepler did not extend an observed
 truth to other cases than those in     
which it had been observed3 he did not  
widen the subject of the proposition    
which expressed the observed facts4 ,the
 alteration he made was in the          
predicate4 ,instead of saying1 the      
successive places of ,mars are so and   
so1 he summed them up in the statement1 
that the successive places of ,mars are 
points in an ellipse4 ,it is true1 this 
statement1 as ,dr4 ,whewell says1 was   
not the sum of the observations merely2 
it was the sum of the observations seen 
under a new point of view4#g ,but it was
 not the sum of more than the           
observations1 as a real induction is4   
,it took in no cases but those which had
 been actually observed1 or which could 
have been inferred from the observations
 before the new point of view presented 
itself4 ,there was not that transition  
from known cases to unknown1 which      

constitutes ,induction in the original  
and acknowledged meaning of the term4   
,old definitions1 it is true1 cannot    
prevail against new knowledge3 and if   
the ,keplerian operation1 as a logical  
process1 be really identical with what  
takes place in acknowledged induction1  
the definition of induction ought to be 
so widened as to take it in2 since      
scientific language ought to adapt      
itself to the true relations which      
subsist between the things it is        
employed to designate4 ,here then it is 
that ,i am at issue with ,dr4 ,whewell4 
,he does think the operations identical4
 ,he allows of no logical process in any
 case of induction1 other than what     
there was in ,kepler's case1 namely1    
guessing until a guess is found which   
tallies with the facts2 and accordingly1
 as we shall see hereafter1 he rejects  
all canons of induction1 because it is  
not by means of them that we guess4 ,dr4
 ,whewell's theory of the logic of      
science would be very perfect if it did 

not pass over altogether the question of
 ,proof4 ,but in my apprehension there  
is such a thing as proof1 and inductions
 differ altogether from descriptions in 
their relation to that element4         
,induction is proof2 it is inferring    
something unobserved from something     
observed3 it requires1 therefore1 an    
appropriate test of proof2 and to       
provide that test1 is the special       
purpose of inductive logic4 ,when1 on   
the contrary1 we merely collate known   
observations1 and1 in ,dr4 ,whewell's   
phraseology1 connect them by means of a 
new conception2 if the conception does  
serve to connect the observations1 we   
have all we want4 ,as the proposition in
 which it is embodied pretends to no    
other truth than what it may share with 
many other modes of representing the    
same facts1 to be consistent with the   
facts is all it requires3 it neither    
needs nor admits of proof2 though it may
 serve to prove other things1 inasmuch  
as1 by placing the facts in mental      

connexion with other facts1 not         
previously seen to resemble them1 it    
assimilates the case to another class of
 phenomena1 concerning which real       
,inductions have already been made4     
,thus ,kepler's so-called law brought   
the orbit of ,mars into the class       
ellipse1 and by doing so1 proved all the
 properties of an ellipse to be true of 
the orbit3 but in this proof ,kepler's  
law supplied the minor premise1 and not 
7as is the case with real ,inductions7  
the major4  ,dr4 ,whewell calls nothing 
,induction where there is not a new     
mental conception introduced1 and       
everything induction where there is4    
,but this is to confound two very       
different things1 ,invention and ,proof4
 ,the introduction of a new conception  
belongs to ,invention3 and invention may
 be required in any operation1 but is   
the essence of none4 ,a new conception  
may be introduced for descriptive       
purposes1 and so it may for inductive   
purposes4 ,but it is so far from        

constituting induction1 that induction  
does not necessarily stand in need of   
it4 ,most inductions require no         
conception but what was present in every
 one of the particular instances on     
which the induction is grounded4 ,that  
all men are mortal is surely an         
inductive conclusion2 yet no new        
conception is introduced by it4 ,whoever
 knows that any man has died1 has all   
the conceptions involved in the         
inductive generalization4 ,but ,dr4     
,whewell considers the process of       
invention which consists in framing a   
new conception consistent with the      
facts1 to be not merely a necessary part
 of all induction1 but the whole of it4 
,the mental operation which extracts    
from a number of detached observations  
certain general characters in which the 
observed phenomena resemble one another1
 or resemble other known facts1 is what 
,bacon1 ,locke1 and most subsequent     
metaphysicians1 have understood by the  
word ,abstraction4 ,a general expression

 obtained by abstraction1 connecting    
known facts by means of common          
characters1 but without concluding from 
them to unknown1 may1 ,i think1 with    
strict logical correctness1 be termed a 
,description2 nor do ,i know in what    
other way things can ever be described4 
,my position1 however1 does not depend  
on the employment of that particular    
word2 ,i am quite content to use ,dr4   
,whewell's term ,colligation1 or the    
more general phrases1 mode of           
representing1 or of expressing1         
phenomena3 provided it be clearly seen  
that the process is not ,induction1 but 
something radically different4  ,what   
more may usefully be said on the subject
 of ,colligation1 or of the correlative 
expression invented by ,dr4 ,whewell1   
the ,explication of ,conceptions1 and   
generally on the subject of ideas and   
mental representations as connected with
 the study of facts1 will find a more   
appropriate place in the ,fourth ,book1 
on the ,operations ,subsidiary to       

,induction3 to which ,i must refer the  
reader for the removal of any difficulty
 which the present discussion may have  
left4     ,,chapter ,,iii4  ,,of ,,the  
,,ground ,,of ,,induction4    #a4       
,induction properly so called1 as       
distinguished from those mental         
operations1 sometimes though improperly 
designated by the name1 which ,i have   
attempted in the preceding chapter to   
characterize1 may1 then1 be summarily   
defined as ,generalization from         
,experience4 ,it consists in inferring  
from some individual instances in which 
a phenomenon is observed to occur1 that 
it occurs in all instances of a certain 
class2 namely1 in all which resemble the
 former1 in what are regarded as the    
material circumstances4  ,in what way   
the material circumstances are to be    
distinguished from those which are      
immaterial1 or why some of the          
circumstances are material and others   
not so1 we are not yet ready to point   
out4 ,we must first observe1 that there 

is a principle implied in the very      
statement of what ,induction is2 an     
assumption with regard to the course of 
nature and the order of the universe2   
namely1 that there are such things in   
nature as parallel cases2 that what     
happens once1 will1 under a sufficient  
degree of similarity of circumstances1  
happen again1 and not only again1 but as
 often as the same circumstances recur4 
,this1 ,i say1 is an assumption1        
involved in every case of induction4    
,and1 if we consult the actual course of
 nature1 we find that the assumption is 
warranted4 ,the universe1 so far as     
known to us1 is so constituted1 that    
whatever is true in any one case1 is    
true in all cases of a certain          
description2 the only difficulty is1 to 
find what description4  ,this universal 
fact1 which is our warrant for all      
inferences from experience1 has been    
described by different philosophers in  
different forms of language3 that the   
course of nature is uniform2 that the   

universe is governed by general laws2   
and the like4 ,one of the most usual of 
these modes of expression1 but also one 
of the most inadequate1 is that which   
has been brought into familiar use by   
the metaphysicians of the school of     
,reid and ,stewart4 ,the disposition of 
the human mind to generalize from       
experience1--a propensity considered by 
these philosophers as an instinct of our
 nature1--they usually describe under   
some such name as our intuitive         
conviction that the future will resemble
 the past4 ,now it has been well pointed
 out by ,mr4 ,bailey1#h that 7whether   
the tendency be or not an original and  
ultimate element of our nature71 ,time1 
in its modifications of past1 present1  
and future1 has no concern either with  
the belief itself1 or with the grounds  
of it4 ,we believe that fire will burn  
to-morrow1 because it burned to-day and 
yesterday2 but we believe1 on precisely 
the same grounds1 that it burned before 
we were born1 and that it burns this    

very day in ,cochin-,china4 ,it is not  
from the past to the future1 as past and
 future1 that we infer1 but from the    
known to the unknown2 from facts        
observed to facts unobserved2 from what 
we have perceived1 or been directly     
conscious of1 to what has not come      
within our experience4 ,in this last    
predicament is the whole region of the  
future2 but also the vastly greater     
portion of the present and of the past4 
,whatever be the most proper mode of    
expressing it1 the proposition that the 
course of nature is uniform1 is the     
fundamental principle1 or general axiom1
 of ,induction4 ,it would yet be a great
 error to offer this large              
generalization as any explanation of the
 inductive process4 ,on the contrary1 ,i
 hold it to be itself an instance of    
induction1 and induction by no means of 
the most obvious kind4 ,far from being  
the first induction we make1 it is one  
of the last1 or at all events one of    
those which are latest in attaining     

strict philosophical accuracy4 ,as a    
general maxim1 indeed1 it has scarcely  
entered into the minds of any but       
philosophers2 nor even by them1 as we   
shall have many opportunities of        
remarking1 have its extent and limits   
been always very justly conceived4 ,the 
truth is1 that this great generalization
 is itself founded on prior             
generalizations4 ,the obscurer laws of  
nature were discovered by means of it1  
but the more obvious ones must have been
 understood and assented to as general  
truths before it was ever heard of4 ,we 
should never have thought of affirming  
that all phenomena take place according 
to general laws1 if we had not first    
arrived1 in the case of a great         
multitude of phenomena1 at some         
knowledge of the laws themselves2 which 
could be done no otherwise than by      
induction4 ,in what sense1 then1 can a  
principle1 which is so far from being   
our earliest induction1 be regarded as  
our warrant for all the others8 ,in the 

only sense1 in which 7as we have already
 seen7 the general propositions which we
 place at the head of our reasonings    
when we throw them into syllogisms1 ever
 really contribute to their validity4   
,as ,archbishop ,whately remarks1 every 
induction is a syllogism with the major 
premise suppressed2 or 7as ,i prefer    
expressing it7 every induction may be   
thrown into the form of a syllogism1 by 
supplying a major premise4 ,if this be  
actually done1 the principle which we   
are now considering1 that of the        
uniformity of the course of nature1 will
 appear as the ultimate major premise of
 all inductions1 and will1 therefore1   
stand to all inductions in the relation 
in which1 as has been shown at so much  
length1 the major proposition of a      
syllogism always stands to the          
conclusion2 not contributing at all to  
prove it1 but being a necessary         
condition of its being proved2 since no 
conclusion is proved1 for which there   
cannot be found a true major premise4#i 

,the statement1 that the uniformity of  
the course of nature is the ultimate    
major premise in all cases of induction1
 may be thought to require some         
explanation4 ,the immediate major       
premise in every inductive argument1 it 
certainly is not4 ,of that1 ,archbishop 
,whately's must be held to be the       
correct account4 ,the induction1 ,john1 
,peter1 c4 are mortal1 therefore all    
mankind are mortal1 may1 as he justly   
says1 be thrown into a syllogism by     
prefixing as a major premise 7what is at
 any rate a necessary condition of the  
validity of the argument7 namely1 that  
what is true of ,john1 ,peter1 c4 is    
true of all mankind4 ,but how came we by
 this major premise8 ,it is not         
self-evident2 nay1 in all cases of      
unwarranted generalization1 it is not   
true4 ,how1 then1 is it arrived at8     
,necessarily either by induction or     
ratiocination2 and if by induction1 the 
process1 like all other inductive       
arguments1 may be thrown into the form  

of a syllogism4 ,this previous syllogism
 it is1 therefore1 necessary to         
construct4 ,there is1 in the long run1  
only one possible construction4 ,the    
real proof that what is true of ,john1  
,peter1 c4 is true of all mankind1 can  
only be1 that a different supposition   
would be inconsistent with the          
uniformity which we know to exist in the
 course of nature4 ,whether there would 
be this inconsistency or not1 may be a  
matter of long and delicate inquiry2 but
 unless there would1 we have no         
sufficient ground for the major of the  
inductive syllogism4 ,it hence appears1 
that if we throw the whole course of any
 inductive argument into a series of    
syllogisms1 we shall arrive by more or  
fewer steps at an ultimate syllogism1   
which will have for its major premise   
the principle1 or axiom1 of the         
uniformity of the course of nature4#aj  
,it was not to be expected that in the  
case of this axiom1 any more than of    
other axioms1 there should be unanimity 

among thinkers with respect to the      
grounds on which it is to be received as
 true4 ,i have already stated that ,i   
regard it as itself a generalization    
from experience4 ,others hold it to be a
 principle which1 antecedently to any   
verification by experience1 we are      
compelled by the constitution of our    
thinking faculty to assume as true4     
,having so recently1 and at so much     
length1 combated a similar doctrine as  
applied to the axioms of mathematics1 by
 arguments which are in a great measure 
applicable to the present case1 ,i shall
 defer the more particular discussion of
 this controverted point in regard to   
the fundamental axiom of induction1     
until a more advanced period of our     
inquiry4#aa ,at present it is of more   
importance to understand thoroughly the 
import of the axiom itself4 ,for the    
proposition1 that the course of nature  
is uniform1 possesses rather the brevity
 suitable to popular1 than the precision
 requisite in philosophical language3   

its terms require to be explained1 and a
 stricter than their ordinary           
signification given to them1 before the 
truth of the assertion can be admitted4 
#b4 ,every person's consciousness       
assures him that he does not always     
expect uniformity in the course of      
events2 he does not always believe that 
the unknown will be similar to the      
known1 that the future will resemble the
 past4 ,nobody believes that the        
succession of rain and fine weather will
 be the same in every future year as in 
the present4 ,nobody expects to have the
 same dreams repeated every night4 ,on  
the contrary1 everybody mentions it as  
something extraordinary1 if the course  
of nature is constant1 and resembles    
itself1 in these particulars4 ,to look  
for constancy where constancy is not to 
be expected1 as for instance that a day 
which has once brought good fortune will
 always be a fortunate day1 is justly   
accounted superstition4  ,the course of 
nature1 in truth1 is not only uniform1  

it is also infinitely various4 ,some    
phenomena are always seen to recur in   
the very same combinations in which we  
met with them at first2 others seem     
altogether capricious2 while some1 which
 we had been accustomed to regard as    
bound down exclusively to a particular  
set of combinations1 we unexpectedly    
find detached from some of the elements 
with which we had hitherto found them   
conjoined1 and united to others of quite
 a contrary description4 ,to an         
inhabitant of ,central ,africa1 fifty   
years ago1 no fact probably appeared to 
rest on more uniform experience than    
this1 that all human beings are black4  
,to ,europeans1 not many years ago1 the 
proposition1 ,all swans are white1      
appeared an equally unequivocal instance
 of uniformity in the course of nature4 
,further experience has proved to both  
that they were mistaken2 but they had to
 wait fifty centuries for this          
experience4 ,during that long time1     
mankind believed in an uniformity of the

 course of nature where no such         
uniformity really existed4  ,according  
to the notion which the ancients        
entertained of induction1 the foregoing 
were cases of as legitimate inference as
 any inductions whatever4 ,in these two 
instances1 in which1 the conclusion     
being false1 the ground of inference    
must have been insufficient1 there was1 
nevertheless1 as much ground for it as  
this conception of induction admitted   
of4 ,the induction of the ancients has  
been well described by ,bacon1 under the
 name of ,inductio per enumerationem    
simplicem1 ubi non reperitur instantia  
contradictoria4 ,it consists in         
ascribing the character of general      
truths to all propositions which are    
true in every instance that we happen to
 know of4 ,this is the kind of induction
 which is natural to the mind when      
unaccustomed to scientific methods4 ,the
 tendency1 which some call an instinct1 
and which others account for by         
association1 to infer the future from   

the past1 the known from the unknown1 is
 simply a habit of expecting that what  
has been found true once or several     
times1 and never yet found false1 will  
be found true again4 ,whether the       
instances are few or many1 conclusive or
 inconclusive1 does not much affect the 
matter3 these are considerations which  
occur only on reflection2 the unprompted
 tendency of the mind is to generalize  
its experience1 provided this points all
 in one direction2 provided no other    
experience of a conflicting character   
comes unsought4 ,the notion of seeking  
it1 of experimenting for it1 of         
interrogating nature 7to use ,bacon's   
expression7 is of much later growth4    
,the observation of nature1 by          
uncultivated intellects1 is purely      
passive3 they accept the facts which    
present themselves1 without taking the  
trouble of searching for more3 it is a  
superior mind only which asks itself    
what facts are needed to enable it to   
come to a safe conclusion1 and then     

looks out for these4  ,but though we    
have always a propensity to generalize  
from unvarying experience1 we are not   
always warranted in doing so4 ,before we
 can be at liberty to conclude that     
something is universally true because we
 have never known an instance to the    
contrary1 we must have reason to believe
 that if there were in nature any       
instances to the contrary1 we should    
have known of them4 ,this assurance1 in 
the great majority of cases1 we cannot  
have1 or can have only in a very        
moderate degree4 ,the possibility of    
having it1 is the foundation on which we
 shall see hereafter that induction by  
simple enumeration may in some          
remarkable cases amount practically to  
proof4#ab ,no such assurance1 however1  
can be had1 on any of the ordinary      
subjects of scientific inquiry4 ,popular
 notions are usually founded on         
induction by simple enumeration2 in     
science it carries us but a little way4 
,we are forced to begin with it2 we must

 often rely on it provisionally1 in the 
absence of means of more searching      
investigation4 ,but1 for the accurate   
study of nature1 we require a surer and 
a more potent instrument4  ,it was1     
above all1 by pointing out the          
insufficiency of this rude and loose    
conception of ,induction1 that ,bacon   
merited the title so generally awarded  
to him1 of ,founder of the ,inductive   
,philosophy4 ,the value of his own      
contributions to a more philosophical   
theory of the subject has certainly been
 exaggerated4 ,although 7along with some
 fundamental errors7 his writings       
contain1 more or less fully developed1  
several of the most important principles
 of the ,inductive ,method1 physical    
investigation has now far outgrown the  
,baconian conception of ,induction4     
,moral and political inquiry1 indeed1   
are as yet far behind that conception4  
,the current and approved modes of      
reasoning on these subjects are still of
 the same vicious description against   

which ,bacon protested2 the method      
almost exclusively employed by those    
professing to treat such matters        
inductively1 is the very inductio per   
enumerationem simplicem which he        
condemns2 and the experience which we   
hear so confidently appealed to by all  
sects1 parties1 and interests1 is still1
 in his own emphatic words1 mera        
palpatio4    #c4 ,in order to a better  
understanding of the problem which the  
logician must solve if he would         
establish a scientific theory of        
,induction1 let us compare a few cases  
of incorrect inductions with others     
which are acknowledged to be legitimate4
 ,some1 we know1 which were believed for
 centuries to be correct1 were          
nevertheless incorrect4 ,that all swans 
are white1 cannot have been a good      
induction1 since the conclusion has     
turned out erroneous4 ,the experience1  
however1 on which the conclusion rested1
 was genuine4 ,from the earliest        
records1 the testimony of the           

inhabitants of the known world was      
unanimous on the point4 ,the uniform    
experience1 therefore1 of the           
inhabitants of the known world1 agreeing
 in a common result1 without one known  
instance of deviation from that result1 
is not always sufficient to establish a 
general conclusion4  ,but let us now    
turn to an instance apparently not very 
dissimilar to this4 ,mankind were wrong1
 it seems1 in concluding that all swans 
were white3 are we also wrong1 when we  
conclude that all men's heads grow above
 their shoulders1 and never below1 in   
spite of the conflicting testimony of   
the naturalist ,pliny8 ,as there were   
black swans1 though civilized people had
 existed for three thousand years on the
 earth without meeting with them1 may   
there not also be men whose heads do    
grow beneath their shoulders1           
notwithstanding a rather less perfect   
unanimity of negative testimony from    
observers8 ,most persons would answer   
,no2 it was more credible that a bird   

should vary in its colour1 than that men
 should vary in the relative position of
 their principal organs4 ,and there is  
no doubt that in so saying they would be
 right3 but to say why they are right1  
would be impossible1 without entering   
more deeply than is usually done1 into  
the true theory of ,induction4  ,again1 
there are cases in which we reckon with 
the most unfailing confidence upon      
uniformity1 and other cases in which we 
do not count upon it at all4 ,in some we
 feel complete assurance that the future
 will resemble the past1 the unknown be 
precisely similar to the known4 ,in     
others1 however invariable may be the   
result obtained from the instances which
 have been observed1 we draw from them  
no more than a very feeble presumption  
that the like result will hold in all   
other cases4 ,that a straight line is   
the shortest distance between two       
points1 we do not doubt to be true even 
in the region of the fixed stars4 ,when 
a chemist announces the existence and   

properties of a newly-discovered        
substance1 if we confide in his         
accuracy1 we feel assured that the      
conclusions he has arrived at will hold 
universally1 though the induction be    
founded but on a single instance4 ,we do
 not withhold our assent1 waiting for a 
repetition of the experiment2 or if we  
do1 it is from a doubt whether the one  
experiment was properly made1 not       
whether if properly made it would be    
conclusive4 ,here1 then1 is a general   
law of nature1 inferred without         
hesitation from a single instance2 an   
universal proposition from a singular   
one4 ,now mark another case1 and        
contrast it with this4 ,not all the     
instances which have been observed since
 the beginning of the world1 in support 
of the general proposition that all     
crows are black1 would be deemed a      
sufficient presumption of the truth of  
the proposition1 to outweigh the        
testimony of one unexceptionable witness
 who should affirm that in some region  

of the earth not fully explored1 he had 
caught and examined a crow1 and had     
found it to be grey4  ,why is a single  
instance1 in some cases1 sufficient for 
a complete induction1 while in others1  
myriads of concurring instances1 without
 a single exception known or presumed1  
go such a very little way towards       
establishing an universal proposition8  
,whoever can answer this question knows 
more of the philosophy of logic than the
 wisest of the ancients1 and has solved 
the problem of induction4     ,,chapter 
,,iv4  ,,of ,,laws ,,of ,,nature4    #a4
 ,in the contemplation of that          
uniformity in the course of nature1     
which is assumed in every inference from
 experience1 one of the first           
observations that present themselves is1
 that the uniformity in question is not 
properly uniformity1 but uniformities4  
,the general regularity results from the
 coexistence of partial regularities4   
,the course of nature in general is     
constant1 because the course of each of 

the various phenomena that compose it is
 so4 ,a certain fact invariably occurs  
whenever certain circumstances are      
present1 and does not occur when they   
are absent2 the like is true of another 
fact2 and so on4 ,from these separate   
threads of connexion between parts of   
the great whole which we term nature1 a 
general tissue of connexion unavoidably 
weaves itself1 by which the whole is    
held together4 ,if ,a is always         
accompanied by ,d1 ,b by ,e1 and ,c by  
,f1 it follows that ,a ,b is accompanied
 by ,d ,e1 ,a ,c by ,d ,f1 ,b ,c by ,e  
,f1 and finally ,a ,b ,c by ,d ,e ,f2   
and thus the general character of       
regularity is produced1 which1 along    
with and in the midst of infinite       
diversity1 pervades all nature4  ,the   
first point1 therefore1 to be noted in  
regard to what is called the uniformity 
of the course of nature1 is1 that it is 
itself a complex fact1 compounded of all
 the separate uniformities which exist  
in respect to single phenomena4 ,these  

various uniformities1 when ascertained  
by what is regarded as a sufficient     
induction1 we call in common parlance1  
,laws of ,nature4 ,scientifically       
speaking1 that title is employed in a   
more restricted sense1 to designate the 
uniformities when reduced to their most 
simple expression4 ,thus in the         
illustration already employed1 there    
were seven uniformities2 all of which1  
if considered sufficiently certain1     
would in the more lax application of the
 term1 be called laws of nature4 ,but of
 the seven1 three alone are properly    
distinct and independent3 these being   
presupposed1 the others follow of       
course4 ,the three first1 therefore1    
according to the stricter acceptation1  
are called laws of nature2 the remainder
 not2 because they are in truth mere    
cases of the three first2 virtually     
included in them2 said1 therefore1 to   
result from them3 whoever affirms those 
three has already affirmed all the rest4
  ,to substitute real examples for      

symbolical ones1 the following are three
 uniformities1 or call them laws of     
nature3 the law that air has weight1 the
 law that pressure on a fluid is        
propagated equally in all directions1   
and the law that pressure in one        
direction1 not opposed by equal pressure
 in the contrary direction1 produces    
motion1 which does not cease until      
equilibrium is restored4 ,from these    
three uniformities we should be able to 
predict another uniformity1 namely1 the 
rise of the mercury in the ,torricellian
 tube4 ,this1 in the stricter use of the
 phrase1 is not a law of nature4 ,it is 
the result of laws of nature4 ,it is a  
case of each and every one of the three 
laws3 and is the only occurrence by     
which they could all be fulfilled4 ,if  
the mercury were not sustained in the   
barometer1 and sustained at such a      
height that the column of mercury were  
equal in weight to a column of the      
atmosphere of the same diameter2 here   
would be a case1 either of the air not  

pressing upon the surface of the mercury
 with the force which is called its     
weight1 or of the downward pressure on  
the mercury not being propagated equally
 in an upward direction1 or of a body   
pressed in one direction and not in the 
direction opposite1 either not moving in
 the direction in which it is pressed1  
or stopping before it had attained      
equilibrium4 ,if we knew1 therefore1 the
 three simple laws1 but had never tried 
the ,torricellian experiment1 we might  
deduce its result from those laws4 ,the 
known weight of the air1 combined with  
the position of the apparatus1 would    
bring the mercury within the first of   
the three inductions2 the first         
induction would bring it within the     
second1 and the second within the third1
 in the manner which we characterized in
 treating of ,ratiocination4 ,we should 
thus come to know the more complex      
uniformity1 independently of specific   
experience1 through our knowledge of the
 simpler ones from which it results2    

though1 for reasons which will appear   
hereafter1 verification by specific     
experience would still be desirable1 and
 might possibly be indispensable4       
,complex uniformities which1 like this1 
are mere cases of simpler ones1 and     
have1 therefore1 been virtually affirmed
 in affirming those1 may with propriety 
be called laws1 but can scarcely1 in the
 strictness of scientific speech1 be    
termed ,laws of ,nature4 ,it is the     
custom in science1 wherever regularity  
of any kind can be traced1 to call the  
general proposition which expresses the 
nature of that regularity1 a law2 as    
when1 in mathematics1 we speak of the   
law of decrease of the successive terms 
of a converging series4 ,but the        
expression law of nature has generally  
been employed with a sort of tacit      
reference to the original sense of the  
word law1 namely1 the expression of the 
will of a superior4 ,when1 therefore1 it
 appeared that any of the uniformities  
which were observed in nature1 would    

result spontaneously from certain other 
uniformities1 no separate act of        
creative will being supposed necessary  
for the production of the derivative    
uniformities1 these have not usually    
been spoken of as laws of nature4       
,according to one mode of expression1   
the question1 ,what are the laws of     
nature8 may be stated thus3--,what are  
the fewest and simplest assumptions1    
which being granted1 the whole existing 
order of nature would result8 ,another  
mode of stating it would be thus3 ,what 
are the fewest general propositions from
 which all the uniformities which exist 
in the universe might be deductively    
inferred8  ,every great advance which   
marks an epoch in the progress of       
science1 has consisted in a step made   
towards the solution of this problem4   
,even a simple colligation of inductions
 already made1 without any fresh        
extension of the inductive inference1 is
 already an advance in that direction4  
,when ,kepler expressed the regularity  

which exists in the observed motions of 
the heavenly bodies1 by the three       
general propositions called his laws1   
he1 in so doing1 pointed out three      
simple suppositions which1 instead of a 
much greater number1 would suffice to   
construct the whole scheme of the       
heavenly motions1 so far as it was known
 up to that time4 ,a similar and still  
greater step was made when these laws1  
which at first did not seem to be       
included in any more general truths1    
were discovered to be cases of the three
 laws of motion1 as obtaining among     
bodies which mutually tend towards one  
another with a certain force1 and have  
had a certain instantaneous impulse     
originally impressed upon them4 ,after  
this great discovery1 ,kepler's three   
propositions1 though still called laws1 
would hardly1 by any person accustomed  
to use language with precision1 be      
termed laws of nature3 that phrase would
 be reserved for the simpler and more   
general laws into which ,newton is said 

to have resolved them4  ,according to   
this language1 every well-grounded      
inductive generalization is either a law
 of nature1 or a result of laws of      
nature1 capable1 if those laws are      
known1 of being predicted from them4    
,and the problem of ,inductive ,logic   
may be summed up in two questions3 how  
to ascertain the laws of nature2 and    
how1 after having ascertained them1 to  
follow them into their results4 ,on the 
other hand1 we must not suffer ourselves
 to imagine that this mode of statement 
amounts to a real analysis1 or to       
anything but a mere verbal              
transformation of the problem2 for the  
expression1 ,laws of ,nature1 means     
nothing but the uniformities which exist
 among natural phenomena 7or1 in other  
words1 the results of induction71 when  
reduced to their simplest expression4   
,it is1 however1 something to have      
advanced so far1 as to see that the     
study of nature is the study of laws1   
not a law2 of uniformities1 in the      

plural number3 that the different       
natural phenomena have their separate   
rules or modes of taking place1 which1  
though much intermixed and entangled    
with one another1 may1 to a certain     
extent1 be studied apart3 that 7to      
resume our former metaphor7 the         
regularity which exists in nature is a  
web composed of distinct threads1 and   
only to be understood by tracing each of
 the threads separately2 for which      
purpose it is often necessary to unravel
 some portion of the web1 and exhibit   
the fibres apart4 ,the rules of         
experimental inquiry are the            
contrivances for unravelling the web4   
#b4 ,in thus attempting to ascertain the
 general order of nature by ascertaining
 the particular order of the occurrence 
of each one of the phenomena of nature1 
the most scientific proceeding can be no
 more than an improved form of that     
which was primitively pursued by the    
human understanding1 while undirected by
 science4 ,when mankind first formed the

 idea of studying phenomena according to
 a stricter and surer method than that  
which they had in the first instance    
spontaneously adopted1 they did not1    
conformably to the well-meant but       
impracticable precept of ,descartes1 set
 out from the supposition that nothing  
had been already ascertained4 ,many of  
the uniformities existing among         
phenomena are so constant1 and so open  
to observation1 as to force themselves  
upon involuntary recognition4 ,some     
facts are so perpetually and familiarly 
accompanied by certain others1 that     
mankind learnt1 as children learn1 to   
expect the one where they found the     
other1 long before they knew how to put 
their expectation into words by         
asserting1 in a proposition1 the        
existence of a connexion between those  
phenomena4 ,no science was needed to    
teach that food nourishes1 that water   
drowns1 or quenches thirst1 that the sun
 gives light and heat1 that bodies fall 
to the ground4 ,the first scientific    

inquirers assumed these and the like as 
known truths1 and set out from them to  
discover others which were unknown3 nor 
were they wrong in so doing1 subject1   
however1 as they afterwards began to    
see1 to an ulterior revision of these   
spontaneous generalizations themselves1 
when the progress of knowledge pointed  
out limits to them1 or showed their     
truth to be contingent on some          
circumstance not originally attended to4
 ,it will appear1 ,i think1 from the    
subsequent part of our inquiry1 that    
there is no logical fallacy in this mode
 of proceeding2 but we may see already  
that any other mode is rigorously       
impracticable3 since it is impossible to
 frame any scientific method of         
induction1 or test of the correctness of
 inductions1 unless on the hypothesis   
that some inductions deserving of       
reliance have been already made4  ,let  
us revert1 for instance1 to one of our  
former illustrations1 and consider why  
it is that1 with exactly the same amount

 of evidence1 both negative and         
positive1 we did not reject the         
assertion that there are black swans1   
while we should refuse credence to any  
testimony which asserted that there were
 men wearing their heads underneath     
their shoulders4 ,the first assertion   
was more credible than the latter4 ,but 
why more credible8 ,so long as neither  
phenomenon had been actually witnessed1 
what reason was there for finding the   
one harder to be believed than the      
other8 ,apparently because there is less
 constancy in the colours of animals1   
than in the general structure of their  
anatomy4 ,but how do we know this8      
,doubtless1 from experience4 ,it        
appears1 then1 that we need experience  
to inform us1 in what degree1 and in    
what cases1 or sort of cases1 experience
 is to be relied on4 ,experience must be
 consulted in order to learn from it    
under what circumstances arguments from 
it will be valid4 ,we have no ulterior  
test to which we subject experience in  

general2 but we make experience its own 
test4 ,experience testifies1 that among 
the uniformities which it exhibits or   
seems to exhibit1 some are more to be   
relied on than others2 and uniformity1  
therefore1 may be presumed1 from any    
given number of instances1 with a       
greater degree of assurance1 in         
proportion as the case belongs to a     
class in which the uniformities have    
hitherto been found more uniform4  ,this
 mode of correcting one generalization  
by means of another1 a narrower         
generalization by a wider1 which common 
sense suggests and adopts in practice1  
is the real type of scientific          
,induction4 ,all that art can do is but 
to give accuracy and precision to this  
process1 and adapt it to all varieties  
of cases1 without any essential         
alteration in its principle4  ,there are
 of course no means of applying such a  
test as that above described1 unless we 
already possess a general knowledge of  
the prevalent character of the          

uniformities existing throughout nature4
 ,the indispensable foundation1         
therefore1 of a scientific formula of   
induction1 must be a survey of the      
inductions to which mankind have been   
conducted in unscientific practice2 with
 the special purpose of ascertaining    
what kinds of uniformities have been    
found perfectly invariable1 pervading   
all nature1 and what are those which    
have been found to vary with difference 
of time1 place1 or other changeable     
circumstances4    #c4 ,the necessity of 
such a survey is confirmed by the       
consideration1 that the stronger        
inductions are the touchstone to which  
we always endeavour to bring the weaker4
 ,if we find any means of deducing one  
of the less strong inductions from      
stronger ones1 it acquires1 at once1 all
 the strength of those from which it is 
deduced2 and even adds to that strength2
 since the independent experience on    
which the weaker induction previously   
rested1 becomes additional evidence of  

the truth of the better established law 
in which it is now found to be included4
 ,we may have inferred1 from historical 
evidence1 that the uncontrolled power of
 a monarch1 of an aristocracy1 or of the
 majority1 will often be abused3 but we 
are entitled to rely on this            
generalization with much greater        
assurance when it is shown to be a      
corollary from still better established 
facts2 the very low degree of elevation 
of character ever yet attained by the   
average of mankind1 and the little      
efficacy1 for the most part1 of the     
modes of education hitherto practised1  
in maintaining the predominance of      
reason and conscience over the selfish  
propensities4 ,it is at the same time   
obvious that even these more general    
facts derive an accession of evidence   
from the testimony which history bears  
to the effects of despotism4 ,the strong
 induction becomes still stronger when a
 weaker one has been bound up with it4  
,on the other hand1 if an induction     

conflicts with stronger inductions1 or  
with conclusions capable of being       
correctly deduced from them1 then1      
unless on reconsideration it should     
appear that some of the stronger        
inductions have been expressed with     
greater universality than their evidence
 warrants1 the weaker one must give way4
 ,the opinion so long prevalent that a  
comet1 or any other unusual appearance  
in the heavenly regions1 was the        
precursor of calamities to mankind1 or  
to those at least who witnessed it2 the 
belief in the veracity of the oracles of
 ,delphi or ,dodona2 the reliance on    
astrology1 or on the weather-prophecies 
in almanacs1 were doubtless inductions  
supposed to be grounded on              
experience3#ac and faith in such        
delusions seems quite capable of holding
 out against a great multitude of       
failures1 provided it be nourished by a 
reasonable number of casual coincidences
 between the prediction and the event4  
,what has really put an end to these    

insufficient inductions1 is their       
inconsistency with the stronger         
inductions subsequently obtained by     
scientific inquiry1 respecting the      
causes on which terrestrial events      
really depend2 and where those          
scientific truths have not yet          
penetrated1 the same or similar         
delusions still prevail4  ,it may be    
affirmed as a general principle1 that   
all inductions1 whether strong or weak1 
which can be connected by ratiocination1
 are confirmatory of one another2 while 
any which lead deductively to           
consequences that are incompatible1     
become mutually each other's test1      
showing that one or other must be given 
up1 or at least more guardedly          
expressed4 ,in the case of inductions   
which confirm each other1 the one which 
becomes a conclusion from ratiocination 
rises to at least the level of certainty
 of the weakest of those from which it  
is deduced2 while in general all are    
more or less increased in certainty4    

,thus the ,torricellian experiment1     
though a mere case of three more general
 laws1 not only strengthened greatly the
 evidence on which those laws rested1   
but converted one of them 7the weight of
 the atmosphere7 from a doubtful        
generalization into a completely        
established doctrine4  ,if1 then1 a     
survey of the uniformities which have   
been ascertained to exist in nature1    
should point out some which1 as far as  
any human purpose requires certainty1   
may be considered quite certain and     
quite universal2 then by means of these 
uniformities we may be able to raise    
multitudes of other inductions to the   
same point in the scale4 ,for if we can 
show1 with respect to any inductive     
inference1 that either it must be true1 
or one of these certain and universal   
inductions must admit of an exception2  
the former generalization will attain   
the same certainty1 and indefeasibleness
 within the bounds assigned to it1 which
 are the attributes of the latter4 ,it  

will be proved to be a law2 and if not a
 result of other and simpler laws1 it   
will be a law of nature4  ,there are    
such certain and universal inductions2  
and it is because there are such1 that a
 ,logic of ,induction is possible4      
,,chapter ,v4  ,,of ,,the ,,law ,,of    
,,universal ,,causation4    #a4 ,the    
phenomena of nature exist in two        
distinct relations to one another2 that 
of simultaneity1 and that of succession4
 ,every phenomenon is related1 in an    
uniform manner1 to some phenomena that  
coexist with it1 and to some that have  
preceded and will follow it4  ,of the   
uniformities which exist among          
synchronous phenomena1 the most         
important1 on every account1 are the    
laws of number2 and next to them those  
of space1 or1 in other words1 of        
extension and figure4 ,the laws of      
number are common to synchronous and    
successive phenomena4 ,that two and two 
make four1 is equally true whether the  
second two follow the first two or      

accompany them4 ,it is as true of days  
and years as of feet and inches4 ,the   
laws of extension and figure 7in other  
words1 the theorems of geometry1 from   
its lowest to its highest branches7 are1
 on the contrary1 laws of simultaneous  
phenomena only4 ,the various parts of   
space1 and of the objects which are said
 to fill space1 coexist2 and the        
unvarying laws which are the subject of 
the science of geometry1 are an         
expression of the mode of their         
coexistence4  ,this is a class of laws1 
or in other words1 of uniformities1 for 
the comprehension and proof of which it 
is not necessary to suppose any lapse of
 time1 any variety of facts or events   
succeeding one another4 ,if all the     
objects in the universe were            
unchangeably fixed1 and had remained in 
that condition from eternity1 the       
propositions of geometry would still be 
true of those objects4 ,all things which
 possess extension1 or1 in other words1 
which fill space1 are subject to        

geometrical laws4 ,possessing extension1
 they possess figure2 possessing figure1
 they must possess some figure in       
particular1 and have all the properties 
which geometry assigns to that figure4  
,if one body be a sphere and another a  
cylinder1 of equal height and diameter1 
the one will be exactly two-thirds of   
the other1 let the nature and quality of
 the material be what it will4 ,again1  
each body1 and each point of a body1    
must occupy some place or position among
 other bodies2 and the position of two  
bodies relatively to each other1 of     
whatever nature the bodies be1 may be   
unerringly inferred from the position of
 each of them relatively to any third   
body4  ,in the laws of number1 then1 and
 in those of space1 we recognise in the 
most unqualified manner1 the rigorous   
universality of which we are in quest4  
,those laws have been in all ages the   
type of certainty1 the standard of      
comparison for all inferior degrees of  
evidence4 ,their invariability is so    

perfect1 that it renders us unable even 
to conceive any exception to them2 and  
philosophers have been led1 though 7as  
,i have endeavoured to show7            
erroneously1 to consider their evidence 
as lying not in experience1 but in the  
original constitution of the intellect4 
,if therefore1 from the laws of space   
and number1 we were able to deduce      
uniformities of any other description1  
this would be conclusive evidence to us 
that those other uniformities possessed 
the same rigorous certainty4 ,but this  
we cannot do4 ,from laws of space and   
number alone1 nothing can be deduced but
 laws of space and number4  ,of all     
truths relating to phenomena1 the most  
valuable to us are those which relate to
 the order of their succession4 ,on a   
knowledge of these is founded every     
reasonable anticipation of future facts1
 and whatever power we possess of       
influencing those facts to our          
advantage4 ,even the laws of geometry   
are chiefly of practical importance to  

us as being a portion of the premises   
from which the order of the succession  
of phenomena may be inferred4 ,inasmuch 
as the motion of bodies1 the action of  
forces1 and the propagation of          
influences of all sorts1 take place in  
certain lines and over definite spaces1 
the properties of those lines and spaces
 are an important part of the laws to   
which those phenomena are themselves    
subject4 ,again1 motions1 forces or     
other influences1 and times1 are        
numerable quantities2 and the properties
 of number are applicable to them as to 
all other things4 ,but though the laws  
of number and space are important       
elements in the ascertainment of        
uniformities of succession1 they can do 
nothing towards it when taken by        
themselves4 ,they can only be made      
instrumental to that purpose when we    
combine with them additional premises1  
expressive of uniformities of succession
 already known4 ,by taking1 for         
instance1 as premises these             

propositions1 that bodies acted upon by 
an instantaneous force move with uniform
 velocity in straight lines2 that bodies
 acted upon by a continuous force move  
with accelerated velocity in straight   
lines2 and that bodies acted upon by two
 forces in different directions move in 
the diagonal of a parallelogram1 whose  
sides represent the direction and       
quantity of those forces2 we may by     
combining these truths with propositions
 relating to the properties of straight 
lines and of parallelograms1 7as that a 
triangle is half a parallelogram of the 
same base and altitude17 deduce another 
important uniformity of succession1     
viz41 that a body moving round a centre 
of force describes areas proportional to
 the times4 ,but unless there had been  
laws of succession in our premises1     
there could have been no truths of      
succession in our conclusions4 ,a       
similar remark might be extended to     
every other class of phenomena really   
peculiar2 and1 had it been attended to1 

would have prevented many chimerical    
attempts at demonstrations of the       
indemonstrable1 and explanations which  
do not explain4  ,it is not1 therefore1 
enough for us that the laws of space1   
which are only laws of simultaneous     
phenomena1 and the laws of number1 which
 though true of successive phenomena do 
not relate to their succession1 possess 
the rigorous certainty and universality 
of which we are in search4 ,we must     
endeavour to find some law of succession
 which has those same attributes1 and is
 therefore fit to be made the foundation
 of processes for discovering1 and of a 
test for verifying1 all other           
uniformities of succession4 ,this       
fundamental law must resemble the truths
 of geometry in their most remarkable   
peculiarity1 that of never being1 in any
 instance whatever1 defeated or         
suspended by any change of              
circumstances4  ,now among all those    
uniformities in the succession of       
phenomena1 which common observation is  

sufficient to bring to light1 there are 
very few which have any1 even apparent1 
pretension to this rigorous             
indefeasibility3 and of those few1 one  
only has been found capable of          
completely sustaining it4 ,in that one1 
however1 we recognise a law which is    
universal also in another sense2 it is  
coextensive with the entire field of    
successive phenomena1 all instances     
whatever of succession being examples of
 it4 ,this law is the ,law of           
,causation4 ,the truth that every fact  
which has a beginning has a cause1 is   
coextensive with human experience4      
,this generalization may appear to some 
minds not to amount to much1 since after
 all it asserts only this3 it is a law2 
that every event depends on some law3 it
 is a law1 that there is a law for      
everything4 ,we must not1 however1      
conclude that the generality of the     
principle is merely verbal2 it will be  
found on inspection to be no vague or   
unmeaning assertion1 but a most         

important and really fundamental truth4 
#b4 ,the notion of ,cause being the root
 of the whole theory of ,induction1 it  
is indispensable that this idea should1 
at the very outset of our inquiry1 be1  
with the utmost practicable degree of   
precision1 fixed and determined4 ,if1   
indeed1 it were necessary for the       
purpose of inductive logic that the     
strife should be quelled1 which has so  
long raged among the different schools  
of metaphysicians1 respecting the origin
 and analysis of our idea of causation2 
the promulgation1 or at least the       
general reception1 of a true theory of  
induction1 might be considered desperate
 for a long time to come4 ,but the      
science of the ,investigation of ,truth 
by means of ,evidence1 is happily       
independent of many of the controversies
 which perplex the science of the       
ultimate constitution of the human mind1
 and is under no necessity of pushing   
the analysis of mental phenomena to that
 extreme limit which alone ought to     

satisfy a metaphysician4  ,i premise1   
then1 that when in the course of this   
inquiry ,i speak of the cause of any    
phenomenon1 ,i do not mean a cause which
 is not itself a phenomenon2 ,i make no 
research into the ultimate or           
ontological cause of anything4 ,to adopt
 a distinction familiar in the writings 
of the ,scotch metaphysicians1 and      
especially of ,reid1 the causes with    
which ,i concern myself are not         
efficient1 but physical causes4 ,they   
are causes in that sense alone1 in which
 one physical fact is said to be the    
cause of another4 ,of the efficient     
causes of phenomena1 or whether any such
 causes exist at all1 ,i am not called  
upon to give an opinion4 ,the notion of 
causation is deemed1 by the schools of  
metaphysics most in vogue at the present
 moment1 to imply a mysterious and most 
powerful tie1 such as cannot1 or at     
least does not1 exist between any       
physical fact and that other physical   
fact on which it is invariably          

consequent1 and which is popularly      
termed its cause3 and thence is deduced 
the supposed necessity of ascending     
higher1 into the essences and inherent  
constitution of things1 to find the true
 cause1 the cause which is not only     
followed by1 but actually produces1 the 
effect4 ,no such necessity exists for   
the purposes of the present inquiry1 nor
 will any such doctrine be found in the 
following pages4 ,the only notion of a  
cause1 which the theory of induction    
requires1 is such a notion as can be    
gained from experience4 ,the ,law of    
,causation1 the recognition of which is 
the main pillar of inductive science1 is
 but the familiar truth1 that           
invariability of succession is found by 
observation to obtain between every fact
 in nature and some other fact which has
 preceded it2 independently of all      
consideration respecting the ultimate   
mode of production of phenomena1 and of 
every other question regarding the      
nature of ,things in themselves4        

,between the phenomena1 then1 which     
exist at any instant1 and the phenomena 
which exist at the succeeding instant1  
there is an invariable order of         
succession2 and1 as we said in speaking 
of the general uniformity of the course 
of nature1 this web is composed of      
separate fibres2 this collective order  
is made up of particular sequences1     
obtaining invariably among the separate 
parts4 ,to certain facts1 certain facts 
always do1 and1 as we believe1 will     
continue to1 succeed4 ,the invariable   
antecedent is termed the cause2 the     
invariable consequent1 the effect4 ,and 
the universality of the law of causation
 consists in this1 that every consequent
 is connected in this manner with some  
particular antecedent1 or set of        
antecedents4 ,let the fact be what it   
may1 if it has begun to exist1 it was   
preceded by some fact or facts1 with    
which it is invariably connected4 ,for  
every event there exists some           
combination of objects or events1 some  

given concurrence of circumstances1     
positive and negative1 the occurrence of
 which is always followed by that       
phenomenon4 ,we may not have found out  
what this concurrence of circumstances  
may be2 but we never doubt that there is
 such a one1 and that it never occurs   
without having the phenomenon in        
question as its effect or consequence4  
,on the universality of this truth      
depends the possibility of reducing the 
inductive process to rules4 ,the        
undoubted assurance we have that there  
is a law to be found if we only knew how
 to find it1 will be seen presently to  
be the source from which the canons of  
the ,inductive ,logic derive their      
validity4    #c4 ,it is seldom1 if ever1
 between a consequent and a single      
antecedent1 that this invariable        
sequence subsists4 ,it is usually       
between a consequent and the sum of     
several antecedents2 the concurrence of 
all of them being requisite to produce1 
that is1 to be certain of being followed

 by1 the consequent4 ,in such cases it  
is very common to single out one only of
 the antecedents under the denomination 
of ,cause1 calling the others merely    
,conditions4 ,thus1 if a person eats of 
a particular dish1 and dies in          
consequence1 that is1 would not have    
died if he had not eaten of it1 people  
would be apt to say that eating of that 
dish was the cause of his death4 ,there 
needs not1 however1 be any invariable   
connexion between eating of the dish and
 death2 but there certainly is1 among   
the circumstances which took place1 some
 combination or other on which death is 
invariably consequent3 as1 for instance1
 the act of eating of the dish1 combined
 with a particular bodily constitution1 
a particular state of present health1   
and perhaps even a certain state of the 
atmosphere2 the whole of which          
circumstances perhaps constituted in    
this particular case the conditions of  
the phenomenon1 or1 in other words1 the 
set of antecedents which determined it1 

and but for which it would not have     
happened4 ,the real ,cause1 is the whole
 of these antecedents2 and we have1     
philosophically speaking1 no right to   
give the name of cause to one of them1  
exclusively of the others4 ,what1 in the
 case we have supposed1 disguises the   
incorrectness of the expression1 is     
this3 that the various conditions1      
except the single one of eating the     
food1 were not events 7that is1         
instantaneous changes1 or successions of
 instantaneous changes7 but states1     
possessing more or less of permanency2  
and might therefore have preceded the   
effect by an indefinite length of       
duration1 for want of the event which   
was requisite to complete the required  
concurrence of conditions3 while as soon
 as that event1 eating the food1 occurs1
 no other cause is waited for1 but the  
effect begins immediately to take place3
 and hence the appearance is presented  
of a more immediate and close connexion 
between the effect and that one         

antecedent1 than between the effect and 
the remaining conditions4 ,but though we
 may think proper to give the name of   
cause to that one condition1 the        
fulfilment of which completes the tale1 
and brings about the effect without     
further delay2 this condition has really
 no closer relation to the effect than  
any of the other conditions has4 ,the   
production of the consequent required   
that they should all exist immediately  
previous1 though not that they should   
all begin to exist immediately previous4
 ,the statement of the cause is         
incomplete1 unless in some shape or     
other we introduce all the conditions4  
,a man takes mercury1 goes out of doors1
 and catches cold4 ,we say1 perhaps1    
that the cause of his taking cold was   
exposure to the air4 ,it is clear1      
however1 that his having taken mercury  
may have been a necessary condition of  
catching cold2 and though it might      
consist with usage to say that the cause
 of his attack was exposure to the air1 

to be accurate we ought to say that the 
cause was exposure to the air while     
under the effect of mercury4  ,if we do 
not1 when aiming at accuracy1 enumerate 
all the conditions1 it is only because  
some of them will in most cases be      
understood without being expressed1 or  
because for the purpose in view they may
 without detriment be overlooked4 ,for  
example1 when we say1 the cause of a    
man's death was that his foot slipped in
 climbing a ladder1 we omit as a thing  
unnecessary to be stated the            
circumstance of his weight1 though quite
 as indispensable a condition of the    
effect which took place4 ,when we say   
that the assent of the crown to a bill  
makes it law1 we mean that the assent1  
being never given until all the other   
conditions are fulfilled1 makes up the  
sum of the conditions1 though no one now
 regards it as the principal one4 ,when 
the decision of a legislative assembly  
has been determined by the casting vote 
of the chairman1 we sometimes say that  

this one person was the cause of all the
 effects which resulted from the        
enactment4 ,yet we do not really suppose
 that his single vote contributed more  
to the result than that of any other    
person who voted in the affirmative2    
but1 for the purpose we have in view1   
which is to insist on his individual    
responsibility1 the part which any other
 person had in the transaction is not   
material4  ,in all these instances the  
fact which was dignified with the name  
of cause1 was the one condition which   
came last into existence4 ,but it must  
not be supposed that in the employment  
of the term this or any other rule is   
always adhered to4 ,nothing can better  
show the absence of any scientific      
ground for the distinction between the  
cause of a phenomenon and its           
conditions1 than the capricious manner  
in which we select from among the       
conditions that which we choose to      
denominate the cause4 ,however numerous 
the conditions may be1 there is hardly  

any of them which may not1 according to 
the purpose of our immediate discourse1 
obtain that nominal pre-eminence4 ,this 
will be seen by analysing the conditions
 of some one familiar phenomenon4 ,for  
example1 a stone thrown into water falls
 to the bottom4 ,what are the conditions
 of this event8 ,in the first place     
there must be a stone1 and water1 and   
the stone must be thrown into the water2
 but these suppositions forming part of 
the enunciation of the phenomenon       
itself1 to include them also among the  
conditions would be a vicious tautology2
 and this class of conditions1          
therefore1 have never received the name 
of cause from any but the               
,aristotelians1 by whom they were called
 the material cause1 causa materialis4  
,the next condition is1 there must be an
 earth3 and accordingly it is often     
said1 that the fall of a stone is caused
 by the earth2 or by a power or property
 of the earth1 or a force exerted by the
 earth1 all of which are merely         

roundabout ways of saying that it is    
caused by the earth2 or1 lastly1 the    
earth's attraction2 which also is only a
 technical mode of saying that the earth
 causes the motion1 with the additional 
particularity that the motion is towards
 the earth1 which is not a character of 
the cause1 but of the effect4 ,let us   
now pass to another condition4 ,it is   
not enough that the earth should exist2 
the body must be within that distance   
from it1 in which the earth's attraction
 preponderates over that of any other   
body4 ,accordingly we may say1 and the  
expression would be confessedly correct1
 that the cause of the stone's falling  
is its being within the sphere of the   
earth's attraction4 ,we proceed to a    
further condition4 ,the stone is        
immersed in water3 it is therefore a    
condition of its reaching the ground1   
that its specific gravity exceed that of
 the surrounding fluid1 or in other     
words that it surpass in weight an equal
 volume of water4 ,accordingly any one  

would be acknowledged to speak correctly
 who said1 that the cause of the stone's
 going to the bottom is its exceeding in
 specific gravity the fluid in which it 
is immersed4  ,thus we see that each and
 every condition of the phenomenon may  
be taken in its turn1 and1 with equal   
propriety in common parlance1 but with  
equal impropriety in scientific         
discourse1 may be spoken of as if it    
were the entire cause4 ,and in practice1
 that particular condition is usually   
styled the cause1 whose share in the    
matter is superficially the most        
conspicuous1 or whose requisiteness to  
the production of the effect we happen  
to be insisting on at the moment4 ,so   
great is the force of this last         
consideration1 that it sometimes induces
 us to give the name of cause even to   
one of the negative conditions4 ,we say1
 for example1 ,the army was surprised   
because the sentinel was off his post4  
,but since the sentinel's absence was   
not what created the enemy1 or put the  

soldiers asleep1 how did it cause them  
to be surprised8 ,all that is really    
meant is1 that the event would not have 
happened if he had been at his duty4    
,his being off his post was no producing
 cause1 but the mere absence of a       
preventing cause3 it was simply         
equivalent to his non-existence4 ,from  
nothing1 from a mere negation1 no       
consequences can proceed4 ,all effects  
are connected1 by the law of causation1 
with some set of positive conditions2   
negative ones1 it is true1 being almost 
always required in addition4 ,in other  
words1 every fact or phenomenon which   
has a beginning1 invariably arises when 
some certain combination of positive    
facts exists1 provided certain other    
positive facts do not exist4  ,there is1
 no doubt1 a tendency 7which our first  
example1 that of death from taking a    
particular food1 sufficiently           
illustrates7 to associate the idea of   
causation with the proximate antecedent 
event1 rather than with any of the      

antecedent states1 or permanent facts1  
which may happen also to be conditions  
of the phenomenon2 the reason being that
 the event not only exists1 but begins  
to exist immediately previous2 while the
 other conditions may have pre-existed  
for an indefinite time4 ,and this       
tendency shows itself very visibly in   
the different logical fictions which are
 resorted to1 even by men of science1 to
 avoid the necessity of giving the name 
of cause to anything which had existed  
for an indeterminate length of time     
before the effect4 ,thus1 rather than   
say that the earth causes the fall of   
bodies1 they ascribe it to a force      
exerted by the earth1 or an attraction  
by the earth1 abstractions which they   
can represent to themselves as exhausted
 by each effort1 and therefore          
constituting at each successive instant 
a fresh fact1 simultaneous with1 or only
 immediately preceding1 the effect4     
,inasmuch as the coming of the          
circumstance which completes the        

assemblage of conditions1 is a change or
 event1 it thence happens that an event 
is always the antecedent in closest     
apparent proximity to the consequent3   
and this may account for the illusion   
which disposes us to look upon the      
proximate event as standing more        
peculiarly in the position of a cause   
than any of the antecedent states4 ,but 
even this peculiarity1 of being in      
closer proximity to the effect than any 
other of its conditions1 is1 as we have 
already seen1 far from being necessary  
to the common notion of a cause2 with   
which notion1 on the contrary1 any one  
of the conditions1 either positive or   
negative1 is found1 on occasion1        
completely to accord4#ad  ,the cause1   
then1 philosophically speaking1 is the  
sum total of the conditions1 positive   
and negative taken together2 the whole  
of the contingencies of every           
description1 which being realized1 the  
consequent invariably follows4 ,the     
negative conditions1 however1 of any    

phenomenon1 a special enumeration of    
which would generally be very prolix1   
may be all summed up under one head1    
namely1 the absence of preventing or    
counteracting causes4 ,the convenience  
of this mode of expression is mainly    
grounded on the fact1 that the effects  
of any cause in counteracting another   
cause may in most cases be1 with strict 
scientific exactness1 regarded as a mere
 extension of its own proper and        
separate effects4 ,if gravity retards   
the upward motion of a projectile1 and  
deflects it into a parabolic trajectory1
 it produces1 in so doing1 the very same
 kind of effect1 and even 7as           
mathematicians know7 the same quantity  
of effect1 as it does in its ordinary   
operation of causing the fall of bodies 
when simply deprived of their support4  
,if an alkaline solution mixed with an  
acid destroys its sourness1 and prevents
 it from reddening vegetable blues1 it  
is because the specific effect of the   
alkali is to combine with the acid1 and 

form a compound with totally different  
qualities4 ,this property1 which causes 
of all descriptions possess1 of         
preventing the effects of other causes  
by virtue 7for the most part7 of the    
same laws according to which they       
produce their own1#ae enables us1 by    
establishing the general axiom that all 
causes are liable to be counteracted in 
their effects by one another1 to        
dispense with the consideration of      
negative conditions entirely1 and limit 
the notion of cause to the assemblage of
 the positive conditions of the         
phenomenon3 one negative condition      
invariably understood1 and the same in  
all instances 7namely1 the absence of   
counteracting causes7 being sufficient1 
along with the sum of the positive      
conditions1 to make up the whole set of 
circumstances on which the phenomenon is
 dependent4    #d4 ,among the positive  
conditions1 as we have seen that there  
are some to which1 in common parlance1  
the term cause is more readily and      

frequently awarded1 so there are others 
to which it is1 in ordinary             
circumstances1 refused4 ,in most cases  
of causation a distinction is commonly  
drawn between something which acts1 and 
some other thing which is acted upon2   
between an agent and a patient4 ,both of
 these1 it would be universally allowed1
 are conditions of the phenomenon2 but  
it would be thought absurd to call the  
latter the cause1 that title being      
reserved for the former4 ,the           
distinction1 however1 vanishes on       
examination1 or rather is found to be   
only verbal2 arising from an incident of
 mere expression1 namely1 that the      
object said to be acted upon1 and which 
is considered as the scene in which the 
effect takes place1 is commonly included
 in the phrase by which the effect is   
spoken of1 so that if it were also      
reckoned as part of the cause1 the      
seeming incongruity would arise of its  
being supposed to cause itself4 ,in the 
instance which we have already had1 of  

falling bodies1 the question was thus   
put3 ,what is the cause which makes a   
stone fall8 and if the answer had been  
the stone itself1 the expression would  
have been in apparent contradiction to  
the meaning of the word cause4 ,the     
stone1 therefore1 is conceived as the   
patient1 and the earth 7or1 according to
 the common and most unphilosophical    
practice1 some occult quality of the    
earth7 is represented as the agent or   
cause4 ,but that there is nothing       
fundamental in the distinction may be   
seen from this1 that it is quite        
possible to conceive the stone as       
causing its own fall1 provided the      
language employed be such as to save the
 mere verbal incongruity4 ,we might say 
that the stone moves towards the earth  
by the properties of the matter         
composing it2 and according to this mode
 of presenting the phenomenon1 the stone
 itself might without impropriety be    
called the agent2 though1 to save the   
established doctrine of the inactivity  

of matter1 men usually prefer here also 
to ascribe the effect to an occult      
quality1 and say that the cause is not  
the stone itself1 but the weight or     
gravitation of the stone4  ,those who   
have contended for a radical distinction
 between agent and patient1 have        
generally conceived the agent as that   
which causes some state of1 or some     
change in the state of1 another object  
which is called the patient4 ,but a     
little reflection will show that the    
licence we assume of speaking of        
phenomena as states of the various      
objects which take part in them1 7an    
artifice of which so much use has been  
made by some philosophers1 ,brown in    
particular1 for the apparent explanation
 of phenomena17 is simply a sort of     
logical fiction1 useful sometimes as one
 among several modes of expression1 but 
which should never be supposed to be the
 enunciation of a scientific truth4     
,even those attributes of an object     
which might seem with greatest propriety

 to be called states of the object      
itself1 its sensible qualities1 its     
colour1 hardness1 shape1 and the like1  
are in reality 7as no one has pointed   
out more clearly than ,brown himself7   
phenomena of causation1 in which the    
substance is distinctly the agent1 or   
producing cause1 the patient being our  
own organs1 and those of other sentient 
beings4 ,what we call states of objects1
 are always sequences into which the    
objects enter1 generally as antecedents 
or causes2 and things are never more    
active than in the production of those  
phenomena in which they are said to be  
acted upon4 ,thus1 in the example of a  
stone falling to the earth1 according to
 the theory of gravitation the stone is 
as much an agent as the earth1 which not
 only attracts1 but is itself attracted 
by1 the stone4 ,in the case of a        
sensation produced in our organs1 the   
laws of our organization1 and even those
 of our minds1 are as directly operative
 in determining the effect produced1 as 

the laws of the outward object4 ,though 
we call prussic acid the agent of a     
person's death1 the whole of the vital  
and organic properties of the patient   
are as actively instrumental as the     
poison1 in the chain of effects which so
 rapidly terminates his sentient        
existence4 ,in the process of education1
 we may call the teacher the agent1 and 
the scholar only the material acted     
upon2 yet in truth all the facts which  
pre-existed in the scholar's mind exert 
either co-operating or counteracting    
agencies in relation to the teacher's   
efforts4 ,it is not light alone which is
 the agent in vision1 but light coupled 
with the active properties of the eye   
and brain1 and with those of the visible
 object4 ,the distinction between agent 
and patient is merely verbal3 patients  
are always agents2 in a great           
proportion1 indeed1 of all natural      
phenomena1 they are so to such a degree 
as to react forcibly on the causes which
 acted upon them3 and even when this is 

not the case1 they contribute1 in the   
same manner as any of the other         
conditions1 to the production of the    
effect of which they are vulgarly       
treated as the mere theatre4 ,all the   
positive conditions of a phenomenon are 
alike agents1 alike active2 and in any  
expression of the cause which professes 
to be complete1 none of them can with   
reason be excluded1 except such as have 
already been implied in the words used  
for describing the effect2 nor by       
including even these would there be     
incurred any but a merely verbal        
impropriety4    #e4 ,it now remains to  
advert to a distinction which is of     
first-rate importance both for clearing 
up the notion of cause1 and for         
obviating a very specious objection     
often made against the view which we    
have taken of the subject4  ,when we    
define the cause of anything 7in the    
only sense in which the present inquiry 
has any concern with causes7 to be the  
antecedent which it invariably follows1 

we do not use this phrase as exactly    
synonymous with the antecedent which it 
invariably has followed in our past     
experience4 ,such a mode of conceiving  
causation would be liable to the        
objection very plausibly urged by ,dr4  
,reid1 namely1 that according to this   
doctrine night must be the cause of day1
 and day the cause of night2 since these
 phenomena have invariably succeeded one
 another from the beginning of the      
world4 ,but it is necessary to our using
 the word cause1 that we should believe 
not only that the antecedent always has 
been followed by the consequent1 but    
that1 as long as the present            
constitution of things#af endures1 it   
always will be so4 ,and this would not  
be true of day and night4 ,we do not    
believe that night will be followed by  
day under all imaginable circumstances1 
but only that it will be so provided the
 sun rises above the horizon4 ,if the   
sun ceased to rise1 which1 for aught we 
know1 may be perfectly compatible with  

the general laws of matter1 night would 
be1 or might be1 eternal4 ,on the other 
hand1 if the sun is above the horizon1  
his light not extinct1 and no opaque    
body between us and him1 we believe     
firmly that unless a change takes place 
in the properties of matter1 this       
combination of antecedents will be      
followed by the consequent1 day2 that if
 the combination of antecedents could be
 indefinitely prolonged1 it would be    
always day2 and that if the same        
combination had always existed1 it would
 always have been day1 quite            
independently of night as a previous    
condition4 ,therefore is it that we do  
not call night the cause1 nor even a    
condition1 of day4 ,the existence of the
 sun 7or some such luminous body71 and  
there being no opaque medium in a       
straight line#ag between that body and  
the part of the earth where we are      
situated1 are the sole conditions2 and  
the union of these1 without the addition
 of any superfluous circumstance1       

constitutes the cause4 ,this is what    
writers mean when they say that the     
notion of cause involves the idea of    
necessity4 ,if there be any meaning     
which confessedly belongs to the term   
necessity1 it is unconditionalness4     
,that which is necessary1 that which    
must be1 means that which will be1      
whatever supposition we may make in     
regard to all other things4 ,the        
succession of day and night evidently is
 not necessary in this sense4 ,it is    
conditional on the occurrence of other  
antecedents4 ,that which will be        
followed by a given consequent when1 and
 only when1 some third circumstance also
 exists1 is not the cause1 even though  
no case should ever have occurred in    
which the phenomenon took place without 
it4  ,invariable sequence1 therefore1 is
 not synonymous with causation1 unless  
the sequence1 besides being invariable1 
is unconditional4 ,there are sequences1 
as uniform in past experience as any    
others whatever1 which yet we do not    

regard as cases of causation1 but as    
conjunctions in some sort accidental4   
,such1 to an accurate thinker1 is that  
of day and night4 ,the one might have   
existed for any length of time1 and the 
other not have followed the sooner for  
its existence2 it follows only if       
certain other antecedents exist2 and    
where those antecedents existed1 it     
would follow in any case4 ,no one1      
probably1 ever called night the cause of
 day2 mankind must so soon have arrived 
at the very obvious generalization1 that
 the state of general illumination which
 we call day would follow from the      
presence of a sufficiently luminous     
body1 whether darkness had preceded or  
not4  ,we may define1 therefore1 the    
cause of a phenomenon1 to be the        
antecedent1 or the concurrence of       
antecedents1 on which it is invariably  
and unconditionally consequent4 ,or if  
we adopt the convenient modification of 
the meaning of the word cause1 which    
confines it to the assemblage of        

positive conditions without the         
negative1 then instead of               
unconditionally1 we must say1 subject to
 no other than negative conditions4  ,to
 some it may appear1 that the sequence  
between night and day being invariable  
in our experience1 we have as much      
ground in this case as experience can   
give in any case1 for recognising the   
two phenomena as cause and effect2 and  
that to say that more is necessary--to  
require a belief that the succession is 
unconditional1 or in other words that it
 would be invariable under all changes  
of circumstances1 is to acknowledge in  
causation an element of belief not      
derived from experience4 ,the answer to 
this is1 that it is experience itself   
which teaches us that one uniformity of 
sequence is conditional and another     
unconditional4 ,when we judge that the  
succession of night and day is a        
derivative sequence1 depending on       
something else1 we proceed on grounds of
 experience4 ,it is the evidence of     

experience which convinces us that day  
could equally exist without being       
followed by night1 and that night could 
equally exist without being followed by 
day4 ,to say that these beliefs are not 
generated by our mere observation of    
sequence1#ah is to forget that twice in 
every twenty-four hours1 when the sky is
 clear1 we have an experimentum crucis  
that the cause of day is the sun4 ,we   
have an experimental knowledge of the   
sun which justifies us on experimental  
grounds in concluding1 that if the sun  
were always above the horizon there     
would be day1 though there had been no  
night1 and that if the sun were always  
below the horizon there would be night1 
though there had been no day4 ,we thus  
know from experience that the succession
 of night and day is not unconditional4 
,let me add1 that the antecedent which  
is only conditionally invariable1 is not
 the invariable antecedent4 ,though a   
fact may1 in experience1 have always    
been followed by another fact1 yet if   

the remainder of our experience teaches 
us that it might not always be so       
followed1 or if the experience itself is
 such as leaves room for a possibility  
that the known cases may not correctly  
represent all possible cases1 the       
hitherto invariable antecedent is not   
accounted the cause2 but why8 ,because  
we are not sure that it is the          
invariable antecedent4  ,such cases of  
sequence as that of day and night not   
only do not contradict the doctrine     
which resolves causation into invariable
 sequence1 but are necessarily implied  
in that doctrine4 ,it is evident1 that  
from a limited number of unconditional  
sequences1 there will result a much     
greater number of conditional ones4     
,certain causes being given1 that is1   
certain antecedents which are           
unconditionally followed by certain     
consequents2 the mere coexistence of    
these causes will give rise to an       
unlimited number of additional          
uniformities4 ,if two causes exist      

together1 the effects of both will exist
 together2 and if many causes coexist1  
these causes 7by what we shall term     
hereafter the intermixture of their     
laws7 will give rise to new effects1    
accompanying or succeeding one another  
in some particular order1 which order   
will be invariable while the causes     
continue to coexist1 but no longer4 ,the
 motion of the earth in a given orbit   
round the sun1 is a series of changes   
which follow one another as antecedents 
and consequents1 and will continue to do
 so while the sun's attraction1 and the 
force with which the earth tends to     
advance in a direct line through space1 
continue to coexist in the same         
quantities as at present4 ,but vary     
either of these causes1 and this        
particular succession of motions would  
cease to take place4 ,the series of the 
earth's motions1 therefore1 though a    
case of sequence invariable within the  
limits of human experience1 is not a    
case of causation4 ,it is not           

unconditional4  ,this distinction       
between the relations of succession     
which so far as we know are             
unconditional1 and those relations1     
whether of succession or of coexistence1
 which1 like the earth's motions1 or the
 succession of day and night1 depend on 
the existence or on the coexistence of  
other antecedent facts--corresponds to  
the great division which ,dr4 ,whewell  
and other writers have made of the field
 of science1 into the investigation of  
what they term the ,laws of ,phenomena1 
and the investigation of causes2 a      
phraseology1 as ,i conceive1 not        
philosophically sustainable1 inasmuch as
 the ascertainment of causes1 such      
causes as the human faculties can       
ascertain1 namely1 causes which are     
themselves phenomena1 is1 therefore1    
merely the ascertainment of other and   
more universal ,laws of ,phenomena4 ,and
 let me here observe1 that ,dr4         
,whewell1 and in some degree even ,sir  
,john ,herschel1 seem to have           

misunderstood the meaning of those      
writers who1 like ,m4 ,comte1 limit the 
sphere of scientific investigation to   
,laws of ,phenomena1 and speak of the   
inquiry into causes as vain and futile4 
,the causes which ,m4 ,comte designates 
as inaccessible1 are efficient causes4  
,the investigation of physical1 as      
opposed to efficient1 causes 7including 
the study of all the active forces in   
,nature1 considered as facts of         
observation7 is as important a part of  
,m4 ,comte's conception of science as of
 ,dr4 ,whewell's4 ,his objection to the 
word cause is a mere matter of          
nomenclature1 in which1 as a matter of  
nomenclature1 ,i consider him to be     
entirely wrong4 ,those1 it is justly    
remarked by ,mr4 ,bailey1#ai who1 like  
,m4 ,comte1 object to designate events  
as causes1 are objecting without any    
real ground to a mere but extremely     
convenient generalization1 to a very    
useful common name1 the employment of   
which involves1 or needs involve1 no    

particular theory4 ,to which it may be  
added1 that by rejecting this form of   
expression1 ,m4 ,comte leaves himself   
without any term for marking a          
distinction which1 however incorrectly  
expressed1 is not only real1 but is one 
of the fundamental distinctions in      
science2 indeed it is on this alone1 as 
we shall hereafter find1 that the       
possibility rests of framing a rigorous 
,canon of ,induction4 ,and as things    
left without a name are apt to be       
forgotten1 a ,canon of that description 
is not one of the many benefits which   
the philosophy of ,induction has        
received from ,m4 ,comte's great powers4
    #f4 ,does a cause always stand with 
its effect in the relation of antecedent
 and consequent8 ,do we not often say of
 two simultaneous facts that they are   
cause and effect--as when we say that   
fire is the cause of warmth1 the sun and
 moisture the cause of vegetation1 and  
the like8 ,since a cause does not       
necessarily perish because its effect   

has been produced1 the two things do    
very generally coexist2 and there are   
some appearances1 and some common       
expressions1 seeming to imply not only  
that causes may1 but that they must1 be 
contemporaneous with their effects4     
,cessante caus cessat et effectus1 has  
been a dogma of the schools3 the        
necessity for the continued existence of
 the cause in order to the continuance  
of the effect1 seems to have been once a
 generally received doctrine4 ,kepler's 
numerous attempts to account for the    
motions of the heavenly bodies on       
mechanical principles1 were rendered    
abortive by his always supposing that   
the agency which set those bodies in    
motion must continue to operate in order
 to keep up the motion which it at first
 produced4 ,yet there were at all times 
many familiar instances of the          
continuance of effects1 long after their
 causes had ceased4 ,a coup de soleil   
gives a person a brain fever3 will the  
fever go off as soon as he is moved out 

of the sunshine8 ,a sword is run through
 his body3 must the sword remain in his 
body in order that he may continue dead8
 ,a ploughshare once made1 remains a    
ploughshare1 without any continuance of 
heating and hammering1 and even after   
the man who heated and hammered it has  
been gathered to his fathers4 ,on the   
other hand1 the pressure which forces up
 the mercury in an exhausted tube must  
be continued in order to sustain it in  
the tube4 ,this 7it may be replied7 is  
because another force is acting without 
intermission1 the force of gravity1     
which would restore it to its level1    
unless counterpoised by a force equally 
constant4 ,but again2 a tight bandage   
causes pain1 which pain will sometimes  
go off as soon as the bandage is        
removed4 ,the illumination which the sun
 diffuses over the earth ceases when the
 sun goes down4  ,there is1 therefore1 a
 distinction to be drawn4 ,the          
conditions which are necessary for the  
first production of a phenomenon1 are   

occasionally also necessary for its     
continuance2 though more commonly its   
continuance requires no condition except
 negative ones4 ,most things1 once      
produced1 continue as they are1 until   
something changes or destroys them2 but 
some require the permanent presence of  
the agencies which produced them at     
first4 ,these may1 if we please1 be     
considered as instantaneous phenomena1  
requiring to be renewed at each instant 
by the cause by which they were at first
 generated4 ,accordingly1 the           
illumination of any given point of space
 has always been looked upon as an      
instantaneous fact1 which perishes and  
is perpetually renewed as long as the   
necessary conditions subsist4 ,if we    
adopt this language we avoid the        
necessity of admitting that the         
continuance of the cause is ever        
required to maintain the effect4 ,we may
 say1 it is not required to maintain1   
but to reproduce1 the effect1 or else to
 counteract some force tending to       

destroy it4 ,and this may be a          
convenient phraseology4 ,but it is only 
a phraseology4 ,the fact remains1 that  
in some cases 7though these are a       
minority7 the continuance of the        
conditions which produced an effect is  
necessary to the continuance of the     
effect4  ,as to the ulterior question1  
whether it is strictly necessary that   
the cause1 or assemblage of conditions1 
should precede1 by ever so short an     
instant1 the production of the effect1  
7a question raised and argued with much 
ingenuity by ,sir ,john ,herschel in an 
,essay already quoted1#bj7 the inquiry  
is of no consequence for our present    
purpose4 ,there certainly are cases in  
which the effect follows without any    
interval perceptible by our faculties3  
and when there is an interval1 we cannot
 tell by how many intermediate links    
imperceptible to us that interval may   
really be filled up4 ,but even granting 
that an effect may commence             
simultaneously with its cause1 the view 

,i have taken of causation is in no way 
practically affected4 ,whether the cause
 and its effect be necessarily          
successive or not1 the beginning of a   
phenomenon is what implies a cause1 and 
causation is the law of the succession  
of phenomena4 ,if these axioms be       
granted1 we can afford1 though ,i see no
 necessity for doing so1 to drop the    
words antecedent and consequent as      
applied to cause and effect4 ,i have no 
objection to define a cause1 the        
assemblage of phenomena1 which          
occurring1 some other phenomenon        
invariably commences1 or has its origin4
 ,whether the effect coincides in point 
of time with1 or immediately follows1   
the hindmost of its conditions1 is      
immaterial4 ,at all events it does not  
precede it2 and when we are in doubt1   
between two coexistent phenomena1 which 
is cause and which effect1 we rightly   
deem the question solved if we can      
ascertain which of them preceded the    
other4    #g4 ,it continually happens   

that several different phenomena1 which 
are not in the slightest degree         
dependent or conditional on one another1
 are found all to depend1 as the phrase 
is1 on one and the same agent2 in other 
words1 one and the same phenomenon is   
seen to be followed by several sorts of 
effects quite heterogeneous1 but which  
go on simultaneously one with another2  
provided1 of course1 that all other     
conditions requisite for each of them   
also exist4 ,thus1 the sun produces the 
celestial motions1 it produces daylight1
 and it produces heat4 ,the earth causes
 the fall of heavy bodies1 and it also1 
in its capacity of a great magnet1      
causes the phenomena of the magnetic    
needle4 ,a crystal of galena causes the 
sensations of hardness1 of weight1 of   
cubical form1 of grey colour1 and many  
others between which we can trace no    
interdependence4 ,the purpose to which  
the phraseology of ,properties and      
,powers is specially adapted1 is the    
expression of this sort of cases4 ,when 

the same phenomenon is followed 7either 
subject or not to the presence of other 
conditions7 by effects of different and 
dissimilar orders1 it is usual to say   
that each different sort of effect is   
produced by a different property of the 
cause4 ,thus we distinguish the         
attractive or gravitative property of   
the earth1 and its magnetic property3   
the gravitative1 luminiferous1 and      
calorific properties of the sun3 the    
colour1 shape1 weight1 and hardness of a
 crystal4 ,these are mere phrases1 which
 explain nothing1 and add nothing to our
 knowledge of the subject2 but1         
considered as abstract names denoting   
the connexion between the different     
effects produced and the object which   
produces them1 they are a very powerful 
instrument of abridgment1 and of that   
acceleration of the process of thought  
which abridgment accomplishes4  ,this   
class of considerations leads to a      
conception which we shall find to be of 
great importance1 that of a ,permanent  

,cause1 or original natural agent4      
,there exist in nature a number of      
permanent causes1 which have subsisted  
ever since the human race has been in   
existence1 and for an indefinite and    
probably an enormous length of time     
previous4 ,the sun1 the earth1 and      
planets1 with their various             
constituents1 air1 water1 and other     
distinguishable substances1 whether     
simple or compound1 of which nature is  
made up1 are such ,permanent ,causes4   
,these have existed1 and the effects or 
consequences which they were fitted to  
produce have taken place 7as often as   
the other conditions of the production  
met17 from the very beginning of our    
experience4 ,but we can give no account 
of the origin of the ,permanent ,causes 
themselves4 ,why these particular       
natural agents existed originally and no
 others1 or why they are commingled in  
such and such proportions1 and          
distributed in such and such a manner   
throughout space1 is a question we      

cannot answer4 ,more than this3 we can  
discover nothing regular in the         
distribution itself2 we can reduce it to
 no uniformity1 to no law4 ,there are no
 means by which1 from the distribution  
of these causes or agents in one part of
 space1 we could conjecture whether a   
similar distribution prevails in        
another4 ,the coexistence1 therefore1 of
 ,primeval ,causes1 ranks1 to us1 among 
merely casual concurrences3 and all     
those sequences or coexistences among   
the effects of several such causes1     
which1 though invariable while those    
causes coexist1 would1 if the           
coexistence terminated1 terminate along 
with it1 we do not class as cases of    
causation1 or laws of nature3 we can    
only calculate on finding these         
sequences or coexistences where we know 
by direct evidence1 that the natural    
agents on the properties of which they  
ultimately depend1 are distributed in   
the requisite manner4 ,these ,permanent 
,causes are not always objects2 they are

 sometimes events1 that is to say1      
periodical cycles of events1 that being 
the only mode in which events can       
possess the property of permanence4 ,not
 only1 for instance1 is the earth itself
 a permanent cause1 or primitive natural
 agent1 but the earth's rotation is so  
too3 it is a cause which has produced1  
from the earliest period1 7by the aid of
 other necessary conditions17 the       
succession of day and night1 the ebb and
 flow of the sea1 and many other        
effects1 while1 as we can assign no     
cause 7except conjecturally7 for the    
rotation itself1 it is entitled to be   
ranked as a primeval cause4 ,it is1     
however1 only the origin of the rotation
 which is mysterious to us3 once begun1 
its continuance is accounted for by the 
first law of motion 7that of the        
permanence of rectilinear motion once   
impressed7 combined with the gravitation
 of the parts of the earth towards one  
another4  ,all phenomena without        
exception which begin to exist1 that is1

 all except the primeval causes1 are    
effects either immediate or remote of   
those primitive facts1 or of some       
combination of them4 ,there is no ,thing
 produced1 no event happening1 in the   
known universe1 which is not connected  
by an uniformity1 or invariable         
sequence1 with some one or more of the  
phenomena which preceded it2 insomuch   
that it will happen again as often as   
those phenomena occur again1 and as no  
other phenomenon having the character of
 a counteracting cause shall coexist4   
,these antecedent phenomena1 again1 were
 connected in a similar manner with some
 that preceded them2 and so on1 until we
 reach1 as the ultimate step attainable 
by us1 either the properties of some one
 primeval cause1 or the conjunction of  
several4 ,the whole of the phenomena of 
nature were therefore the necessary1 or 
in other words1 the unconditional1      
consequences of some former collocation 
of the ,permanent ,causes4  ,the state  
of the whole universe at any instant1 we

 believe to be the consequence of its   
state at the previous instant2 insomuch 
that one who knew all the agents which  
exist at the present moment1 their      
collocation in space1 and all their     
properties1 in other words1 the laws of 
their agency1 could predict the whole   
subsequent history of the universe1 at  
least unless some new volition of a     
power capable of controlling the        
universe should supervene4#ba ,and if   
any particular state of the entire      
universe could ever recur a second time1
 all subsequent states would return too1
 and history would1 like a circulating  
decimal of many figures1 periodically   
repeat itself3--      ,jam redit et     
virgo1 redeunt ,saturnia regna4444      
,alter erit tum ,tiphys1 et altera qu   
vehat ,argo     ,delectos heroas2 erunt 
quoque altera bella1     ,atque iterum  
ad ,trojam magnus mittetur ,achilles4   
,and though things do not really revolve
 in this eternal round1 the whole series
 of events in the history of the        

universe1 past and future1 is not the   
less capable1 in its own nature1 of     
being constructed  priori by any one    
whom we can suppose acquainted with the 
original distribution of all natural    
agents1 and with the whole of their     
properties1 that is1 the laws of        
succession existing between them and    
their effects3 saving the far more than 
human powers of combination and         
calculation which would be required1    
even in one possessing the data1 for the
 actual performance of the task4    #h4 
,since everything which occurs is       
determined by laws of causation and     
collocations of the original causes1 it 
follows that the coexistences which are 
observable among effects cannot be      
themselves the subject of any similar   
set of laws1 distinct from laws of      
causation4 ,uniformities there are1 as  
well of coexistence as of succession1   
among effects2 but these must in all    
cases be a mere result either of the    
identity or of the coexistence of their 

causes3 if the causes did not coexist1  
neither could the effects4 ,and these   
causes being also effects of prior      
causes1 and these of others1 until we   
reach the primeval causes1 it follows   
that 7except in the case of effects     
which can be traced immediately or      
remotely to one and the same cause7 the 
coexistences of phenomena can in no case
 be universal1 unless the coexistences  
of the primeval causes to which the     
effects are ultimately traceable1 can be
 reduced to an universal law3 but we    
have seen that they cannot4 ,there are1 
accordingly1 no original and            
independent1 in other words no          
unconditional1 uniformities of          
coexistence1 between effects of         
different causes2 if they coexist1 it is
 only because the causes have casually  
coexisted4 ,the only independent and    
unconditional coexistences which are    
sufficiently invariable to have any     
claim to the character of laws1 are     
between different and mutually          

independent effects of the same cause2  
in other words1 between different       
properties of the same natural agent4   
,this portion of the ,laws of ,nature   
will be treated of in the latter part of
 the present ,book1 under the name of   
the ,specific ,properties of ,kinds4    
#i4 ,it is proper in this place to      
advert to a rather ancient doctrine     
respecting causation1 which has been    
revived during the last few years in    
many quarters1 and at present gives more
 signs of life than any other theory of 
causation at variance with that set     
forth in the preceding pages4           
,according to the theory in question1   
,mind1 or1 to speak more precisely1     
,will1 is the only cause of phenomena4  
,the type of ,causation1 as well as the 
exclusive source from which we derive   
the idea1 is our own voluntary agency4  
,here1 and here only 7it is said7 we    
have direct evidence of causation4 ,we  
know that we can move our bodies4       
,respecting the phenomena of inanimate  

nature1 we have no other direct         
knowledge than that of antecedence and  
sequence4 ,but in the case of our       
voluntary actions1 it is affirmed that  
we are conscious of power1 before we    
have experience of results4 ,an act of  
volition1 whether followed by an effect 
or not1 is accompanied by a             
consciousness of effort1 of force       
exerted1 of power in action1 which is   
necessarily causal1 or causative4 ,this 
feeling of energy or force1 inherent in 
an act of will1 is knowledge  priori2   
assurance1 prior to experience1 that we 
have the power of causing effects4      
,volition1 therefore1 it is asserted1 is
 something more than an unconditional   
antecedent2 it is a cause1 in a         
different sense from that in which      
physical phenomena are said to cause one
 another3 it is an ,efficient ,cause4   
,from this the transition is easy to the
 further doctrine1 that ,volition is the
 sole ,efficient ,cause of all          
phenomena4 ,it is inconceivable that    

dead force could continue unsupported   
for a moment beyond its creation4 ,we   
cannot even conceive of change or       
phenomena without the energy of a mind4 
,the word action itself1 says another   
writer of the same school1 has no real  
significance except when applied to the 
doings of an intelligent agent4 ,let any
 one conceive1 if he can1 of any power1 
energy1 or force1 inherent in a lump of 
matter4 ,phenomena may have the         
semblance of being produced by physical 
causes1 but they are in reality         
produced1 say these writers1 by the     
immediate agency of mind4 ,all things   
which do not proceed from a human 7or1  
,i suppose1 an animal7 will1 proceed1   
they say1 directly from divine will4    
,the earth is not moved by the          
combination of a centripetal and a      
projectile force2 this is but a mode of 
speaking1 which serves to facilitate our
 conceptions4 ,it is moved by the direct
 volition of an omnipotent ,being1 in a 
path coinciding with that which we      

deduce from the hypothesis of these two 
forces4  ,as ,i have so often observed1 
the general question of the existence of
 ,efficient ,causes does not fall within
 the limits of our subject3 but a theory
 which represents them as capable of    
being subjects of human knowledge1 and  
which passes off as efficient causes    
what are only physical or phenomenal    
causes1 belongs as much to ,logic as to 
,metaphysics1 and is a fit subject for  
discussion here4  ,to my apprehension1 a
 volition is not an efficient1 but      
simply a physical1 cause4 ,our will     
causes our bodily actions in the same   
sense1 and in no other1 in which cold   
causes ice1 or a spark causes an        
explosion of gunpowder4 ,the volition1 a
 state of our mind1 is the antecedent2  
the motion of our limbs in conformity to
 the volition1 is the consequent4 ,this 
sequence ,i conceive to be not a subject
 of direct consciousness1 in the sense  
intended by the theory4 ,the antecedent1
 indeed1 and the consequent1 are        

subjects of consciousness4 ,but the     
connexion between them is a subject of  
experience4 ,i cannot admit that our    
consciousness of the volition contains  
in itself any  priori knowledge that the
 muscular motion will follow4 ,if our   
nerves of motion were paralysed1 or our 
muscles stiff and inflexible1 and had   
been so all our lives1 ,i do not see the
 slightest ground for supposing that we 
should ever 7unless by information from 
other people7 have known anything of    
volition as a physical power1 or been   
conscious of any tendency in feelings of
 our mind to produce motions of our     
body1 or of other bodies4 ,i will not   
undertake to say whether we should in   
that case have had the physical feeling 
which ,i suppose is meant when these    
writers speak of consciousness of       
effort3 ,i see no reason why we should  
not2 since that physical feeling is     
probably a state of nervous sensation   
beginning and ending in the brain1      
without involving the motory apparatus3 

but we certainly should not have        
designated it by any term equivalent to 
effort1 since effort implies consciously
 aiming at an end1 which we should not  
only in that case have had no reason to 
do1 but could not even have had the idea
 of doing4 ,if conscious at all of this 
peculiar sensation1 we should have been 
conscious of it1 ,i conceive1 only as a 
kind of uneasiness1 accompanying our    
feelings of desire4  ,it is well argued 
by ,sir ,william ,hamilton against the  
theory in question1 that it is refuted  
by the consideration1 that between the  
overt fact of corporeal movement of     
which we are cognisant1 and the internal
 act of mental determination of which we
 are also cognisant1 there intervenes a 
numerous series of intermediate agencies
 of which we have no knowledge2 and1    
consequently1 that we can have no       
consciousness of any causal connexion   
between the extreme links of this chain1
 the volition to move and the limb      
moving1 as this hypothesis asserts4 ,no 

one is immediately conscious1 for       
example1 of moving his arm through his  
volition4 ,previously to this ultimate  
movement1 muscles1 nerves1 a multitude  
of solid and fluid parts1 must be set in
 motion by the will1 but of this motion 
we know1 from consciousness1 absolutely 
nothing4 ,a person struck with paralysis
 is conscious of no inability in his    
limb to fulfil the determinations of his
 will2 and it is only after having      
willed1 and finding that his limbs do   
not obey his volition1 that he learns by
 this experience1 that the external     
movement does not follow the internal   
act4 ,but as the paralytic learns after 
the volition that his limbs do not obey 
his mind2 so it is only after volition  
that the man in health learns1 that his 
limbs do obey the mandates of his       
will4#bb  ,those against whom ,i am     
contending have never produced1 and do  
not pretend to produce1 any positive    
evidence#bc that the power of our will  
to move our bodies would be known to us 

independently of experience4 ,what they 
have to say on the subject is1 that the 
production of physical events by a will 
seems to carry its own explanation with 
it1 while the action of matter upon     
matter seems to require something else  
to explain it2 and is even1 according to
 them1 inconceivable on any other       
supposition than that some will         
intervenes between the apparent cause   
and its apparent effect4 ,they thus rest
 their case on an appeal to the inherent
 laws of our conceptive faculty2        
mistaking1 as ,i apprehend1 for the laws
 of that faculty its acquired habits1   
grounded on the spontaneous tendencies  
of its uncultured state4 ,the succession
 between the will to move a limb and the
 actual motion1 is one of the most      
direct and instantaneous of all         
sequences which come under our          
observation1 and is familiar to every   
moment's experience from our earliest   
infancy2 more familiar than any         
succession of events exterior to our    

bodies1 and especially more so than any 
other case of the apparent origination  
7as distinguished from the mere         
communication7 of motion4 ,now1 it is   
the natural tendency of the mind to be  
always attempting to facilitate its     
conception of unfamiliar facts by       
assimilating them to others which are   
familiar4 ,accordingly1 our voluntary   
acts1 being the most familiar to us of  
all cases of causation1 are1 in the     
infancy and early youth of the human    
race1 spontaneously taken as the type of
 causation in general1 and all phenomena
 are supposed to be directly produced by
 the will of some sentient being4 ,this 
original ,fetichism ,i shall not        
characterize in the words of ,hume1 or  
of any follower of ,hume1 but in those  
of a religious metaphysician1 ,dr4      
,reid1 in order more effectually to show
 the unanimity which exists on the      
subject among all competent thinkers4   
,when we turn our attention to external 
objects1 and begin to exercise our      

rational faculties about them1 we find  
that there are some motions and changes 
in them which we have power to produce1 
and that there are many which must have 
some other cause4 ,either the objects   
must have life and active power1 as we  
have1 or they must be moved or changed  
by something that has life and active   
power1 as external objects are moved by 
us4  ,our first thoughts seem to be1    
that the objects in which we perceive   
such motion have understanding and      
active power as we have4 ',savages1'    
says the ,abb ,raynal1 'wherever they   
see motion which they cannot account    
for1 there they suppose a soul4' ,all   
men may be considered as savages in this
 respect1 until they are capable of     
instruction1 and of using their         
faculties in a more perfect manner than 
savages do4  ,the ,abb ,raynal's        
observation is sufficiently confirmed1  
both from fact1 and from the structure  
of all languages4  ,rude nations do     
really believe sun1 moon1 and stars1    

earth1 sea1 and air1 fountains1 and     
lakes1 to have understanding and active 
power4 ,to pay homage to them1 and      
implore their favour1 is a kind of      
idolatry natural to savages4  ,all      
languages carry in their structure the  
marks of their being formed when this   
belief prevailed4 ,the distinction of   
verbs and participles into active and   
passive1 which is found in all          
languages1 must have been originally    
intended to distinguish what is really  
active from what is merely passive2 and 
in all languages1 we find active verbs  
applied to those objects1 in which1     
according to the ,abb ,raynal's         
observation1 savages suppose a soul4    
,thus we say the sun rises and sets1 and
 comes to the meridian1 the moon        
changes1 the sea ebbs and flows1 the    
winds blow4 ,languages were formed by   
men who believed these objects to have  
life and active power in themselves4 ,it
 was therefore proper and natural to    
express their motions and changes by    

active verbs4  ,there is no surer way of
 tracing the sentiments of nations      
before they have records1 than by the   
structure of their language1 which1     
notwithstanding the changes produced in 
it by time1 will always retain some     
signatures of the thoughts of those by  
whom it was invented4 ,when we find the 
same sentiments indicated in the        
structure of all languages1 those       
sentiments must have been common to the 
human species when languages were       
invented4  ,when a few1 of superior     
intellectual abilities1 find leisure for
 speculation1 they begin to             
philosophize1 and soon discover1 that   
many of those objects which at first    
they believed to be intelligent and     
active are really lifeless and passive4 
,this is a very important discovery4 ,it
 elevates the mind1 emancipates from    
many vulgar superstitions1 and invites  
to further discoveries of the same kind4
  ,as philosophy advances1 life and     
activity in natural objects retires1 and

 leaves them dead and inactive4 ,instead
 of moving voluntarily1 we find them to 
be moved necessarily2 instead of acting1
 we find them to be acted upon2 and     
,nature appears as one great machine1   
where one wheel is turned by another1   
that by a third2 and how far this       
necessary succession may reach1 the     
philosopher does not know4#bd  ,there   
is1 then1 a spontaneous tendency of the 
intellect to account to itself for all  
cases of causation by assimilating them 
to the intentional acts of voluntary    
agents like itself4 ,this is the        
instinctive philosophy of the human mind
 in its earliest stage1 before it has   
become familiar with any other          
invariable sequences than those between 
its own volitions or those of other     
human beings and their voluntary acts4  
,as the notion of fixed laws of         
succession among external phenomena     
gradually establishes itself1 the       
propensity to refer all phenomena to    
voluntary agency slowly gives way before

 it4 ,the suggestions1 however1 of daily
 life continuing to be more powerful    
than those of scientific thought1 the   
original instinctive philosophy         
maintains its ground in the mind1       
underneath the growths obtained by      
cultivation1 and keeps up a constant    
resistance to their throwing their roots
 deep into the soil4 ,the theory against
 which ,i am contending derives its     
nourishment from that substratum4 ,its  
strength does not lie in argument1 but  
in its affinity to an obstinate tendency
 of the infancy of the human mind4      
,that this tendency1 however1 is not the
 result of an inherent mental law1 is   
proved by superabundant evidence4 ,the  
history of science1 from its earliest   
dawn1 shows that mankind have not been  
unanimous in thinking either that the   
action of matter upon matter was not    
conceivable1 or that the action of mind 
upon matter was4 ,to some thinkers1 and 
some schools of thinkers1 both in       
ancient and in modern times1 this last  

has appeared much more inconceivable    
than the former4 ,sequences entirely    
physical and material1 as soon as they  
had become sufficiently familiar to the 
human mind1 came to be thought perfectly
 natural1 and were regarded not only as 
needing no explanation themselves1 but  
as being capable of affording it to     
others1 and even of serving as the      
ultimate explanation of things in       
general4  ,one of the ablest recent     
supporters of the ,volitional theory has
 furnished an explanation1 at once      
historically true and philosophically   
acute1 of the failure of the ,greek     
philosophers in physical inquiry1 in    
which1 as ,i conceive1 he unconsciously 
depicts his own state of mind4 ,their   
stumbling-block was one as to the nature
 of the evidence they had to expect for 
their conviction4444 ,they had not      
seized the idea that they must not      
expect to understand the processes of   
outward causes1 but only their results3 
and consequently1 the whole physical    

philosophy of the ,greeks was an attempt
 to identify mentally the effect with   
its cause1 to feel after some not only  
necessary but natural connexion1 where  
they meant by natural that which would  
per se carry some presumption to their  
own mind4444 ,they wanted to see some   
reason why the physical antecedent      
should produce this particular          
consequent1 and their only attempts were
 in directions where they could find    
such reasons4#be ,in other words1 they  
were not content merely to know that one
 phenomenon was always followed by      
another2 they thought that they had not 
attained the true aim of science1 unless
 they could perceive something in the   
nature of the one phenomenon from which 
it might have been known or presumed    
previous to trial that it would be      
followed by the other3 just what the    
writer1 who has so clearly pointed out  
their error1 thinks that he perceives in
 the nature of the phenomenon ,volition4
 ,and to complete the statement of the  

case1 he should have added that these   
early speculators not only made this    
their aim1 but were quite satisfied with
 their success in it2 not only sought   
for causes which should carry in their  
mere statement evidence of their        
efficiency1 but fully believed that they
 had found such causes4 ,the reviewer   
can see plainly that this was an error1 
because he does not believe that there  
exist any relations between material    
phenomena which can account for their   
producing one another3 but the very fact
 of the persistency of the ,greeks in   
this error1 shows that their minds were 
in a very different state3 they were    
able to derive from the assimilation of 
physical facts to other physical facts1 
the kind of mental satisfaction which we
 connect with the word explanation1 and 
which the reviewer would have us think  
can only be found in referring phenomena
 to a will4 ,when ,thales and ,hippo    
held that moisture was the universal    
cause1 and external element1 of which   

all other things were but the infinitely
 various sensible manifestations2 when  
,anaximenes predicated the same thing of
 air1 ,pythagoras of numbers1 and the   
like1 they all thought that they had    
found a real explanation2 and were      
content to rest in this explanation as  
ultimate4 ,the ordinary sequences of the
 external universe appeared to them1 no 
less than to their critic1 to be        
inconceivable without the supposition of
 some universal agency to connect the   
antecedents with the consequents2 but   
they did not think that ,volition1      
exerted by minds1 was the only agency   
which fulfilled this requirement4       
,moisture1 or air1 or numbers1 carried  
to their minds a precisely similar      
impression of making intelligible what  
was otherwise inconceivable1 and gave   
the same full satisfaction to the       
demands of their conceptive faculty4    
,it was not the ,greeks alone1 who      
wanted to see some reason why the       
physical antecedent should produce this 

particular consequent1 some connexion   
which would per se carry some           
presumption to their own mind4 ,among   
modern philosophers1 ,leibnitz laid it  
down as a self-evident principle that   
all physical causes without exception   
must contain in their own nature        
something which makes it intelligible   
that they should be able to produce the 
effects which they do produce4 ,far from
 admitting ,volition as the only kind of
 cause which carried internal evidence  
of its own power1 and as the real bond  
of connexion between physical           
antecedents and their consequents1 he   
demanded some naturally and per se      
efficient physical antecedent as the    
bond of connexion between ,volition     
itself and its effects4 ,he distinctly  
refused to admit the will of ,god as a  
sufficient explanation of anything      
except miracles2 and insisted upon      
finding something that would account    
better for the phenomena of nature than 
a mere reference to divine volition4#bf 

,again1 and conversely1 the action of   
mind upon matter 7which1 we are now     
told1 not only needs no explanation     
itself1 but is the explanation of all   
other effects71 has appeared to some    
thinkers to be itself the grand         
inconceivability4 ,it was to get over   
this very difficulty that the           
,cartesians invented the system of      
,occasional ,causes4 ,they could not    
conceive that thoughts in a mind could  
produce movements in a body1 or that    
bodily movements could produce thoughts4
 ,they could see no necessary connexion1
 no relation  priori1 between a motion  
and a thought4 ,and as the ,cartesians1 
more than any other school of           
philosophical speculation before or     
since1 made their own minds the measure 
of all things1 and refused1 on          
principle1 to believe that ,nature had  
done what they were unable to see any   
reason why she must do1 they affirmed it
 to be impossible that a material and a 
mental fact could be causes one of      

another4 ,they regarded them as mere    
,occasions on which the real agent1     
,god1 thought fit to exert his power as 
a ,cause4 ,when a man wills to move his 
foot1 it is not his will that moves it1 
but ,god 7they said7 moves it on the    
occasion of his will4 ,god1 according to
 this system1 is the only efficient     
cause1 not qu mind1 or qu endowed with  
volition1 but qu omnipotent4 ,this      
hypothesis was1 as ,i said1 originally  
suggested by the supposed               
inconceivability of any real mutual     
action between ,mind and ,matter3 but it
 was afterwards extended to the action  
of ,matter upon ,matter1 for on a nicer 
examination they found this             
inconceivable too1 and therefore1       
according to their logic1 impossible4   
,the deus ex machin was ultimately      
called in to produce a spark on the     
occasion of a flint and steel coming    
together1 or to break an egg on the     
occasion of its falling on the ground4  
,all this1 undoubtedly1 shows that it is

 the disposition of mankind in general1 
not to be satisfied with knowing that   
one fact is invariably antecedent and   
another consequent1 but to look out for 
something which may seem to explain     
their being so4 ,but we also see that   
this demand may be completely satisfied 
by an agency purely physical1 provided  
it be much more familiar than that which
 it is invoked to explain4 ,to ,thales  
and ,anaximenes1 it appeared            
inconceivable that the antecedents which
 we see in nature1 should produce the   
consequents2 but perfectly natural that 
water1 or air1 should produce them4 ,the
 writers whom ,i oppose declare this    
inconceivable1 but can conceive that    
mind1 or volition1 is per se an         
efficient cause3 while the ,cartesians  
could not conceive even that1 but       
peremptorily declared that no mode of   
production of any fact whatever was     
conceivable1 except the direct agency of
 an omnipotent being4 ,thus giving      
additional proof of what finds new      

confirmation in every stage of the      
history of science3 that both what      
persons can1 and what they cannot1      
conceive1 is very much an affair of     
accident1 and depends altogether on     
their experience1 and their habits of   
thought2 that by cultivating the        
requisite associations of ideas1 people 
may make themselves unable to conceive  
any given thing2 and may make themselves
 able to conceive most things1 however  
inconceivable these may at first appear3
 and the same facts in each person's    
mental history which determine what is  
or is not conceivable to him1 determine 
also which among the various sequences  
in nature will appear to him so natural 
and plausible1 as to need no other proof
 of their existence2 to be evident by   
their own light1 independent equally of 
experience and of explanation4  ,by what
 rule is any one to decide between one  
theory of this description and another8 
,the theorists do not direct us to any  
external evidence2 they appeal each to  

his own subjective feelings4 ,one says1 
the succession ,c1 ,b1 appears to me    
more natural1 conceivable1 and credible 
per se1 than the succession ,a1 ,b2 you 
are therefore mistaken in thinking that 
,b depends upon ,a2 ,i am certain1      
though ,i can give no other evidence of 
it1 that ,c comes in between ,a and ,b1 
and is the real and only cause of ,b4   
,the other answers--the successions ,c1 
,b1 and ,a1 ,b1 appear to me equally    
natural and conceivable1 or the latter  
more so than the former3 ,a is quite    
capable of producing ,b without any     
other intervention4 ,a third agrees with
 the first in being unable to conceive  
that ,a can produce ,b1 but finds the   
sequence ,d1 ,b1 still more natural than
 ,c1 ,b1 or of nearer kin to the subject
 matter1 and prefers his ,d theory to   
the ,c theory4 ,it is plain that there  
is no universal law operating here1     
except the law that each person's       
conceptions are governed and limited by 
his individual experience and habits of 

thought4 ,we are warranted in saying of 
all three1 what each of them already    
believes of the other two1 namely1 that 
they exalt into an original law of the  
human intellect and of outward nature1  
one particular sequence of phenomena1   
which appears to them more natural and  
more conceivable than other sequences1  
only because it is more familiar4 ,and  
from this judgment ,i am unable to      
except the theory1 that ,volition is an 
,efficient ,cause4  ,i am unwilling to  
leave the subject without adverting to  
the additional fallacy contained in the 
corollary from this theory2 in the      
inference that because ,volition is an  
efficient cause1 therefore it is the    
only cause1 and the direct agent in     
producing even what is apparently       
produced by something else4 ,volitions  
are not known to produce anything       
directly except nervous action1 for the 
will influences even the muscles only   
through the nerves4 ,though it were     
granted1 then1 that every phenomenon has

 an efficient1 and not merely a         
phenomenal cause1 and that volition1 in 
the case of the peculiar phenomena which
 are known to be produced by it1 is that
 efficient cause2 are we therefore to   
say1 with these writers1 that since we  
know of no other efficient cause1 and   
ought not to assume one without         
evidence1 there is no other1 and        
volition is the direct cause of all     
phenomena8 ,a more outrageous stretch of
 inference could hardly be made4        
,because among the infinite variety of  
the phenomena of nature there is one1   
namely1 a particular mode of action of  
certain nerves1 which has for its cause1
 and as we are now supposing for its    
efficient cause1 a state of our mind2   
and because this is the only efficient  
cause of which we are conscious1 being  
the only one of which in the nature of  
the case we can be conscious1 since it  
is the only one which exists within     
ourselves2 does this justify us in      
concluding that all other phenomena must

 have the same kind of efficient cause  
with that one eminently special1 narrow1
 and peculiarly human or animal1        
phenomenon8 ,the nearest parallel to    
this specimen of generalization is      
suggested by the recently revived       
controversy on the old subject of       
,plurality of ,worlds1 in which the     
contending parties have been so         
conspicuously successful in overthrowing
 one another4 ,here also we have        
experience only of a single case1 that  
of the world in which we live1 but that 
this is inhabited we know absolutely1   
and without possibility of doubt4 ,now  
if on this evidence any one were to     
infer that every heavenly body without  
exception1 sun1 planet1 satellite1      
comet1 fixed star or nebula1 is         
inhabited1 and must be so from the      
inherent constitution of things1 his    
inference would exactly resemble that of
 the writers who conclude that because  
volition is the efficient cause of our  
own bodily motions1 it must be the      

efficient cause of everything else in   
the universe4 ,it is true there are     
cases in which1 with acknowledged       
propriety1 we generalize from a single  
instance to a multitude of instances4   
,but they must be instances which       
resemble the one known instance1 and not
 such as have no circumstance in common 
with it except that of being instances4 
,i have1 for example1 no direct evidence
 that any creature is alive except      
myself3 yet ,i attribute1 with full     
assurance1 life and sensation to other  
human beings and animals4 ,but ,i do not
 conclude that all other things are     
alive merely because ,i am4 ,i ascribe  
to certain other creatures a life like  
my own1 because they manifest it by the 
same sort of indications by which mine  
is manifested4 ,i find that their       
phenomena and mine conform to the same  
laws1 and it is for this reason that ,i 
believe both to arise from a similar    
cause4 ,accordingly ,i do not extend the
 conclusion beyond the grounds for it4  

,earth1 fire1 mountains1 trees1 are     
remarkable agencies1 but their phenomena
 do not conform to the same laws as my  
actions do1 and ,i therefore do not     
believe earth or fire1 mountains or     
trees1 to possess animal life4 ,but the 
supporters of the ,volition ,theory ask 
us to infer that volition causes        
everything1 for no reason except that it
 causes one particular thing2 although  
that one phenomenon1 far from being a   
type of all natural phenomena1 is       
eminently peculiar2 its laws bearing    
scarcely any resemblance to those of any
 other phenomenon1 whether of inorganic 
or of organic nature4   ,,note          
,,supplementary ,,to ,,the ,,preceding  
,,chapter4       ,the author of the     
,second ,burnett ,prize ,essay 7,dr4    
,tulloch71 who      has employed a      
considerable number of pages in         
controverting      the doctrines of the 
preceding chapter1 has somewhat         
surprised      me by denying a fact1    
which ,i imagined too well known to     

require proof--that there have been     
philosophers who found in      physical 
explanations of phenomena the same      
complete mental      satisfaction which 
we are told is only given by volitional 
explanation1 and others who denied the  
,volitional ,theory on the      same    
ground of inconceivability on which it  
is defended4 ,the      assertion of the 
,essayist is countersigned still more   
positively by an able reviewer of the   
,essay3#bg ,two      illustrations1 says
 the reviewer1 are advanced by ,mr4     
,mill3      the case of ,thales and     
,anaximenes1 stated by him to have      
maintained1 the one ,moisture and the   
other ,air to be the origin      of all 
things2 and that of ,descartes and      
,leibnitz1 whom he      asserts to have 
found the action of ,mind upon ,matter  
the grand      inconceivability4 ,in    
counterstatement as to the first of     
these      cases the author shows--what 
we believe now hardly admits of         
doubt--that the ,greek philosophers     

distinctly recognised as      beyond and
 above their primal material source1 the
 ,greek3      nous1 or ,divine          
,intelligence1 as the efficient and     
originating      ,source of all3 and as 
to the second1 by proof that it was the 
mode1 not the fact1 of that action on   
matter1 which was      represented as   
inconceivable4       ,a greater quantity
 of historical error has seldom been    
comprised in a single sentence4 ,with   
regard to ,thales1 the      assertion   
that he considered water as a mere      
material in the      hands of ,greek3   
nous rests on a passage of ,cicero de   
,natur      ,deorum3 and whoever will   
refer to any of the accurate            
historians of philosophy1 will find that
 they treat this as a      mere fancy of
 ,cicero1 resting on no authority1      
opposed to all      the evidence2 and   
make surmises as to the manner in which 
,cicero may have been led into the      
error4 7,see ,ritter1 vol4 i4      p4   
#baa1 #bnd ed42 ,brandis1 vol4 i4 pp4   

#aah-i1 #ast ed42 ,preller1             
,historia ,philosophi ,grco-,roman1 p4  
#aj4 ,schiefe ,ansicht1      durchaus zu
 verwerfen2 augenscheinlich folgernd    
statt zu      berichten2 quibus vera    
sententia ,thaletis plane detorquetur2  
are the expressions of these writers47  
,as for ,anaximenes1 he1      even      
according to ,cicero1 maintained1 not   
that air was the      material out of   
which ,god made the world1 but that the 
air was      a god3 ,anaximenes ara deum
 statuit3 or according to ,st4          
,augustine1 that it was the material out
 of which the gods were      made2 non  
tamen ab ipsis ,diis arem factum1 sed   
ipsos ex      are ortos credidit4 ,those
 who are not familiar with the          
metaphysical terminology of antiquity1  
must not be misled by      finding it   
stated that ,anaximenes attributed      
,greek3 psych      7translated soul1 or 
life7 to his universal element1 the     
air4 ,the ,greek philosophers           
acknowledged several kinds of           

,greek3 psych1 the nutritive1 the       
sensitive1 and the      intellective4#bh
 ,even the moderns with admitted        
correctness      attribute life to      
plants4 ,as far as we can make out the  
meaning      of ,anaximenes1 he made    
choice of ,air as the universal agent1  
on      the ground that it is           
perpetually in motion1 without any      
apparent cause external to itself3 so   
that he conceived it as      exercising 
spontaneous force1 and as the principle 
of life and      activity in all things1
 men and gods inclusive4 ,if this be not
      representing it as the ,efficient 
,cause1 the dispute altogether      has 
no meaning4       ,if either            
,anaximenes1 or ,thales1 or any of their
 cotemporaries1      had held the       
doctrine that ,greek3 nous was the      
,efficient      ,cause1 that doctrine   
could not have been reputed1 as it was  
throughout antiquity1 to have originated
 with ,anaxagoras4 ,the      testimony  
of ,aristotle1 in the first book of his 

,metaphysics1      is perfectly decisive
 with respect to these early            
speculations4      ,after enumerating   
four kinds of causes1 or rather four    
different meanings of the word ,cause1  
viz4 the ,essence of a      thing1 the  
,matter of it1 the ,origin of ,motion   
7,efficient      ,cause71 and the ,end  
or ,final ,cause1 he proceeds to say1   
that      most of the early philosophers
 recognised only the second kind      of
 ,cause1 the ,matter of a thing1 ,greek3
 tas en hyls eidei      monas thsan     
archas einai pantn4 ,as his first       
example he      specifies ,thales1 whom 
he describes as taking the lead in this 
view of the subject1 ,greek3 ho ts      
toiauts archgos      philosophias1 and  
goes on to ,hippon1 ,anaximenes1        
,diogenes 7of      ,apollonia71         
,hippasus of ,metapontum1 ,heraclitus1  
and ,empedocles4      ,anaxagoras1      
however1 7he proceeds to say17 taught a 
different      doctrine1 as we know1 and
 it is alleged that ,hermotimus of      

,clazomen taught it before him4         
,anaxagoras represented1 that      even 
if these various theories of the        
universal material were      true1 there
 would be need of some other cause to   
account for      the transformations of 
the material1 since the material cannot 
originate its own changes3 ,greek3 ou   
gar d to ge hypokeimenon      auto poiei
 metaballein heauto2 leg d' oion oute to
 xylon oute      ho chalkos aitios tou  
metaballein hekateron autn1 oude poiei  
to men xylon klinn ho de chalkos        
andrianta1 all' heteron ti      ts      
metabols aition1 viz41 the other kind of
 cause ,greek3      hothen h arch ts    
kinses--an ,efficient ,cause4 ,aristotle
      expresses great approbation of    
this doctrine 7which he says      made  
its author appear the only sober man    
among persons raving1      ,greek3 oion 
nphn ephan par' eik legontas tous       
proteron72      but while describing the
 influence which it exercised over      
subsequent speculation1 he remarks that 

the philosophers      against whom this1
 as he thinks1 insuperable difficulty   
was      urged1 had not felt it to be   
any difficulty3 ,greek3 ouden           
edyscheranan en heautois4 ,it is surely 
unnecessary to say more      in proof of
 the matter of fact which ,dr4 ,tulloch 
and his      reviewer deny4             
,having pointed out what he thinks the  
error of these early      speculators in
 not recognising the need of an         
efficient cause1      ,aristotle goes on
 to mention two other efficient causes  
to      which they might have had       
recourse1 instead of intelligence3      
,greek3 tych1 chance1 and ,greek3 to    
automaton1 spontaneity4      ,he indeed 
puts these aside as not sufficiently    
worthy causes      for the order in the 
universe1 ,greek3 oud' au t automat kai 
t tych tosouton epitrepsai pragma kals  
eichen3 but he does      not reject them
 as incapable of producing any effect1  
but only      as incapable of producing 
that effect4 ,he himself recognises     

,greek3 tych and ,greek3 to automaton as
 co-ordinate agents      with ,mind in  
producing the phenomena of the universe2
 the      department allotted to them   
being composed of all the classes       
of phenomena which are not supposed to  
follow any uniform law4      ,by thus   
including ,chance among efficient       
causes1 ,aristotle fell      into an    
error which philosophy has now outgrown1
 but which is      by no means so alien 
to the spirit even of modern speculation
      as it may at first sight appear4  
,up to quite a recent period            
philosophers went on ascribing1 and many
 of them have not yet      ceased to    
ascribe1 a real existence to the results
 of      abstraction4 ,chance could make
 out as good a title to that            
dignity as many other of the mind's     
abstract creations3 it had      had a   
name given to it1 and why should it not 
be a reality8 ,as      for ,greek3 to   
automaton1 it is recognised even yet as 
one of      the modes of origination of 

phenomena1 by all those thinkers        
who maintain what is called the ,freedom
 of the ,will4 ,the same                
self-determining power which that       
doctrine attributes to      volitions1  
was supposed by the ancients to be      
possessed also by      some other       
natural phenomena3 a circumstance which 
throws      considerable light on more  
than one of the supposed invincible     
necessities of belief4 ,i have          
introduced it here1 because this        
belief of ,aristotle1 or rather of the  
,greek philosophers      generally1 is  
as fatal as the doctrines of ,thales and
 the ,ionic      school1 to the theory  
that the human mind is compelled by its 
constitution to conceive volition as the
 origin of all force1      and the      
efficient cause of all phenomena4#bi    
,with regard to the modern philosophers 
7,leibnitz and the      ,cartesians7    
whom ,i had cited as having maintained  
that the      action of mind upon       
matter1 so far from being the only      

conceivable origin of material          
phenomena1 is itself      inconceivable2
 the attempt to rebut this argument by  
asserting      that the mode1 not the   
fact1 of the action of mind on matter   
was represented as inconceivable1 is an 
abuse of the privilege      of writing  
confidently about authors without       
reading them3 for      any knowledge    
whatever of ,leibnitz would have taught 
those who      thus speak of him1 that  
the inconceivability of the mode1 and   
the impossibility of the thing1 were in 
his mind convertible      expressions4  
,what was his famous ,principle of the  
,sufficient      ,reason1 the very      
corner stone of his philosophy1 from    
which the      ,preestablished ,harmony1
 the doctrine of ,monads1 and all the   
opinions most characteristic of         
,leibnitz1 were corollaries8 ,it        
was1 that nothing exists1 the existence 
of which is not capable      of being   
proved and explained  priori2 the proof 
and      explanation in the case of     

contingent facts being derived from     
the nature of their causes2 which could 
not be the causes      unless there was 
something in their nature showing them  
to be      capable of producing those   
particular effects4 ,and this           
something which accounts for the        
production of physical      effects1 he 
was able to find in many physical       
causes1 but could      not find it in   
any finite minds1 which therefore he    
unhesitatingly asserted to be incapable 
of producing any      physical effects  
whatever4 ,on ne saurait concevoir1 he  
says1      une action rciproque de la   
matire et de l'intelligence l'une       
sur l'autre1 and there is therefore 7he 
contends7 no choice      but between the
 ,occasional ,causes of the ,cartesians1
 and his      own ,preestablished       
,harmony1 according to which there is no
 more      connexion between our        
volitions and our muscular actions than 
there is between two clocks which are   
wound up to strike at the      same     

instant4 ,but he felt no similar        
difficulty as to physical      causes3  
and throughout his speculations1 as in  
the passage ,i      have already cited  
respecting gravitation1 he distinctly   
refuses to consider as part of the order
 of nature any fact      which is not   
explicable from the nature of its       
physical cause4       ,with regard to   
the ,cartesians 7not ,descartes2 ,i did 
not make      that mistake1 though the  
reviewer of ,dr4 ,tulloch's ,essay      
attributes it to me7 ,i take a passage  
almost at random from      ,malebranche1
 who is the best known of the           
,cartesians1 and1      though not the   
inventor of the system of ,occasional   
,causes1 is      its principal          
expositor4 ,in ,part #b1 chap4 #c1 of   
his ,sixth ,book1      having first said
 that matter cannot have the power of   
moving      itself1 he proceeds to argue
 that neither can mind have the         
power of moving it4 ,quand on examine   
l'ide que l'on a de tous      les       

esprits finis1 on ne voit point de      
liaison ncessaire entre      leur volont
 et le mouvement de quelque corps que ce
 soit1 on      voit au contraire qu'il  
n'y en a point1 et qu'il n'y en peut    
avoir2 7there is nothing in the idea of 
finite mind which can      account for  
its causing the motion of a body27 on   
doit aussi      conclure1 si on veut    
raisonner selon ses lumires1 qu'il n'y a
      aucun esprit cr qui puisse remuer 
quelque corps que ce soit      comme    
cause vritable ou principale1 de mme que
 l'on a dit      qu'aucun corps ne se   
pouvait remuer soi-mme3 thus the idea of
      ,mind is according to him as      
incompatible as the idea of ,matter     
with the exercise of active force4 ,but 
when1 he continues1 we      consider not
 a created but a ,divine ,mind1 the case
 is altered2      for the idea of a     
,divine ,mind includes omnipotence2 and 
the      idea of omnipotence does       
contain the idea of being able to move  
bodies4 ,thus it is the nature of       

omnipotence which renders the           
motion of bodies even by the divine mind
 credible or      conceivable1 while1 so
 far as depended on the mere nature of  
mind1 it would have been inconceivable  
and incredible4 ,if      ,malebranche   
had not believed in an omnipotent being1
 he would      have held all action of  
mind on body to be a demonstrated       
impossibility4#cj       ,a doctrine more
 precisely the reverse of the           
,volitional theory      of causation    
cannot well be imagined4 ,the volitional
 theory is1      that we know by        
intuition or by direct experience the   
action of      our own mental volitions 
on matter2 that we may hence infer all  
other action upon matter to be that of  
volition1 and might thus      know1     
without any other evidence1 that matter 
is under the      government of a divine
 mind4 ,leibnitz and the ,cartesians1 on
      the contrary1 maintain that our   
volitions do not and cannot act         
upon matter1 and that it is only the    

existence of an      all-governing      
,being1 and that ,being omnipotent1     
which can      account for the sequence 
between our volitions and our bodily    
actions4 ,when we consider that each of 
these two theories1      which1 as      
theories of causation1 stand at the     
opposite extremes      of possible      
divergence from one another1 invokes not
 only as      its evidence1 but as its  
sole evidence1 the absolute             
inconceivability of any theory but      
itself1 we are enabled to      measure  
the worth of this kind of evidence2 and 
when we find      the ,volitional theory
 entirely built upon the assertion that 
by      our mental constitution we are  
compelled to recognise our              
volitions as efficient causes1 and then 
find other thinkers      maintaining    
that we know that they are not1 and     
cannot be such      causes1 and cannot  
conceive them to be so1 ,i think we have
 a      right to say1 that this supposed
 law of our mental constitution         

does not exist4       ,dr4 ,tulloch 7pp4
 #de-g7 thinks it a sufficient answer to
 this1      that ,leibnitz and the      
,cartesians were ,theists1 and believed 
the      will of ,god to be an efficient
 cause4 ,doubtless they did1 and        
the ,cartesians even believed1 though   
,leibnitz did not1 that it      is the  
only such cause4 ,dr4 ,tulloch mistakes 
the nature of the      question4 ,i was 
not writing on ,theism1 as ,dr4 ,tulloch
 is1 but      against a particular      
theory of causation1 which if it be     
unfounded1 can give no effective support
 to ,theism or to      anything else4 ,i
 found it asserted that volition is the 
only      efficient cause1 on the ground
 that no other efficient cause is       
conceivable4 ,to this assertion ,i      
oppose the instances of      ,leibnitz  
and of the ,cartesians1 who affirmed    
with equal      positiveness that       
volition as an efficient cause is itself
 not      conceivable1 and that         
omnipotence1 which renders all things   

conceivable1 can alone take away the    
impossibility4 ,this ,i      thought1   
and think1 a conclusive answer to the   
argument on      which this theory of   
causation avowedly depends4 ,but ,i     
certainly did not imagine that ,theism  
was bound up with that      theory2 nor 
expected to be charged with denying     
,leibnitz and      the ,cartesians to be
 ,theists because ,i denied that they   
held      the theory4     ,,chapter     
,,vi4  ,,on ,,the ,,composition ,,of    
,,causes4    #a4 ,to complete the       
general notion of causation on which the
 rules of experimental inquiry into the 
laws of nature must be founded1 one     
distinction still remains to be pointed 
out3 a distinction so radical1 and of so
 much importance1 as to require a       
chapter to itself4  ,the preceding      
discussions have rendered us familiar   
with the case in which several agents1  
or causes1 concur as conditions to the  
production of an effect3 a case1 in     
truth1 almost universal1 there being    

very few effects to the production of   
which no more than one agent            
contributes4 ,suppose1 then1 that two   
different agents1 operating jointly1 are
 followed1 under a certain set of       
collateral conditions1 by a given       
effect4 ,if either of these agents1     
instead of being joined with the other1 
had operated alone1 under the same set  
of conditions in all other respects1    
some effect would probably have         
followed2 which would have been         
different from the joint effect of the  
two1 and more or less dissimilar to it4 
,now1 if we happen to know what would be
 the effect of each cause when acting   
separately from the other1 we are often 
able to arrive deductively1 or  priori1 
at a correct prediction of what will    
arise from their conjunct agency4 ,to   
enable us to do this1 it is only        
necessary that the same law which       
expresses the effect of each cause      
acting by itself1 shall also correctly  
express the part due to that cause1 of  

the effect which follows from the two   
together4 ,this condition is realized in
 the extensive and important class of   
phenomena commonly called mechanical1   
namely the phenomena of the             
communication of motion 7or of pressure1
 which is tendency to motion7 from one  
body to another4 ,in this important     
class of cases of causation1 one cause  
never1 properly speaking1 defeats or    
frustrates another2 both have their full
 effect4 ,if a body is propelled in two 
directions by two forces1 one tending to
 drive it to the north and the other to 
the east1 it is caused to move in a     
given time exactly as far in both       
directions as the two forces would      
separately have carried it2 and is left 
precisely where it would have arrived if
 it had been acted upon first by one of 
the two forces1 and afterwards by the   
other4 ,this law of nature is called1 in
 dynamics1 the principle of the         
,composition of ,forces3 and in         
imitation of that well-chosen           

expression1 ,i shall give the name of   
the ,composition of ,causes to the      
principle which is exemplified in all   
cases in which the joint effect of      
several causes is identical with the sum
 of their separate effects4  ,this      
principle1 however1 by no means prevails
 in all departments of the field of     
nature4 ,the chemical combination of two
 substances produces1 as is well known1 
a third substance with properties       
entirely different from those of either 
of the two substances separately1 or    
both of them taken together4 ,not a     
trace of the properties of hydrogen or  
of oxygen is observable in those of     
their compound1 water4 ,the taste of    
sugar of lead is not the sum of the     
tastes of its component elements1 acetic
 acid and lead or its oxide2 nor is the 
colour of blue vitriol a mixture of the 
colours of sulphuric acid and copper4   
,this explains why mechanics is a       
deductive or demonstrative science1 and 
chemistry not4 ,in the one1 we can      

compute the effects of all combinations 
of causes1 whether real or hypothetical1
 from the laws which we know to govern  
those causes when acting separately2    
because they continue to observe the    
same laws when in combination which they
 observed when separate3 whatever would 
have happened in consequence of each    
cause taken by itself1 happens when they
 are together1 and we have only to cast 
up the results4 ,not so in the phenomena
 which are the peculiar subject of the  
science of chemistry4 ,there1 most of   
the uniformities to which the causes    
conformed when separate1 cease          
altogether when they are conjoined2 and 
we are not1 at least in the present     
state of our knowledge1 able to foresee 
what result will follow from any new    
combination1 until we have tried the    
specific experiment4  ,if this be true  
of chemical combinations1 it is still   
more true of those far more complex     
combinations of elements which          
constitute organized bodies2 and in     

which those extraordinary new           
uniformities arise1 which are called the
 laws of life4 ,all organized bodies are
 composed of parts similar to those     
composing inorganic nature1 and which   
have even themselves existed in an      
inorganic state2 but the phenomena of   
life1 which result from the             
juxtaposition of those parts in a       
certain manner1 bear no analogy to any  
of the effects which would be produced  
by the action of the component          
substances considered as mere physical  
agents4 ,to whatever degree we might    
imagine our knowledge of the properties 
of the several ingredients of a living  
body to be extended and perfected1 it is
 certain that no mere summing up of the 
separate actions of those elements will 
ever amount to the action of the living 
body itself4 ,the tongue1 for instance1 
is1 like all other parts of the animal  
frame1 composed of gelatine1 fibrin1 and
 other products of the chemistry of     
digestion1 but from no knowledge of the 

properties of those substances could we 
ever predict that it could taste1 unless
 gelatine or fibrin could themselves    
taste2 for no elementary fact can be in 
the conclusion1 which was not in the    
premises4  ,there are thus two different
 modes of the conjunct action of causes2
 from which arise two modes of conflict1
 or mutual interference1 between laws of
 nature4 ,suppose1 at a given point of  
time and space1 two or more causes1     
which1 if they acted separately1 would  
produce effects contrary1 or at least   
conflicting with each other2 one of them
 tending to undo1 wholly or partially1  
what the other tends to do4 ,thus1 the  
expansive force of the gases generated  
by the ignition of gunpowder tends to   
project a bullet towards the sky1 while 
its gravity tends to make it fall to the
 ground4 ,a stream running into a       
reservoir at one end tends to fill it   
higher and higher1 while a drain at the 
other extremity tends to empty it4 ,now1
 in such cases as these1 even if the two

 causes which are in joint action       
exactly annul one another1 still the    
laws of both are fulfilled2 the effect  
is the same as if the drain had been    
open for half an hour first1#ca and the 
stream had flowed in for as long        
afterwards4 ,each agent produced the    
same amount of effect as if it had acted
 separately1 though the contrary effect 
which was taking place during the same  
time obliterated it as fast as it was   
produced4 ,here then are two causes1    
producing by their joint operation an   
effect which at first seems quite       
dissimilar to those which they produce  
separately1 but which on examination    
proves to be really the sum of those    
separate effects4 ,it will be noticed   
that we here enlarge the idea of the sum
 of two effects1 so as to include what  
is commonly called their difference1 but
 which is in reality the result of the  
addition of opposites2 a conception to  
which mankind are indebted for that     
admirable extension of the algebraical  

calculus1 which has so vastly increased 
its powers as an instrument of          
discovery1 by introducing into its      
reasonings 7with the sign of subtraction
 prefixed1 and under the name of        
,negative ,quantities7 every description
 whatever of positive phenomena1        
provided they are of such a quality in  
reference to those previously           
introduced1 that to add the one is      
equivalent to subtracting an equal      
quantity of the other4  ,there is1 then1
 one mode of the mutual interference of 
laws of nature1 in which1 even when the 
concurrent causes annihilate each       
other's effects1 each exerts its full   
efficacy according to its own law1 its  
law as a separate agent4 ,but in the    
other description of cases1 the agencies
 which are brought together cease       
entirely1 and a totally different set of
 phenomena arise3 as in the experiment  
of two liquids which1 when mixed in     
certain proportions1 instantly become1  
not a larger amount of liquid1 but a    

solid mass4    #b4 ,this difference     
between the case in which the joint     
effect of causes is the sum of their    
separate effects1 and the case in which 
it is heterogeneous to them2 between    
laws which work together without        
alteration1 and laws which1 when called 
upon to work together1 cease and give   
place to others2 is one of the          
fundamental distinctions in nature4 ,the
 former case1 that of the ,composition  
of ,causes1 is the general one2 the     
other is always special and exceptional4
 ,there are no objects which do not1 as 
to some of their phenomena1 obey the    
principle of the ,composition of        
,causes2 none that have not some laws   
which are rigidly fulfilled in every    
combination into which the objects      
enter4 ,the weight of a body1 for       
instance1 is a property which it retains
 in all the combinations in which it is 
placed4 ,the weight of a chemical       
compound1 or of an organized body1 is   
equal to the sum of the weights of the  

elements which compose it4 ,the weight  
either of the elements or of the        
compound will vary1 if they be carried  
farther from their centre of attraction1
 or brought nearer to it2 but whatever  
affects the one affects the other4 ,they
 always remain precisely equal4 ,so     
again1 the component parts of a         
vegetable or animal substance do not    
lose their mechanical and chemical      
properties as separate agents1 when1 by 
a peculiar mode of juxtaposition1 they1 
as an aggregate whole1 acquire          
physiological or vital properties in    
addition4 ,those bodies continue1 as    
before1 to obey mechanical and chemical 
laws1 in so far as the operation of     
those laws is not counteracted by the   
new laws which govern them as organized 
beings4 ,when1 in short1 a concurrence  
of causes takes place which calls into  
action new laws bearing no analogy to   
any that we can trace in the separate   
operation of the causes1 the new laws1  
while they supersede one portion of the 

previous laws1 may coexist with another 
portion1 and may even compound the      
effect of those previous laws with their
 own4  ,again1 laws which were          
themselves generated in the second mode1
 may generate others in the first4      
,though there are laws which1 like those
 of chemistry and physiology1 owe their 
existence to a breach of the principle  
of ,composition of ,causes1 it does not 
follow that these peculiar1 or as they  
might be termed1 heteropathic laws1 are 
not capable of composition with one     
another4 ,the causes which by one       
combination have had their laws altered1
 may carry their new laws with them     
unaltered into their ulterior           
combinations4 ,and hence there is no    
reason to despair of ultimately raising 
chemistry and physiology to the         
condition of deductive sciences2 for    
though it is impossible to deduce all   
chemical and physiological truths from  
the laws or properties of simple        
substances or elementary agents1 they   

may possibly be deducible from laws     
which commence when these elementary    
agents are brought together into some   
moderate number of not very complex     
combinations4 ,the ,laws of ,life will  
never be deducible from the mere laws of
 the ingredients1 but the prodigiously  
complex ,facts of ,life may all be      
deducible from comparatively simple laws
 of life2 which laws 7depending indeed  
on combinations1 but on comparatively   
simple combinations1 of antecedents7    
may1 in more complex circumstances1 be  
strictly compounded with one another1   
and with the physical and chemical laws 
of the ingredients4 ,the details of the 
vital phenomena1 even now1 afford       
innumerable exemplifications of the     
,composition of ,causes2 and in         
proportion as these phenomena are more  
accurately studied1 there appears more  
reason to believe that the same laws    
which operate in the simpler            
combinations of circumstances do1 in    
fact1 continue to be observed in the    

more complex4 ,this will be found       
equally true in the phenomena of mind2  
and even in social and political        
phenomena1 the results of the laws of   
mind4 ,it is in the case of chemical    
phenomena that the least progress has   
yet been made in bringing the special   
laws under general ones from which they 
may be deduced2 but there are even in   
chemistry many circumstances to         
encourage the hope that such general    
laws will hereafter be discovered4 ,the 
different actions of a chemical compound
 will never1 undoubtedly1 be found to be
 the sums of the actions of its separate
 elements2 but there may exist1 between 
the properties of the compound and those
 of its elements1 some constant         
relation1 which1 if discoverable by a   
sufficient induction1 would enable us to
 foresee the sort of compound which will
 result from a new combination before we
 have actually tried it1 and to judge of
 what sort of elements some new         
substance is compounded before we have  

analysed it4 ,the law of definite       
proportions1 first discovered in its    
full generality by ,dalton1 is a        
complete solution of this problem in    
one1 though but a secondary aspect1 that
 of quantity3 and in respect to quality1
 we have already some partial           
generalizations sufficient to indicate  
the possibility of ultimately proceeding
 farther4 ,we can predicate some common 
properties of the kind of compounds     
which result from the combination1 in   
each of the small number of possible    
proportions1 of any acid whatever with  
any base4 ,we have also the curious law1
 discovered by ,berthollet1 that two    
soluble salts mutually decompose one    
another whenever the new combinations   
which result produce an insoluble       
compound1 or one less soluble than the  
two former4 ,another uniformity is that 
called the law of isomorphism2 the      
identity of the crystalline forms of    
substances which possess in common      
certain peculiarities of chemical       

composition4 ,thus it appears that even 
heteropathic laws1 such laws of combined
 agency as are not compounded of the    
laws of the separate agencies1 are yet1 
at least in some cases1 derived from    
them according to a fixed principle4    
,there may1 therefore1 be laws of the   
generation of laws from others          
dissimilar to them2 and in chemistry1   
these undiscovered laws of the          
dependence of the properties of the     
compound on the properties of its       
elements1 may1 together with the laws of
 the elements themselves1 furnish the   
premises by which the science is perhaps
 destined one day to be rendered        
deductive4  ,it would seem1 therefore1  
that there is no class of phenomena in  
which the ,composition of ,causes does  
not obtain3 that as a general rule1     
causes in combination produce exactly   
the same effects as when acting singly3 
but that this rule1 though general1 is  
not universal3 that in some instances1  
at some particular points in the        

transition from separate to united      
action1 the laws change1 and an entirely
 new set of effects are either added to1
 or take the place of1 those which arise
 from the separate agency of the same   
causes3 the laws of these new effects   
being again susceptible of composition1 
to an indefinite extent1 like the laws  
which they superseded4    #c4 ,that     
effects are proportional to their causes
 is laid down by some writers as an     
axiom in the theory of causation2 and   
great use is sometimes made of this     
principle in reasonings respecting the  
laws of nature1 though it is incumbered 
with many difficulties and apparent     
exceptions1 which much ingenuity has    
been expended in showing not to be real 
ones4 ,this proposition1 in so far as it
 is true1 enters as a particular case   
into the general principle of the       
,composition of ,causes2 the causes     
compounded being1 in this instance1     
homogeneous2 in which case1 if in any1  
their joint effect might be expected to 

be identical with the sum of their      
separate effects4 ,if a force equal to  
one hundred weight will raise a certain 
body along an inclined plane1 a force   
equal to two hundred weight will raise  
two bodies exactly similar1 and thus the
 effect is proportional to the cause4   
,but does not a force equal to two      
hundred weight actually contain in      
itself two forces each equal to one     
hundred weight1 which1 if employed      
apart1 would separately raise the two   
bodies in question8 ,the fact1          
therefore1 that when exerted jointly    
they raise both bodies at once1 results 
from the ,composition of ,causes1 and is
 a mere instance of the general fact    
that mechanical forces are subject to   
the law of ,composition4 ,and so in     
every other case which can be supposed4 
,for the doctrine of the proportionality
 of effects to their causes cannot of   
course be applicable to cases in which  
the augmentation of the cause alters the
 kind of effect2 that is1 in which the  

surplus quantity superadded to the cause
 does not become compounded with it1 but
 the two together generate an altogether
 new phenomenon4 ,suppose that the      
application of a certain quantity of    
heat to a body merely increases its     
bulk1 that a double quantity melts it1  
and a triple quantity decomposes it3    
these three effects being heterogeneous1
 no ratio1 whether corresponding or not 
to that of the quantities of heat       
applied1 can be established between     
them4 ,thus the supposed axiom of the   
proportionality of effects to their     
causes fails at the precise point where 
the principle of the ,composition of    
,causes also fails2 viz41 where the     
concurrence of causes is such as to     
determine a change in the properties of 
the body generally1 and render it       
subject to new laws1 more or less       
dissimilar to those to which it         
conformed in its previous state4 ,the   
recognition1 therefore1 of any such law 
of proportionality1 is superseded by the

 more comprehensive principle1 in which 
as much of it as is true is implicitly  
asserted4  ,the general remarks on      
causation1 which seemed necessary as an 
introduction to the theory of the       
inductive process1 may here terminate4  
,that process is essentially an inquiry 
into cases of causation4 ,all the       
uniformities which exist in the         
succession of phenomena1 and most of the
 uniformities in their coexistence1 are 
either1 as we have seen1 themselves laws
 of causation1 or consequences resulting
 from1 and corollaries capable of being 
deduced from1 such laws4 ,if we could   
determine what causes are correctly     
assigned to what effects1 and what      
effects to what causes1 we should be    
virtually acquainted with the whole     
course of nature4 ,all those            
uniformities which are mere results of  
causation1 might then be explained and  
accounted for2 and every individual fact
 or event might be predicted1 provided  
we had the requisite data1 that is1 the 

requisite knowledge of the circumstances
 which1 in the particular instance1     
preceded it4  ,to ascertain1 therefore1 
what are the laws of causation which    
exist in nature2 to determine the effect
 of every cause1 and the causes of all  
effects1--is the main business of       
,induction2 and to point out how this is
 done is the chief object of ,inductive 
,logic4     ,,chapter ,,vii4  ,,of      
,,observation ,,and ,,experiment4    #a4
 ,it results from the preceding         
exposition1 that the process of         
ascertaining what consequents1 in       
nature1 are invariably connected with   
what antecedents1 or in other words what
 phenomena are related to each other as 
causes and effects1 is in some sort a   
process of analysis4 ,that every fact   
which begins to exist has a cause1 and  
that this cause must be found somewhere 
among the facts which immediately       
preceded the occurrence1 may be taken   
for certain4 ,the whole of the present  
facts are the infallible result of all  

past facts1 and more immediately of all 
the facts which existed at the moment   
previous4 ,here1 then1 is a great       
sequence1 which we know to be uniform4  
,if the whole prior state of the entire 
universe could again recur1 it would    
again be followed by the present state4 
,the question is1 how to resolve this   
complex uniformity into the simpler     
uniformities which compose it1 and      
assign to each portion of the vast      
antecedent the portion of the consequent
 which is attendant on it4  ,this       
operation1 which we have called         
analytical1 inasmuch as it is the       
resolution of a complex whole into the  
component elements1 is more than a      
merely mental analysis4 ,no mere        
contemplation of the phenomena1 and     
partition of them by the intellect      
alone1 will of itself accomplish the end
 we have now in view4 ,nevertheless1    
such a mental partition is an           
indispensable first step4 ,the order of 
nature1 as perceived at a first glance1 

presents at every instant a chaos       
followed by another chaos4 ,we must     
decompose each chaos into single facts4 
,we must learn to see in the chaotic    
antecedent a multitude of distinct      
antecedents1 in the chaotic consequent a
 multitude of distinct consequents4     
,this1 supposing it done1 will not of   
itself tell us on which of the          
antecedents each consequent is          
invariably attendant4 ,to determine that
 point1 we must endeavour to effect a   
separation of the facts from one        
another1 not in our minds only1 but in  
nature4 ,the mental analysis1 however1  
must take place first4 ,and every one   
knows that in the mode of performing it1
 one intellect differs immensely from   
another4 ,it is the essence of the act  
of observing2 for the observer is not he
 who merely sees the thing which is     
before his eyes1 but he who sees what   
parts that thing is composed of4 ,to do 
this well is a rare talent4 ,one person1
 from inattention1 or attending only in 

the wrong place1 overlooks half of what 
he sees3 another sets down much more    
than he sees1 confounding it with what  
he imagines1 or with what he infers2    
another takes note of the kind of all   
the circumstances1 but being inexpert in
 estimating their degree1 leaves the    
quantity of each vague and uncertain2   
another sees indeed the whole1 but makes
 such an awkward division of it into    
parts1 throwing things into one mass    
which require to be separated1 and      
separating others which might more      
conveniently be considered as one1 that 
the result is much the same1 sometimes  
even worse1 than if no analysis had been
 attempted at all4 ,it would be possible
 to point out what qualities of mind1   
and modes of mental culture1 fit a      
person for being a good observer3 that1 
however1 is a question not of ,logic1   
but of the ,theory of ,education1 in the
 most enlarged sense of the term4 ,there
 is not properly an ,art of ,observing4 
,there may be rules for observing4 ,but 

these1 like rules for inventing1 are    
properly instructions for the           
preparation of one's own mind2 for      
putting it into the state in which it   
will be most fitted to observe1 or most 
likely to invent4 ,they are1 therefore1 
essentially rules of self-education1    
which is a different thing from ,logic4 
,they do not teach how to do the thing1 
but how to make ourselves capable of    
doing it4 ,they are an art of           
strengthening the limbs1 not an art of  
using them4  ,the extent and minuteness 
of observation which may be requisite1  
and the degree of decomposition to which
 it may be necessary to carry the mental
 analysis1 depend on the particular     
purpose in view4 ,to ascertain the state
 of the whole universe at any particular
 moment is impossible1 but would also be
 useless4 ,in making chemical           
experiments1 we do not think it         
necessary to note the position of the   
planets2 because experience has shown1  
as a very superficial experience is     

sufficient to show1 that in such cases  
that circumstance is not material to the
 result3 and1 accordingly1 in the ages  
when men believed in the occult         
influences of the heavenly bodies1 it   
might have been unphilosophical to omit 
ascertaining the precise condition of   
those bodies at the moment of the       
experiment4 ,as to the degree of        
minuteness of the mental subdivision2 if
 we were obliged to break down what we  
observe into its very simplest elements1
 that is1 literally into single facts1  
it would be difficult to say where we   
should find them3 we can hardly ever    
affirm that our divisions of any kind   
have reached the ultimate unit4 ,but    
this too is fortunately unnecessary4    
,the only object of the mental          
separation is to suggest the requisite  
physical separation1 so that we may     
either accomplish it ourselves1 or seek 
for it in nature2 and we have done      
enough when we have carried the         
subdivision as far as the point at which

 we are able to see what observations or
 experiments we require4 ,it is only    
essential1 at whatever point our mental 
decomposition of facts may for the      
present have stopped1 that we should    
hold ourselves ready and able to carry  
it farther as occasion requires1 and    
should not allow the freedom of our     
discriminating faculty to be imprisoned 
by the swathes and bands of ordinary    
classification2 as was the case with all
 early speculative inquirers1 not       
excepting the ,greeks1 to whom it seldom
 occurred that what was called by one   
abstract name might1 in reality1 be     
several phenomena1 or that there was a  
possibility of decomposing the facts of 
the universe into any elements but those
 which ordinary language already        
recognised4    #b4 ,the different       
antecedents and consequents1 being1     
then1 supposed to be1 so far as the case
 requires1 ascertained and discriminated
 from one another2 we are to inquire    
which is connected with which4 ,in every

 instance which comes under our         
observation1 there are many antecedents 
and many consequents4 ,if those         
antecedents could not be severed from   
one another except in thought1 or if    
those consequents never were found      
apart1 it would be impossible for us to 
distinguish 7 posteriori at least7 the  
real laws1 or to assign to any cause its
 effect1 or to any effect its cause4 ,to
 do so1 we must be able to meet with    
some of the antecedents apart from the  
rest1 and observe what follows from     
them2 or some of the consequents1 and   
observe by what they are preceded4 ,we  
must1 in short1 follow the ,baconian    
rule of varying the circumstances4 ,this
 is1 indeed1 only the first rule of     
physical inquiry1 and not1 as some have 
thought1 the sole rule2 but it is the   
foundation of all the rest4  ,for the   
purpose of varying the circumstances1 we
 may have recourse 7according to a      
distinction commonly made7 either to    
observation or to experiment2 we may    

either find an instance in nature1      
suited to our purposes1 or1 by an       
artificial arrangement of circumstances1
 make one4 ,the value of the instance   
depends on what it is in itself1 not on 
the mode in which it is obtained3 its   
employment for the purposes of induction
 depends on the same principles in the  
one case and in the other2 as the uses  
of money are the same whether it is     
inherited or acquired4 ,there is1 in    
short1 no difference in kind1 no real   
logical distinction1 between the two    
processes of investigation4 ,there are1 
however1 practical distinctions to which
 it is of considerable importance to    
advert4    #c4 ,the first and most      
obvious distinction between ,observation
 and ,experiment is1 that the latter is 
an immense extension of the former4 ,it 
not only enables us to produce a much   
greater number of variations in the     
circumstances than nature spontaneously 
offers1 but also1 in thousands of cases1
 to produce the precise sort of         

variation which we are in want of for   
discovering the law of the phenomenon2 a
 service which nature1 being constructed
 on a quite different scheme from that  
of facilitating our studies1 is seldom  
so friendly as to bestow upon us4 ,for  
example1 in order to ascertain what     
principle in the atmosphere enables it  
to sustain life1 the variation we       
require is that a living animal should  
be immersed in each component element of
 the atmosphere separately4 ,but nature 
does not supply either oxygen or azote  
in a separate state4 ,we are indebted to
 artificial experiment for our knowledge
 that it is the former1 and not the     
latter1 which supports respiration2 and 
for our knowledge of the very existence 
of the two ingredients4  ,thus far the  
advantage of experimentation over simple
 observation is universally recognised3 
all are aware that it enables us to     
obtain innumerable combinations of      
circumstances which are not to be found 
in nature1 and so add to nature's       

experiments a multitude of experiments  
of our own4 ,but there is another       
superiority 7or1 as ,bacon would have   
expressed it1 another prerogative7 of   
instances artificially obtained over    
spontaneous instances1--of our own      
experiments over even the same          
experiments when made by nature1--which 
is not of less importance1 and which is 
far from being felt and acknowledged in 
the same degree4  ,when we can produce a
 phenomenon artificially1 we can take   
it1 as it were1 home with us1 and       
observe it in the midst of circumstances
 with which in all other respects we are
 accurately acquainted4 ,if we desire to
 know what are the effects of the cause 
,a1 and are able to produce ,a by means 
at our disposal1 we can generally       
determine at our own discretion1 so far 
as is compatible with the nature of the 
phenomenon ,a1 the whole of the         
circumstances which shall be present    
along with it3 and thus1 knowing exactly
 the simultaneous state of everything   

else which is within the reach of ,a's  
influence1 we have only to observe what 
alteration is made in that state by the 
presence of ,a4  ,for example1 by the   
electric machine we can produce in the  
midst of known circumstances1 the       
phenomena which nature exhibits on a    
grander scale in the form of lightning  
and thunder4 ,now let any one consider  
what amount of knowledge of the effects 
and laws of electric agency mankind     
could have obtained from the mere       
observation of thunder-storms1 and      
compare it with that which they have    
gained1 and may expect to gain1 from    
electrical and galvanic experiments4    
,this example is the more striking1 now 
that we have reason to believe that     
electric action is of all natural       
phenomena 7except heat7 the most        
pervading and universal1 which1         
therefore1 it might antecedently have   
been supposed could stand least in need 
of artificial means of production to    
enable it to be studied2 while the fact 

is so much the contrary1 that without   
the electric machine1 the ,leyden jar1  
and the voltaic battery1 we probably    
should never have suspected the         
existence of electricity as one of the  
great agents in nature2 the few electric
 phenomena we should have known of would
 have continued to be regarded either as
 supernatural1 or as a sort of anomalies
 and eccentricities in the order of the 
universe4  ,when we have succeeded in   
insulating the phenomenon which is the  
subject of inquiry1 by placing it among 
known circumstances1 we may produce     
further variations of circumstances to  
any extent1 and of such kinds as we     
think best calculated to bring the laws 
of the phenomenon into a clear light4   
,by introducing one well-defined        
circumstance after another into the     
experiment1 we obtain assurance of the  
manner in which the phenomenon behaves  
under an indefinite variety of possible 
circumstances4 ,thus1 chemists1 after   
having obtained some newly-discovered   

substance in a pure state1 7that is1    
having made sure that there is nothing  
present which can interfere with and    
modify its agency17 introduce various   
other substances1 one by one1 to        
ascertain whether it will combine with  
them1 or decompose them1 and with what  
result2 and also apply heat1 or         
electricity1 or pressure1 to discover   
what will happen to the substance under 
each of these circumstances4  ,but if1  
on the other hand1 it is out of our     
power to produce the phenomenon1 and we 
have to seek for instances in which     
nature produces it1 the task before us  
is very different4 ,instead of being    
able to choose what the concomitant     
circumstances shall be1 we now have to  
discover what they are2 which1 when we  
go beyond the simplest and most         
accessible cases1 it is next to         
impossible to do1 with any precision and
 completeness4 ,let us take1 as an      
exemplification of a phenomenon which we
 have no means of fabricating           

artificially1 a human mind4 ,nature     
produces many2 but the consequence of   
our not being able to produce them by   
art is1 that in every instance in which 
we see a human mind developing itself1  
or acting upon other things1 we see it  
surrounded and obscured by an indefinite
 multitude of unascertainable           
circumstances1 rendering the use of the 
common experimental methods almost      
delusive4 ,we may conceive to what      
extent this is true1 if we consider1    
among other things1 that whenever nature
 produces a human mind1 she produces1 in
 close connexion with it1 a body2 that  
is1 a vast complication of physical     
facts1 in no two cases perhaps exactly  
similar1 and most of which 7except the  
mere structure1 which we can examine in 
a sort of coarse way after it has ceased
 to act71 are radically out of the reach
 of our means of exploration4 ,if1      
instead of a human mind1 we suppose the 
subject of investigation to be a human  
society or ,state1 all the same         

difficulties recur in a greatly         
augmented degree4  ,we have thus already
 come within sight of a conclusion1     
which the progress of the inquiry will1 
,i think1 bring before us with the      
clearest evidence3 namely1 that in the  
sciences which deal with phenomena in   
which artificial experiments are        
impossible 7as in the case of           
astronomy71 or in which they have a very
 limited range 7as in mental philosophy1
 social science1 and even physiology71  
induction from direct experience is     
practised at a disadvantage in most     
cases equivalent to impracticability3   
from which it follows that the methods  
of those sciences1 in order to          
accomplish anything worthy of           
attainment1 must be to a great extent1  
if not principally1 deductive4 ,this is 
already known to be the case with the   
first of the sciences we have mentioned1
 astronomy2 that it is not generally    
recognised as true of the others1 is    
probably one of the reasons why they are

 not in a more advanced state4    #d4   
,if what is called pure observation is  
at so great a disadvantage1 compared    
with artificial experimentation1 in one 
department of the direct exploration of 
phenomena1 there is another branch in   
which the advantage is all on the side  
of the former4  ,inductive inquiry      
having for its object to ascertain what 
causes are connected with what effects1 
we may begin this search at either end  
of the road which leads from the one    
point to the other3 we may either       
inquire into the effects of a given     
cause1 or into the causes of a given    
effect4 ,the fact that light blackens   
chloride of silver might have been      
discovered either by experiments on     
light1 trying what effect it would      
produce on various substances1 or by    
observing that portions of the chloride 
had repeatedly become black1 and        
inquiring into the circumstances4 ,the  
effect of the urali poison might have   
become known either by administering it 

to animals1 or by examining how it      
happened that the wounds which the      
,indians of ,guiana inflict with their  
arrows prove so uniformly mortal4 ,now  
it is manifest from the mere statement  
of the examples1 without any theoretical
 discussion1 that artificial            
experimentation is applicable only to   
the former of these modes of            
investigation4 ,we can take a cause1 and
 try what it will produce3 but we cannot
 take an effect1 and try what it will be
 produced by4 ,we can only watch till we
 see it produced1 or are enabled to     
produce it by accident4  ,this would be 
of little importance1 if it always      
depended on our choice from which of the
 two ends of the sequence we would      
undertake our inquiries4 ,but we have   
seldom any option4 ,as we can only      
travel from the known to the unknown1 we
 are obliged to commence at whichever   
end we are best acquainted with4 ,if the
 agent is more familiar to us than its  
effects1 we watch for1 or contrive1     

instances of the agent1 under such      
varieties of circumstances as are open  
to us1 and observe the result4 ,if1 on  
the contrary1 the conditions on which a 
phenomenon depends are obscure1 but the 
phenomenon itself familiar1 we must     
commence our inquiry from the effect4   
,if we are struck with the fact that    
chloride of silver has been blackened1  
and have no suspicion of the cause1 we  
have no resource but to compare         
instances in which the fact has chanced 
to occur1 until by that comparison we   
discover that in all those instances the
 substances had been exposed to light4  
,if we knew nothing of the ,indian      
arrows but their fatal effect1 accident 
alone could turn our attention to       
experiments on the urali2 in the regular
 course of investigation1 we could only 
inquire1 or try to observe1 what had    
been done to the arrows in particular   
instances4  ,wherever1 having nothing to
 guide us to the cause1 we are obliged  
to set out from the effect1 and to apply

 the rule of varying the circumstances  
to the consequents1 not the antecedents1
 we are necessarily destitute of the    
resource of artificial experimentation4 
,we cannot1 at our choice1 obtain       
consequents1 as we can antecedents1     
under any set of circumstances          
compatible with their nature4 ,there are
 no means of producing effects but      
through their causes1 and by the        
supposition the causes of the effect in 
question are not known to us4 ,we have  
therefore no expedient but to study it  
where it offers itself spontaneously4   
,if nature happens to present us with   
instances sufficiently varied in their  
circumstances1 and if we are able to    
discover1 either among the proximate    
antecedents or among some other order of
 antecedents1 something which is always 
found when the effect is found1 however 
various the circumstances1 and never    
found when it is not2 we may discover1  
by mere observation without experiment1 
a real uniformity in nature4  ,but      

though this is certainly the most       
favourable case for sciences of pure    
observation1 as contrasted with those in
 which artificial experiments are       
possible1 there is in reality no case   
which more strikingly illustrates the   
inherent imperfection of direct         
induction when not founded on           
experimentation4 ,suppose that1 by a    
comparison of cases of the effect1 we   
have found an antecedent which appears  
to be1 and perhaps is1 invariably       
connected with it3 we have not yet      
proved that antecedent to be the cause1 
until we have reversed the process1 and 
produced the effect by means of that    
antecedent4 ,if we can produce the      
antecedent artificially1 and if1 when we
 do so1 the effect follows1 the         
induction is complete2 that antecedent  
is the cause of that consequent4#cb ,but
 we have then added the evidence of     
experiment to that of simple            
observation4 ,until we had done so1 we  
had only proved invariable antecedence  

within the limits of experience1 but not
 unconditional antecedence1 or          
causation4 ,until it had been shown by  
the actual production of the antecedent 
under known circumstances1 and the      
occurrence thereupon of the consequent1 
that the antecedent was really the      
condition on which it depended2 the     
uniformity of succession which was      
proved to exist between them might1 for 
aught we knew1 be 7like the succession  
of day and night7 not a case of         
causation at all2 both antecedent and   
consequent might be successive stages of
 the effect of an ulterior cause4       
,observation1 in short1 without         
experiment 7supposing no aid from       
deduction7 can ascertain sequences and  
coexistences1 but cannot prove          
causation4  ,in order to see these      
remarks verified by the actual state of 
the sciences1 we have only to think of  
the condition of natural history4 ,in   
zoology1 for example1 there is an       
immense number of uniformities          

ascertained1 some of coexistence1 others
 of succession1 to many of which1       
notwithstanding considerable variations 
of the attendant circumstances1 we know 
not any exception3 but the antecedents1 
for the most part1 are such as we cannot
 artificially produce2 or if we can1 it 
is only by setting in motion the exact  
process by which nature produces them2  
and this being to us a mysterious       
process1 of which the main circumstances
 are not only unknown but unobservable1 
we do not succeed in obtaining the      
antecedents under known circumstances4  
,what is the result8 ,that on this vast 
subject1 which affords so much and such 
varied scope for observation1 we have   
made most scanty progress in            
ascertaining any laws of causation4 ,we 
know not with certainty1 in the case of 
most of the phenomena that we find      
conjoined1 which is the condition of the
 other2 which is cause1 and which       
effect1 or whether either of them is so1
 or they are not rather conjunct effects

 of causes yet to be discovered1 complex
 results of laws hitherto unknown4      
,although some of the foregoing         
observations may be1 in technical       
strictness of arrangement1 premature in 
this place1 it seemed that a few general
 remarks on the difference between      
sciences of mere observation and        
sciences of experimentation1 and the    
extreme disadvantage under which        
directly inductive inquiry is           
necessarily carried on in the former1   
were the best preparation for discussing
 the methods of direct induction2 a     
preparation rendering superfluous much  
that must otherwise have been           
introduced1 with some inconvenience1    
into the heart of that discussion4 ,to  
the consideration of these methods we   
now proceed4     ,,chapter ,,viii4  ,,of
 ,,the ,,four ,,methods ,,of            
,,experimental ,,inquiry4    #a4 ,the   
simplest and most obvious modes of      
singling out from among the             
circumstances which precede or follow a 

phenomenon1 those with which it is      
really connected by an invariable law1  
are two in number4 ,one is1 by comparing
 together different instances in which  
the phenomenon occurs4 ,the other is1 by
 comparing instances in which the       
phenomenon does occur1 with instances in
 other respects similar in which it does
 not4 ,these two methods may be         
respectively denominated1 the ,method of
 ,agreement1 and the ,method of         
,difference4  ,in illustrating these    
methods1 it will be necessary to bear in
 mind the twofold character of inquiries
 into the laws of phenomena2 which may  
be either inquiries into the cause of a 
given effect1 or into the effects or    
properties of a given cause4 ,we shall  
consider the methods in their           
application to either order of          
investigation1 and shall draw our       
examples equally from both4  ,we shall  
denote antecedents by the large letters 
of the alphabet1 and the consequents    
corresponding to them by the small4 ,let

 ,a1 then1 be an agent or cause1 and let
 the object of our inquiry be to        
ascertain what are the effects of this  
cause4 ,if we can either find1 or       
produce1 the agent ,a in such varieties 
of circumstances1 that the different    
cases have no circumstance in common    
except ,a2 then whatever effect we find 
to be produced in all our trials1 is    
indicated as the effect of ,a4 ,suppose1
 for example1 that ,a is tried along    
with ,b and ,c1 and that the effect is a
 b c2 and suppose that ,a is next tried 
with ,d and ,e1 but without ,b and ,c1  
and that the effect is a d e4 ,then we  
may reason thus3 b and c are not effects
 of ,a1 for they were not produced by it
 in the second experiment2 nor are d and
 e1 for they were not produced in the   
first4 ,whatever is really the effect of
 ,a must have been produced in both     
instances2 now this condition is        
fulfilled by no circumstance except a4  
,the phenomenon a cannot have been the  
effect of ,b or ,c1 since it was        

produced where they were not2 nor of ,d 
or ,e1 since it was produced where they 
were not4 ,therefore it is the effect of
 ,a4  ,for example1 let the antecedent  
,a be the contact of an alkaline        
substance and an oil4 ,this combination 
being tried under several varieties of  
circumstances1 resembling each other in 
nothing else1 the results agree in the  
production of a greasy and detersive or 
saponaceous substance3 it is therefore  
concluded that the combination of an oil
 and an alkali causes the production of 
a soap4 ,it is thus we inquire1 by the  
,method of ,agreement1 into the effect  
of a given cause4  ,in a similar manner 
we may inquire into the cause of a given
 effect4 ,let a be the effect4 ,here1 as
 shown in the last chapter1 we have only
 the resource of observation without    
experiment3 we cannot take a phenomenon 
of which we know not the origin1 and try
 to find its mode of production by      
producing it3 if we succeeded in such a 
random trial it could only be by        

accident4 ,but if we can observe a in   
two different combinations1 a b c1 and a
 d e2 and if we know1 or can discover1  
that the antecedent circumstances in    
these cases respectively were ,a ,b ,c  
and ,a ,d ,e2 we may conclude by a      
reasoning similar to that in the        
preceding example1 that ,a is the       
antecedent connected with the consequent
 a by a law of causation4 ,b and ,c1 we 
may say1 cannot be causes of a1 since on
 its second occurrence they were not    
present2 nor are ,d and ,e1 for they    
were not present on its first           
occurrence4 ,a1 alone of the five       
circumstances1 was found among the      
antecedents of a in both instances4     
,for example1 let the effect a be       
crystallization4 ,we compare instances  
in which bodies are known to assume     
crystalline structure1 but which have no
 other point of agreement2 and we find  
them to have one1 and as far as we can  
observe1 only one1 antecedent in common3
 the deposition of a solid matter from a

 liquid state1 either a state of fusion 
or of solution4 ,we conclude1 therefore1
 that the solidification of a substance 
from a liquid state is an invariable    
antecedent of its crystallization4  ,in 
this example we may go farther1 and say1
 it is not only the invariable          
antecedent but the cause2 or at least   
the proximate event which completes the 
cause4 ,for in this case we are able1   
after detecting the antecedent ,a1 to   
produce it artificially1 and by finding 
that a follows it1 verify the result of 
our induction4 ,the importance of thus  
reversing the proof was strikingly      
manifested when by keeping a phial of   
water charged with siliceous particles  
undisturbed for years1 a chemist 7,i    
believe ,dr4 ,wollaston7 succeeded in   
obtaining crystals of quartz3 and in the
 equally interesting experiment in which
 ,sir ,james ,hall produced artificial  
marble1 by the cooling of its materials 
from fusion under immense pressure3 two 
admirable examples of the light which   

may be thrown upon the most secret      
processes of nature by well-contrived   
interrogation of her4  ,but if we cannot
 artificially produce the phenomenon ,a1
 the conclusion that it is the cause of 
a remains subject to very considerable  
doubt4 ,though an invariable1 it may not
 be the unconditional antecedent of a1  
but may precede it as day precedes night
 or night day4 ,this uncertainty arises 
from the impossibility of assuring      
ourselves that ,a is the only immediate 
antecedent common to both the instances4
 ,if we could be certain of having      
ascertained all the invariable          
antecedents1 we might be sure that the  
unconditional invariable antecedent1 or 
cause1 must be found somewhere among    
them4 ,unfortunately it is hardly ever  
possible to ascertain all the           
antecedents1 unless the phenomenon is   
one which we can produce artificially4  
,even then1 the difficulty is merely    
lightened1 not removed3 men knew how to 
raise water in pumps long before they   

adverted to what was really the         
operating circumstance in the means they
 employed1 namely1 the pressure of the  
atmosphere on the open surface of the   
water4 ,it is1 however1 much easier to  
analyse completely a set of arrangements
 made by ourselves1 than the whole      
complex mass of the agencies which      
nature happens to be exerting at the    
moment of the production of a given     
phenomenon4 ,we may overlook some of the
 material circumstances in an experiment
 with an electrical machine2 but we     
shall1 at the worst1 be better          
acquainted with them than with those of 
a thunder-storm4  ,the mode of          
discovering and proving laws of nature1 
which we have now examined1 proceeds on 
the following axiom3 ,whatever          
circumstances can be excluded1 without  
prejudice to the phenomenon1 or can be  
absent notwithstanding its presence1 is 
not connected with it in the way of     
causation4 ,the casual circumstances    
being thus eliminated1 if only one      

remains1 that one is the cause which we 
are in search of3 if more than one1 they
 either are1 or contain among them1 the 
cause2 and so1 mutatis mutandis1 of the 
effect4 ,as this method proceeds by     
comparing different instances to        
ascertain in what they agree1 ,i have   
termed it the ,method of ,agreement3 and
 we may adopt as its regulating         
principle the following canon3--        
,,first ,,canon4  ,if two or more       
instances of the phenomenon under       
investigation have only one circumstance
 in common1 the circumstance in which   
alone all the instances agree1 is the   
cause 7or effect7 of the given          
phenomenon4  ,quitting for the present  
the ,method of ,agreement1 to which we  
shall almost immediately return1 we     
proceed to a still more potent          
instrument of the investigation of      
nature1 the ,method of ,difference4     
#b4 ,in the ,method of ,agreement1 we   
endeavoured to obtain instances which   
agreed in the given circumstance but    

differed in every other3 in the present 
method we require1 on the contrary1 two 
instances resembling one another in     
every other respect1 but differing in   
the presence or absence of the          
phenomenon we wish to study4 ,if our    
object be to discover the effects of an 
agent ,a1 we must procure ,a in some set
 of ascertained circumstances1 as ,a ,b 
,c1 and having noted the effects        
produced1 compare them with the effect  
of the remaining circumstances ,b ,c1   
when ,a is absent4 ,if the effect of ,a 
,b ,c is a b c1 and the effect of ,b ,c1
 b c1 it is evident that the effect of  
,a is a4 ,so again1 if we begin at the  
other end1 and desire to investigate the
 cause of an effect a1 we must select an
 instance1 as a b c1 in which the effect
 occurs1 and in which the antecedents   
were ,a ,b ,c1 and we must look out for 
another instance in which the remaining 
circumstances1 b c1 occur without a4 ,if
 the antecedents1 in that instance1 are 
,b ,c1 we know that the cause of a must 

be ,a3 either ,a alone1 or ,a in        
conjunction with some of the other      
circumstances present4  ,it is scarcely 
necessary to give examples of a logical 
process to which we owe almost all the  
inductive conclusions we draw in daily  
life4 ,when a man is shot through the   
heart1 it is by this method we know that
 it was the gun-shot which killed him3  
for he was in the fulness of life       
immediately before1 all circumstances   
being the same1 except the wound4  ,the 
axioms implied in this method are       
evidently the following4 ,whatever      
antecedent cannot be excluded without   
preventing the phenomenon1 is the cause1
 or a condition1 of that phenomenon3    
,whatever consequent can be excluded1   
with no other difference in the         
antecedents than the absence of a       
particular one1 is the effect of that   
one4 ,instead of comparing different    
instances of a phenomenon1 to discover  
in what they agree1 this method compares
 an instance of its occurrence with an  

instance of its non-occurrence1 to      
discover in what they differ4 ,the canon
 which is the regulating principle of   
the ,method of ,difference may be       
expressed as follows3  ,,second ,,canon4
  ,if an instance in which the          
phenomenon under investigation occurs1  
and an instance in which it does not    
occur1 have every circumstance in common
 save one1 that one occurring only in   
the former2 the circumstance in which   
alone the two instances differ1 is the  
effect1 or the cause1 or an             
indispensable part of the cause1 of the 
phenomenon4    #c4 ,the two methods     
which we have now stated have many      
features of resemblance1 but there are  
also many distinctions between them4    
,both are methods of elimination4 ,this 
term 7employed in the theory of         
equations to denote the process by which
 one after another of the elements of a 
question is excluded1 and the solution  
made to depend on the relation between  
the remaining elements only7 is well    

suited to express the operation1        
analogous to this1 which has been       
understood since the time of ,bacon to  
be the foundation of experimental       
inquiry3 namely1 the successive         
exclusion of the various circumstances  
which are found to accompany a          
phenomenon in a given instance1 in order
 to ascertain what are those among them 
which can be absent consistently with   
the existence of the phenomenon4 ,the   
,method of ,agreement stands on the     
ground that whatever can be eliminated1 
is not connected with the phenomenon by 
any law4 ,the ,method of ,difference has
 for its foundation1 that whatever      
cannot be eliminated1 is connected with 
the phenomenon by a law4  ,of these     
methods1 that of ,difference is more    
particularly a method of artificial     
experiment2 while that of ,agreement is 
more especially the resource employed   
where experimentation is impossible4 ,a 
few reflections will prove the fact1 and
 point out the reason of it4  ,it is    

inherent in the peculiar character of   
the ,method of ,difference1 that the    
nature of the combinations which it     
requires is much more strictly defined  
than in the ,method of ,agreement4 ,the 
two instances which are to be compared  
with one another must be exactly        
similar1 in all circumstances except the
 one which we are attempting to         
investigate3 they must be in the        
relation of ,a ,b ,c and ,b ,c1 or of a 
b c and b c4 ,it is true that this      
similarity of circumstances needs not   
extend to such as are already known to  
be immaterial to the result4 ,and in the
 case of most phenomena we learn at     
once1 from the commonest experience1    
that most of the coexistent phenomena of
 the universe may be either present or  
absent without affecting the given      
phenomenon2 or1 if present1 are present 
indifferently when the phenomenon does  
not happen and when it does4 ,still1    
even limiting the identity which is     
required between the two instances1 ,a  

,b ,c and ,b ,c1 to such circumstances  
as are not already known to be          
indifferent2 it is very seldom that     
nature affords two instances1 of which  
we can be assured that they stand in    
this precise relation to one another4   
,in the spontaneous operations of nature
 there is generally such complication   
and such obscurity1 they are mostly     
either on so overwhelmingly large or on 
so inaccessibly minute a scale1 we are  
so ignorant of a great part of the facts
 which really take place1 and even those
 of which we are not ignorant are so    
multitudinous1 and therefore so seldom  
exactly alike in any two cases1 that a  
spontaneous experiment1 of the kind     
required by the ,method of ,difference1 
is commonly not to be found4 ,when1 on  
the contrary1 we obtain a phenomenon by 
an artificial experiment1 a pair of     
instances such as the method requires is
 obtained almost as a matter of course1 
provided the process does not last a    
long time4 ,a certain state of          

surrounding circumstances existed before
 we commenced the experiment2 this is ,b
 ,c4 ,we then introduce ,a2 say1 for    
instance1 by merely bringing an object  
from another part of the room1 before   
there has been time for any change in   
the other elements4 ,it is1 in short 7as
 ,m4 ,comte observes71 the very nature  
of an experiment1 to introduce into the 
pre-existing state of circumstances a   
change perfectly definite4 ,we choose a 
previous state of things with which we  
are well acquainted1 so that no         
unforeseen alteration in that state is  
likely to pass unobserved2 and into this
 we introduce1 as rapidly as possible1  
the phenomenon which we wish to study2  
so that in general we are entitled to   
feel complete assurance that the        
pre-existing state1 and the state which 
we have produced1 differ in nothing     
except the presence or absence of that  
phenomenon4 ,if a bird is taken from a  
cage1 and instantly plunged into        
carbonic acid gas1 the experimentalist  

may be fully assured 7at all events     
after one or two repetitions7 that no   
circumstance capable of causing         
suffocation had supervened in the       
interim1 except the change from         
immersion in the atmosphere to immersion
 in carbonic acid gas4 ,there is one    
doubt1 indeed1 which may remain in some 
cases of this description2 the effect   
may have been produced not by the       
change1 but by the means employed to    
produce the change4 ,the possibility1   
however1 of this last supposition       
generally admits of being conclusively  
tested by other experiments4 ,it thus   
appears that in the study of the various
 kinds of phenomena which we can1 by our
 voluntary agency1 modify or control1 we
 can in general satisfy the requisitions
 of the ,method of ,difference2 but that
 by the spontaneous operations of nature
 those requisitions are seldom          
fulfilled4  ,the reverse of this is the 
case with the ,method of ,agreement4 ,we
 do not here require instances of so    

special and determinate a kind4 ,any    
instances whatever1 in which nature     
presents us with a phenomenon1 may be   
examined for the purposes of this       
method2 and if all such instances agree 
in anything1 a conclusion of            
considerable value is already attained4 
,we can seldom1 indeed1 be sure that the
 one point of agreement is the only one2
 but this ignorance does not1 as in the 
,method of ,difference1 vitiate the     
conclusion2 the certainty of the result1
 as far as it goes1 is not affected4 ,we
 have ascertained one invariable        
antecedent or consequent1 however many  
other invariable antecedents or         
consequents may still remain            
unascertained4 ,if ,a ,b ,c1 ,a ,d ,e1  
,a ,f ,g1 are all equally followed by a1
 then a is an invariable consequent of  
,a4 ,if a b c1 a d e1 a f g1 all number 
,a among their antecedents1 then ,a is  
connected as an antecedent1 by some     
invariable law1 with a4 ,but to         
determine whether this invariable       

antecedent is a cause1 or this          
invariable consequent an effect1 we must
 be able1 in addition1 to produce the   
one by means of the other2 or1 at least1
 to obtain that which alone constitutes 
our assurance of having produced        
anything1 namely1 an instance in which  
the effect1 a1 has come into existence1 
with no other change in the pre-existing
 circumstances than the addition of ,a4 
,and this1 if we can do it1 is an       
application of the ,method of           
,difference1 not of the ,method of      
,agreement4  ,it thus appears to be by  
the ,method of ,difference alone that we
 can ever1 in the way of direct         
experience1 arrive with certainty at    
causes4 ,the ,method of ,agreement leads
 only to laws of phenomena 7as some     
writers call them1 but improperly1 since
 laws of causation are also laws of     
phenomena73 that is1 to uniformities1   
which either are not laws of causation1 
or in which the question of causation   
must for the present remain undecided4  

,the ,method of ,agreement is chiefly to
 be resorted to1 as a means of          
suggesting applications of the ,method  
of ,difference 7as in the last example  
the comparison of ,a ,b ,c1 ,a ,d ,e1 ,a
 ,f ,g1 suggested that ,a was the       
antecedent on which to try the          
experiment whether it could produce a72 
or as an inferior resource1 in case the 
,method of ,difference is impracticable2
 which1 as we before showed1 generally  
arises from the impossibility of        
artificially producing the phenomena4   
,and hence it is that the ,method of    
,agreement1 though applicable in        
principle to either case1 is more       
emphatically the method of investigation
 on those subjects where artificial     
experimentation is impossible3 because  
on those it is1 generally1 our only     
resource of a directly inductive nature2
 while1 in the phenomena which we can   
produce at pleasure1 the ,method of     
,difference generally affords a more    
efficacious process1 which will         

ascertain causes as well as mere laws4  
#d4 ,there are1 however1 many cases in  
which1 though our power of producing the
 phenomenon is complete1 the ,method of 
,difference either cannot be made       
available at all1 or not without a      
previous employment of the ,method of   
,agreement4 ,this occurs when the agency
 by which we can produce the phenomenon 
is not that of one single antecedent1   
but a combination of antecedents1 which 
we have no power of separating from each
 other1 and exhibiting apart4 ,for      
instance1 suppose the subject of inquiry
 to be the cause of the double          
refraction of light4 ,we can produce    
this phenomenon at pleasure1 by         
employing any one of the many substances
 which are known to refract light in    
that peculiar manner4 ,but if1 taking   
one of those substances1 as ,iceland    
spar for example1 we wish to determine  
on which of the properties of ,iceland  
spar this remarkable phenomenon depends1
 we can make no use1 for that purpose1  

of the ,method of ,difference2 for we   
cannot find another substance precisely 
resembling ,iceland spar except in some 
one property4 ,the only mode1 therefore1
 of prosecuting this inquiry is that    
afforded by the ,method of ,agreement2  
by which1 in fact1 through a comparison 
of all the known substances which have  
the property of doubly refracting light1
 it was ascertained that they agree in  
the circumstance of being crystalline   
substances2 and though the converse does
 not hold1 though all crystalline       
substances have not the property of     
double refraction1 it was concluded1    
with reason1 that there is a real       
connexion between these two properties2 
that either crystalline structure1 or   
the cause which gives rise to that      
structure1 is one of the conditions of  
double refraction4  ,out of this        
employment of the ,method of ,agreement 
arises a peculiar modification of that  
method1 which is sometimes of great     
avail in the investigation of nature4   

,in cases similar to the above1 in which
 it is not possible to obtain the       
precise pair of instances which our     
second canon requires--instances        
agreeing in every antecedent except ,a1 
or in every consequent except a2 we may 
yet be able1 by a double employment of  
the ,method of ,agreement1 to discover  
in what the instances which contain ,a  
or a1 differ from those which do not4   
,if we compare various instances in     
which a occurs1 and find that they all  
have in common the circumstance ,a1 and 
7as far as can be observed7 no other    
circumstance1 the ,method of ,agreement1
 so far1 bears testimony to a connexion 
between ,a and a4 ,in order to convert  
this evidence of connexion into proof of
 causation by the direct ,method of     
,difference1 we ought to be able1 in    
some one of these instances1 as for     
example ,a ,b ,c1 to leave out ,a1 and  
observe whether by doing so1 a is       
prevented4 ,now supposing 7what is often
 the case7 that we are not able to try  

this decisive experiment2 yet1 provided 
we can by any means discover what would 
be its result if we could try it1 the   
advantage will be the same4 ,suppose1   
then1 that as we previously examined a  
variety of instances in which a         
occurred1 and found them to agree in    
containing ,a1 so we now observe a      
variety of instances in which a does not
 occur1 and find them agree in not      
containing ,a2 which establishes1 by the
 ,method of ,agreement1 the same        
connexion between the absence of ,a and 
the absence of a1 which was before      
established between their presence4 ,as1
 then1 it had been shown that whenever  
,a is present a is present1 so it being 
now shown that when ,a is taken away a  
is removed along with it1 we have by the
 one proposition ,a ,b ,c1 a b c1 by the
 other ,b ,c1 b c1 the positive and     
negative instances which the ,method of 
,difference requires4  ,this method may 
be called the ,indirect ,method of      
,difference1 or the ,joint ,method of   

,agreement and ,difference2 and consists
 in a double employment of the ,method  
of ,agreement1 each proof being         
independent of the other1 and           
corroborating it4 ,but it is not        
equivalent to a proof by the direct     
,method of ,difference4 ,for the        
requisitions of the ,method of          
,difference are not satisfied1 unless we
 can be quite sure either that the      
instances affirmative of a agree in no  
antecedent whatever but ,a1 or that the 
instances negative of a agree in nothing
 but the negation of ,a4 ,now if it were
 possible1 which it never is1 to have   
this assurance1 we should not need the  
joint method2 for either of the two sets
 of instances separately would then be  
sufficient to prove causation4 ,this    
indirect method1 therefore1 can only be 
regarded as a great extension and       
improvement of the ,method of           
,agreement1 but not as participating in 
the more cogent nature of the ,method of
 ,difference4 ,the following may be     

stated as its canon3--  ,,third ,,canon4
  ,if two or more instances in which the
 phenomenon occurs have only one        
circumstance in common1 while two or    
more instances in which it does not     
occur have nothing in common save the   
absence of that circumstance2 the       
circumstance in which alone the two sets
 of instances differ1 is the effect1 or 
the cause1 or an indispensable part of  
the cause1 of the phenomenon4  ,we shall
 presently see that the ,joint ,method  
of ,agreement and ,difference           
constitutes1 in another respect not yet 
adverted to1 an improvement upon the    
common ,method of ,agreement1 namely1 in
 being unaffected by a characteristic   
imperfection of that method1 the nature 
of which still remains to be pointed    
out4 ,but as we cannot enter into this  
exposition without introducing a new    
element of complexity into this long and
 intricate discussion1 ,i shall postpone
 it to a subsequent chapter1 and shall  
at once proceed to a statement of two   

other methods1 which will complete the  
enumeration of the means which mankind  
possess for exploring the laws of nature
 by specific observation and experience4
    #e4 ,the first of these has been    
aptly denominated the ,method of        
,residues4 ,its principle is very       
simple4 ,subducting from any given      
phenomenon all the portions which1 by   
virtue of preceding inductions1 can be  
assigned to known causes1 the remainder 
will be the effect of the antecedents   
which had been overlooked1 or of which  
the effect was as yet an unknown        
quantity4  ,suppose1 as before1 that we 
have the antecedents ,a ,b ,c1 followed 
by the consequents a b c1 and that by   
previous inductions 7founded1 we will   
suppose1 on the ,method of ,difference7 
we have ascertained the causes of some  
of these effects1 or the effects of some
 of these causes2 and are thence        
apprised that the effect of ,a is a1 and
 that the effect of ,b is b4            
,subtracting the sum of these effects   

from the total phenomenon1 there remains
 c1 which now1 without any fresh        
experiments1 we may know to be the      
effect of ,c4 ,this ,method of ,residues
 is in truth a peculiar modification of 
the ,method of ,difference4 ,if the     
instance ,a ,b ,c1 a b c1 could have    
been compared with a single instance ,a 
,b1 a b1 we should have proved ,c to be 
the cause of c1 by the common process of
 the ,method of ,difference4 ,in the    
present case1 however1 instead of a     
single instance ,a ,b1 we have had to   
study separately the causes ,a and ,b1  
and to infer from the effects which they
 produce separately1 what effect they   
must produce in the case ,a ,b ,c where 
they act together4 ,of the two          
instances1 therefore1 which the ,method 
of ,difference requires1--the one       
positive1 the other negative1--the      
negative one1 or that in which the given
 phenomenon is absent1 is not the direct
 result of observation and experiment1  
but has been arrived at by deduction4   

,as one of the forms of the ,method of  
,difference1 the ,method of ,residues   
partakes of its rigorous certainty1     
provided the previous inductions1 those 
which gave the effects of ,a and ,b1    
were obtained by the same infallible    
method1 and provided we are certain that
 ,c is the only antecedent to which the 
residual phenomenon c can be referred2  
the only agent of which we had not      
already calculated and subducted the    
effect4 ,but as we can never be quite   
certain of this1 the evidence derived   
from the ,method of ,residues is not    
complete unless we can obtain ,c        
artificially and try it separately1 or  
unless its agency1 when once suggested1 
can be accounted for1 and proved        
deductively from known laws4  ,even with
 these reservations1 the ,method of     
,residues is one of the most important  
among our instruments of discovery4 ,of 
all the methods of investigating laws of
 nature1 this is the most fertile in    
unexpected results2 often informing us  

of sequences in which neither the cause 
nor the effect were sufficiently        
conspicuous to attract of themselves the
 attention of observers4 ,the agent ,c  
may be an obscure circumstance1 not     
likely to have been perceived unless    
sought for1 nor likely to have been     
sought for until attention had been     
awakened by the insufficiency of the    
obvious causes to account for the whole 
of the effect4 ,and c may be so         
disguised by its intermixture with a and
 b1 that it would scarcely have         
presented itself spontaneously as a     
subject of separate study4 ,of these    
uses of the method1 we shall presently  
cite some remarkable examples4 ,the     
canon of the ,method of ,residues is as 
follows3--  ,,fourth ,,canon4  ,subduct 
from any phenomenon such part as is     
known by previous inductions to be the  
effect of certain antecedents1 and the  
residue of the phenomenon is the effect 
of the remaining antecedents4    #f4    
,there remains a class of laws which it 

is impracticable to ascertain by any of 
the three methods which ,i have         
attempted to characterize2 namely1 the  
laws of those ,permanent ,causes1 or    
indestructible natural agents1 which it 
is impossible either to exclude or to   
isolate2 which we can neither hinder    
from being present1 nor contrive that   
they shall be present alone4 ,it would  
appear at first sight that we could by  
no means separate the effects of these  
agents from the effects of those other  
phenomena with which they cannot be     
prevented from coexisting4 ,in respect1 
indeed1 to most of the permanent causes1
 no such difficulty exists2 since though
 we cannot eliminate them as coexisting 
facts1 we can eliminate them as         
influencing agents1 by simply trying our
 experiment in a local situation beyond 
the limits of their influence4 ,the     
pendulum1 for example1 has its          
oscillations disturbed by the vicinity  
of a mountain3 we remove the pendulum to
 a sufficient distance from the         

mountain1 and the disturbance ceases3   
from these data we can determine by the 
,method of ,difference1 the amount of   
effect due to the mountain2 and beyond a
 certain distance everything goes on    
precisely as it would do if the mountain
 exercised no influence whatever1 which1
 accordingly1 we1 with sufficient       
reason1 conclude to be the fact4  ,the  
difficulty1 therefore1 in applying the  
methods already treated of to determine 
the effects of ,permanent ,causes1 is   
confined to the cases in which it is    
impossible for us to get out of the     
local limits of their influence4 ,the   
pendulum can be removed from the        
influence of the mountain1 but it cannot
 be removed from the influence of the   
earth3 we cannot take away the earth    
from the pendulum1 nor the pendulum from
 the earth1 to ascertain whether it     
would continue to vibrate if the action 
which the earth exerts upon it were     
withdrawn4 ,on what evidence1 then1 do  
we ascribe its vibrations to the earth's

 influence8 ,not on any sanctioned by   
the ,method of ,difference2 for one of  
the two instances1 the negative         
instance1 is wanting4 ,nor by the       
,method of ,agreement2 for though all   
pendulums agree in this1 that during    
their oscillations the earth is always  
present1 why may we not as well ascribe 
the phenomenon to the sun1 which is     
equally a coexistent fact in all the    
experiments8 ,it is evident that to     
establish even so simple a fact of      
causation as this1 there was required   
some method over and above those which  
we have yet examined4  ,as another      
example1 let us take the phenomenon     
,heat4 ,independently of all hypothesis 
as to the real nature of the agency so  
called1 this fact is certain1 that we   
are unable to exhaust any body of the   
whole of its heat4 ,it is equally       
certain1 that no one ever perceived heat
 not emanating from a body4 ,being      
unable1 then1 to separate ,body and     
,heat1 we cannot effect such a variation

 of circumstances as the foregoing three
 methods require2 we cannot ascertain1  
by those methods1 what portion of the   
phenomena exhibited by any body is due  
to the heat contained in it4 ,if we     
could observe a body with its heat1 and 
the same body entirely divested of heat1
 the ,method of ,difference would show  
the effect due to the heat1 apart from  
that due to the body4 ,if we could      
observe heat under circumstances        
agreeing in nothing but heat1 and       
therefore not characterized also by the 
presence of a body1 we could ascertain  
the effects of heat1 from an instance of
 heat with a body and an instance of    
heat without a body1 by the ,method of  
,agreement2 or we could determine by the
 ,method of ,difference what effect was 
due to the body1 when the remainder     
which was due to the heat would be given
 by the ,method of ,residues4 ,but we   
can do none of these things2 and without
 them the application of any of the     
three methods to the solution of this   

problem would be illusory4 ,it would be 
idle1 for instance1 to attempt to       
ascertain the effect of heat by         
subtracting from the phenomena exhibited
 by a body1 all that is due to its other
 properties2 for as we have never been  
able to observe any bodies without a    
portion of heat in them1 effects due to 
that heat might form a part of the very 
results1 which we were affecting to     
subtract in order that the effect of    
heat might be shown by the residue4     
,if1 therefore1 there were no other     
methods of experimental investigation   
than these three1 we should be unable to
 determine the effects due to heat as a 
cause4 ,but we have still a resource4   
,though we cannot exclude an antecedent 
altogether1 we may be able to produce1  
or nature may produce for us1 some      
modification in it4 ,by a modification  
is here meant1 a change in it1 not      
amounting to its total removal4 ,if some
 modification in the antecedent ,a is   
always followed by a change in the      

consequent a1 the other consequents b   
and c remaining the same2 or vice vers1 
if every change in a is found to have   
been preceded by some modification in   
,a1 none being observable in any of the 
other antecedents2 we may safely        
conclude that a is1 wholly or in part1  
an effect traceable to ,a1 or at least  
in some way connected with it through   
causation4 ,for example1 in the case of 
heat1 though we cannot expel it         
altogether from any body1 we can modify 
it in quantity1 we can increase or      
diminish it2 and doing so1 we find by   
the various methods of experimentation  
or observation already treated of1 that 
such increase or diminution of heat is  
followed by expansion or contraction of 
the body4 ,in this manner we arrive at  
the conclusion1 otherwise unattainable  
by us1 that one of the effects of heat  
is to enlarge the dimensions of bodies2 
or what is the same thing in other      
words1 to widen the distances between   
their particles4  ,a change in a thing1 

not amounting to its total removal1 that
 is1 a change which leaves it still the 
same thing it was1 must be a change     
either in its quantity1 or in some of   
its variable relations to other things1 
of which variable relations the         
principal is its position in space4 ,in 
the previous example1 the modification  
which was produced in the antecedent was
 an alteration in its quantity4 ,let us 
now suppose the question to be1 what    
influence the moon exerts on the surface
 of the earth4 ,we cannot try an        
experiment in the absence of the moon1  
so as to observe what terrestrial       
phenomena her annihilation would put an 
end to2 but when we find that all the   
variations in the position of the moon  
are followed by corresponding variations
 in the time and place of high water1   
the place being always either the part  
of the earth which is nearest to1 or    
that which is most remote from1 the     
moon1 we have ample evidence that the   
moon is1 wholly or partially1 the cause 

which determines the tides4 ,it very    
commonly happens1 as it does in this    
instance1 that the variations of an     
effect are correspondent1 or analogous1 
to those of its cause2 as the moon moves
 farther towards the east1 the high     
water point does the same3 but this is  
not an indispensable condition2 as may  
be seen in the same example1 for along  
with that high water point there is at  
the same instant another high water     
point diametrically opposite to it1 and 
which1 therefore1 of necessity1 moves   
towards the west1 as the moon1 followed 
by the nearer of the tide waves1        
advances towards the east3 and yet both 
these motions are equally effects of the
 moon's motion4  ,that the oscillations 
of the pendulum are caused by the earth1
 is proved by similar evidence4 ,those  
oscillations take place between         
equidistant points on the two sides of a
 line1 which1 being perpendicular to the
 earth1 varies with every variation in  
the earth's position1 either in space or

 relatively to the object4 ,speaking    
accurately1 we only know by the method  
now characterized1 that all terrestrial 
bodies tend to the earth1 and not to    
some unknown fixed point lying in the   
same direction4 ,in every twenty-four   
hours1 by the earth's rotation1 the line
 drawn from the body at right angles to 
the earth coincides successively with   
all the radii of a circle1 and in the   
course of six months the place of that  
circle varies by nearly two hundred     
millions of miles2 yet in all these     
changes of the earth's position1 the    
line in which bodies tend to fall       
continues to be directed towards it3    
which proves that terrestrial gravity is
 directed to the earth1 and not1 as was 
once fancied by some1 to a fixed point  
of space4  ,the method by which these   
results were obtained1 may be termed the
 ,method of ,concomitant ,variations3 it
 is regulated by the following canon3-- 
,,fifth ,,canon4  ,whatever phenomenon  
varies in any manner whenever another   

phenomenon varies in some particular    
manner1 is either a cause or an effect  
of that phenomenon1 or is connected with
 it through some fact of causation4     
,the last clause is subjoined1 because  
it by no means follows when two         
phenomena accompany each other in their 
variations1 that the one is cause and   
the other effect4 ,the same thing may1  
and indeed must happen1 supposing them  
to be two different effects of a common 
cause3 and by this method alone it would
 never be possible to ascertain which of
 the suppositions is the true one4 ,the 
only way to solve the doubt would be    
that which we have so often adverted to1
 viz4 by endeavouring to ascertain      
whether we can produce the one set of   
variations by means of the other4 ,in   
the case of heat1 for example1 by       
increasing the temperature of a body we 
increase its bulk1 but by increasing its
 bulk we do not increase its            
temperature2 on the contrary1 7as in the
 rarefaction of air under the receiver  

of an air-pump17 we generally diminish  
it3 therefore heat is not an effect1 but
 a cause1 of increase of bulk4 ,if we   
cannot ourselves produce the variations1
 we must endeavour1 though it is an     
attempt which is seldom successful1 to  
find them produced by nature in some    
case in which the pre-existing          
circumstances are perfectly known to us4
  ,it is scarcely necessary to say1 that
 in order to ascertain the uniform      
concomitance of variations in the effect
 with variations in the cause1 the same 
precautions must be used as in any other
 case of the determination of an        
invariable sequence4 ,we must endeavour 
to retain all the other antecedents     
unchanged1 while that particular one is 
subjected to the requisite series of    
variations2 or in other words1 that we  
may be warranted in inferring causation 
from concomitance of variations1 the    
concomitance itself must be proved by   
the ,method of ,difference4  ,it might  
at first appear that the ,method of     

,concomitant ,variations assumes a new  
axiom1 or law of causation in general1  
namely1 that every modification of the  
cause is followed by a change in the    
effect4 ,and it does usually happen that
 when a phenomenon ,a causes a          
phenomenon a1 any variation in the      
quantity or in the various relations of 
,a1 is uniformly followed by a variation
 in the quantity or relations of a4 ,to 
take a familiar instance1 that of       
gravitation4 ,the sun causes a certain  
tendency to motion in the earth2 here we
 have cause and effect2 but that        
tendency is towards the sun1 and        
therefore varies in direction as the sun
 varies in the relation of position2 and
 moreover the tendency varies in        
intensity1 in a certain numerical       
correspondence to the sun's distance    
from the earth1 that is1 according to   
another relation of the sun4 ,thus we   
see that there is not only an invariable
 connexion between the sun and the      
earth's gravitation1 but that two of the

 relations of the sun1 its position with
 respect to the earth and its distance  
from the earth1 are invariably connected
 as antecedents with the quantity and   
direction of the earth's gravitation4   
,the cause of the earth's gravitating at
 all1 is simply the sun2 but the cause  
of its gravitating with a given         
intensity and in a given direction1 is  
the existence of the sun in a given     
direction and at a given distance4 ,it  
is not strange that a modified cause1   
which is in truth a different cause1    
should produce a different effect4      
,although it is for the most part true  
that a modification of the cause is     
followed by a modification of the       
effect1 the ,method of ,concomitant     
,variations does not1 however1          
presuppose this as an axiom4 ,it only   
requires the converse proposition2 that 
anything on whose modifications1        
modifications of an effect are          
invariably consequent1 must be the cause
 7or connected with the cause7 of that  

effect2 a proposition1 the truth of     
which is evident2 for if the thing      
itself had no influence on the effect1  
neither could the modifications of the  
thing have any influence4 ,if the stars 
have no power over the fortunes of      
mankind1 it is implied in the very      
terms1 that the conjunctions or         
oppositions of different stars can have 
no such power4  ,although the most      
striking applications of the ,method of 
,concomitant ,variations take place in  
the cases in which the ,method of       
,difference1 strictly so called1 is     
impossible1 its use is not confined to  
those cases2 it may often usefully      
follow after the ,method of ,difference1
 to give additional precision to a      
solution which that has found4 ,when by 
the ,method of ,difference it has first 
been ascertained that a certain object  
produces a certain effect1 the ,method  
of ,concomitant ,variations may be      
usefully called in1 to determine        
according to what law the quantity or   

the different relations of the effect   
follow those of the cause4    #g4 ,the  
case in which this method admits of the 
most extensive employment1 is that in   
which the variations of the cause are   
variations of quantity4 ,of such        
variations we may in general affirm with
 safety1 that they will be attended not 
only with variations1 but with similar  
variations1 of the effect3 the          
proposition1 that more of the cause is  
followed by more of the effect1 being a 
corollary from the principle of the     
,composition of ,causes1 which1 as we   
have seen1 is the general rule of       
causation2 cases of the opposite        
description1 in which causes change     
their properties on being conjoined with
 one another1 being1 on the contrary1   
special and exceptional4 ,suppose1 then1
 that when ,a changes in quantity1 a    
also changes in quantity1 and in such a 
manner that we can trace the numerical  
relation which the changes of the one   
bear to such changes of the other as    

take place within our limits of         
observation4 ,we may then1 with certain 
precautions1 safely conclude that the   
same numerical relation will hold beyond
 those limits4 ,if1 for instance1 we    
find that when ,a is double1 a is       
double2 that when ,a is treble or       
quadruple1 a is treble or quadruple2 we 
may conclude that if ,a were a half or a
 third1 a would be a half or a third1   
and finally1 that if ,a were            
annihilated1 a would be annihilated1 and
 that a is wholly the effect of ,a1 or  
wholly the effect of the same cause with
 ,a4 ,and so with any other numerical   
relation according to which ,a and a    
would vanish simultaneously2 as for     
instance1 if a were proportional to the 
square of ,a4 ,if1 on the other hand1 a 
is not wholly the effect of ,a1 but yet 
varies when ,a varies1 it is probably a 
mathematical function not of ,a alone1  
but of ,a and something else3 its       
changes1 for example1 may be such as    
would occur if part of it remained      

constant1 or varied on some other       
principle1 and the remainder varied in  
some numerical relation to the          
variations of ,a4 ,in that case1 when ,a
 diminishes1 a will be seen to approach 
not towards zero1 but towards some other
 limit3 and when the series of          
variations is such as to indicate what  
that limit is1 if constant1 or the law  
of its variation if variable1 the limit 
will exactly measure how much of a is   
the effect of some other and independent
 cause1 and the remainder will be the   
effect of ,a 7or of the cause of ,a74   
,these conclusions1 however1 must not be
 drawn without certain precautions4 ,in 
the first place1 the possibility of     
drawing them at all1 manifestly supposes
 that we are acquainted not only with   
the variations1 but with the absolute   
quantities both of ,a and a4 ,if we do  
not know the total quantities1 we       
cannot1 of course1 determine the real   
numerical relation according to which   
those quantities vary4 ,it is therefore 

an error to conclude1 as some have      
concluded1 that because increase of heat
 expands bodies1 that is1 increases the 
distance between their particles1       
therefore the distance is wholly the    
effect of heat1 and that if we could    
entirely exhaust the body of its heat1  
the particles would be in complete      
contact4 ,this is no more than a guess1 
and of the most hazardous sort1 not a   
legitimate induction3 for since we      
neither know how much heat there is in  
any body1 nor what is the real distance 
between any two of its particles1 we    
cannot judge whether the contraction of 
the distance does or does not follow the
 diminution of the quantity of heat     
according to such a numerical relation  
that the two quantities would vanish    
simultaneously4  ,in contrast with this1
 let us consider a case in which the    
absolute quantities are known2 the case 
contemplated in the first law of motion2
 viz4 that all bodies in motion continue
 to move in a straight line with uniform

 velocity until acted upon by some new  
force4 ,this assertion is in open       
opposition to first appearances2 all    
terrestrial objects1 when in motion1    
gradually abate their velocity and at   
last stop2 which accordingly the        
ancients1 with their inductio per       
enumerationem simplicem1 imagined to be 
the law4 ,every moving body1 however1   
encounters various obstacles1 as        
friction1 the resistance of the         
atmosphere1 c41 which we know by daily  
experience to be causes capable of      
destroying motion4 ,it was suggested    
that the whole of the retardation might 
be owing to these causes4 ,how was this 
inquired into8 ,if the obstacles could  
have been entirely removed1 the case    
would have been amenable to the ,method 
of ,difference4 ,they could not be      
removed1 they could only be diminished1 
and the case1 therefore1 admitted only  
of the ,method of ,concomitant          
,variations4 ,this accordingly being    
employed1 it was found that every       

diminution of the obstacles diminished  
the retardation of the motion3 and      
inasmuch as in this case 7unlike the    
case of heat7 the total quantities both 
of the antecedent and of the consequent 
were known2 it was practicable to       
estimate1 with an approach to accuracy1 
both the amount of the retardation and  
the amount of the retarding causes1 or  
resistances1 and to judge how near they 
both were to being exhausted2 and it    
appeared that the effect dwindled as    
rapidly1 and at each step was as far on 
the road towards annihilation1 as the   
cause was4 ,the simple oscillation of a 
weight suspended from a fixed point1 and
 moved a little out of the              
perpendicular1 which in ordinary        
circumstances lasts but a few minutes1  
was prolonged in ,borda's experiments to
 more than thirty hours1 by diminishing 
as much as possible the friction at the 
point of suspension1 and by making the  
body oscillate in a space exhausted as  
nearly as possible of its air4 ,there   

could therefore be no hesitation in     
assigning the whole of the retardation  
of motion to the influence of the       
obstacles2 and since1 after subducting  
this retardation from the total         
phenomenon1 the remainder was an uniform
 velocity1 the result was the           
proposition known as the first law of   
motion4  ,there is also another         
characteristic uncertainty affecting the
 inference that the law of variation    
which the quantities observe within our 
limits of observation1 will hold beyond 
those limits4 ,there is of course1 in   
the first instance1 the possibility that
 beyond the limits1 and in circumstances
 therefore of which we have no direct   
experience1 some counteracting cause    
might develop itself2 either a new      
agent1 or a new property of the agents  
concerned1 which lies dormant in the    
circumstances we are able to observe4   
,this is an element of uncertainty which
 enters largely into all our predictions
 of effects2 but it is not peculiarly   

applicable to the ,method of            
,concomitant ,variations4 ,the          
uncertainty1 however1 of which ,i am    
about to speak1 is characteristic of    
that method2 especially in the cases in 
which the extreme limits of our         
observation are very narrow1 in         
comparison with the possible variations 
in the quantities of the phenomena4 ,any
 one who has the slightest acquaintance 
with mathematics1 is aware that very    
different laws of variation may produce 
numerical results which differ but      
slightly from one another within narrow 
limits2 and it is often only when the   
absolute amounts of variation are       
considerable1 that the difference       
between the results given by one law and
 by another becomes appreciable4 ,when1 
therefore1 such variations in the       
quantity of the antecedents as we have  
the means of observing1 are small in    
comparison with the total quantities1   
there is much danger lest we should     
mistake the numerical law1 and be led to

 miscalculate the variations which would
 take place beyond the limits2 a        
miscalculation which would vitiate any  
conclusion respecting the dependence of 
the effect upon the cause1 that could be
 founded on those variations4 ,examples 
are not wanting of such mistakes4 ,the  
formul1 says ,sir ,john ,herschel1#cc   
which have been empirically deduced for 
the elasticity of steam1 7till very     
recently17 and those for the resistance 
of fluids1 and other similar subjects1  
when relied on beyond the limits of the 
observations from which they were       
deduced1 have almost invariably failed  
to support the theoretical structures   
which have been erected on them4  ,in   
this uncertainty1 the conclusion we may 
draw from the concomitant variations of 
a and ,a1 to the existence of an        
invariable and exclusive connexion      
between them1 or to the permanency of   
the same numerical relation between     
their variations when the quantities are
 much greater or smaller than those     

which we have had the means of          
observing1 cannot be considered to rest 
on a complete induction4 ,all that in   
such a case can be regarded as proved on
 the subject of causation is1 that there
 is some connexion between the two      
phenomena2 that ,a1 or something which  
can influence ,a1 must be one of the    
causes which collectively determine a4  
,we may1 however1 feel assured that the 
relation which we have observed to exist
 between the variations of ,a and a1    
will hold true in all cases which fall  
between the same extreme limits2 that   
is1 wherever the utmost increase or     
diminution in which the result has been 
found by observation to coincide with   
the law1 is not exceeded4  ,the four    
methods which it has now been attempted 
to describe1 are the only possible modes
 of experimental inquiry--of direct     
induction  posteriori1 as distinguished 
from deduction3 at least1 ,i know not1  
nor am able to imagine1 any others4 ,and
 even of these1 the ,method of          

,residues1 as we have seen1 is not      
independent of deduction2 though1 as it 
also requires specific experience1 it   
may1 without impropriety1 be included   
among methods of direct observation and 
experiment4  ,these1 then1 with such    
assistance as can be obtained from      
,deduction1 compose the available       
resources of the human mind for         
ascertaining the laws of the succession 
of phenomena4 ,before proceeding to     
point out certain circumstances1 by     
which the employment of these methods is
 subjected to an immense increase of    
complication and of difficulty1 it is   
expedient to illustrate the use of the  
methods1 by suitable examples drawn from
 actual physical investigations4 ,these1
 accordingly1 will form the subject of  
the succeeding chapter4     ,,chapter   
,,ix4  ,,miscellaneous ,,examples ,,of  
,,the ,,four ,,methods4    #a4 ,i shall 
select1 as a first example1 an          
interesting speculation of one of the   
most eminent of theoretical chemists1   

,baron ,liebig4 ,the object in view1 is 
to ascertain the immediate cause of the 
death produced by metallic poisons4     
,arsenious acid1 and the salts of lead1 
bismuth1 copper1 and mercury1 if        
introduced into the animal organism1    
except in the smallest doses1 destroy   
life4 ,these facts have long been known1
 as insulated truths of the lowest order
 of generalization2 but it was reserved 
for ,liebig1 by an apt employment of the
 first two of our methods of            
experimental inquiry1 to connect these  
truths together by a higher induction1  
pointing out what property1 common to   
all these deleterious substances1 is the
 really operating cause of their fatal  
effect4  ,when solutions of these       
substances are placed in sufficiently   
close contact with many animal products1
 albumen1 milk1 muscular fibre1 and     
animal membranes1 the acid or salt      
leaves the water in which it was        
dissolved1 and enters into combination  
with the animal substance3 which        

substance1 after being thus acted upon1 
is found to have lost its tendency to   
spontaneous decomposition1 or           
putrefaction4  ,observation also shows1 
in cases where death has been produced  
by these poisons1 that the parts of the 
body with which the poisonous substances
 have been brought into contact1 do not 
afterwards putrefy4  ,and1 finally1 when
 the poison has been supplied in too    
small a quantity to destroy life1       
eschars are produced1 that is1 certain  
superficial portions of the tissues are 
destroyed1 which are afterwards thrown  
off by the reparative process taking    
place in the healthy parts4  ,these     
three sets of instances admit of being  
treated according to the ,method of     
,agreement4 ,in all of them the metallic
 compounds are brought into contact with
 the substances which compose the human 
or animal body2 and the instances do not
 seem to agree in any other             
circumstance4 ,the remaining antecedents
 are as different1 and even opposite1 as

 they could possibly be made2 for in    
some the animal substances exposed to   
the action of the poisons are in a state
 of life1 in others only in a state of  
organization1 in others not even in     
that4 ,and what is the result which     
follows in all the cases8 ,the          
conversion of the animal substance 7by  
combination with the poison7 into a     
chemical compound1 held together by so  
powerful a force as to resist the       
subsequent action of the ordinary causes
 of decomposition4 ,now1 organic life   
7the necessary condition of sensitive   
life7 consisting in a continual state of
 decomposition and recomposition of the 
different organs and tissues2 whatever  
incapacitates them for this             
decomposition destroys life4 ,and thus  
the proximate cause of the death        
produced by this description of poisons1
 is ascertained1 as far as the ,method  
of ,agreement can ascertain it4  ,let us
 now bring our conclusion to the test of
 the ,method of ,difference4 ,setting   

out from the cases already mentioned1 in
 which the antecedent is the presence of
 substances forming with the tissues a  
compound incapable of putrefaction1 7and
  fortiori incapable of the chemical    
actions which constitute life17 and the 
consequent is death1 either of the whole
 organism1 or of some portion of it2 let
 us compare with these cases other      
cases1 as much resembling them as       
possible1 but in which that effect is   
not produced4 ,and1 first1 many         
insoluble basic salts of arsenious acid 
are known not to be poisonous4 ,the     
substance called alkargen1 discovered by
 ,bunsen1 which contains a very large   
quantity of arsenic1 and approaches very
 closely in composition to the organic  
arsenious compounds found in the body1  
has not the slightest injurious action  
upon the organism4 ,now when these      
substances are brought into contact with
 the tissues in any way1 they do not    
combine with them2 they do not arrest   
their progress to decomposition4 ,as    

far1 therefore1 as these instances go1  
it appears that when the effect is      
absent1 it is by reason of the absence  
of that antecedent which we had already 
good ground for considering as the      
proximate cause4  ,but the rigorous     
conditions of the ,method of ,difference
 are not yet satisfied2 for we cannot be
 sure that these unpoisonous bodies     
agree with the poisonous substances in  
every property1 except the particular   
one1 of entering into a difficultly     
decomposable compound with the animal   
tissues4 ,to render the method strictly 
applicable1 we need an instance1 not of 
a different substance1 but of one of the
 very same substances1 in circumstances 
which would prevent it from forming1    
with the tissues1 the sort of compound  
in question2 and then1 if death does not
 follow1 our case is made out4 ,now such
 instances are afforded by the antidotes
 to these poisons4 ,for example1 in case
 of poisoning by arsenious acid1 if     
hydrated peroxide of iron is            

administered1 the destructive agency is 
instantly checked4 ,now this peroxide is
 known to combine with the acid1 and    
form a compound1 which1 being insoluble1
 cannot act at all on animal tissues4   
,so1 again1 sugar is a well-known       
antidote to poisoning by salts of       
copper2 and sugar reduces those salts   
either into metallic copper1 or into the
 red suboxide1 neither of which enters  
into combination with animal matter4    
,the disease called painter's colic1 so 
common in manufactories of white lead1  
is unknown where the workmen are        
accustomed to take1 as a preservative1  
sulphuric acid lemonade 7a solution of  
sugar rendered acid by sulphuric acid74 
,now diluted sulphuric acid has the     
property of decomposing all compounds of
 lead with organic matter1 or of        
preventing them from being formed4      
,there is another class of instances1 of
 the nature required by the ,method of  
,difference1 which seem at first sight  
to conflict with the theory4 ,soluble   

salts of silver1 such for instance as   
the nitrate1 have the same stiffening   
antiseptic effect on decomposing animal 
substances as corrosive sublimate and   
the most deadly metallic poisons2 and   
when applied to the external parts of   
the body1 the nitrate is a powerful     
caustic2 depriving those parts of all   
active vitality1 and causing them to be 
thrown off by the neighbouring living   
structures1 in the form of an eschar4   
,the nitrate and the other salts of     
silver ought1 then1 it would seem1 if   
the theory be correct1 to be poisonous2 
yet they may be administered internally 
with perfect impunity4 ,from this       
apparent exception arises the strongest 
confirmation which the theory has yet   
received4 ,nitrate of silver1 in spite  
of its chemical properties1 does not    
poison when introduced into the stomach2
 but in the stomach1 as in all animal   
liquids1 there is common salt2 and in   
the stomach there is also free muriatic 
acid4 ,these substances operate as      

natural antidotes1 combining with the   
nitrate1 and if its quantity is not too 
great1 immediately converting it into   
chloride of silver2 a substance very    
slightly soluble1 and therefore         
incapable of combining with the tissues1
 although to the extent of its          
solubility it has a medicinal influence1
 though an entirely different class of  
organic actions4  ,the preceding        
instances have afforded an induction of 
a high order of conclusiveness1         
illustrative of the two simplest of our 
four methods2 though not rising to the  
maximum of certainty which the ,method  
of ,difference1 in its most perfect     
exemplification1 is capable of          
affording4 ,for 7let us not forget7 the 
positive instance and the negative one  
which the rigour of that method         
requires1 ought to differ only in the   
presence or absence of one single       
circumstance4 ,now1 in the preceding    
argument1 they differ in the presence or
 absence not of a single circumstance1  

but of a single substance3 and as every 
substance has innumerable properties1   
there is no knowing what number of real 
differences are involved in what is     
nominally and apparently only one       
difference4 ,it is conceivable that the 
antidote1 the peroxide of iron for      
example1 may counteract the poison      
through some other of its properties    
than that of forming an insoluble       
compound with it2 and if so1 the theory 
would fall to the ground1 so far as it  
is supported by that instance4 ,this    
source of uncertainty1 which is a       
serious hindrance to all extensive      
generalizations in chemistry1 is however
 reduced in the present case to almost  
the lowest degree possible1 when we find
 that not only one substance1 but many  
substances1 possess the capacity of     
acting as antidotes to metallic poisons1
 and that all these agree in the        
property of forming insoluble compounds 
with the poisons1 while they cannot be  
ascertained to agree in any other       

property whatsoever4 ,we have thus1 in  
favour of the theory1 all the evidence  
which can be obtained by what we termed 
the ,indirect ,method of ,difference1 or
 the ,joint ,method of ,agreement and   
,difference2 the evidence of which1     
though it never can amount to that of   
the ,method of ,difference properly so  
called1 may approach indefinitely near  
to it4    #b4 ,let the object be#cd to  
ascertain the law of what is termed     
induced electricity2 to find under what 
conditions any electrified body1 whether
 positively or negatively electrified1  
gives rise to a contrary electric state 
in some other body adjacent to it4  ,the
 most familiar exemplification of the   
phenomenon to be investigated is the    
following4 ,around the prime conductors 
of an electrical machine1 the atmosphere
 to some distance1 or any conducting    
surface suspended in that atmosphere1 is
 found to be in an electric condition   
opposite to that of the prime conductor 
itself4 ,near and around the positive   

prime conductor there is negative       
electricity1 and near and around the    
negative prime conductor there is       
positive electricity4 ,when pith balls  
are brought near to either of the       
conductors1 they become electrified with
 the opposite electricity to it2 either 
receiving a share from the already      
electrified atmosphere by conduction1 or
 acted upon by the direct inductive     
influence of the conductor itself3 they 
are then attracted by the conductor to  
which they are in opposition2 or1 if    
withdrawn in their electrified state1   
they will be attracted by any other     
oppositely charged body4 ,in like manner
 the hand1 if brought near enough to the
 conductor1 receives or gives an        
electric discharge2 now we have no      
evidence that a charged conductor can be
 suddenly discharged unless by the      
approach of a body oppositely           
electrified4 ,in the case1 therefore1 of
 the electric machine1 it appears that  
the accumulation of electricity in an   

insulated conductor is always           
accompanied by the excitement of the    
contrary electricity in the surrounding 
atmosphere1 and in every conductor      
placed near the former conductor4 ,it   
does not seem possible1 in this case1 to
 produce one electricity by itself4     
,let us now examine all the other       
instances which we can obtain1          
resembling this instance in the given   
consequent1 namely1 the evolution of an 
opposite electricity in the             
neighbourhood of an electrified body4   
,as one remarkable instance we have the 
,leyden jar2 and after the splendid     
experiments of ,faraday in complete and 
final establishment of the substantial  
identity of magnetism and electricity1  
we may cite the magnet1 both the natural
 and the electro-magnet1 in neither of  
which it is possible to produce one kind
 of electricity by itself1 or to charge 
one pole without charging an opposite   
pole with the contrary electricity at   
the same time4 ,we cannot have a magnet 

with one pole3 if we break a natural    
loadstone into a thousand pieces1 each  
piece will have its two oppositely      
electrified poles complete within       
itself4 ,in the voltaic circuit1 again1 
we cannot have one current without its  
opposite4 ,in the ordinary electric     
machine1 the glass cylinder or plate1   
and the rubber1 acquire opposite        
electricities4  ,from all these         
instances1 treated by the ,method of    
,agreement1 a general law appears to    
result4 ,the instances embrace all the  
known modes in which a body can become  
charged with electricity2 and in all of 
them there is found1 as a concomitant or
 consequent1 the excitement of the      
opposite electric state in some other   
body or bodies4 ,it seems to follow that
 the two facts are invariably connected1
 and that the excitement of electricity 
in any body has for one of its necessary
 conditions the possibility of a        
simultaneous excitement of the opposite 
electricity in some neighbouring body4  

,as the two contrary electricities can  
only be produced together1 so they can  
only cease together4 ,this may be shown 
by an application of the ,method of     
,difference to the example of the       
,leyden jar4 ,it needs scarcely be here 
remarked that in the ,leyden jar1       
electricity can be accumulated and      
retained in considerable quantity1 by   
the contrivance of having two conducting
 surfaces of equal extent1 and parallel 
to each other through the whole of that 
extent1 with a non-conducting substance 
such as glass between them4 ,when one   
side of the jar is charged positively1  
the other is charged negatively1 and it 
was by virtue of this fact that the     
,leyden jar served just now as an       
instance in our employment of the       
,method of ,agreement4 ,now it is       
impossible to discharge one of the      
coatings unless the other can be        
discharged at the same time4 ,a         
conductor held to the positive side     
cannot convey away any electricity      

unless an equal quantity be allowed to  
pass from the negative side3 if one     
coating be perfectly insulated1 the     
charge is safe4 ,the dissipation of one 
must proceed pari passu with that of the
 other4  ,the law thus strongly         
indicated admits of corroboration by the
 ,method of ,concomitant ,variations4   
,the ,leyden jar is capable of receiving
 a much higher charge than can          
ordinarily be given to the conductor of 
an electrical machine4 ,now in the case 
of the ,leyden jar1 the metallic surface
 which receives the induced electricity 
is a conductor exactly similar to that  
which receives the primary charge1 and  
is therefore as susceptible of receiving
 and retaining the one electricity1 as  
the opposite surface of receiving and   
retaining the other2 but in the machine1
 the neighbouring body which is to be   
oppositely electrified is the           
surrounding atmosphere1 or any body     
casually brought near to the conductor2 
and as these are generally much inferior

 in their capacity of becoming          
electrified1 to the conductor itself1   
their limited power imposes a           
corresponding limit to the capacity of  
the conductor for being charged4 ,as the
 capacity of the neighbouring body for  
supporting the opposition increases1 a  
higher charge becomes possible3 and to  
this appears to be owing the great      
superiority of the ,leyden jar4  ,a     
further and most decisive confirmation  
by the ,method of ,difference1 is to be 
found in one of ,faraday's experiments  
in the course of his researches on the  
subject of induced electricity4  ,since 
common or machine electricity1 and      
voltaic electricity1 may be considered  
for the present purpose to be identical1
 ,faraday wished to know whether1 as the
 prime conductor develops opposite      
electricity upon a conductor in its     
vicinity1 so a voltaic current running  
along a wire would induce an opposite   
current upon another wire laid parallel 
to it at a short distance4 ,now this    

case is similar to the cases previously 
examined1 in every circumstance except  
the one to which we have ascribed the   
effect4 ,we found in the former         
instances that whenever electricity of  
one kind was excited in one body1       
electricity of the opposite kind must be
 excited in a neighbouring body4 ,but in
 ,faraday's experiment this             
indispensable opposition exists within  
the wire itself4 ,from the nature of a  
voltaic charge1 the two opposite        
currents necessary to the existence of  
each other are both accommodated in one 
wire2 and there is no need of another   
wire placed beside it to contain one of 
them1 in the same way as the ,leyden jar
 must have a positive and a negative    
surface4 ,the exciting cause can and    
does produce all the effect which its   
laws require1 independently of any      
electric excitement of a neighbouring   
body4 ,now the result of the experiment 
with the second wire was1 that no       
opposite current was produced4 ,there   

was an instantaneous effect at the      
closing and breaking of the voltaic     
circuit2 electric inductions appeared   
when the two wires were moved to and    
from one another2 but these are         
phenomena of a different class4 ,there  
was no induced electricity in the sense 
in which this is predicated of the      
,leyden jar2 there was no sustained     
current running up the one wire while an
 opposite current ran down the          
neighbouring wire2 and this alone would 
have been a true parallel case to the   
other4  ,it thus appears by the combined
 evidence of the ,method of ,agreement1 
the ,method of ,concomitant ,variations1
 and the most rigorous form of the      
,method of ,difference1 that neither of 
the two kinds of electricity can be     
excited without an equal excitement of  
the other and opposite kind3 that both  
are effects of the same cause2 that the 
possibility of the one is a condition of
 the possibility of the other1 and the  
quantity of the one an impassable limit 

to the quantity of the other4 ,a        
scientific result of considerable       
interest in itself1 and illustrating    
those three methods in a manner both    
characteristic and easily               
intelligible4#ce    #c4 ,our third      
example shall be extracted from ,sir    
,john ,herschel's ,discourse on the     
,study of ,natural ,philosophy1 a work  
replete with happily-selected           
exemplifications of inductive processes 
from almost every department of physical
 science1 and in which alone1 of all    
books which ,i have met with1 the four  
methods of induction are distinctly     
recognised1 though not so clearly       
characterized and defined1 nor their    
correlation so fully shown1 as has      
appeared to me desirable4 ,the present  
example is described by ,sir ,john      
,herschel as one of the most beautiful  
specimens which can be cited of         
inductive experimental inquiry lying    
within a moderate compass2 the theory of
 dew1 first promulgated by the late ,dr4

 ,wells1 and now universally adopted by 
scientific authorities4 ,the passages in
 inverted commas are extracted verbatim 
from the ,discourse4#cf  ,suppose dew   
were the phenomenon proposed1 whose     
cause we would know4 ,in the first place
 we must determine precisely what we    
mean by dew3 what the fact really is1   
whose cause we desire to investigate4   
,we must separate dew from rain1 and the
 moisture of fogs1 and limit the        
application of the term to what is      
really meant1 which is the spontaneous  
appearance of moisture on substances    
exposed in the open air when no rain or 
visible wet is falling4 ,this answers to
 a preliminary operation which will be  
characterized in the ensuing book1      
treating of operations subsidiary to    
induction4#cg  ,now1 here we have       
analogous phenomena in the moisture     
which bedews a cold metal or stone when 
we breathe upon it2 that which appears  
on a glass of water fresh from the well 
in hot weather2 that which appears on   

the inside of windows when sudden rain  
or hail chills the external air2 that   
which runs down our walls when1 after a 
long frost1 a warm moist thaw comes on4 
,comparing these cases1 we find that    
they all contain the phenomenon which   
was proposed as the subject of          
investigation4 ,now all these instances 
agree in one point1 the coldness of the 
object dewed1 in comparison with the air
 in contact with it4 ,but there still   
remains the most important case of all1 
that of nocturnal dew3 does the same    
circumstance exist in this case8 ,is it 
a fact that the object dewed is colder  
than the air8 ,certainly not1 one would 
at first be inclined to say2 for what is
 to make it so8 ,but 444 the experiment 
is easy3 we have only to lay a          
thermometer in contact with the dewed   
substance1 and hang one at a little     
distance above it1 out of reach of its  
influence4 ,the experiment has been     
therefore made1 the question has been   
asked1 and the answer has been          

invariably in the affirmative4 ,whenever
 an object contracts dew1 it is colder  
than the air4  ,here then is a complete 
application of the ,method of           
,agreement1 establishing the fact of an 
invariable connexion between the        
deposition of dew on a surface1 and the 
coldness of that surface compared with  
the external air4 ,but which of these is
 cause1 and which effect8 or are they   
both effects of something else8 ,on this
 subject the ,method of ,agreement can  
afford us no light3 we must call in a   
more potent method4 ,we must collect    
more facts1 or1 which comes to the same 
thing1 vary the circumstances2 since    
every instance in which the             
circumstances differ is a fresh fact3   
and especially1 we must note the        
contrary or negative cases1 i4e4 where  
no dew is produced3 a comparison between
 instances of dew and instances of no   
dew1 being the condition necessary to   
bring the ,method of ,difference into   
play4  ,now1 first1 no dew is produced  

on the surface of polished metals1 but  
it is very copiously on glass1 both     
exposed with their faces upwards1 and in
 some cases the under side of a         
horizontal plate of glass is also dewed4
 ,here is an instance in which the      
effect is produced1 and another instance
 in which it is not produced2 but we    
cannot yet pronounce1 as the canon of   
the ,method of ,difference requires1    
that the latter instance agrees with the
 former in all its circumstances except 
one2 for the differences between glass  
and polished metals are manifold1 and   
the only thing we can as yet be sure of 
is1 that the cause of dew will be found 
among the circumstances by which the    
former substance is distinguished from  
the latter4 ,but if we could be sure    
that glass1 and the various other       
substances on which dew is deposited1   
have only one quality in common1 and    
that polished metals and the other      
substances on which dew is not deposited
 have also nothing in common but the one

 circumstance1 of not having the one    
quality which the others have2 the      
requisitions of the ,method of          
,difference would be completely         
satisfied1 and we should recognise1 in  
that quality of the substances1 the     
cause of dew4 ,this1 accordingly1 is the
 path of inquiry which is next to be    
pursued4  ,in the cases of polished     
metal and polished glass1 the contrast  
shows evidently that the substance has  
much to do with the phenomenon2         
therefore let the substance alone be    
diversified as much as possible1 by     
exposing polished surfaces of various   
kinds4 ,this done1 a scale of intensity 
becomes obvious4 ,those polished        
substances are found to be most strongly
 dewed which conduct heat worst2 while  
those which conduct well1 resist dew    
most effectually4 ,the complication     
increases2 here is the ,method of       
,concomitant ,variations called to our  
assistance2 and no other method was     
practicable on this occasion2 for the   

quality of conducting heat could not be 
excluded1 since all substances conduct  
heat in some degree4 ,the conclusion    
obtained is1 that cteris paribus the    
deposition of dew is in some proportion 
to the power which the body possesses of
 resisting the passage of heat2 and that
 this1 therefore1 7or something         
connected with this17 must be at least  
one of the causes which assist in       
producing the deposition of dew on the  
surface4  ,but if we expose rough       
surfaces instead of polished1 we        
sometimes find this law interfered with4
 ,thus1 roughened iron1 especially if   
painted over or blackened1 becomes dewed
 sooner than varnished paper2 the kind  
of surface1 therefore1 has a great      
influence4 ,expose1 then1 the same      
material in very diversified states as  
to surface1 7that is1 employ the ,method
 of ,difference to ascertain            
concomitance of variations17 and another
 scale of intensity becomes at once     
apparent2 those surfaces which part with

 their heat most readily by radiation1  
are found to contract dew most          
copiously4 ,here1 therefore1 are the    
requisites for a second employment of   
the ,method of ,concomitant ,variations2
 which in this case also is the only    
method available1 since all substances  
radiate heat in some degree or other4   
,the conclusion obtained by this new    
application of the method is1 that      
cteris paribus the deposition of dew is 
also in some proportion to the power of 
radiating heat2 and that the quality of 
doing this abundantly 7or some cause on 
which that quality depends7 is another  
of the causes which promote the         
deposition of dew on the substance4     
,again1 the influence ascertained to    
exist of substance and surface leads us 
to consider that of texture3 and here1  
again1 we are presented on trial with   
remarkable differences1 and with a third
 scale of intensity1 pointing out       
substances of a close firm texture1 such
 as stones1 metals1 c41 as unfavourable1

 but those of a loose one1 as cloth1    
velvet1 wool1 eider-down1 cotton1 c41 as
 eminently favourable to the contraction
 of dew4 ,the ,method of ,concomitant   
,variations is here1 for the third time1
 had recourse to2 and1 as before1 from  
necessity1 since the texture of no      
substance is absolutely firm or         
absolutely loose4 ,looseness of texture1
 therefore1 or something which is the   
cause of that quality1 is another       
circumstance which promotes the         
deposition of dew2 but this third cause 
resolves itself into the first1 viz4 the
 quality of resisting the passage of    
heat3 for substances of loose texture   
are precisely those which are best      
adapted for clothing1 or for impeding   
the free passage of heat from the skin  
into the air1 so as to allow their outer
 surfaces to be very cold1 while they   
remain warm within2 and this last is1   
therefore1 an induction 7from fresh     
instances7 simply corroborative of a    
former induction4  ,it thus appears that

 the instances in which much dew is     
deposited1 which are very various1 agree
 in this1 and1 so far as we are able to 
observe1 in this only1 that they either 
radiate heat rapidly or conduct it      
slowly3 qualities between which there is
 no other circumstance of agreement1    
than that by virtue of either1 the body 
tends to lose heat from the surface more
 rapidly than it can be restored from   
within4 ,the instances1 on the contrary1
 in which no dew1 or but a small        
quantity of it1 is formed1 and which are
 also extremely various1 agree 7as far  
as we can observe7 in nothing except in 
not having this same property4 ,we seem1
 therefore1 to have detected the        
characteristic difference between the   
substances on which dew is produced1 and
 those on which it is not produced4 ,and
 thus have been realized the            
requisitions of what we have termed the 
,indirect ,method of ,difference1 or the
 ,joint ,method of ,agreement and       
,difference4 ,the example afforded of   

this indirect method1 and of the manner 
in which the data are prepared for it by
 the ,methods of ,agreement and of      
,concomitant ,variations1 is the most   
important of all the illustrations of   
induction afforded by this interesting  
speculation4  ,we might now consider the
 question1 on what the deposition of dew
 depends1 to be completely solved1 if we
 could be quite sure that the substances
 on which dew is produced differ from   
those on which it is not1 in nothing but
 in the property of losing heat from the
 surface faster than the loss can be    
repaired from within4 ,and though we    
never can have that complete certainty1 
this is not of so much importance as    
might at first be supposed2 for we have1
 at all events1 ascertained that even if
 there be any other quality hitherto    
unobserved which is present in all the  
substances which contract dew1 and      
absent in those which do not1 this other
 property must be one which1 in all that
 great number of substances1 is present 

or absent exactly where the property of 
being a better radiator than conductor  
is present or absent2 an extent of      
coincidence which affords a strong      
presumption of a community of cause1 and
 a consequent invariable coexistence    
between the two properties2 so that the 
property of being a better radiator than
 conductor1 if not itself the cause1    
almost certainly always accompanies the 
cause1 and1 for purposes of prediction1 
no error is likely to be committed by   
treating it as if it were really such4  
,reverting now to an earlier stage of   
the inquiry1 let us remember that we had
 ascertained that1 in every instance    
where dew is formed1 there is actual    
coldness of the surface below the       
temperature of the surrounding air2 but 
we were not sure whether this coldness  
was the cause of dew1 or its effect4    
,this doubt we are now able to resolve4 
,we have found that1 in every such      
instance1 the substance is one which1 by
 its own properties or laws1 would1 if  

exposed in the night1 become colder than
 the surrounding air4 ,the coldness     
therefore being accounted for           
independently of the dew1 while it is   
proved that there is a connexion between
 the two1 it must be the dew which      
depends on the coldness2 or in other    
words1 the coldness is the cause of the 
dew4  ,this law of causation1 already so
 amply established1 admits1 however1 of 
efficient additional corroboration in no
 less than three ways4 ,first1 by       
deduction from the known laws of aqueous
 vapour when diffused through air or any
 other gas2 and though we have not yet  
come to the ,deductive ,method1 we will 
not omit what is necessary to render    
this speculation complete4 ,it is known 
by direct experiment that only a limited
 quantity of water can remain suspended 
in the state of vapour at each degree of
 temperature1 and that this maximum     
grows less and less as the temperature  
diminishes4 ,from this it follows1      
deductively1 that if there is already as

 much vapour suspended as the air will  
contain at its existing temperature1 any
 lowering of that temperature will cause
 a portion of the vapour to be          
condensed1 and become water4 ,but1      
again1 we know deductively1 from the    
laws of heat1 that the contact of the   
air with a body colder than itself1 will
 necessarily lower the temperature of   
the stratum of air immediately applied  
to its surface2 and will therefore cause
 it to part with a portion of its water1
 which accordingly will1 by the ordinary
 laws of gravitation or cohesion1 attach
 itself to the surface of the body1     
thereby constituting dew4 ,this         
deductive proof1 it will have been seen1
 has the advantage of at once proving   
causation as well as coexistence2 and it
 has the additional advantage that it   
also accounts for the exceptions to the 
occurrence of the phenomenon1 the cases 
in which1 although the body is colder   
than the air1 yet no dew is deposited2  
by showing that this will necessarily be

 the case when the air is so            
under-supplied with aqueous vapour1     
comparatively to its temperature1 that  
even when somewhat cooled by the contact
 of the colder body1 it can still       
continue to hold in suspension all the  
vapour which was previously suspended in
 it3 thus in a very dry summer there are
 no dews1 in a very dry winter no hoar  
frost4 ,here1 therefore1 is an          
additional condition of the production  
of dew1 which the methods we previously 
made use of failed to detect1 and which 
might have remained still undetected1 if
 recourse had not been had to the plan  
of deducing the effect from the         
ascertained properties of the agents    
known to be present4  ,the second       
corroboration of the theory is by direct
 experiment1 according to the canon of  
the ,method of ,difference4 ,we can1 by 
cooling the surface of any body1 find in
 all cases some temperature1 7more or   
less inferior to that of the surrounding
 air1 according to its hygrometric      

condition17 at which dew will begin to  
be deposited4 ,here1 too1 therefore1 the
 causation is directly proved4 ,we can1 
it is true1 accomplish this only on a   
small scale2 but we have ample reason to
 conclude that the same operation1 if   
conducted in ,nature's great laboratory1
 would equally produce the effect4      
,and1 finally1 even on that great scale 
we are able to verify the result4 ,the  
case is one of those rare cases1 as we  
have shown them to be1 in which nature  
works the experiment for us in the same 
manner in which we ourselves perform it2
 introducing into the previous state of 
things a single and perfectly definite  
new circumstance1 and manifesting the   
effect so rapidly that there is not time
 for any other material change in the   
pre-existing circumstances4 ,it is      
observed that dew is never copiously    
deposited in situations much screened   
from the open sky1 and not at all in a  
cloudy night2 but if the clouds withdraw
 even for a few minutes1 and leave a    

clear opening1 a deposition of dew      
presently begins1 and goes on           
increasing4444 ,dew formed in clear     
intervals will often even evaporate     
again when the sky becomes thickly      
overcast4 ,the proof1 therefore1 is     
complete1 that the presence or absence  
of an uninterrupted communication with  
the sky causes the deposition or        
non-deposition of dew4 ,now1 since a    
clear sky is nothing but the absence of 
clouds1 and it is a known property of   
clouds1 as of all other bodies between  
which and any given object nothing      
intervenes but an elastic fluid1 that   
they tend to raise or keep up the       
superficial temperature of the object by
 radiating heat to it1 we see at once   
that the disappearance of clouds will   
cause the surface to cool2 so that      
,nature1 in this case1 produces a change
 in the antecedent by definite and known
 means1 and the consequent follows      
accordingly3 a natural experiment which 
satisfies the requisitions of the       

,method of ,difference4#ch  ,the        
accumulated proof of which the ,theory  
of ,dew has been found susceptible1 is a
 striking instance of the fulness of    
assurance which the inductive evidence  
of laws of causation may attain1 in     
cases in which the invariable sequence  
is by no means obvious to a superficial 
view4    #d4 ,the admirable             
physiological investigations of ,dr4    
,brown-,squard afford brilliant examples
 of the application of the ,inductive   
,methods to a class of inquiries in     
which1 for reasons which will presently 
be given1 direct induction takes place  
under peculiar difficulties and         
disadvantages4 ,as one of the most apt  
instances ,i select his speculation 7in 
the ,proceedings of the ,royal ,society 
for ,may #af1 #ahfa7 on the relations   
between muscular irritability1 cadaveric
 rigidity1 and putrefaction4  ,the law  
which ,dr4 ,brown-,squard's             
investigation tends to establish1 is the
 following3--,the greater the degree of 

muscular irritability at the time of    
death1 the later the cadaveric rigidity 
sets in1 and the longer it lasts1 and   
the later also putrefaction appears1 and
 the slower it progresses4 ,one would   
say at first sight that the method here 
required must be that of ,concomitant   
,variations4 ,but this is a delusive    
appearance1 arising from the            
circumstance that the conclusion to be  
tested is itself a fact of concomitant  
variation4 ,for the establishment of    
that fact any of the ,methods may be put
 in requisition1 and it will be found   
that the fourth ,method1 though really  
employed1 has only a subordinate place  
in this particular investigation4  ,the 
evidences by which ,dr4 ,brown-,squard  
establishes the law may be enumerated as
 follows3--  #ast4 ,paralysed muscles   
have greater irritability than healthy  
muscles4 ,now1 paralysed muscles are    
later in assuming the cadaveric rigidity
 than healthy muscles1 the rigidity     
lasts longer1 and putrefaction sets in  

later and proceeds more slowly4  ,both  
these propositions had to be proved by  
experiment2 and for the experiments     
which prove them1 science is also       
indebted to ,dr4 ,brown-,squard4 ,the   
former of the two--that paralysed       
muscles have greater irritability than  
healthy muscles--he ascertained in      
various ways1 but most decisively by    
comparing the duration of irritability  
in a paralysed muscle and in the        
corresponding healthy one of the        
opposite side1 while they are both      
submitted to the same excitation4 ,he   
often found in experimenting in that    
way1 that the paralysed muscle remained 
irritable twice1 three times1 or even   
four times as long as the healthy one4  
,this is a case of induction by the     
,method of ,difference4 ,the two limbs1 
being those of the same animal1 were    
presumed to differ in no circumstance   
material to the case except the         
paralysis1 to the presence and absence  
of which1 therefore1 the difference in  

the muscular irritability was to be     
attributed4 ,this assumption of complete
 resemblance in all material            
circumstances save one1 evidently could 
not be safely made in any one pair of   
experiments1 because the two legs of any
 given animal might be accidentally in  
very different pathological conditions2 
but if1 besides taking pains to avoid   
any such difference1 the experiment was 
repeated sufficiently often in different
 animals to exclude the supposition that
 any abnormal circumstance could be     
present in them all1 the conditions of  
the ,method of ,difference were         
adequately secured4  ,in the same manner
 in which ,dr4 ,brown-,squard proved    
that paralysed muscles have greater     
irritability1 he also proved the        
correlative proposition respecting      
cadaveric rigidity and putrefaction4    
,having1 by section of the roots of the 
sciatic nerve1 and again of a lateral   
half of the spinal cord1 produced       
paralysis in one hind leg of an animal  

while the other remained healthy1 he    
found that not only did muscular        
irritability last much longer in the    
paralysed limb1 but rigidity set in     
later and ended later1 and putrefaction 
began later and was less rapid than on  
the healthy side4 ,this is a common case
 of the ,method of ,difference1         
requiring no comment4 ,a further and    
very important corroboration was        
obtained by the same method4 ,when the  
animal was killed1 not shortly after the
 section of the nerve1 but a month      
later1 the effect was reversed2 rigidity
 set in sooner1 and lasted a shorter    
time1 than in the healthy muscles4 ,but 
after this lapse of time1 the paralysed 
muscles1 having been kept by the        
paralysis in a state of rest1 had lost a
 great part of their irritability1 and  
instead of more1 had become less        
irritable than those on the healthy     
side4 ,this gives the ,a ,b ,c1 a b c1  
and ,b ,c1 b c1 of the ,method of       
,difference4 ,one antecedent1 increased 

irritability1 being changed1 and the    
other circumstances being the same1 the 
consequence did not follow2 and         
moreover1 when a new antecedent1        
contrary to the first1 was supplied1 it 
was followed by a contrary consequent4  
,this instance is attended with the     
special advantage1 of proving that the  
retardation and prolongation of the     
rigidity do not depend directly on the  
paralysis1 since that was the same in   
both the instances2 but specifically on 
one effect of the paralysis1 namely1 the
 increased irritability2 since they     
ceased when it ceased1 and were reversed
 when it was reversed4  #bndly4         
,diminution of the temperature of       
muscles before death increases their    
irritability4 ,but diminution of their  
temperature also retards cadaveric      
rigidity and putrefaction4  ,both these 
truths were first made known by ,dr4    
,brown-,squard himself1 through         
experiments which conclude according to 
the ,method of ,difference4 ,there is   

nothing in the nature of the process    
requiring specific analysis4  #crdly4   
,muscular exercise1 prolonged to        
exhaustion1 diminishes the muscular     
irritability4 ,this is a well-known     
truth1 dependent on the most general    
laws of muscular action1 and proved by  
experiments under the ,method of        
,difference1 constantly repeated4 ,now  
it has been shown by observation that   
overdriven cattle1 if killed before     
recovery from their fatigue1 become     
rigid and putrefy in a surprisingly     
short time4 ,a similar fact has been    
observed in the case of animals hunted  
to death2 cocks killed during or shortly
 after a fight2 and soldiers slain in   
the field of battle4 ,these various     
cases agree in no circumstance1 directly
 connected with the muscles1 except that
 these have just been subjected to      
exhausting exercise4 ,under the canon1  
therefore1 of the ,method of ,agreement1
 it may be inferred that there is a     
connexion between the two facts4 ,the   

,method of ,agreement1 indeed1 as has   
been shown1 is not competent to prove   
causation4 ,the present case1 however1  
is already known to be a case of        
causation1 it being certain that the    
state of the body after death must      
somehow depend upon its state at the    
time of death4 ,we are therefore        
warranted in concluding that the single 
circumstance in which all the instances 
agree1 is the part of the antecedent    
which is the cause of that particular   
consequent4  #dthly4 ,in proportion as  
the nutrition of muscles is in a good   
state1 their irritability is high4 ,this
 fact also rests on the general evidence
 of the laws of physiology1 grounded on 
many familiar applications of the       
,method of ,difference4 ,now1 in the    
case of those who die from accident or  
violence1 with their muscles in a good  
state of nutrition1 the muscular        
irritability continues long after death1
 rigidity sets in late1 and persists    
long without the putrefactive change4   

,on the contrary1 in cases of disease in
 which nutrition has been diminished for
 a long time before death1 all these    
effects are reversed4 ,these are the    
conditions of the ,joint ,method of     
,agreement and ,difference4 ,the cases  
of retarded and long continued rigidity 
here in question1 agree only in being   
preceded by a high state of nutrition of
 the muscles2 the cases of rapid and    
brief rigidity agree only in being      
preceded by a low state of muscular     
nutrition2 a connexion is therefore     
inductively proved between the degree of
 the nutrition1 and the slowness and    
prolongation of the rigidity4  #ethly4  
,convulsions1 like exhausting exercise1 
but in a still greater degree1 diminish 
the muscular irritability4 ,now1 when   
death follows violent and prolonged     
convulsions1 as in tetanus1 hydrophobia1
 some cases of cholera1 and certain     
poisons1 rigidity sets in very rapidly1 
and after a very brief duration1 gives  
place to putrefaction4 ,this is another 

example of the ,method of ,agreement1 of
 the same character with ,no4 #c4       
#fthly4 ,the series of instances which  
we shall take last1 is of a more complex
 character1 and requires a more minute  
analysis4  ,it has long been observed   
that in some cases of death by          
lightning1 cadaveric rigidity either    
does not take place at all1 or is of    
such extremely brief duration as to     
escape notice1 and that in these cases  
putrefaction is very rapid4 ,in other   
cases1 however1 the usual cadaveric     
rigidity appears4 ,there must be some   
difference in the cause1 to account for 
this difference in the effect4 ,now     
death by lightning may be the result of1
 #ast1 a syncope by fright1 or in       
consequence of a direct or reflex       
influence of lightning on the par vagum2
 #bndly1 hemorrhage in or around the    
brain1 or in the lungs1 the pericardium1
 c42 #crdly1 concussion1 or some other  
alteration in the brain2 none of which  
phenomena have any known property       

capable of accounting for the           
suppression1 or almost suppression1 of  
the cadaveric rigidity4 ,but the cause  
of death may also be that the lightning 
produces a violent convulsion of every  
muscle in the body1 of which1 if of     
sufficient intensity1 the known effect  
would be that muscular irritability     
ceases almost at once4 ,if ,dr4         
,brown-,squard's generalization is a    
true law1 these will be the very cases  
in which rigidity is so much abridged as
 to escape notice2 and the cases in     
which1 on the contrary1 rigidity takes  
place as usual1 will be those in which  
the stroke of lightning operates in some
 of the other modes which have been     
enumerated4 ,how1 then1 is this brought 
to the test8 ,by experiments not on     
lightning1 which cannot be commanded at 
pleasure1 but on the same natural agency
 in a manageable form1 that of          
artificial galvanism4 ,dr4              
,brown-,squard galvanized the entire    
bodies of animals immediately after     

death4 ,galvanism cannot operate in any 
of the modes in which the stroke of     
lightning may have operated1 except the 
single one of producing muscular        
convulsions4 ,if1 therefore1 after the  
bodies have been galvanized1 the        
duration of rigidity is much shortened  
and putrefaction much accelerated1 it is
 reasonable to ascribe the same effects 
when produced by lightning1 to the      
property which galvanism shares with    
lightning1 and not to those which it    
does not4 ,now this ,dr4 ,brown-,squard 
found to be the fact4 ,the galvanic     
experiment was tried with charges of    
very various degrees of strength2 and   
the more powerful the charge1 the       
shorter was found to be the duration of 
rigidity1 and the more speedy and rapid 
the putrefaction4 ,in the experiment in 
which the charge was strongest1 and the 
muscular irritability most promptly     
destroyed1 the rigidity only lasted     
fifteen minutes4 ,on the principle1     
therefore1 of the ,method of            

,concomitant ,variations1 it maybe      
inferred that the duration of the       
rigidity depends on the degree of the   
irritability2 and that if the charge had
 been as much stronger than ,dr4        
,brown-,squard's strongest1 as a stroke 
of lightning must be stronger than any  
electric shock which we can produce     
artificially1 the rigidity would have   
been shortened in a corresponding ratio1
 and might have disappeared altogether4 
,this conclusion having been arrived at1
 the case of an electric shock1 whether 
natural or artificial1 becomes an       
instance in addition to all those       
already ascertained1 of correspondence  
between the irritability of the muscle  
and the duration of rigidity4  ,all     
these instances are summed up in the    
following statement3--,that when the    
degree of muscular irritability at the  
time of death is considerable1 either in
 consequence of a good state of         
nutrition1 as in persons who die in full
 health from an accidental cause1 or in 

consequence of rest1 as in cases of     
paralysis1 or on account of the         
influence of cold1 cadaveric rigidity in
 all these cases sets in late and lasts 
long1 and putrefaction appears late1 and
 progresses slowly3 but that when the   
degree of muscular irritability at the  
time of death is slight1 either in      
consequence of a bad state of nutrition1
 or of exhaustion from over-exertion1 or
 from convulsions caused by disease or  
poison1 cadaveric rigidity sets in and  
ceases soon1 and putrefaction appears   
and progresses quickly4 ,these facts    
present1 in all their completeness1 the 
conditions of the ,joint ,method of     
,agreement and ,difference4 ,early and  
brief rigidity takes place in cases     
which agree only in the circumstance of 
a low state of muscular irritability4   
,rigidity begins late and lasts long in 
cases which agree only in the contrary  
circumstance1 of a muscular irritability
 high and unusually prolonged4 ,it      
follows that there is a connexion       

through causation between the degree of 
muscular irritability after death1 and  
the tardiness and prolongation of the   
cadaveric rigidity4 ,this investigation 
places in a strong light the value and  
efficacy of the ,joint ,method4 ,for1 as
 we have already seen1 the defect of    
that ,method is1 that like the ,method  
of ,agreement1 of which it is only an   
improved form1 it cannot prove          
causation4 ,but in the present case 7as 
in one of the steps in the argument     
which led up to it7 causation is already
 proved2 since there could never be any 
doubt that the rigidity altogether1 and 
the putrefaction which follows it1 are  
caused by the fact of death3 the        
observations and experiments on which   
this rests are too familiar to need     
analysis1 and fall under the ,method of 
,difference4 ,it being1 therefore1      
beyond doubt that the aggregate         
antecedent1 the death1 is the actual    
cause of the whole train of consequents1
 whatever of the circumstances attending

 the death can be shown to be followed  
in all its variations by variations in  
the effect under investigation1 must be 
the particular feature of the fact of   
death on which that effect depends4 ,the
 degree of muscular irritability at the 
time of death fulfils this condition4   
,the only point that could be brought   
into question1 would be whether the     
effect depended on the irritability     
itself1 or on something which always    
accompanied the irritability3 and this  
doubt is set at rest by establishing1 as
 the instances do1 that by whatever     
cause the high or low irritability is   
produced1 the effect equally follows2   
and cannot1 therefore1 depend upon the  
causes of irritability1 nor upon the    
other effects of those causes1 which are
 as various as the causes themselves2   
but upon the irritability1 solely4      
#e4 ,the last two examples will have    
conveyed to any one by whom they have   
been duly followed1 so clear a          
conception of the use and practical     

management of three of the four methods 
of experimental inquiry1 as to supersede
 the necessity of any further           
exemplification of them4 ,the remaining 
method1 that of ,residues1 not having   
found a place in any of the preceding   
investigations1 ,i shall quote from ,sir
 ,john ,herschel some examples of that  
method1 with the remarks by which they  
are introduced4  ,it is by this process1
 in fact1 that science1 in its present  
advanced state1 is chiefly promoted4    
,most of the phenomena which ,nature    
presents are very complicated2 and when 
the effects of all known causes are     
estimated with exactness1 and subducted1
 the residual facts are constantly      
appearing in the form of phenomena      
altogether new1 and leading to the most 
important conclusions4  ,for example3   
the return of the comet predicted by    
,professor ,encke1 a great many times in
 succession1 and the general good       
agreement of its calculated with its    
observed place during any one of its    

periods of visibility1 would lead us to 
say that its gravitation towards the sun
 and planets is the sole and sufficient 
cause of all the phenomena of its       
orbitual motion2 but when the effect of 
this cause is strictly calculated and   
subducted from the observed motion1     
there is found to remain behind a       
residual phenomenon1 which would never  
have been otherwise ascertained to      
exist1 which is a small anticipation of 
the time of its reappearance1 or a      
diminution of its periodic time1 which  
cannot be accounted for by gravity1 and 
whose cause is therefore to be inquired 
into4 ,such an anticipation would be    
caused by the resistance of a medium    
disseminated through the celestial      
regions2 and as there are other good    
reasons for believing this to be a vera 
causa1 7an actually existing            
antecedent17 it has therefore been      
ascribed to such a resistance4#ci  ,m4  
,arago1 having suspended a magnetic     
needle by a silk thread1 and set it in  

vibration1 observed1 that it came much  
sooner to a state of rest when suspended
 over a plate of copper1 than when no   
such plate was beneath it4 ,now1 in both
 cases there were two ver caus          
7antecedents known to exist7 why it     
should come at length to rest1 viz4 the 
resistance of the air1 which opposes1   
and at length destroys1 all motions     
performed in it2 and the want of perfect
 mobility in the silk thread4 ,but the  
effect of these causes being exactly    
known by the observation made in the    
absence of the copper1 and being thus   
allowed for and subducted1 a residual   
phenomenon appeared1 in the fact that a 
retarding influence was exerted by the  
copper itself2 and this fact1 once      
ascertained1 speedily led to the        
knowledge of an entirely new and        
unexpected class of relations4 ,this    
example belongs1 however1 not to the    
,method of ,residues but to the ,method 
of ,difference1 the law being           
ascertained by a direct comparison of   

the results of two experiments1 which   
differed in nothing but the presence or 
absence of the plate of copper4 ,to have
 made it exemplify the ,method of       
,residues1 the effect of the resistance 
of the air and that of the rigidity of  
the silk should have been calculated    
priori1 from the laws obtained by       
separate and foregone experiments4      
,unexpected and peculiarly striking     
confirmations of inductive laws         
frequently occur in the form of residual
 phenomena1 in the course of            
investigations of a widely different    
nature from those which gave rise to the
 inductions themselves4 ,a very elegant 
example may be cited in the unexpected  
confirmation of the law of the          
development of heat in elastic fluids by
 compression1 which is afforded by the  
phenomena of sound4 ,the inquiry into   
the cause of sound had led to           
conclusions respecting its mode of      
propagation1 from which its velocity in 
the air could be precisely calculated4  

,the calculations were performed2 but1  
when compared with fact1 though the     
agreement was quite sufficient to show  
the general correctness of the cause and
 mode of propagation assigned1 yet the  
whole velocity could not be shown to    
arise from this theory4 ,there was still
 a residual velocity to be accounted    
for1 which placed dynamical philosophers
 for a long time in great dilemma4 ,at  
length ,laplace struck on the happy     
idea1 that this might arise from the    
heat developed in the act of that       
condensation which necessarily takes    
place at every vibration by which sound 
is conveyed4 ,the matter was subjected  
to exact calculation1 and the result was
 at once the complete explanation of the
 residual phenomenon1 and a striking    
confirmation of the general law of the  
development of heat by compression1     
under circumstances beyond artificial   
imitation4  ,many of the new elements of
 chemistry have been detected in the    
investigation of residual phenomena4    

,thus ,arfwedson discovered lithia by   
perceiving an excess of weight in the   
sulphate produced from a small portion  
of what he considered as magnesia       
present in a mineral he had analysed4   
,it is on this principle1 too1 that the 
small concentrated residues of great    
operations in the arts are almost sure  
to be the lurking places of new chemical
 ingredients3 witness iodine1 brome1    
selenium1 and the new metals            
accompanying platina in the experiments 
of ,wollaston and ,tennant4 ,it was a   
happy thought of ,glauber to examine    
what everybody else threw away4#dj      
,almost all the greatest discoveries in 
,astronomy1 says the same author1#da    
have resulted from the consideration of 
residual phenomena of a quantitative or 
numerical kind4444 ,it was thus that the
 grand discovery of the precession of   
the equinoxes resulted as a residual    
phenomenon1 from the imperfect          
explanation of the return of the seasons
 by the return of the sun to the same   

apparent place among the fixed stars4   
,thus1 also1 aberration and nutation    
resulted as residual phenomena from that
 portion of the changes of the apparent 
places of the fixed stars which was left
 unaccounted for by precession4 ,and    
thus again the apparent proper motions  
of the stars are the observed residues  
of their apparent movements outstanding 
and unaccounted for by strict           
calculation of the effects of           
precession1 nutation1 and aberration4   
,the nearest approach which human       
theories can make to perfection is to   
diminish this residue1 this caput       
mortuum of observation1 as it may be    
considered1 as much as practicable1 and1
 if possible1 to reduce it to nothing1  
either by showing that something has    
been neglected in our estimation of     
known causes1 or by reasoning upon it as
 a new fact1 and on the principle of the
 inductive philosophy ascending from the
 effect to its cause or causes4  ,the   
disturbing effects mutually produced by 

the earth and planets upon each other's 
motions were first brought to light as  
residual phenomena1 by the difference   
which appeared between the observed     
places of those bodies1 and the places  
calculated on a consideration solely of 
their gravitation towards the sun4 ,it  
was this which determined astronomers to
 consider the law of gravitation as     
obtaining between all bodies whatever1  
and therefore between all particles of  
matter2 their first tendency having been
 to regard it as a force acting only    
between each planet or satellite and the
 central body to whose system it        
belonged4 ,again1 the catastrophists1 in
 geology1 be their opinion right or     
wrong1 support it on the plea1 that     
after the effect of all causes now in   
operation has been allowed for1 there   
remains in the existing constitution of 
the earth a large residue of facts1     
proving the existence at former periods 
either of other forces1 or of the same  
forces in a much greater degree of      

intensity4 ,to add one more example3    
those who assert1 what no one has shown 
any real ground for believing1 that     
there is in one human individual1 one   
sex1 or one race of mankind over        
another1 an inherent and inexplicable   
superiority in mental faculties1 could  
only substantiate their proposition by  
subtracting from the differences of     
intellect which we in fact see1 all that
 can be traced by known laws either to  
the ascertained differences of physical 
organization1 or to the differences     
which have existed in the outward       
circumstances in which the subjects of  
the comparison have hitherto been       
placed4 ,what these causes might fail to
 account for1 would constitute a        
residual phenomenon1 which and which    
alone would be evidence of an ulterior  
original distinction1 and the measure of
 its amount4 ,but the assertors of such 
supposed differences have not provided  
themselves with these necessary logical 
conditions of the establishment of their

 doctrine4  ,the spirit of the ,method  
of ,residues being1 it is hoped1        
sufficiently intelligible from these    
examples1 and the other three methods   
having already been so fully            
exemplified1 we may here close our      
exposition of the four methods1         
considered as employed in the           
investigation of the simpler and more   
elementary order of the combinations of 
phenomena4    #f4 ,dr4 ,whewell has     
expressed a very unfavourable opinion of
 the utility of the ,four ,methods1 as  
well as of the aptness of the examples  
by which ,i have attempted to illustrate
 them4 ,his words are these3--#db  ,upon
 these methods1 the obvious thing to    
remark is1 that they take for granted   
the very thing which is most difficult  
to discover1 the reduction of the       
phenomena to formul such as are here    
presented to us4 ,when we have any set  
of complex facts offered to us2 for     
instance1 those which were offered in   
the cases of discovery which ,i have    

mentioned1--the facts of the planetary  
paths1 of falling bodies1 of refracted  
rays1 of cosmical motions1 of chemical  
analysis2 and when1 in any of these     
cases1 we would discover the law of     
nature which governs them1 or1 if any   
one chooses so to term it1 the feature  
in which all the cases agree1 where are 
we to look for our ,a1 ,b1 ,c1 and a1 b1
 c8 ,nature does not present to us the  
cases in this form2 and how are we to   
reduce them to this form8 ,you say1 when
 we find the combination of ,a ,b ,c    
with a b c and ,a ,b ,d with a b d1 then
 we may draw our inference4 ,granted2   
but when and where are we to find such  
combinations8 ,even now that the        
discoveries are made1 who will point out
 to us what are the ,a1 ,b1 ,c1 and a1  
b1 c elements of the cases which have   
just been enumerated8 ,who will tell us 
which of the methods of inquiry those   
historically real and successful        
inquiries exemplify8 ,who will carry    
these formul through the history of the 

sciences1 as they have really grown up2 
and show us that these four methods have
 been operative in their formation2 or  
that any light is thrown upon the steps 
of their progress by reference to these 
formul8  ,he adds that1 in this work1   
the methods have not been applied to a  
large body of conspicuous and undoubted 
examples of discovery1 extending along  
the whole history of science2 which     
ought to have been done in order that   
the methods might be shown to possess   
the advantage 7which he claims as       
belonging to his own7 of being those by 
which all great discoveries in science  
have really been made4--7p4 #bgg47      
,there is a striking similarity between 
the objections here made against ,canons
 of ,induction1 and what was alleged1 in
 the last century1 by as able men as    
,dr4 ,whewell1 against the acknowledged 
,canon of ,ratiocination4 ,those who    
protested against the ,aristotelian     
,logic said of the ,syllogism1 what ,dr4
 ,whewell says of the ,inductive        

,methods1 that it takes for granted the 
very thing which is most difficult to   
discover1 the reduction of the argument 
to formul such as are here presented to 
us4 ,the grand difficulty1 they said1 is
 to obtain your syllogism1 not to judge 
of its correctness when obtained4 ,on   
the matter of fact1 both they and ,dr4  
,whewell are right4 ,the greatest       
difficulty in both cases is first that  
of obtaining the evidence1 and next1 of 
reducing it to the form which tests its 
conclusiveness4 ,but if we try to reduce
 it without knowing to what1 we are not 
likely to make much progress4 ,it is a  
more difficult thing to solve a         
geometrical problem1 than to judge      
whether a proposed solution is correct3 
but if people were not able to judge of 
the solution when found1 they would have
 little chance of finding it4 ,and it   
cannot be pretended that to judge of an 
induction when found1 is perfectly easy1
 is a thing for which aids and          
instruments are superfluous2 for        

erroneous inductions1 false inferences  
from experience1 are quite as common1 on
 some subjects much commoner1 than true 
ones4 ,the business of ,inductive ,logic
 is to provide rules and models 7such as
 the ,syllogism and its rules are for   
ratiocination7 to which if inductive    
arguments conform1 those arguments are  
conclusive1 and not otherwise4 ,this is 
what the ,four ,methods profess to be1  
and what ,i believe they are universally
 considered to be by experimental       
philosophers1 who had practised all of  
them long before any one sought to      
reduce the practice to theory4  ,the    
assailants of the ,syllogism had also   
anticipated ,dr4 ,whewell in the other  
branch of his argument4 ,they said that 
no discoveries were ever made by        
syllogism2 and ,dr4 ,whewell says1 or   
seems to say1 that none were ever made  
by the four ,methods of ,induction4 ,to 
the former objectors1 ,archbishop       
,whately very pertinently answered1 that
 their argument1 if good at all1 was    

good against the reasoning process      
altogether2 for whatever cannot be      
reduced to syllogism1 is not reasoning4 
,and ,dr4 ,whewell's argument1 if good  
at all1 is good against all inferences  
from experience4 ,in saying that no     
discoveries were ever made by the four  
,methods1 he affirms that none were ever
 made by observation and experiment2 for
 assuredly if any were1 it was by       
processes reducible to one or other of  
those methods4  ,this difference between
 us accounts for the dissatisfaction    
which my examples give him2 for ,i did  
not select them with a view to satisfy  
any one who required to be convinced    
that observation and experiment are     
modes of acquiring knowledge3 ,i confess
 that in the choice of them ,i thought  
only of illustration1 and of            
facilitating the conception of the      
,methods by concrete instances4 ,if it  
had been my object to justify the       
processes themselves as means of        
investigation1 there would have been no 

need to look far off1 or make use of    
recondite or complicated instances4 ,as 
a specimen of a truth ascertained by the
 ,method of ,agreement1 ,i might have   
chosen the proposition ,dogs bark4 ,this
 dog1 and that dog1 and the other dog1  
answer to ,a ,b ,c1 ,a ,d ,e1 ,a ,f ,g4 
,the circumstance of being a dog1       
answers to ,a4 ,barking answers to a4   
,as a truth made known by the ,method of
 ,difference1 ,fire burns might have    
sufficed4 ,before ,i touch the fire ,i  
am not burnt2 this is ,b ,c2 ,i touch   
it1 and am burnt2 this is ,a ,b ,c1 a ,b
 ,c4  ,such familiar experimental       
processes are not regarded as inductions
 by ,dr4 ,whewell2 but they are         
perfectly homogeneous with those by     
which1 even on his own showing1 the     
pyramid of science is supplied with its 
base4 ,in vain he attempts to escape    
from this conclusion by laying the most 
arbitrary restrictions on the choice of 
examples admissible as instances of     
,induction3 they must neither be such as

 are still matter of discussion 7p4     
#bfe71 nor must any of them be drawn    
from mental and social subjects 7p4     
#bfi71 nor from ordinary observation and
 practical life 7pp4 #bda-bdg74 ,they   
must be taken exclusively from the      
generalizations by which scientific     
thinkers have ascended to great and     
comprehensive laws of natural phenomena4
 ,now it is seldom possible1 in these   
complicated inquiries1 to go much beyond
 the initial steps1 without calling in  
the instrument of ,deduction1 and the   
temporary aid of hypotheses2 as ,i      
myself1 in common with ,dr4 ,whewell1   
have maintained against the purely      
empirical school4 ,since therefore such 
cases could not conveniently be selected
 to illustrate the principles of mere   
observation and experiment1 ,dr4        
,whewell is misled by their absence into
 representing the ,experimental ,methods
 as serving no purpose in scientific    
investigation2 forgetting that if those 
methods had not supplied the first      

generalizations1 there would have been  
no materials for his own conception of  
,induction to work upon4  ,his          
challenge1 however1 to point out which  
of the four methods are exemplified in  
certain important cases of scientific   
inquiry1 is easily answered4 ,the       
planetary paths1 as far as they are a   
case of induction at all1#dc fall under 
the ,method of ,agreement4 ,the law of  
falling bodies1 namely that they        
describe spaces proportional to the     
squares of the times1 was historically a
 deduction from the first law of motion2
 but the experiments by which it was    
verified1 and by which it might have    
been discovered1 were examples of the   
,method of ,agreement2 and the apparent 
variation from the true law1 caused by  
the resistance of the air1 was cleared  
up by experiments in vacuo1 constituting
 an application of the ,method of       
,difference4 ,the law of refracted rays 
7the constancy of the ratio between the 
sines of incidence and of refraction for

 each refracting substance7 was         
ascertained by direct measurement1 and  
therefore by the ,method of ,agreement4 
,the cosmical motions were determined by
 highly complex processes of thought1 in
 which ,deduction was predominant1 but  
the ,methods of ,agreement and of       
,concomitant ,variations had a large    
part in establishing the empirical laws4
 ,every case without exception of       
chemical analysis constitutes a         
well-marked example of the ,method of   
,difference4 ,to any one acquainted with
 the subjects--to ,dr4 ,whewell himself1
 there would not be the smallest        
difficulty in setting out the ,a ,b ,c  
and a b c elements of these cases4  ,if 
discoveries are ever made by observation
 and experiment without ,deduction1 the 
four methods are methods of discovery3  
but even if they were not methods of    
discovery1 it would not be the less true
 that they are the sole methods of      
,proof2 and in that character1 even the 
results of deduction are amenable to    

them4 ,the great generalizations which  
begin as ,hypotheses1 must end by being 
proved1 and are in reality 7as will be  
shown hereafter7 proved1 by the ,four   
,methods4 ,now it is with ,proof1 as    
such1 that ,logic is principally        
concerned4 ,this distinction has indeed 
no chance of finding favour with ,dr4   
,whewell2 for it is the peculiarity of  
his system1 not to recognise1 in cases  
of ,induction1 any necessity for proof4 
,if1 after assuming an hypothesis and   
carefully collating it with facts1      
nothing is brought to light inconsistent
 with it1 that is1 if experience does   
not disprove it1 he is content3 at least
 until a simpler hypothesis1 equally    
consistent with experience1 presents    
itself4 ,if this be ,induction1         
doubtless there is no necessity for the 
four methods4 ,but to suppose that it is
 so1 appears to me a radical            
misconception of the nature of the      
evidence of physical truths4  ,so real  
and practical is the need of a test for 

induction1 similar to the syllogistic   
test of ratiocination1 that inferences  
which bid defiance to the most          
elementary notions of inductive logic   
are put forth without misgiving by      
persons eminent in physical science1 as 
soon as they are off the ground on which
 they are conversant with the facts1 and
 not reduced to judge only by the       
arguments2 and as for educated persons  
in general1 it may be doubted if they   
are better judges of a good or a bad    
induction than they were before ,bacon  
wrote4 ,the improvement in the results  
of thinking has seldom extended to the  
processes2 or has reached1 if any       
process1 that of investigation only1 not
 that of proof4 ,a knowledge of many    
laws of nature has doubtless been       
arrived at1 by framing hypotheses and   
finding that the facts corresponded to  
them2 and many errors have been got rid 
of by coming to a knowledge of facts    
which were inconsistent with them1 but  
not by discovering that the mode of     

thought which led to the errors was     
itself faulty1 and might have been known
 to be such independently of the facts  
which disproved the specific conclusion4
 ,hence it is1 that while the thoughts  
of mankind have on many subjects worked 
themselves practically right1 the       
thinking power remains as weak as ever3 
and on all subjects on which the facts  
which would check the result are not    
accessible1 as in what relates to the   
invisible world1 and even1 as has been  
seen lately1 to the visible world of the
 planetary regions1 men of the greatest 
scientific acquirements argue as        
pitiably as the merest ignoramus4 ,for  
though they have made many sound        
inductions1 they have not learnt from   
them 7and ,dr4 ,whewell thinks there is 
no necessity that they should learn7 the
 principles of inductive evidence4      
,,chapter ,x4  ,,of ,,plurality ,,of    
,,causes2 ,,and ,,of ,,the              
,,intermixture ,,of ,,effects4    #a4   
,in the preceding exposition of the four

 methods of observation and experiment1 
by which we contrive to distinguish     
among a mass of coexistent phenomena the
 particular effect due to a given cause1
 or the particular cause which gave     
birth to a given effect2 it has been    
necessary to suppose1 in the first      
instance1 for the sake of               
simplification1 that this analytical    
operation is encumbered by no other     
difficulties than what are essentially  
inherent in its nature2 and to represent
 to ourselves1 therefore1 every effect1 
on the one hand as connected exclusively
 with a single cause1 and on the other  
hand as incapable of being mixed and    
confounded with any other coexistent    
effect4 ,we have regarded a b c d e1 the
 aggregate of the phenomena existing at 
any moment1 as consisting of dissimilar 
facts1 a1 b1 c1 d1 and e1 for each of   
which one1 and only one1 cause needs be 
sought2 the difficulty being only that  
of singling out this one cause from the 
multitude of antecedent circumstances1  

,a1 ,b1 ,c1 ,d1 and ,e4 ,the cause      
indeed may not be simple2 it may consist
 of an assemblage of conditions2 but we 
have supposed that there was only one   
possible assemblage of conditions1 from 
which the given effect could result4    
,if such were the fact1 it would be     
comparatively an easy task to           
investigate the laws of nature4 ,but the
 supposition does not hold1 in either of
 its parts4 ,in the first place1 it is  
not true that the same phenomenon is    
always produced by the same cause3 the  
effect a may sometimes arise from ,a1   
sometimes from ,b4 ,and1 secondly1 the  
effects of different causes are often   
not dissimilar1 but homogeneous1 and    
marked out by no assignable boundaries  
from one another3 ,a and ,b may produce 
not a and b1 but different portions of  
an effect a4 ,the obscurity and         
difficulty of the investigation of the  
laws of phenomena is singularly         
increased by the necessity of adverting 
to these two circumstances2             

,intermixture of ,effects1 and          
,plurality of ,causes4 ,to the latter1  
being the simpler of the two            
considerations1 we shall first direct   
our attention4  ,it is not true1 then1  
that one effect must be connected with  
only one cause1 or assemblage of        
conditions2 that each phenomenon can be 
produced only in one way4 ,there are    
often several independent modes in which
 the same phenomenon could have         
originated4 ,one fact may be the        
consequent in several invariable        
sequences2 it may follow1 with equal    
uniformity1 any one of several          
antecedents1 or collections of          
antecedents4 ,many causes may produce   
motion3 many causes may produce some    
kinds of sensation3 many causes may     
produce death4 ,a given effect may      
really be produced by a certain cause1  
and yet be perfectly capable of being   
produced without it4    #b4 ,one of the 
principal consequences of this fact of  
,plurality of ,causes is1 to render the 

first of the inductive methods1 that of 
,agreement1 uncertain4 ,to illustrate   
that method1 we supposed two instances1 
,a ,b ,c followed by a b c1 and ,a ,d ,e
 followed by a d e4 ,from these         
instances it might apparently be        
concluded that ,a is an invariable      
antecedent of a1 and even that it is the
 unconditional invariable antecedent1 or
 cause1 if we could be sure that there  
is no other antecedent common to the two
 cases4 ,that this difficulty may not   
stand in the way1 let us suppose the two
 cases positively ascertained to have no
 antecedent in common except ,a4 ,the   
moment1 however1 that we let in the     
possibility of a plurality of causes1   
the conclusion fails4 ,for it involves a
 tacit supposition1 that a must have    
been produced in both instances by the  
same cause4 ,if there can possibly have 
been two causes1 those two may1 for     
example1 be ,c and ,e3 the one may have 
been the cause of a in the former of the
 instances1 the other in the latter1 ,a 

having no influence in either case4     
,suppose1 for example1 that two great   
artists1 or great philosophers1 that two
 extremely selfish1 or extremely        
generous characters1 were compared      
together as to the circumstances of     
their education and history1 and the two
 cases were found to agree only in one  
circumstance3 would it follow that this 
one circumstance was the cause of the   
quality which characterized both those  
individuals8 ,not at all2 for the causes
 which may produce any type of character
 are innumerable2 and the two persons   
might equally have agreed in their      
character1 though there had been no     
manner of resemblance in their previous 
history4  ,this1 therefore1 is a        
characteristic imperfection of the      
,method of ,agreement2 from which       
imperfection the ,method of ,difference 
is free4 ,for if we have two instances1 
,a ,b ,c and ,b ,c1 of which ,b ,c gives
 b c1 and ,a being added converts it    
into a b c1 it is certain that in this  

instance at least1 ,a was either the    
cause of a1 or an indispensable portion 
of its cause1 even though the cause     
which produces it in other instances may
 be altogether different4 ,plurality of 
,causes1 therefore1 not only does not   
diminish the reliance due to the ,method
 of ,difference1 but does not even      
render a greater number of observations 
or experiments necessary3 two instances1
 the one positive and the other         
negative1 are still sufficient for the  
most complete and rigorous induction4   
,not so1 however1 with the ,method of   
,agreement4 ,the conclusions which that 
yields1 when the number of instances    
compared is small1 are of no real value1
 except as1 in the character of         
suggestions1 they may lead either to    
experiments bringing them to the test of
 the ,method of ,difference1 or to      
reasonings which may explain and verify 
them deductively4  ,it is only when the 
instances1 being indefinitely multiplied
 and varied1 continue to suggest the    

same result1 that this result acquires  
any high degree of independent value4   
,if there are but two instances1 ,a ,b  
,c and ,a ,d ,e1 though these instances 
have no antecedent in common except ,a1 
yet as the effect may possibly have been
 produced in the two cases by different 
causes1 the result is at most only a    
slight probability in favour of ,a2     
there may be causation1 but it is almost
 equally probable that there was only a 
coincidence4 ,but the oftener we repeat 
the observation1 varying the            
circumstances1 the more we advance      
towards a solution of this doubt4 ,for  
if we try ,a ,f ,g1 ,a ,h ,k1 c41 all   
unlike one another except in containing 
the circumstance ,a1 and if we find the 
effect a entering into the result in all
 these cases1 we must suppose one of two
 things1 either that it is caused by ,a1
 or that it has as many different causes
 as there are instances4 ,with each     
addition1 therefore1 to the number of   
instances1 the presumption is           

strengthened in favour of ,a4 ,the      
inquirer1 of course1 will not neglect1  
if an opportunity present itself1 to    
exclude ,a from some one of these       
combinations1 from ,a ,h ,k for         
instance1 and by trying ,h ,k           
separately1 appeal to the ,method of    
,difference in aid of the ,method of    
,agreement4 ,by the ,method of          
,difference alone can it be ascertained 
that ,a is the cause of a2 but that it  
is either the cause1 or another effect  
of the same cause1 may be placed beyond 
any reasonable doubt by the ,method of  
,agreement1 provided the instances are  
very numerous1 as well as sufficiently  
various4  ,after how great a            
multiplication1 then1 of varied         
instances1 all agreeing in no other     
antecedent except ,a1 is the supposition
 of a plurality of causes sufficiently  
rebutted1 and the conclusion that a is  
connected with ,a divested of the       
characteristic imperfection1 and reduced
 to a virtual certainty8 ,this is a     

question which we cannot be exempted    
from answering3 but the consideration of
 it belongs to what is called the       
,theory of ,probability1 which will form
 the subject of a chapter hereafter4 ,it
 is seen1 however1 at once1 that the    
conclusion does amount to a practical   
certainty after a sufficient number of  
instances1 and that the method1         
therefore1 is not radically vitiated by 
the characteristic imperfection4 ,the   
result of these considerations is only1 
in the first place1 to point out a new  
source of inferiority in the ,method of 
,agreement as compared with other modes 
of investigation1 and new reasons for   
never resting contented with the results
 obtained by it1 without attempting to  
confirm them either by the ,method of   
,difference1 or by connecting them      
deductively with some law or laws       
already ascertained by that superior    
method4 ,and1 in the second place1 we   
learn from this the true theory of the  
value of mere number of instances in    

inductive inquiry4 ,the ,plurality of   
,causes is the only reason why mere     
number is of any importance4 ,the       
tendency of unscientific inquirers is to
 rely too much on number1 without       
analysing the instances2 without looking
 closely enough into their nature1 to   
ascertain what circumstances are or are 
not eliminated by means of them4 ,most  
people hold their conclusions with a    
degree of assurance proportioned to the 
mere mass of the experience on which    
they appear to rest2 not considering    
that by the addition of instances to    
instances1 all of the same kind1 that   
is1 differing from one another only in  
points already recognised as immaterial1
 nothing whatever is added to the       
evidence of the conclusion4 ,a single   
instance eliminating some antecedent    
which existed in all the other cases1 is
 of more value than the greatest        
multitude of instances which are        
reckoned by their number alone4 ,it is  
necessary1 no doubt1 to assure          

ourselves1 by repetition of the         
observation or experiment1 that no error
 has been committed concerning the      
individual facts observed2 and until we 
have assured ourselves of this1 instead 
of varying the circumstances1 we cannot 
too scrupulously repeat the same        
experiment or observation without any   
change4 ,but when once this assurance   
has been obtained1 the multiplication of
 instances which do not exclude any more
 circumstances is entirely useless1     
provided there have been already enough 
to exclude the supposition of ,plurality
 of ,causes4  ,it is of importance to   
remark1 that the peculiar modification  
of the ,method of ,agreement1 which1 as 
partaking in some degree of the nature  
of the ,method of ,difference1 ,i have  
called the ,joint ,method of ,agreement 
and ,difference1 is not affected by the 
characteristic imperfection now pointed 
out4 ,for1 in the joint method1 it is   
supposed not only that the instances in 
which a is1 agree only in containing ,a1

 but also that the instances in which a 
is not1 agree only in not containing ,a4
 ,now1 if this be so1 ,a must be not    
only the cause of a1 but the only       
possible cause3 for if there were       
another1 as for example ,b1 then in the 
instances in which a is not1 ,b must    
have been absent as well as ,a1 and it  
would not be true that these instances  
agree only in not containing ,a4 ,this1 
therefore1 constitutes an immense       
advantage of the joint method over the  
simple ,method of ,agreement4 ,it may   
seem1 indeed1 that the advantage does   
not belong so much to the joint method1 
as to one of its two premises1 7if they 
may be so called17 the negative premise4
 ,the ,method of ,agreement1 when       
applied to negative instances1 or those 
in which a phenomenon does not take     
place1 is certainly free from the       
characteristic imperfection which       
affects it in the affirmative case4 ,the
 negative premise1 it might therefore be
 supposed1 could be worked as a simple  

case of the ,method of ,agreement1      
without requiring an affirmative premise
 to be joined with it4 ,but though this 
is true in principle1 it is generally   
altogether impossible to work the       
,method of ,agreement by negative       
instances without positive ones3 it is  
so much more difficult to exhaust the   
field of negation than that of          
affirmation4 ,for instance1 let the     
question be1 what is the cause of the   
transparency of bodies2 with what       
prospect of success could we set        
ourselves to inquire directly in what   
the multifarious substances which are   
not transparent1 agree8 ,but we might   
hope much sooner to seize some point of 
resemblance among the comparatively few 
and definite species of objects which   
are transparent2 and this being         
attained1 we should quite naturally be  
put upon examining whether the absence  
of this one circumstance be not         
precisely the point in which all opaque 
substances will be found to resemble4   

,the ,joint ,method of ,agreement and   
,difference1 therefore1 or1 as ,i have  
otherwise called it1 the ,indirect      
,method of ,difference 7because1 like   
the ,method of ,difference properly so  
called1 it proceeds by ascertaining how 
and in what the cases where the         
phenomenon is present1 differ from those
 in which it is absent7 is1 after the   
,direct ,method of ,difference1 the most
 powerful of the remaining instruments  
of inductive investigation2 and in the  
sciences which depend on pure           
observation1 with little or no aid from 
experiment1 this method1 so well        
exemplified in the speculation on the   
cause of dew1 is the primary resource1  
so far as direct appeals to experience  
are concerned4    #c4 ,we have thus far 
treated ,plurality of ,causes only as a 
possible supposition1 which1 until      
removed1 renders our inductions         
uncertain2 and have only considered by  
what means1 where the plurality does not
 really exist1 we may be enabled to     

disprove it4 ,but we must also consider 
it as a case actually occurring in      
nature1 and which1 as often as it does  
occur1 our methods of induction ought to
 be capable of ascertaining and         
establishing4 ,for this1 however1 there 
is required no peculiar method4 ,when an
 effect is really producible by two or  
more causes1 the process for detecting  
them is in no way different from that by
 which we discover single causes4 ,they 
may 7first7 be discovered as separate   
sequences1 by separate sets of          
instances4 ,one set of observations or  
experiments shows that the sun is a     
cause of heat1 another that friction is 
a source of it1 another that percussion1
 another that electricity1 another that 
chemical action is such a source4 ,or   
7secondly7 the plurality may come to    
light in the course of collating a      
number of instances1 when we attempt to 
find some circumstance in which they all
 agree1 and fail in doing so4 ,we find  
it impossible to trace1 in all the cases

 in which the effect is met with1 any   
common circumstance4 ,we find that we   
can eliminate all the antecedents2 that 
no one of them is present in all the    
instances1 no one of them indispensable 
to the effect4 ,on closer scrutiny1     
however1 it appears that though no one  
is always present1 one or other of      
several always is4 ,if1 on further      
analysis1 we can detect in these any    
common element1 we may be able to ascend
 from them to some one cause which is   
the really operative circumstance in    
them all4 ,thus it is now thought that  
in the production of heat by friction1  
percussion1 chemical action1 c41 the    
ultimate source is one and the same4    
,but if 7as continually happens7 we     
cannot take this ulterior step1 the     
different antecedents must be set down  
provisionally as distinct causes1 each  
sufficient of itself to produce the     
effect4  ,we here close our remarks on  
the ,plurality of ,causes1 and proceed  
to the still more peculiar and more     

complex case of the ,intermixture of    
,effects1 and the interference of causes
 with one another3 a case constituting  
the principal part of the complication  
and difficulty of the study of nature2  
and with which the four only possible   
methods of directly inductive           
investigation by observation and        
experiment1 are for the most part1 as   
will appear presently1 quite unequal to 
cope4 ,the instrument of ,deduction     
alone is adequate to unravel the        
complexities proceeding from this       
source2 and the four methods have little
 more in their power than to supply     
premises for1 and a verification of1 our
 deductions4    #d4 ,a concurrence of   
two or more causes1 not separately      
producing each its own effect1 but      
interfering with or modifying the       
effects of one another1 takes place1 as 
has already been explained1 in two      
different ways4 ,in the one1 which is   
exemplified by the joint operation of   
different forces in mechanics1 the      

separate effects of all the causes      
continue to be produced1 but are        
compounded with one another1 and        
disappear in one total4 ,in the other1  
illustrated by the case of chemical     
action1 the separate effects cease      
entirely1 and are succeeded by phenomena
 altogether different1 and governed by  
different laws4  ,of these cases the    
former is by far the more frequent1 and 
this case it is which1 for the most     
part1 eludes the grasp of our           
experimental methods4 ,the other and    
exceptional case is essentially amenable
 to them4 ,when the laws of the original
 agents cease entirely1 and a phenomenon
 makes its appearance1 which1 with      
reference to those laws1 is quite       
heterogeneous2 when1 for example1 two   
gaseous substances1 hydrogen and oxygen1
 on being brought together1 throw off   
their peculiar properties1 and produce  
the substance called water2 in such     
cases the new fact may be subjected to  
experimental inquiry1 like any other    

phenomenon2 and the elements which are  
said to compose it may be considered as 
the mere agents of its production2 the  
conditions on which it depends1 the     
facts which make up its cause4  ,the    
effects of the new phenomenon1 the      
properties of water1 for instance1 are  
as easily found by experiment as the    
effects of any other cause4 ,but to     
discover the cause of it1 that is1 the  
particular conjunction of agents from   
which it results1 is often difficult    
enough4 ,in the first place1 the origin 
and actual production of the phenomenon 
are most frequently inaccessible to our 
observation4 ,if we could not have      
learned the composition of water until  
we found instances in which it was      
actually produced from oxygen and       
hydrogen1 we should have been forced to 
wait until the casual thought struck    
some one of passing an electric spark   
through a mixture of the two gases1 or  
inserting a lighted taper into it1      
merely to try what would happen4        

,besides1 many substances1 though they  
can be analysed1 cannot by any known    
artificial means be recompounded4       
,further1 even if we could have         
ascertained1 by the ,method of          
,agreement1 that oxygen and hydrogen    
were both present when water is         
produced1 no experimentation on oxygen  
and hydrogen separately1 no knowledge of
 their laws1 could have enabled us      
deductively to infer that they would    
produce water4 ,we require a specific   
experiment on the two combined4  ,under 
these difficulties1 we should generally 
have been indebted for our knowledge of 
the causes of this class of effects1 not
 to any inquiry directed specifically   
towards that end1 but either to         
accident1 or to the gradual progress of 
experimentation on the different        
combinations of which the producing     
agents are susceptible2 if it were not  
for a peculiarity belonging to effects  
of this description1 that they often1   
under some particular combination of    

circumstances1 reproduce their causes4  
,if water results from the juxtaposition
 of hydrogen and oxygen whenever this   
can be made sufficiently close and      
intimate1 so1 on the other hand1 if     
water itself be placed in certain       
situations1 hydrogen and oxygen are     
reproduced from it3 an abrupt           
termination is put to the new laws1 and 
the agents reappear separately with     
their own properties as at first4 ,what 
is called chemical analysis is the      
process of searching for the causes of a
 phenomenon among its effects1 or rather
 among the effects produced by the      
action of some other causes upon it4    
,lavoisier1 by heating mercury to a high
 temperature in a close vessel          
containing air1 found that the mercury  
increased in weight1 and became what was
 then called red precipitate1 while the 
air1 on being examined after the        
experiment1 proved to have lost weight1 
and to have become incapable of         
supporting life or combustion4 ,when red

 precipitate was exposed to a still     
greater heat1 it became mercury again1  
and gave off a gas which did support    
life and flame4 ,thus the agents which  
by their combination produced red       
precipitate1 namely the mercury and the 
gas1 reappear as effects resulting from 
that precipitate when acted upon by     
heat4 ,so1 if we decompose water by     
means of iron filings1 we produce two   
effects1 rust and hydrogen3 now rust is 
already known by experiments upon the   
component substances1 to be an effect of
 the union of iron and oxygen3 the iron 
we ourselves supplied1 but the oxygen   
must have been produced from the water4 
,the result therefore is that water has 
disappeared1 and hydrogen and oxygen    
have appeared in its stead3 or in other 
words1 the original laws of these       
gaseous agents1 which had been suspended
 by the superinduction of the new laws  
called the properties of water1 have    
again started into existence1 and the   
causes of water are found among its     

effects4  ,where two phenomena1 between 
the laws or properties of which         
considered in themselves no connexion   
can be traced1 are thus reciprocally    
cause and effect1 each capable in its   
turn of being produced from the other1  
and each1 when it produces the other1   
ceasing itself to exist 7as water is    
produced from oxygen and hydrogen1 and  
oxygen and hydrogen are reproduced from 
water72 this causation of the two       
phenomena by one another1 each being    
generated by the other's destruction1 is
 properly transformation4 ,the idea of  
chemical composition is an idea of      
transformation1 but of a transformation 
which is incomplete2 since we consider  
the oxygen and hydrogen to be present in
 the water as oxygen and hydrogen1 and  
capable of being discovered in it if our
 senses were sufficiently keen3 a       
supposition 7for it is no more7 grounded
 solely on the fact1 that the weight of 
the water is the sum of the separate    
weights of the two ingredients4 ,if     

there had not been this exception to the
 entire disappearance1 in the compound1 
of the laws of the separate ingredients2
 if the combined agents had not1 in this
 one particular of weight1 preserved    
their own laws1 and produced a joint    
result equal to the sum of their        
separate results2 we should never1      
probably1 have had the notion now       
implied by the words chemical           
composition3 and1 in the facts of water 
produced from hydrogen and oxygen1 and  
hydrogen and oxygen produced from water1
 as the transformation would have been  
complete1 we should have seen only a    
transformation4  ,the very promising    
generalization now commonly known as the
 ,conservation or ,persistence of       
,force1 bears a close resemblance to    
what the conception of chemical         
composition would become1 if divested of
 the one circumstance which now         
distinguishes it from simple            
transformation4 ,it has long been known 
that heat is capable of producing       

electricity1 and electricity heat2 that 
mechanical motion in numerous cases     
produces and is produced by them both2  
and so of all other physical forces4 ,it
 has of late become the general belief  
of scientific inquirers that mechanical 
force1 electricity1 magnetism1 heat1    
light1 and chemical action 7to which has
 subsequently been added vital action7  
are not so much causes of one another as
 convertible into one another2 and they 
are now generally spoken of as forms of 
one and the same force1 varying only in 
its manifestations4 ,this doctrine may  
be admitted1 without by any means       
implying that ,force is a real entity1 a
 ,thing in itself1 distinct from all its
 phenomenal manifestations to our       
organs4 ,supposing the doctrine true1   
the several kinds of phenomena which it 
identifies in respect of their origin   
would nevertheless remain different     
facts2 facts which would be causes of   
one another--reciprocally causes and    
effects1 which is the first element in  

the form of causation properly called   
transformation4 ,what the doctrine      
contains more than this1 is1 that in    
each of these cases of reciprocal       
causation1 the causes are reproduced    
without alteration in quantity4 ,this is
 what takes place in the transformations
 of matter3 when water has been         
converted into hydrogen and oxygen1     
these can be reconverted into precisely 
the same quantity of water from which   
they were produced4 ,to establish a     
corresponding law in regard to ,force1  
it has to be proved that heat is capable
 of being converted into electricity1   
electricity into chemical action1       
chemical action into mechanical force1  
and mechanical force back again into the
 exact quantity of heat which was       
originally expended2 and so through all 
the interchanges4 ,were this proved1 it 
would establish what constitutes        
transformation1 as distinguished from   
the simple fact of reciprocal causation4
 ,the fact in issue is simply the       

quantitative equivalence of all these   
natural agencies2 whereby a given       
quantity of any one is convertible into1
 and interchangeable with1 a given1 and 
always the same1 quantity of any other3 
this1 no less1 but also no more4 ,it    
cannot yet be said that the law has been
 fully proved of any case1 except that  
of interchange between heat and         
mechanical motion4 ,it does seem to be  
ascertained1 not only that these two are
 convertible into each other1 but that  
after any number of conversions the     
original quantities reappear without    
addition or diminution1 like the        
original quantities of hydrogen and     
oxygen after passing through the        
condition of water4 ,if the same thing  
comes to be proved true of all the other
 forces1 in relation to these two and to
 one another1 the law of ,conservation  
will be established2 and it will be a   
legitimate mode of expressing the fact1 
to speak of ,force1 as we already speak 
of ,matter1 as indestructible4 ,but     

,force will not the less remain1 to the 
philosopher1 a mere abstraction of the  
mind4 ,all that will have been proved   
is1 that in the phenomena of ,nature1   
nothing actually ceases without         
generating a calculable1 and always the 
same1 quantity of some other natural    
phenomenon1 which again1 when it ceases1
 will in its turn either generate a     
calculable1 and always the same1        
quantity of some third phenomenon1 or   
reproduce the original quantity of the  
first4  ,in these cases1 where the      
heteropathic effect 7as we called it in 
a former chapter7#dd is but a           
transformation of its cause1 or in other
 words1 where the effect and its cause  
are reciprocally such1 and mutually     
convertible into each other2 the problem
 of finding the cause resolves itself   
into the far easier one of finding an   
effect1 which is the kind of inquiry    
that admits of being prosecuted by      
direct experiment4 ,but there are other 
cases of heteropathic effects to which  

this mode of investigation is not       
applicable4 ,take1 for instance1 the    
heteropathic laws of mind2 that portion 
of the phenomena of our mental nature   
which are analogous to chemical rather  
than to dynamical phenomena2 as when a  
complex passion is formed by the        
coalition of several elementary         
impulses1 or a complex emotion by       
several simple pleasures or pains1 of   
which it is the result without being the
 aggregate1 or in any respect           
homogeneous with them4 ,the product1 in 
these cases1 is generated by its various
 factors2 but the factors cannot be     
reproduced from the product2 just as a  
youth can grow into an old man1 but an  
old man cannot grow into a youth4 ,we   
cannot ascertain from what simple       
feelings any of our complex states of   
mind are generated1 as we ascertain the 
ingredients of a chemical compound1 by  
making it1 in its turn1 generate them4  
,we can only1 therefore1 discover these 
laws by the slow process of studying the

 simple feelings themselves1 and        
ascertaining synthetically1 by          
experimenting on the various            
combinations of which they are          
susceptible1 what they1 by their mutual 
action upon one another1 are capable of 
generating4    #e4 ,it might have been  
supposed that the other1 and apparently 
simpler variety of the mutual           
interference of causes1 where each cause
 continues to produce its own proper    
effect according to the same laws to    
which it conforms in its separate state1
 would have presented fewer difficulties
 to the inductive inquirer than that of 
which we have just finished the         
consideration4 ,it presents1 however1 so
 far as direct induction apart from     
deduction is concerned1 infinitely      
greater difficulties4 ,when a           
concurrence of causes gives rise to a   
new effect1 bearing no relation to the  
separate effects of those causes1 the   
resulting phenomenon stands forth       
undisguised1 inviting attention to its  

peculiarity1 and presenting no obstacle 
to our recognising its presence or      
absence among any number of surrounding 
phenomena4 ,it admits therefore of being
 easily brought under the canons of     
,induction1 provided instances can be   
obtained such as those canons require3  
and the non-occurrence of such          
instances1 or the want of means to      
produce them artificially1 is the real  
and only difficulty in such             
investigations2 a difficulty not        
logical1 but in some sort physical4 ,it 
is otherwise with cases of what1 in a   
preceding chapter1 has been denominated 
the ,composition of ,causes4 ,there1 the
 effects of the separate causes do not  
terminate and give place to others1     
thereby ceasing to form any part of the 
phenomenon to be investigated2 on the   
contrary1 they still take place1 but are
 intermingled with1 and disguised by1   
the homogeneous and closely allied      
effects of other causes4 ,they are no   
longer a1 b1 c1 d1 e1 existing side by  

side1 and continuing to be separately   
discernible2 they are  a1 - a1 #a_/b b1 
- b1 #b b1 c41 some of which cancel one 
another1 while many others do not appear
 distinguishably1 but merge in one sum3 
forming altogether a result1 between    
which and the causes whereby it was     
produced there is often an              
insurmountable difficulty in tracing by 
observation any fixed relation whatever4
  ,the general idea of the ,composition 
of ,causes has been seen to be1 that    
though two or more laws interfere with  
one another1 and apparently frustrate or
 modify one another's operation1 yet in 
reality all are fulfilled1 the          
collective effect being the exact sum of
 the effects of the causes taken        
separately4 ,a familiar instance is that
 of a body kept in equilibrium by two   
equal and contrary forces4 ,one of the  
forces if acting alone would carry the  
body in a given time a certain distance 
to the west1 the other if acting alone  
would carry it exactly as far towards   

the east2 and the result is the same as 
if it had been first carried to the west
 as far as the one force would carry it1
 and then back towards the east as far  
as the other would carry it1 that is1   
precisely the same distance2 being      
ultimately left where it was found at   
first4  ,all laws of causation are      
liable to be in this manner             
counteracted1 and seemingly frustrated1 
by coming into conflict with other laws1
 the separate result of which is        
opposite to theirs1 or more or less     
inconsistent with it4 ,and hence1 with  
almost every law1 many instances in     
which it really is entirely fulfilled1  
do not1 at first sight1 appear to be    
cases of its operation at all4 ,it is so
 in the example just adduced3 a force1  
in mechanics1 means neither more nor    
less than a cause of motion1 yet the sum
 of the effects of two causes of motion 
may be rest4 ,again1 a body solicited by
 two forces in directions making an     
angle with one another1 moves in the    

diagonal2 and it seems a paradox to say 
that motion in the diagonal is the sum  
of two motions in two other lines4      
,motion1 however1 is but change of      
place1 and at every instant the body is 
in the exact place it would have been in
 if the forces had acted during         
alternate instants instead of acting in 
the same instant2 7saving that if we    
suppose two forces to act successively  
which are in truth simultaneous1 we must
 of course allow them double the time47 
,it is evident1 therefore1 that each    
force has had1 during each instant1 all 
the effect which belonged to it2 and    
that the modifying influence which one  
of two concurrent causes is said to     
exercise with respect to the other1 may 
be considered as exerted not over the   
action of the cause itself1 but over the
 effect after it is completed4 ,for all 
purposes of predicting1 calculating1 or 
explaining their joint result1 causes   
which compound their effects may be     
treated as if they produced             

simultaneously each of them its own     
effect1 and all these effects coexisted 
visibly4  ,since the laws of causes are 
as really fulfilled when the causes are 
said to be counteracted by opposing     
causes1 as when they are left to their  
own undisturbed action1 we must be      
cautious not to express the laws in such
 terms as would render the assertion of 
their being fulfilled in those cases a  
contradiction4 ,if1 for instance1 it    
were stated as a law of nature that a   
body to which a force is applied moves  
in the direction of the force1 with a   
velocity proportioned to the force      
directly1 and to its own mass inversely2
 when in point of fact some bodies to   
which a force is applied do not move at 
all1 and those which do move 7at least  
in the region of our earth7 are1 from   
the very first1 retarded by the action  
of gravity and other resisting forces1  
and at last stopped altogether2 it is   
clear that the general proposition1     
though it would be true under a certain 

hypothesis1 would not express the facts 
as they actually occur4 ,to accommodate 
the expression of the law to the real   
phenomena1 we must say1 not that the    
object moves1 but that it tends to move1
 in the direction and with the velocity 
specified4 ,we might1 indeed1 guard our 
expression in a different mode1 by      
saying that the body moves in that      
manner unless prevented1 or except in so
 far as prevented1 by some counteracting
 cause4 ,but the body does not only move
 in that manner unless counteracted2 it 
tends to move in that manner even when  
counteracted2 it still exerts1 in the   
original direction1 the same energy of  
movement as if its first impulse had    
been undisturbed1 and produces1 by that 
energy1 an exactly equivalent quantity  
of effect4 ,this is true even when the  
force leaves the body as it found it1 in
 a state of absolute rest2 as when we   
attempt to raise a body of three tons   
weight with a force equal to one ton4   
,for if1 while we are applying this     

force1 wind or water or any other agent 
supplies an additional force just       
exceeding two tons1 the body will be    
raised2 thus proving that the force we  
applied exerted its full effect1 by     
neutralizing an equivalent portion of   
the weight which it was insufficient    
altogether to overcome4 ,and if while we
 are exerting this force of one ton upon
 the object in a direction contrary to  
that of gravity1 it be put into a scale 
and weighed1 it will be found to have   
lost a ton of its weight1 or in other   
words1 to press downwards with a force  
only equal to the difference of the two 
forces4  ,these facts are correctly     
indicated by the expression tendency4   
,all laws of causation1 in consequence  
of their liability to be counteracted1  
require to be stated in words           
affirmative of tendencies only1 and not 
of actual results4 ,in those sciences of
 causation which have an accurate       
nomenclature1 there are special words   
which signify a tendency to the         

particular effect with which the science
 is conversant2 thus pressure1 in       
mechanics1 is synonymous with tendency  
to motion1 and forces are not reasoned  
on as causing actual motion1 but as     
exerting pressure4 ,a similar           
improvement in terminology would be very
 salutary in many other branches of     
science4  ,the habit of neglecting this 
necessary element in the precise        
expression of the laws of nature1 has   
given birth to the popular prejudice    
that all general truths have exceptions2
 and much unmerited distrust has thence 
accrued to the conclusions of science1  
when they have been submitted to the    
judgment of minds insufficiently        
disciplined and cultivated4 ,the rough  
generalizations suggested by common     
observation usually have exceptions2 but
 principles of science1 or in other     
words1 laws of causation1 have not4     
,what is thought to be an exception to a
 principle1 7to quote words used on a   
different occasion17 is always some     

other and distinct principle cutting    
into the former2 some other force which 
impinges#de against the first force1 and
 deflects it from its direction4 ,there 
are not a law and an exception to that  
law1 the law acting in ninety-nine      
cases1 and the exception in one4 ,there 
are two laws1 each possibly acting in   
the whole hundred cases1 and bringing   
about a common effect by their conjunct 
operation4 ,if the force which1 being   
the less conspicuous of the two1 is     
called the disturbing force1 prevails   
sufficiently over the other force in    
some one case1 to constitute that case  
what is commonly called an exception1   
the same disturbing force probably acts 
as a modifying cause in many other cases
 which no one will call exceptions4     
,thus if it were stated to be a law of  
nature that all heavy bodies fall to the
 ground1 it would probably be said that 
the resistance of the atmosphere1 which 
prevents a balloon from falling1        
constitutes the balloon an exception to 

that pretended law of nature4 ,but the  
real law is1 that all heavy bodies tend 
to fall2 and to this there is no        
exception1 not even the sun and moon2   
for even they1 as every astronomer      
knows1 tend towards the earth1 with a   
force exactly equal to that with which  
the earth tends towards them4 ,the      
resistance of the atmosphere might1 in  
the particular case of the balloon1 from
 a misapprehension of what the law of   
gravitation is1 be said to prevail over 
the law2 but its disturbing effect is   
quite as real in every other case1 since
 though it does not prevent1 it retards 
the fall of all bodies whatever4 ,the   
rule1 and the so-called exception1 do   
not divide the cases between them2 each 
of them is a comprehensive rule         
extending to all cases4 ,to call one of 
these concurrent principles an exception
 to the other1 is superficial1 and      
contrary to the correct principles of   
nomenclature and arrangement4 ,an effect
 of precisely the same kind1 and arising

 from the same cause1 ought not to be   
placed in two different categories1     
merely as there does or does not exist  
another cause preponderating over it4#df
    #f4 ,we have now to consider        
according to what method these complex  
effects1 compounded of the effects of   
many causes1 are to be studied2 how we  
are enabled to trace each effect to the 
concurrence of causes in which it       
originated1 and ascertain the conditions
 of its recurrence--the circumstances in
 which it may be expected again to      
occur4 ,the conditions of a phenomenon  
which arises from a composition of      
causes1 may be investigated either      
deductively or experimentally4  ,the    
case1 it is evident1 is naturally       
susceptible of the deductive mode of    
investigation4 ,the law of an effect of 
this description is a result of the laws
 of the separate causes on the          
combination of which it depends1 and is 
therefore in itself capable of being    
deduced from these laws4 ,this is called

 the method  priori4 ,the other1 or     
posteriori method1 professes to proceed 
according to the canons of experimental 
inquiry4 ,considering the whole         
assemblage of concurrent causes which   
produced the phenomenon1 as one single  
cause1 it attempts to ascertain the     
cause in the ordinary manner1 by a      
comparison of instances4 ,this second   
method subdivides itself into two       
different varieties4 ,if it merely      
collates instances of the effect1 it is 
a method of pure observation4 ,if it    
operates upon the causes1 and tries     
different combinations of them1 in hopes
 of ultimately hitting the precise      
combination which will produce the given
 total effect1 it is a method of        
experiment4  ,in order more completely  
to clear up the nature of each of these 
three methods1 and determine which of   
them deserves the preference1 it will be
 expedient 7conformably to a favourite  
maxim of ,lord ,chancellor ,eldon1 to   
which1 though it has often incurred     

philosophical ridicule1 a deeper        
philosophy will not refuse its sanction7
 to clothe them in circumstances4 ,we   
shall select for this purpose a case    
which as yet furnishes no very brilliant
 example of the success of any of the   
three methods1 but which is all the more
 suited to illustrate the difficulties  
inherent in them4 ,let the subject of   
inquiry be1 the conditions of health and
 disease in the human body2 or 7for     
greater simplicity7 the conditions of   
recovery from a given disease2 and in   
order to narrow the question still more1
 let it be limited1 in the first        
instance1 to this one inquiry3 ,is1 or  
is not some particular medicament       
7mercury1 for instance7 a remedy for the
 given disease4  ,now1 the deductive    
method would set out from known         
properties of mercury1 and known laws of
 the human body1 and by reasoning from  
these1 would attempt to discover whether
 mercury will act upon the body when in 
the morbid condition supposed1 in such a

 manner as to restore health4 ,the      
experimental method would simply        
administer mercury in as many cases as  
possible1 noting the age1 sex1          
temperament1 and other peculiarities of 
bodily constitution1 the particular form
 or variety of the disease1 the         
particular stage of its progress1 c41   
remarking in which of these cases it    
produced a salutary effect1 and with    
what circumstances it was on those      
occasions combined4 ,the method of      
simple observation would compare        
instances of recovery1 to find whether  
they agreed in having been preceded by  
the administration of mercury2 or would 
compare instances of recovery with      
instances of failure1 to find cases     
which1 agreeing in all other respects1  
differed only in the fact that mercury  
had been administered1 or that it had   
not4    #g4 ,that the last of these     
three modes of investigation is         
applicable to the case1 no one has ever 
seriously contended4 ,no conclusions of 

value on a subject of such intricacy1   
ever were obtained in that way4 ,the    
utmost that could result would be a     
vague general impression for or against 
the efficacy of mercury1 of no avail for
 guidance unless confirmed by one of the
 other two methods4 ,not that the       
results1 which this method strives to   
obtain1 would not be of the utmost      
possible value if they could be         
obtained4 ,if all the cases of recovery 
which presented themselves1 in an       
examination extending to a great number 
of instances1 were cases in which       
mercury had been administered1 we might 
generalize with confidence from this    
experience1 and should have obtained a  
conclusion of real value4 ,but no such  
basis for generalization can we1 in a   
case of this description1 hope to       
obtain4 ,the reason is that which we    
have spoken of as constituting the      
characteristic imperfection of the      
,method of ,agreement2 ,plurality of    
,causes4 ,supposing even that mercury   

does tend to cure the disease1 so many  
other causes1 both natural and          
artificial1 also tend to cure it1 that  
there are sure to be abundant instances 
of recovery in which mercury has not    
been administered3 unless1 indeed1 the  
practice be to administer it in all     
cases2 on which supposition it will     
equally be found in the cases of        
failure4  ,when an effect results from  
the union of many causes1 the share     
which each has in the determination of  
the effect cannot in general be great3  
and the effect is not likely1 even in   
its presence or absence1 still less in  
its variations1 to follow1 even         
approximately1 any one of the causes4   
,recovery from a disease is an event to 
which1 in every case1 many influences   
must concur4 ,mercury may be one such   
influence2 but from the very fact that  
there are many other such1 it will      
necessarily happen that although mercury
 is administered1 the patient1 for want 
of other concurring influences1 will    

often not recover1 and that he often    
will recover when it is not             
administered1 the other favourable      
influences being sufficiently powerful  
without it4 ,neither1 therefore1 will   
the instances of recovery agree in the  
administration of mercury1 nor will the 
instances of failure agree in its       
non-administration4 ,it is much if1 by  
multiplied and accurate returns from    
hospitals and the like1 we can collect  
that there are rather more recoveries   
and rather fewer failures when mercury  
is administered than when it is not2 a  
result of very secondary value even as a
 guide to practice1 and almost worthless
 as a contribution to the theory of the 
subject4    #h4 ,the inapplicability of 
the method of simple observation to     
ascertain the conditions of effects     
dependent on many concurring causes1    
being thus recognised2 we shall next    
inquire whether any greater benefit can 
be expected from the other branch of the
  posteriori method1 that which proceeds

 by directly trying different           
combinations of causes1 either          
artificially produced or found in       
nature1 and taking notice what is their 
effect3 as1 for example1 by actually    
trying the effect of mercury1 in as many
 different circumstances as possible4   
,this method differs from the one which 
we have just examined1 in turning our   
attention directly to the causes or     
agents1 instead of turning it to the    
effect1 recovery from the disease4 ,and 
since1 as a general rule1 the effects of
 causes are far more accessible to our  
study than the causes of effects1 it is 
natural to think that this method has a 
much better chance of proving successful
 than the former4  ,the method now under
 consideration is called the ,empirical 
,method2 and in order to estimate it    
fairly1 we must suppose it to be        
completely1 not incompletely1 empirical4
 ,we must exclude from it everything    
which partakes of the nature not of an  
experimental but of a deductive         

operation4 ,if for instance we try      
experiments with mercury upon a person  
in health1 in order to ascertain the    
general laws of its action upon the     
human body1 and then reason from these  
laws to determine how it will act upon  
persons affected with a particular      
disease1 this may be a really effectual 
method1 but this is deduction4 ,the     
experimental method does not derive the 
law of a complex case from the simpler  
laws which conspire to produce it1 but  
makes its experiments directly upon the 
complex case4 ,we must make entire      
abstraction of all knowledge of the     
simpler tendencies1 the modi operandi of
 mercury in detail4 ,our experimentation
 must aim at obtaining a direct answer  
to the specific question1 ,does or does 
not mercury tend to cure the particular 
disease8  ,let us see1 therefore1 how   
far the case admits of the observance of
 those rules of experimentation1 which  
it is found necessary to observe in     
other cases4 ,when we devise an         

experiment to ascertain the effect of a 
given agent1 there are certain          
precautions which we never1 if we can   
help it1 omit4 ,in the first place1 we  
introduce the agent into the midst of a 
set of circumstances which we have      
exactly ascertained4 ,it needs hardly be
 remarked how far this condition is from
 being realized in any case connected   
with the phenomena of life2 how far we  
are from knowing what are all the       
circumstances which pre-exist in any    
instance in which mercury is            
administered to a living being4 ,this   
difficulty1 however1 though insuperable 
in most cases1 may not be so in all2    
there are sometimes concurrences of many
 causes1 in which we yet know accurately
 what the causes are4 ,moreover1 the    
difficulty may be attenuated by         
sufficient multiplication of            
experiments1 in circumstances rendering 
it improbable that any of the unknown   
causes should exist in them all4 ,but   
when we have got clear of this obstacle1

 we encounter another still more        
serious4 ,in other cases1 when we intend
 to try an experiment1 we do not reckon 
it enough that there be no circumstance 
in the case the presence of which is    
unknown to us4 ,we require also that    
none of the circumstances which we do   
know1 shall have effects susceptible of 
being confounded with those of the agent
 whose properties we wish to study4 ,we 
take the utmost pains to exclude all    
causes capable of composition with the  
given cause2 or if forced to let in any 
such causes1 we take care to make them  
such that we can compute and allow for  
their influence1 so that the effect of  
the given cause may1 after the          
subduction of those other effects1 be   
apparent as a residual phenomenon4      
,these precautions are inapplicable to  
such cases as we are now considering4   
,the mercury of our experiment being    
tried with an unknown multitude 7or even
 let it be a known multitude7 of other  
influencing circumstances1 the mere fact

 of their being influencing             
circumstances implies that they disguise
 the effect of the mercury1 and preclude
 us from knowing whether it has any     
effect or not4 ,unless we already knew  
what and how much is owing to every     
other circumstance1 7that is1 unless we 
suppose the very problem solved which we
 are considering the means of solving17 
we cannot tell that those other         
circumstances may not have produced the 
whole of the effect1 independently or   
even in spite of the mercury4 ,the      
,method of ,difference1 in the ordinary 
mode of its use1 namely by comparing the
 state of things following the          
experiment with the state which preceded
 it1 is thus1 in the case of            
intermixture of effects1 entirely       
unavailing2 because other causes than   
that whose effect we are seeking to     
determine1 have been operating during   
the transition4 ,as for the other mode  
of employing the ,method of ,difference1
 namely by comparing1 not the same case 

at two different periods1 but different 
cases1 this in the present instance is  
quite chimerical4 ,in phenomena so      
complicated it is questionable if two   
cases1 similar in all respects but one1 
ever occurred2 and were they to occur1  
we could not possibly know that they    
were so exactly similar4  ,anything like
 a scientific use of the method of      
experiment1 in these complicated cases1 
is therefore out of the question4 ,we   
can in the most favourable cases only   
discover1 by a succession of trials1    
that a certain cause is very often      
followed by a certain effect4 ,for1 in  
one of these conjunct effects1 the      
portion which is determined by any one  
of the influencing agents1 is generally1
 as we before remarked1 but small2 and  
it must be a more potent cause than     
most1 if even the tendency which it     
really exerts is not thwarted by other  
tendencies in nearly as many cases as it
 is fulfilled4  ,if so little can be    
done by the experimental method to      

determine the conditions of an effect of
 many combined causes1 in the case of   
medical science2 still less is this     
method applicable to a class of         
phenomena more complicated than even    
those of physiology1 the phenomena of   
politics and history4 ,there1 ,plurality
 of ,causes exists in almost boundless  
excess1 and effects are1 for the most   
part1 inextricably interwoven with one  
another4 ,to add to the embarrassment1  
most of the inquiries in political      
science relate to the production of     
effects of a most comprehensive         
description1 such as the public wealth1 
public security1 public morality1 and   
the like3 results liable to be affected 
directly or indirectly either in plus or
 in minus by nearly every fact which    
exists1 or event which occurs1 in human 
society4 ,the vulgar notion1 that the   
safe methods on political subjects are  
those of ,baconian induction--that the  
true guide is not general reasoning1 but
 specific experience--will one day be   

quoted as among the most unequivocal    
marks of a low state of the speculative 
faculties in any age in which it is     
accredited4 ,nothing can be more        
ludicrous than the sort of parodies on  
experimental reasoning which one is     
accustomed to meet with1 not in popular 
discussion only1 but in grave treatises1
 when the affairs of nations are the    
theme4 ,how1 it is asked1 can an        
institution be bad1 when the country has
 prospered under it8 ,how can such or   
such causes have contributed to the     
prosperity of one country1 when another 
has prospered without them8 ,whoever    
makes use of an argument of this kind1  
not intending to deceive1 should be sent
 back to learn the elements of some one 
of the more easy physical sciences4     
,such reasoners ignore the fact of      
,plurality of ,causes in the very case  
which affords the most signal example of
 it4 ,so little could be concluded1 in  
such a case1 from any possible collation
 of individual instances1 that even the 

impossibility1 in social phenomena1 of  
making artificial experiments1 a        
circumstance otherwise so prejudicial to
 directly inductive inquiry1 hardly     
affords1 in this case1 additional reason
 of regret4 ,for even if we could try   
experiments upon a nation or upon the   
human race1 with as little scruple as   
,m4 ,magendie tried them on dogs and    
rabbits1 we should never succeed in     
making two instances identical in every 
respect except the presence or absence  
of some one definite circumstance4 ,the 
nearest approach to an experiment in the
 philosophical sense1 which takes place 
in politics1 is the introduction of a   
new operative element into national     
affairs by some special and assignable  
measure of government1 such as the      
enactment or repeal of a particular law4
 ,but where there are so many influences
 at work1 it requires some time for the 
influence of any new cause upon national
 phenomena to become apparent2 and as   
the causes operating in so extensive a  

sphere are not only infinitely numerous1
 but in a state of perpetual alteration1
 it is always certain that before the   
effect of the new cause becomes         
conspicuous enough to be a subject of   
induction1 so many of the other         
influencing circumstances will have     
changed as to vitiate the experiment4   
,two1 therefore1 of the three possible  
methods for the study of phenomena      
resulting from the composition of many  
causes1 being1 from the very nature of  
the case1 inefficient and illusory1     
there remains only the third1--that     
which considers the causes separately1  
and infers the effect from the balance  
of the different tendencies which       
produce it3 in short1 the deductive1 or 
priori method4 ,the more particular     
consideration of this intellectual      
process requires a chapter to itself4   
,,chapter ,,xi4  ,,of ,,the ,,deductive 
,,method4    #a4 ,the mode of           
investigation which1 from the proved    
inapplicability of direct methods of    

observation and experiment1 remains to  
us as the main source of the knowledge  
we possess or can acquire respecting the
 conditions1 and laws of recurrence1 of 
the more complex phenomena1 is called1  
in its most general expression1 the     
,deductive ,method2 and consists of     
three operations3 the first1 one of     
direct induction2 the second1 of        
ratiocination2 the third1 of            
verification4  ,i call the first step in
 the process an inductive operation1    
because there must be a direct induction
 as the basis of the whole2 though in   
many particular investigations the place
 of the induction may be supplied by a  
prior deduction2 but the premises of    
this prior deduction must have been     
derived from induction4  ,the problem of
 the ,deductive ,method is1 to find the 
law of an effect1 from the laws of the  
different tendencies of which it is the 
joint result4 ,the first requisite1     
therefore1 is to know the laws of those 
tendencies2 the law of each of the      

concurrent causes3 and this supposes a  
previous process of observation or      
experiment upon each cause separately2  
or else a previous deduction1 which also
 must depend for its ultimate premises  
on observation or experiment4 ,thus1 if 
the subject be social or historical     
phenomena1 the premises of the          
,deductive ,method must be the laws of  
the causes which determine that class of
 phenomena2 and those causes are human  
actions1 together with the general      
outward circumstances under the         
influence of which mankind are placed1  
and which constitute man's position on  
the earth4 ,the ,deductive ,method1     
applied to social phenomena1 must begin1
 therefore1 by investigating1 or must   
suppose to have been already            
investigated1 the laws of human action1 
and those properties of outward things  
by which the actions of human beings in 
society are determined4 ,some of these  
general truths will naturally be        
obtained by observation and experiment1 

others by deduction3 the more complex   
laws of human action1 for example1 may  
be deduced from the simpler ones2 but   
the simple or elementary laws will      
always1 and necessarily1 have been      
obtained by a directly inductive        
process4  ,to ascertain1 then1 the laws 
of each separate cause which takes a    
share in producing the effect1 is the   
first desideratum of the ,deductive     
,method4 ,to know what the causes are1  
which must be subjected to this process 
of study1 may or may not be difficult4  
,in the case last mentioned1 this first 
condition is of easy fulfilment4 ,that  
social phenomena depend on the acts and 
mental impressions of human beings1     
never could have been a matter of any   
doubt1 however imperfectly it may have  
been known either by what laws those    
impressions and actions are governed1 or
 to what social consequences their laws 
naturally lead4 ,neither1 again1 after  
physical science had attained a certain 
development1 could there be any real    

doubt where to look for the laws on     
which the phenomena of life depend1     
since they must be the mechanical and   
chemical laws of the solid and fluid    
substances composing the organized body 
and the medium in which it subsists1    
together with the peculiar vital laws of
 the different tissues constituting the 
organic structure4 ,in other cases1     
really far more simple than these1 it   
was much less obvious in what quarter   
the causes were to be looked for3 as in 
the case of the celestial phenomena4    
,until1 by combining the laws of certain
 causes1 it was found that those laws   
explained all the facts which experience
 had proved concerning the heavenly     
motions1 and led to predictions which it
 always verified1 mankind never knew    
that those were the causes4 ,but whether
 we are able to put the question before1
 or not until after1 we have become     
capable of answering it1 in either case 
it must be answered2 the laws of the    
different causes must be ascertained1   

before we can proceed to deduce from    
them the conditions of the effect4  ,the
 mode of ascertaining those laws neither
 is1 nor can be1 any other than the     
fourfold method of experimental inquiry1
 already discussed4 ,a few remarks on   
the application of that method to cases 
of the ,composition of ,causes1 are all 
that is requisite4  ,it is obvious that 
we cannot expect to find the law of a   
tendency1 by an induction from cases in 
which the tendency is counteracted4 ,the
 laws of motion could never have been   
brought to light from the observation of
 bodies kept at rest by the equilibrium 
of opposing forces4 ,even where the     
tendency is not1 in the ordinary sense  
of the word1 counteracted1 but only     
modified1 by having its effects         
compounded with the effects arising from
 some other tendency or tendencies1 we  
are still in an unfavourable position   
for tracing1 by means of such cases1 the
 law of the tendency itself4 ,it would  
have been scarcely possible to discover 

the law that every body in motion tends 
to continue moving in a straight line1  
by an induction from instances in which 
the motion is deflected into a curve1 by
 being compounded with the effect of an 
accelerating force4 ,notwithstanding the
 resources afforded in this description 
of cases by the ,method of ,concomitant 
,variations1 the principles of a        
judicious experimentation prescribe that
 the law of each of the tendencies      
should be studied1 if possible1 in cases
 in which that tendency operates alone1 
or in combination with no agencies but  
those of which the effect can1 from     
previous knowledge1 be calculated and   
allowed for4  ,accordingly1 in the      
cases1 unfortunately very numerous and  
important1 in which the causes do not   
suffer themselves to be separated and   
observed apart1 there is much difficulty
 in laying down with due certainty the  
inductive foundation necessary to       
support the deductive method4 ,this     
difficulty is most of all conspicuous in

 the case of physiological phenomena2 it
 being seldom possible to separate the  
different agencies which collectively   
compose an organized body1 without      
destroying the very phenomena which it  
is our object to investigate3           
--following life1 in creatures we       
dissect1     ,we lose it1 in the moment 
we detect4  ,and for this reason ,i am  
inclined to the opinion1 that physiology
 7greatly and rapidly progressive as it 
now is7 is embarrassed by greater       
natural difficulties1 and is probably   
susceptible of a less degree of ultimate
 perfection1 than even the social       
science2 inasmuch as it is possible to  
study the laws and operations of one    
human mind apart from other minds1 much 
less imperfectly than we can study the  
laws of one organ or tissue of the human
 body apart from the other organs or    
tissues4  ,it has been judiciously      
remarked that pathological facts1 or1 to
 speak in common language1 diseases in  
their different forms and degrees1      

afford in the case of physiological     
investigation the most valuable         
equivalent to experimentation properly  
so called2 inasmuch as they often       
exhibit to us a definite disturbance in 
some one organ or organic function1 the 
remaining organs and functions being1 in
 the first instance at least1           
unaffected4 ,it is true that from the   
perpetual actions and reactions which   
are going on among all parts of the     
organic economy1 there can be no        
prolonged disturbance in any one        
function without ultimately involving   
many of the others2 and when once it has
 done so1 the experiment for the most   
part loses its scientific value4 ,all   
depends on observing the early stages of
 the derangement2 which1 unfortunately1 
are of necessity the least marked4 ,if1 
however1 the organs and functions not   
disturbed in the first instance1 become 
affected in a fixed order of succession1
 some light is thereby thrown upon the  
action which one organ exercises over   

another3 and we occasionally obtain a   
series of effects which we can refer    
with some confidence to the original    
local derangement2 but for this it is   
necessary that we should know that the  
original derangement was local4 ,if it  
was what is termed constitutional1 that 
is1 if we do not know in what part of   
the animal economy it took its rise1 or 
the precise nature of the disturbance   
which took place in that part1 we are   
unable to determine which of the various
 derangements was cause and which       
effect2 which of them were produced by  
one another1 and which by the direct1   
though perhaps tardy1 action of the     
original cause4  ,besides natural       
pathological facts1 we can produce      
pathological facts artificially2 we can 
try experiments1 even in the popular    
sense of the term1 by subjecting the    
living being to some external agent1    
such as the mercury of our former       
example1 or the section of a nerve to   
ascertain the functions of different    

parts of the nervous system4 ,as this   
experimentation is not intended to      
obtain a direct solution of any         
practical question1 but to discover     
general laws1 from which afterwards the 
conditions of any particular effect may 
be obtained by deduction2 the best cases
 to select are those of which the       
circumstances can be best ascertained3  
and such are generally not those in     
which there is any practical object in  
view4 ,the experiments are best tried1  
not in a state of disease1 which is     
essentially a changeable state1 but in  
the condition of health1 comparatively a
 fixed state4 ,in the one1 unusual      
agencies are at work1 the results of    
which we have no means of predicting2 in
 the other1 the course of the accustomed
 physiological phenomena would1 it may  
generally be presumed1 remain           
undisturbed1 were it not for the        
disturbing cause which we introduce4    
,such1 with the occasional aid of the   
,method of ,concomitant ,variations1    

7the latter not less incumbered than the
 more elementary methods by the peculiar
 difficulties of the subject17 are our  
inductive resources for ascertaining the
 laws of the causes considered          
separately1 when we have it not in our  
power to make trial of them in a state  
of actual separation4 ,the insufficiency
 of these resources is so glaring1 that 
no one can be surprised at the backward 
state of the science of physiology2 in  
which indeed our knowledge of causes is 
so imperfect1 that we can neither       
explain1 nor could without specific     
experience have predicted1 many of the  
facts which are certified to us by the  
most ordinary observation4 ,fortunately1
 we are much better informed as to the  
empirical laws of the phenomena1 that   
is1 the uniformities respecting which we
 cannot yet decide whether they are     
cases of causation1 or mere results of  
it4 ,not only has the order in which the
 facts of organization and life         
successively manifest themselves1 from  

the first germ of existence to death1   
been found to be uniform1 and very      
accurately ascertainable2 but1 by a     
great application of the ,method of     
,concomitant ,variations to the entire  
facts of comparative anatomy and        
physiology1 the characteristic organic  
structure corresponding to each class of
 functions has been determined with     
considerable precision4 ,whether these  
organic conditions are the whole of the 
conditions1 and in many cases whether   
they are conditions at all1 or mere     
collateral effects of some common cause1
 we are quite ignorant3 nor are we ever 
likely to know1 unless we could         
construct an organized body1 and try    
whether it would live4  ,under such     
disadvantages do we1 in cases of this   
description1 attempt the initial1 or    
inductive step1 in the application of   
the ,deductive ,method to complex       
phenomena4 ,but such1 fortunately1 is   
not the common case4 ,in general1 the   
laws of the causes on which the effect  

depends may be obtained by an induction 
from comparatively simple instances1 or1
 at the worst1 by deduction from the    
laws of simpler causes1 so obtained4 ,by
 simple instances are meant1 of course1 
those in which the action of each cause 
was not intermixed or interfered with1  
or not to any great extent1 by other    
causes whose laws were unknown4 ,and    
only when the induction which furnished 
the premises to the ,deductive method   
rested on such instances1 has the       
application of such a method to the     
ascertainment of the laws of a complex  
effect1 been attended with brilliant    
results4    #b4 ,when the laws of the   
causes have been ascertained1 and the   
first stage of the great logical        
operation now under discussion          
satisfactorily accomplished1 the second 
part follows2 that of determining from  
the laws of the causes1 what effect any 
given combination of those causes will  
produce4 ,this is a process of          
calculation1 in the wider sense of the  

term2 and very often involves processes 
of calculation in the narrowest sense4  
,it is a ratiocination2 and when our    
knowledge of the causes is so perfect1  
as to extend to the exact numerical laws
 which they observe in producing their  
effects1 the ratiocination may reckon   
among its premises the theorems of the  
science of number1 in the whole immense 
extent of that science4 ,not only are   
the most advanced truths of mathematics 
often required to enable us to compute  
an effect1 the numerical law of which we
 already know2 but1 even by the aid of  
those most advanced truths1 we can go   
but a little way4 ,in so simple a case  
as the common problem of three bodies   
gravitating towards one another1 with a 
force directly as their mass and        
inversely as the square of the distance1
 all the resources of the calculus have 
not hitherto sufficed to obtain any     
general solution but an approximate one4
 ,in a case a little more complex1 but  
still one of the simplest which arise in

 practice1 that of the motion of a      
projectile1 the causes which affect the 
velocity and range 7for example7 of a   
cannon-ball may be all known and        
estimated2 the force of the gunpowder1  
the angle of elevation1 the density of  
the air1 the strength and direction of  
the wind2 but it is one of the most     
difficult of mathematical problems to   
combine all these1 so as to determine   
the effect resulting from their         
collective action4  ,besides the        
theorems of number1 those of geometry   
also come in as premises1 where the     
effects take place in space1 and involve
 motion and extension1 as in mechanics1 
optics1 acoustics1 astronomy4 ,but when 
the complication increases1 and the     
effects are under the influence of so   
many and such shifting causes as to give
 no room either for fixed numbers1 or   
for straight lines and regular curves1  
7as in the case of physiological1 to say
 nothing of mental and social           
phenomena17 the laws of number and      

extension are applicable1 if at all1    
only on that large scale on which       
precision of details becomes            
unimportant4 ,although these laws play a
 conspicuous part in the most striking  
examples of the investigation of nature 
by the ,deductive ,method1 as for       
example in the ,newtonian theory of the 
celestial motions1 they are by no means 
an indispensable part of every such     
process4 ,all that is essential in it is
 reasoning from a general law to a      
particular case1 that is1 determining by
 means of the particular circumstances  
of that case1 what result is required in
 that instance to fulfil the law4 ,thus 
in the ,torricellian experiment1 if the 
fact that air has weight had been       
previously known1 it would have been    
easy1 without any numerical data1 to    
deduce from the general law of          
equilibrium1 that the mercury would     
stand in the tube at such a height that 
the column of mercury would exactly     
balance a column of the atmosphere of   

equal diameter2 because1 otherwise1     
equilibrium would not exist4  ,by such  
ratiocinations from the separate laws of
 the causes1 we may1 to a certain       
extent1 succeed in answering either of  
the following questions3 ,given a       
certain combination of causes1 what     
effect will follow8 and1 ,what          
combination of causes1 if it existed1   
would produce a given effect8 ,in the   
one case1 we determine the effect to be 
expected in any complex circumstances of
 which the different elements are known3
 in the other case we learn1 according  
to what law--under what antecedent      
conditions--a given complex effect will 
occur4    #c4 ,but 7it may here be      
asked7 are not the same arguments by    
which the methods of direct observation 
and experiment were set aside as        
illusory when applied to the laws of    
complex phenomena1 applicable with equal
 force against the ,method of           
,deduction8 ,when in every single       
instance a multitude1 often an unknown  

multitude1 of agencies1 are clashing and
 combining1 what security have we that  
in our computation  priori we have taken
 all these into our reckoning8 ,how many
 must we not generally be ignorant of8  
,among those which we know1 how probable
 that some have been overlooked2 and1   
even were all included1 how vain the    
pretence of summing up the effects of   
many causes1 unless we know accurately  
the numerical law of each1--a condition 
in most cases not to be fulfilled2 and  
even when fulfilled1 to make the        
calculation transcends1 in any but very 
simple cases1 the utmost power of       
mathematical science with all its most  
modern improvements4  ,these objections 
have real weight1 and would be          
altogether unanswerable1 if there were  
no test by which1 when we employ the    
,deductive ,method1 we might judge      
whether an error of any of the above    
descriptions had been committed or not4 
,such a test however there is3 and its  
application forms1 under the name of    

,verification1 the third essential      
component part of the ,deductive        
,method2 without which all the results  
it can give have little other value than
 that of conjecture4 ,to warrant        
reliance on the general conclusions     
arrived at by deduction1 these          
conclusions must be found1 on careful   
comparison1 to accord with the results  
of direct observation wherever it can be
 had4 ,if1 when we have experience to   
compare with them1 this experience      
confirms them1 we may safely trust to   
them in other cases of which our        
specific experience is yet to come4 ,but
 if our deductions have led to the      
conclusion that from a particular       
combination of causes a given effect    
would result1 then in all known cases   
where that combination can be shown to  
have existed1 and where the effect has  
not followed1 we must be able to show   
7or at least to make a probable surmise7
 what frustrated it3 if we cannot1 the  
theory is imperfect1 and not yet to be  

relied upon4 ,nor is the verification   
complete1 unless some of the cases in   
which the theory is borne out by the    
observed result1 are of at least equal  
complexity with any other cases in which
 its application could be called for4   
,if direct observation and collation of 
instances have furnished us with any    
empirical laws of the effect 7whether   
true in all observed cases1 or only true
 for the most part71 the most effectual 
verification of which the theory could  
be susceptible would be1 that it led    
deductively to those empirical laws2    
that the uniformities1 whether complete 
or incomplete1 which were observed to   
exist among the phenomena1 were         
accounted for by the laws of the        
causes--were such as could not but exist
 if those be really the causes by which 
the phenomena are produced4 ,thus it was
 very reasonably deemed an essential    
requisite of any true theory of the     
causes of the celestial motions1 that it
 should lead by deduction to ,kepler's  

laws3 which1 accordingly1 the ,newtonian
 theory did4  ,in order1 therefore1 to  
facilitate the verification of theories 
obtained by deduction1 it is important  
that as many as possible of the         
empirical laws of the phenomena should  
be ascertained1 by a comparison of      
instances1 conformably to the ,method of
 ,agreement3 as well as 7it must be     
added7 that the phenomena themselves    
should be described1 in the most        
comprehensive as well as accurate manner
 possible2 by collecting from the       
observation of parts1 the simplest      
possible correct expressions for the    
corresponding wholes3 as when the series
 of the observed places of a planet was 
first expressed by a circle1 then by a  
system of epicycles1 and subsequently by
 an ellipse4  ,it is worth remarking1   
that complex instances which would have 
been of no use for the discovery of the 
simple laws into which we ultimately    
analyse their phenomena1 nevertheless1  
when they have served to verify the     

analysis1 become additional evidence of 
the laws themselves4 ,although we could 
not have got at the law from complex    
cases1 still when the law1 got at       
otherwise1 is found to be in accordance 
with the result of a complex case1 that 
case becomes a new experiment on the    
law1 and helps to confirm what it did   
not assist to discover4 ,it is a new    
trial of the principle in a different   
set of circumstances2 and occasionally  
serves to eliminate some circumstance   
not previously excluded1 and the        
exclusion of which might require an     
experiment impossible to be executed4   
,this was strikingly conspicuous in the 
example formerly quoted1 in which the   
difference between the observed and the 
calculated velocity of sound was        
ascertained to result from the heat     
extricated by the condensation which    
takes place in each sonorous vibration4 
,this was a trial1 in new circumstances1
 of the law of the development of heat  
by compression2 and it added materially 

to the proof of the universality of that
 law4 ,accordingly any law of nature is 
deemed to have gained in point of       
certainty1 by being found to explain    
some complex case which had not         
previously been thought of in connexion 
with it2 and this indeed is a           
consideration to which it is the habit  
of scientific inquirers to attach rather
 too much value than too little4  ,to   
the ,deductive ,method1 thus            
characterized in its three constituent  
parts1 ,induction1 ,ratiocination1 and  
,verification1 the human mind is        
indebted for its most conspicuous       
triumphs in the investigation of nature4
 ,to it we owe all the theories by which
 vast and complicated phenomena are     
embraced under a few simple laws1 which1
 considered as the laws of those great  
phenomena1 could never have been        
detected by their direct study4 ,we may 
form some conception of what the method 
has done for us1 from the case of the   
celestial motions2 one of the simplest  

among the greater instances of the      
,composition of ,causes1 since 7except  
in a few cases not of primary           
importance7 each of the heavenly bodies 
may be considered1 without material     
inaccuracy1 to be never at one time     
influenced by the attraction of more    
than two bodies1 the sun and one other  
planet or satellite2 making1 with the   
reaction of the body itself1 and the    
force generated by the body's own motion
 and acting in the direction of the     
tangent1 only four different agents on  
the concurrence of which the motions of 
that body depend2 a much smaller number1
 no doubt1 than that by which any other 
of the great phenomena of nature is     
determined or modified4 ,yet how could  
we ever have ascertained the combination
 of forces on which the motions of the  
earth and planets are dependent1 by     
merely comparing the orbits or          
velocities of different planets1 or the 
different velocities or positions of the
 same planet8 ,notwithstanding the      

regularity which manifests itself in    
those motions1 in a degree so rare among
 the effects of a concurrence of causes2
 and although the periodical recurrence 
of exactly the same effect1 affords     
positive proof that all the combinations
 of causes which occur at all1 recur    
periodically2 we should not have known  
what the causes were1 if the existence  
of agencies precisely similar on our own
 earth had not1 fortunately1 brought the
 causes themselves within the reach of  
experimentation under simple            
circumstances4 ,as we shall have        
occasion to analyse1 further on1 this   
great example of the ,method of         
,deduction1 we shall not occupy any time
 with it here1 but shall proceed to that
 secondary application of the ,deductive
 ,method1 the result of which is not to 
prove laws of phenomena1 but to explain 
them4     ,,chapter ,,xii4  ,,of ,,the  
,,explanation ,,of ,,laws ,,of ,,nature4
    #a4 ,the deductive operation by     
which we derive the law of an effect    

from the laws of the causes1 the        
concurrence of which gives rise to it1  
may be undertaken either for the purpose
 of discovering the law1 or of          
explaining a law already discovered4    
,the word explanation occurs so         
continually and holds so important a    
place in philosophy1 that a little time 
spent in fixing the meaning of it will  
be profitably employed4  ,an individual 
fact is said to be explained1 by        
pointing out its cause1 that is1 by     
stating the law or laws of causation1 of
 which its production is an instance4   
,thus1 a conflagration is explained1    
when it is proved to have arisen from a 
spark falling into the midst of a heap  
of combustibles4 ,and in a similar      
manner1 a law or uniformity in nature is
 said to be explained1 when another law 
or laws are pointed out1 of which that  
law itself is but a case1 and from which
 it could be deduced4    #b4 ,there are 
three distinguishable sets of           
circumstances in which a law of         

causation may be explained from1 or1 as 
it also is often expressed1 resolved    
into1 other laws4  ,the first is the    
case already so fully considered2 an    
intermixture of laws1 producing a joint 
effect equal to the sum of the effects  
of the causes taken separately4 ,the law
 of the complex effect is explained1 by 
being resolved into the separate laws of
 the causes which contribute to it4     
,thus1 the law of the motion of a planet
 is resolved into the law of the        
acquired force1 which tends to produce  
an uniform motion in the tangent1 and   
the law of the centripetal force which  
tends to produce an accelerating motion 
towards the sun2 the real motion being a
 compound of the two4  ,it is necessary 
here to remark1 that in this resolution 
of the law of a complex effect1 the laws
 of which it is compounded are not the  
only elements4 ,it is resolved into the 
laws of the separate causes1 together   
with the fact of their coexistence4 ,the
 one is as essential an ingredient as   

the other2 whether the object be to     
discover the law of the effect1 or only 
to explain it4 ,to deduce the laws of   
the heavenly motions1 we require not    
only to know the law of a rectilineal   
and that of a gravitative force1 but the
 existence of both these forces in the  
celestial regions1 and even their       
relative amount4 ,the complex laws of   
causation are thus resolved into two    
distinct kinds of elements3 the one1    
simpler laws of causation1 the other 7in
 the aptly selected expression of ,dr4  
,chalmers7 collocations2 the            
collocations consisting in the existence
 of certain agents or powers1 in certain
 circumstances of place and time4 ,we   
shall hereafter have occasion to return 
to this distinction1 and to dwell on it 
at such length as dispenses with the    
necessity of further insisting on it    
here4 ,the first mode1 then1 of the     
explanation of ,laws of ,causation1 is  
when the law of an effect is resolved   
into the various tendencies of which it 

is the result1 together with the laws of
 those tendencies4    #c4 ,a second case
 is when1 between what seemed the cause 
and what was supposed to be its effect1 
further observation detects an          
intermediate link2 a fact caused by the 
antecedent1 and in its turn causing the 
consequent2 so that the cause at first  
assigned is but the remote cause1       
operating through the intermediate      
phenomenon4 ,a seemed the cause of ,c1  
but it subsequently appeared that ,a was
 only the cause of ,b1 and that it is ,b
 which was the cause of ,c4 ,for        
example3 mankind were aware that the act
 of touching an outward object caused a 
sensation4 ,it was subsequently         
discovered1 that after we have touched  
the object1 and before we experience the
 sensation1 some change takes place in a
 kind of thread called a nerve1 which   
extends from our outward organs to the  
brain4 ,touching the object1 therefore1 
is only the remote cause of our         
sensation2 that is1 not the cause1      

properly speaking1 but the cause of the 
cause2--the real cause of the sensation 
is the change in the state of the nerve4
 ,future experience may not only give us
 more knowledge than we now have of the 
particular nature of this change1 but   
may also interpolate another link3      
between the contact 7for example7 of the
 object with our outward organs1 and the
 production of the change of state in   
the nerve1 there may take place some    
electric phenomenon2 or some phenomenon 
of a nature not resembling the effects  
of any known agency4 ,hitherto1 however1
 no such intermediate link has been     
discovered2 and the touch of the object 
must be considered1 provisionally1 as   
the proximate cause of the affection of 
the nerve4 ,the sequence1 therefore1 of 
a sensation of touch on contact with an 
object1 is ascertained not to be an     
ultimate law2 it is resolved1 as the    
phrase is1 into two other laws1--the    
law1 that contact with an object        
produces an affection of the nerve2 and 

the law1 that an affection of the nerve 
produces sensation4  ,to take another   
example3 the more powerful acids corrode
 or blacken organic compounds4 ,this is 
a case of causation1 but of remote      
causation2 and is said to be explained  
when it is shown that there is an       
intermediate link1 namely1 the          
separation of some of the chemical      
elements of the organic structure from  
the rest1 and their entering into       
combination with the acid4 ,the acid    
causes this separation of the elements1 
and the separation of the elements      
causes the disorganization1 and often   
the charring of the structure4 ,so1     
again1 chlorine extracts colouring      
matters1 7whence its efficacy in        
bleaching17 and purifies the air from   
infection4 ,this law is resolved into   
the two following laws4 ,chlorine has a 
powerful affinity for bases of all      
kinds1 particularly metallic bases and  
hydrogen4 ,such bases are essential     
elements of colouring matters and       

contagious compounds3 which substances1 
therefore1 are decomposed and destroyed 
by chlorine4    #d4 ,it is of importance
 to remark1 that when a sequence of     
phenomena is thus resolved into other   
laws1 they are always laws more general 
than itself4 ,the law that ,a is        
followed by ,c1 is less general than    
either of the laws which connect ,b with
 ,c and ,a with ,b4 ,this will appear   
from very simple considerations4  ,all  
laws of causation are liable to be      
counteracted or frustrated1 by the      
non-fulfilment of some negative         
condition3 the tendency1 therefore1 of  
,b to produce ,c may be defeated4 ,now  
the law that ,a produces ,b1 is equally 
fulfilled whether ,b is followed by ,c  
or not2 but the law that ,a produces ,c 
by means of ,b1 is of course only       
fulfilled when ,b is really followed by 
,c1 and is therefore less general than  
the law that ,a produces ,b4 ,it is also
 less general than the law that ,b      
produces ,c4 ,for ,b may have other     

causes besides ,a2 and as ,a produces ,c
 only by means of ,b1 while ,b produces 
,c whether it has itself been produced  
by ,a or by anything else1 the second   
law embraces a greater number of        
instances1 covers as it were a greater  
space of ground1 than the first4  ,thus1
 in our former example1 the law that the
 contact of an object causes a change in
 the state of the nerve1 is more general
 than the law that contact with an      
object causes sensation1 since1 for     
aught we know1 the change in the nerve  
may equally take place when1 from a     
counteracting cause1 as for instance1   
strong mental excitement1 the sensation 
does not follow2 as in a battle1 where  
wounds are sometimes received without   
any consciousness of receiving them4    
,and again1 the law that change in the  
state of a nerve produces sensation1 is 
more general than the law that contact  
with an object produces sensation2 since
 the sensation equally follows the      
change in the nerve when not produced by

 contact with an object1 but by some    
other cause2 as in the well-known case1 
when a person who has lost a limb1 feels
 the same sensation which he has been   
accustomed to call a pain in the limb4  
,not only are the laws of more immediate
 sequence into which the law of a remote
 sequence is resolved1 laws of greater  
generality than that law is1 but 7as a  
consequence of1 or rather as implied in1
 their greater generality7 they are more
 to be relied on2 there are fewer       
chances of their being ultimately found 
not to be universally true4 ,from the   
moment when the sequence of ,a and ,c is
 shown not to be immediate1 but to      
depend on an intervening phenomenon1    
then1 however constant and invariable   
the sequence of ,a and ,c has hitherto  
been found1 possibilities arise of its  
failure1 exceeding those which can      
affect either of the more immediate     
sequences1 ,a1 ,b1 and ,b1 ,c4 ,the     
tendency of ,a to produce ,c may be     
defeated by whatever is capable of      

defeating either the tendency of ,a to  
produce ,b1 or the tendency of ,b to    
produce ,c2 it is therefore twice as    
liable to failure as either of those    
more elementary tendencies2 and the     
generalization that ,a is always        
followed by ,c1 is twice as likely to be
 found erroneous4 ,and so of the        
converse generalization1 that ,c is     
always preceded and caused by ,a2 which 
will be erroneous not only if there     
should happen to be a second immediate  
mode of production of ,c itself1 but    
moreover if there be a second mode of   
production of ,b1 the immediate         
antecedent of ,c in the sequence4  ,the 
resolution of the one generalization    
into the other two1 not only shows that 
there are possible limitations of the   
former1 from which its two elements are 
exempt1 but shows also where these are  
to be looked for4 ,as soon as we know   
that ,b intervenes between ,a and ,c1 we
 also know that if there be cases in    
which the sequence of ,a and ,c does not

 hold1 these are most likely to be found
 by studying the effects or the         
conditions of the phenomenon ,b4  ,it   
appears1 then1 that in the second of the
 three modes in which a law may be      
resolved into other laws1 the latter are
 more general1 that is1 extend to more  
cases1 and are also less likely to      
require limitation from subsequent      
experience1 than the law which they     
serve to explain4 ,they are more nearly 
unconditional2 they are defeated by     
fewer contingencies2 they are a nearer  
approach to the universal truth of      
nature4 ,the same observations are still
 more evidently true with regard to the 
first of the three modes of resolution4 
,when the law of an effect of combined  
causes is resolved into the separate    
laws of the causes1 the nature of the   
case implies that the law of the effect 
is less general than the law of any of  
the causes1 since it only holds when    
they are combined2 while the law of any 
one of the causes holds good both then1 

and also when that cause acts apart from
 the rest4 ,it is also manifest that the
 complex law is liable to be oftener    
unfulfilled than any one of the simpler 
laws of which it is the result1 since   
every contingency which defeats any of  
the laws prevents so much of the effect 
as depends on it1 and thereby defeats   
the complex law4 ,the mere rusting1 for 
example1 of some small part of a great  
machine1 often suffices entirely to     
prevent the effect which ought to result
 from the joint action of all the parts4
 ,the law of the effect of a combination
 of causes is always subject to the     
whole of the negative conditions which  
attach to the action of all the causes  
severally4  ,there is another and an    
equally strong reason why the law of a  
complex effect must be less general than
 the laws of the causes which conspire  
to produce it4 ,the same causes1 acting 
according to the same laws1 and         
differing only in the proportions in    
which they are combined1 often produce  

effects which differ not merely in      
quantity1 but in kind4 ,the combination 
of a centripetal with a projectile      
force1 in the proportions which obtain  
in all the planets and satellites of our
 solar system1 gives rise to an         
elliptical motion2 but if the ratio of  
the two forces to each other were       
slightly altered1 it is demonstrated    
that the motion produced would be in a  
circle1 or a parabola1 or an hyperbola3 
and it is thought that in the case of   
some comets one of these is probably the
 fact4 ,yet the law of the parabolic    
motion would be resolvable into the very
 same simple laws into which that of the
 elliptical motion is resolved1 namely1 
the law of the permanence of rectilineal
 motion1 and the law of gravitation4    
,if1 therefore1 in the course of ages1  
some circumstance were to manifest      
itself which1 without defeating the law 
of either of those forces1 should merely
 alter their proportion to one another1 
7such as the shock of some solid body1  

or even the accumulating effect of the  
resistance of the medium in which       
astronomers have been led to surmise    
that the motions of the heavenly bodies 
take place17 the elliptical motion might
 be changed into a motion in some other 
conic section2 and the complex law1 that
 the planetary motions take place in    
ellipses1 would be deprived of its      
universality1 though the discovery would
 not at all detract from the            
universality of the simpler laws into   
which that complex law is resolved4 ,the
 law1 in short1 of each of the          
concurrent causes remains the same1     
however their collocations may vary2 but
 the law of their joint effect varies   
with every difference in the            
collocations4 ,there needs no more to   
show how much more general the          
elementary laws must be1 than any of the
 complex laws which are derived from    
them4    #e4 ,besides the two modes     
which have been treated of1 there is a  
third mode in which laws are resolved   

into one another2 and in this it is     
self-evident that they are resolved into
 laws more general than themselves4     
,this third mode is the subsumption 7as 
it has been called7 of one law under    
another3 or 7what comes to the same     
thing7 the gathering up of several laws 
into one more general law which includes
 them all4 ,the most splendid example of
 this operation was when terrestrial    
gravity and the central force of the    
solar system were brought together under
 the general law of gravitation4 ,it had
 been proved antecedently that the earth
 and the other planets tend to the sun2 
and it had been known from the earliest 
times that terrestrial bodies tend      
towards the earth4 ,these were similar  
phenomena2 and to enable them both to be
 subsumed under one law1 it was only    
necessary to prove that1 as the effects 
were similar in quality1 so also they1  
as to quantity1 conform to the same     
rules4 ,this was first shown to be true 
of the moon1 which agreed with          

terrestrial objects not only in tending 
to a centre1 but in the fact that this  
centre was the earth4 ,the tendency of  
the moon towards the earth being        
ascertained to vary as the inverse      
square of the distance1 it was deduced  
from this1 by direct calculation1 that  
if the moon were as near to the earth as
 terrestrial objects are1 and the       
acquired force in the direction of the  
tangent were suspended1 the moon would  
fall towards the earth through exactly  
as many feet in a second as those       
objects do by virtue of their weight4   
,hence the inference was irresistible1  
that the moon also tends to the earth by
 virtue of its weight3 and that the two 
phenomena1 the tendency of the moon to  
the earth and the tendency of           
terrestrial objects to the earth1 being 
not only similar in quality1 but1 when  
in the same circumstances1 identical in 
quantity1 are cases of one and the same 
law of causation4 ,but the tendency of  
the moon to the earth1 and the tendency 

of the earth and planets to the sun1    
were already known to be cases of the   
same law of causation3 and thus the law 
of all these tendencies1 and the law of 
terrestrial gravity1 were recognised as 
identical1 and were subsumed under one  
general law1 that of gravitation4  ,in a
 similar manner1 the laws of magnetic   
phenomena have more recently been       
subsumed under known laws of            
electricity4 ,it is thus that the most  
general laws of nature are usually      
arrived at3 we mount to them by         
successive steps4 ,for1 to arrive by    
correct induction at laws which hold    
under such an immense variety of        
circumstances1 laws so general as to be 
independent of any varieties of space or
 time which we are able to observe1     
requires for the most part many distinct
 sets of experiments or observations1   
conducted at different times and by     
different people4 ,one part of the law  
is first ascertained1 afterwards another
 part3 one set of observations teaches  

us that the law holds good under some   
conditions1 another that it holds good  
under other conditions1 by combining    
which observations we find that it holds
 good under conditions much more        
general1 or even universally4 ,the      
general law1 in this case1 is literally 
the sum of all the partial ones2 it is  
the recognition of the same sequence in 
different sets of instances2 and may1 in
 fact1 be regarded as merely one step in
 the process of elimination4 ,that      
tendency of bodies towards one another1 
which we now call gravity1 had at first 
been observed only on the earth's       
surface1 where it manifested itself only
 as a tendency of all bodies towards the
 earth1 and might1 therefore1 be        
ascribed to a peculiar property of the  
earth itself3 one of the circumstances1 
namely1 the proximity of the earth1 had 
not been eliminated4 ,to eliminate this 
circumstance required a fresh set of    
instances in other parts of the         
universe3 these we could not ourselves  

create2 and though nature had created   
them for us1 we were placed in very     
unfavourable circumstances for observing
 them4 ,to make these observations1 fell
 naturally to the lot of a different set
 of persons from those who studied      
terrestrial phenomena2 and had1 indeed1 
been a matter of great interest at a    
time when the idea of explaining        
celestial facts by terrestrial laws was 
looked upon as the confounding of an    
indefeasible distinction4 ,when1        
however1 the celestial motions were     
accurately ascertained1 and the         
deductive processes performed1 from     
which it appeared that their laws and   
those of terrestrial gravity            
corresponded1 those celestial           
observations became a set of instances  
which exactly eliminated the            
circumstance of proximity to the earth2 
and proved that in the original case1   
that of terrestrial objects1 it was not 
the earth1 as such1 that caused the     
motion or the pressure1 but the         

circumstance common to that case with   
the celestial instances1 namely1 the    
presence of some great body within      
certain limits of distance4    #f4      
,there are1 then1 three modes of        
explaining laws of causation1 or1 which 
is the same thing1 resolving them into  
other laws4 ,first1 when the law of an  
effect of combined causes is resolved   
into the separate laws of the causes1   
together with the fact of their         
combination4 ,secondly1 when the law    
which connects any two links1 not       
proximate1 in a chain of causation1 is  
resolved into the laws which connect    
each with the intermediate links4 ,both 
of these are cases of resolving one law 
into two or more2 in the third1 two or  
more are resolved into one3 when1 after 
the law has been shown to hold good in  
several different classes of cases1 we  
decide that what is true in each of     
these classes of cases1 is true under   
some more general supposition1          
consisting of what all those classes of 

cases have in common4 ,we may here      
remark that this last operation involves
 none of the uncertainties attendant on 
induction by the ,method of ,agreement1 
since we need not suppose the result to 
be extended by way of inference to any  
new class of cases1 different from those
 by the comparison of which it was      
engendered4  ,in all these three        
processes1 laws are1 as we have seen1   
resolved into laws more general than    
themselves2 laws extending to all the   
cases which the former extended to1 and 
others besides4 ,in the first two modes 
they are also resolved into laws more   
certain1 in other words1 more           
universally true than themselves2 they  
are1 in fact1 proved not to be          
themselves laws of nature1 the character
 of which is to be universally true1 but
 results of laws of nature1 which may be
 only true conditionally1 and for the   
most part4 ,no difference of this sort  
exists in the third case2 since here the
 partial laws are1 in fact1 the very    

same law as the general one1 and any    
exception to them would be an exception 
to it too4  ,by all the three processes1
 the range of deductive science is      
extended2 since the laws1 thus resolved1
 may be thenceforth deduced             
demonstratively from the laws into which
 they are resolved4 ,as already         
remarked1 the same deductive process    
which proves a law or fact of causation 
if unknown1 serves to explain it when   
known4  ,the word explanation is here   
used in its philosophical sense4 ,what  
is called explaining one law of nature  
by another1 is but substituting one     
mystery for another2 and does nothing to
 render the general course of nature    
other than mysterious3 we can no more   
assign a why for the more extensive laws
 than for the partial ones4 ,the        
explanation may substitute a mystery    
which has become familiar1 and has grown
 to seem not mysterious1 for one which  
is still strange4 ,and this is the      
meaning of explanation1 in common       

parlance4 ,but the process with which we
 are here concerned often does the very 
contrary3 it resolves a phenomenon with 
which we are familiar1 into one of which
 we previously knew little or nothing2  
as when the common fact of the fall of  
heavy bodies was resolved into the      
tendency of all particles of matter     
towards one another4 ,it must be kept   
constantly in view1 therefore1 that in  
science1 those who speak of explaining  
any phenomenon mean 7or should mean7    
pointing out not some more familiar1 but
 merely some more general1 phenomenon1  
of which it is a partial                
exemplification2 or some laws of        
causation which produce it by their     
joint or successive action1 and from    
which1 therefore1 its conditions may be 
determined deductively4 ,every such     
operation brings us a step nearer       
towards answering the question which was
 stated in a previous chapter as        
comprehending the whole problem of the  
investigation of nature1 viz4 ,what are 

the fewest assumptions1 which being     
granted1 the order of nature as it      
exists would be the result8 ,what are   
the fewest general propositions from    
which all the uniformities existing in  
nature could be deduced8  ,the laws1    
thus explained or resolved1 are         
sometimes said to be accounted for2 but 
the expression is incorrect1 if taken to
 mean anything more than what has been  
already stated4 ,in minds not habituated
 to accurate thinking1 there is often a 
confused notion that the general laws   
are the causes of the partial ones2 that
 the law of general gravitation1 for    
example1 causes the phenomenon of the   
fall of bodies to the earth4 ,but to    
assert this1 would be a misuse of the   
word cause3 terrestrial gravity is not  
an effect of general gravitation1 but a 
case of it2 that is1 one kind of the    
particular instances in which that      
general law obtains4 ,to account for a  
law of nature means1 and can mean1      
nothing more than to assign other laws  

more general1 together with             
collocations1 which laws and            
collocations being supposed1 the partial
 law follows without any additional     
supposition4     ,,chapter ,,xiii4      
,,miscellaneous ,,examples ,,of ,,the   
,,explanation ,,of ,,laws ,,of ,,nature4
    #a4 ,the most striking example which
 the history of science presents1 of the
 explanation of laws of causation and   
other uniformities of sequence among    
special phenomena1 by resolving them    
into laws of greater simplicity and     
generality1 is the great ,newtonian     
generalization3 respecting which typical
 instance so much having already been   
said1 it is sufficient to call attention
 to the great number and variety of the 
special observed uniformities which are 
in this case accounted for1 either as   
particular cases or as consequences of  
one very simple law of universal nature4
 ,the simple fact of a tendency of every
 particle of matter towards every other 
particle1 varying inversely as the      

square of the distance1 explains the    
fall of bodies to the earth1 the        
revolutions of the planets and          
satellites1 the motions 7so far as      
known7 of comets1 and all the various   
regularities which have been observed in
 these special phenomena2 such as the   
elliptical orbits1 and the variations   
from exact ellipses2 the relation       
between the solar distances of the      
planets and the duration of their       
revolutions2 the precession of the      
equinoxes2 the tides1 and a vast number 
of minor astronomical truths4  ,mention 
has also been made in the preceding     
chapter of the explanation of the       
phenomena of magnetism from laws of     
electricity2 the special laws of        
magnetic agency having been affiliated  
by deduction to observed laws of        
electric action1 in which they have ever
 since been considered to be included as
 special cases4 ,an example not so      
complete in itself1 but even more       
fertile in consequences1 having been the

 starting point of the really scientific
 study of physiology1 is the            
affiliation1 commenced by ,bichat1 and  
carried on by subsequent biologists1 of 
the properties of the bodily organs1 to 
the elementary properties of the tissues
 into which they are anatomically       
decomposed4  ,another striking instance 
is afforded by ,dalton's generalization1
 commonly known as the atomic theory4   
,it had been known from the very        
commencement of accurate chemical       
observation1 that any two bodies combine
 chemically with one another in only a  
certain number of proportions2 but those
 proportions were in each case expressed
 by a percentage--so many parts 7by     
weight7 of each ingredient1 in #ajj of  
the compound2 7say #ce and a fraction of
 one element1 #fd and a fraction of the 
other73 in which mode of statement no   
relation was perceived between the      
proportion in which a given element     
combines with one substance1 and that in
 which it combines with others4 ,the    

great step made by ,dalton consisted in 
perceiving1 that a unit of weight might 
be established for each substance1 such 
that by supposing the substance to enter
 into all its combinations in the ratio 
either of that unit1 or of some low     
multiple of that unit1 all the different
 proportions1 previously expressed by   
percentages1 were found to result4 ,thus
 #a being assumed as the unit of        
hydrogen1 if #h were then taken as that 
of oxygen1 the combination of one unit  
of hydrogen with one unit of oxygen     
would produce the exact proportion of   
weight between the two substances which 
is known to exist in water2 the         
combination of one unit of hydrogen with
 two units of oxygen would produce the  
proportion which exists in the other    
compound of the same two elements1      
called peroxide of hydrogen2 and the    
combinations of hydrogen and of oxygen  
with all other substances1 would        
correspond with the supposition that    
those elements enter into combination by

 single units1 or twos1 or threes1 of   
the numbers assigned to them1 #a and #h1
 and the other substances by ones or    
twos or threes of other determinate     
numbers proper to each4 ,the result is  
that a table of the equivalent numbers1 
or1 as they are called1 atomic weights1 
of all the elementary substances1       
comprises in itself1 and scientifically 
explains1 all the proportions in which  
any substance1 elementary or compound1  
is found capable of entering into       
chemical combination with any other     
substance whatever4    #b4 ,some        
interesting cases of the explanation of 
old uniformities by newly ascertained   
laws are afforded by the researches of  
,professor ,graham4 ,that eminent       
chemist was the first who drew attention
 to the distinction which may be made of
 all substances into two classes1 termed
 by him crystalloids and colloids2 or   
rather1 of all states of matter into the
 crystalloid and the colloidal states1  
for many substances are capable of      

existing in either4 ,when in the        
colloidal state1 their sensible         
properties are very different from those
 of the same substance when             
crystallized1 or when in a state easily 
susceptible of crystallization4 ,colloid
 substances pass with extreme difficulty
 and slowness into the crystalline      
state1 and are extremely inert in all   
the ordinary chemical relations4        
,substances in the colloid state are    
almost always1 when combined with water1
 more or less viscous or gelatinous4    
,the most prominent examples of the     
state are certain animal and vegetable  
substances1 particularly gelatine1      
albumen1 starch1 the gums1 caramel1     
tannin1 and some others4 ,among         
substances not of organic origin1 the   
most notable instances are hydrated     
silicic acid1 and hydrated alumina1 with
 other metallic peroxides of the        
aluminous class4  ,now it is found1 that
 while colloidal substances are easily  
penetrated by water1 and by the         

solutions of crystalloid substances1    
they are very little penetrable by one  
another3 which enabled ,professor       
,graham to introduce a highly effective 
process 7termed dialysis7 for separating
 the crystalloid substances contained in
 any liquid mixture1 by passing them    
through a thin septum of colloidal      
matter1 which does not suffer anything  
colloidal to pass1 or suffers it only in
 very minute quantity4 ,this property of
 colloids enabled ,mr4 ,graham to       
account for a number of special results 
of observation1 not previously          
explained4  ,for instance1 while soluble
 crystalloids are always highly sapid1  
soluble colloids are singularly insipid1
 as might be expected2 for1 as the      
sentient extremities of the nerves of   
the palate are probably protected by a  
colloidal membrane1 impermeable to other
 colloids1 a colloid1 when tasted1      
probably never reaches those nerves4    
,again1 it has been observed that       
vegetable gum is not digested in the    

stomach2 the coats of that organ dialyse
 the soluble food1 absorbing            
crystalloids1 and rejecting all         
colloids4 ,one of the mysterious        
processes accompanying digestion1 the   
secretion of free muriatic acid by the  
coats of the stomach1 obtains a probable
 hypothetical explanation through the   
same law4 ,finally1 much light is thrown
 upon the observed phenomena of osmose  
7the passage of fluids outward and      
inward through animal membranes7 by the 
fact that the membranes are colloidal4  
,in consequence1 the water and saline   
solutions contained in the animal body  
pass easily and rapidly through the     
membranes1 while the substances directly
 applicable to nutrition1 which are     
mostly colloidal1 are detained by       
them4#dg  ,the property which salt      
possesses of preserving animal          
substances from putrefaction is resolved
 by ,liebig into two more general laws1 
the strong attraction of salt for water1
 and the necessity of the presence of   

water as a condition of putrefaction4   
,the intermediate phenomenon which is   
interpolated between the remote cause   
and the effect1 can here be not merely  
inferred but seen2 for it is a familiar 
fact1 that flesh upon which salt has    
been thrown is speedily found swimming  
in brine4  ,the second of the two       
factors 7as they may be termed7 into    
which the preceding law has been        
resolved1 the necessity of water to     
putrefaction1 itself affords an         
additional example of the ,resolution of
 ,laws4 ,the law itself is proved by the
 ,method of ,difference1 since flesh    
completely dried and kept in a dry      
atmosphere does not putrefy2 as we see  
in the case of dried provisions1 and    
human bodies in very dry climates4 ,a   
deductive explanation of this same law  
results from ,liebig's speculations4    
,the putrefaction of animal and other   
azotised bodies is a chemical process1  
by which they are gradually dissipated  
in a gaseous form1 chiefly in that of   

carbonic acid and ammonia2 now to       
convert the carbon of the animal        
substance into carbonic acid requires   
oxygen1 and to convert the azote into   
ammonia requires hydrogen1 which are the
 elements of water4 ,the extreme        
rapidity of the putrefaction of azotised
 substances1 compared with the gradual  
decay of non-azotised bodies 7such as   
wood and the like7 by the action of     
oxygen alone1 he explains from the      
general law that substances are much    
more easily decomposed by the action of 
two different affinities upon two of    
their elements1 than by the action of   
only one4    #c4 ,among the many        
important properties of the nervous     
system1 which have either been first    
discovered or strikingly illustrated by 
,dr4 ,brown-,squard1 ,i select the      
reflex influence of the nervous system  
on nutrition and secretion4 ,by reflex  
nervous action is meant1 action which   
one part of the nervous system exerts   
over another part1 without any          

intermediate action on the brain1 and   
consequently without consciousness2 or  
which1 if it does pass through the      
brain1 at least produces its effects    
independently of the will4 ,there are   
many experiments which prove that       
irritation of a nerve in one part of the
 body may in this manner excite powerful
 action in another part2 for example1   
food injected into the stomach through a
 divided oesophagus1 nevertheless       
produces secretion of saliva2 warm water
 injected into the bowels1 and various  
other irritations of the lower          
intestines1 have been found to excite   
secretion of the gastric juice1 and so  
forth4 ,the reality of the power being  
thus proved1 its agency explains a great
 variety of apparently anomalous        
phenomena2 of which ,i select the       
following from ,dr4 ,brown-,squard's    
,lectures on the ,nervous ,system4  ,the
 production of tears by irritation of   
the eye1 or of the mucous membrane of   
the nose3  ,the secretions of the eye   

and nose increased by exposure of other 
parts of the body to cold3              
,inflammation of the eye1 especially    
when of traumatic origin1 very          
frequently excites a similar affection  
in the other eye1 which may be cured by 
section of the intervening nerve3  ,loss
 of sight sometimes produced by         
neuralgia2 and has been known to be at  
once cured by the extirpation 7for      
instance7 of a carious tooth3  ,even    
cataract has been produced in a healthy 
eye by cataract in the other eye1 or by 
neuralgia1 or by a wound of the frontal 
nerve3  ,the well-known phenomenon of a 
sudden stoppage of the heart's action1  
and consequent death1 produced by       
irritation of some of the nervous       
extremities3 e4g41 by drinking very cold
 water2 or by a blow on the abdomen1 or 
other sudden excitation of the abdominal
 sympathetic nerve2 though this nerve   
may be irritated to any extent without  
stopping the heart's action1 if a       
section be made of the communicating    

nerves3  ,the extraordinary effects     
produced on the internal organs by an   
extensive burn on the surface of the    
body2 consisting in violent inflammation
 of the tissues of the abdomen1 chest1  
or head3 which1 when death ensues from  
this kind of injury1 is one of the most 
frequent causes of it3  ,paralysis and  
ansthesia of one part of the body from  
neuralgia in another part2 and muscular 
atrophy from neuralgia1 even when there 
is no paralysis3  ,tetanus produced by  
the lesion of a nerve2 ,dr4             
,brown-,squard thinks it highly probable
 that hydrophobia is a phenomenon of a  
similar nature3  ,morbid changes in the 
nutrition of the brain and spinal cord1 
manifesting themselves by epilepsy1     
chorea1 hysteria1 and other diseases1   
occasioned by lesion of some of the     
nervous extremities in remote places1 as
 by worms1 calculi1 tumours1 carious    
bones1 and in some cases even by very   
slight irritations of the skin4    #d4  
,from the foregoing and similar         

instances1 we may see the importance1   
when a law of nature previously unknown 
has been brought to light1 or when new  
light has been thrown upon a known law  
by experiment1 of examining all cases   
which present the conditions necessary  
for bringing that law into action2 a    
process fertile in demonstrations of    
special laws previously unsuspected1 and
 explanations of others already         
empirically known4  ,for instance1      
,faraday discovered by experiment1 that 
voltaic electricity could be evolved    
from a natural magnet1 provided a       
conducting body were set in motion at   
right angles to the direction of the    
magnet3 and this he found to hold not   
only of small magnets1 but of that great
 magnet1 the earth4 ,the law being thus 
established experimentally1 that        
electricity is evolved1 by a magnet1 and
 a conductor moving at right angles to  
the direction of its poles1 we may now  
look out for fresh instances in which   
these conditions meet4 ,wherever a      

conductor moves or revolves at right    
angles to the direction of the earth's  
magnetic poles1 there we may expect an  
evolution of electricity4 ,in the       
northern regions1 where the polar       
direction is nearly perpendicular to the
 horizon1 all horizontal motions of     
conductors will produce electricity2    
horizontal wheels1 for example1 made of 
metal2 likewise all running streams will
 evolve a current of electricity1 which 
will circulate round them2 and the air  
thus charged with electricity may be one
 of the causes of the ,aurora ,borealis4
 ,in the equatorial regions1 on the     
contrary1 upright wheels placed parallel
 to the equator will originate a voltaic
 circuit1 and waterfalls will naturally 
become electric4  ,for a second example2
 it has been proved1 chiefly by the     
researches of ,professor ,graham1 that  
gases have a strong tendency to permeate
 animal membranes1 and diffuse          
themselves through the spaces which such
 membranes inclose1 notwithstanding the 

presence of other gases in those spaces4
 ,proceeding from this general law1 and 
reviewing a variety of cases in which   
gases lie contiguous to membranes1 we   
are enabled to demonstrate or to explain
 the following more special laws3 #ast4 
,the human or animal body1 when         
surrounded with any gas not already     
contained within the body1 absorbs it   
rapidly2 such1 for instance1 as the     
gases of putrefying matters3 which helps
 to explain malaria4 #bnd4 ,the carbonic
 acid gas of effervescing drinks1       
evolved in the stomach1 permeates its   
membranes1 and rapidly spreads through  
the system4 #crd4 ,alcohol taken into   
the stomach passes into vapour and      
spreads through the system with great   
rapidity2 7which1 combined with the high
 combustibility of alcohol1 or in other 
words its ready combination with oxygen1
 may perhaps help to explain the bodily 
warmth immediately consequent on        
drinking spirituous liquors47 #dth4 ,in 
any state of the body in which peculiar 

gases are formed within it1 these will  
rapidly exhale through all parts of the 
body2 and hence the rapidity with which1
 in certain states of disease1 the      
surrounding atmosphere becomes tainted4 
#eth4 ,the putrefaction of the interior 
parts of a carcase will proceed as      
rapidly as that of the exterior1 from   
the ready passage outwards of the       
gaseous products4 #fth4 ,the exchange of
 oxygen and carbonic acid in the lungs  
is not prevented1 but rather promoted1  
by the intervention of the membrane of  
the lungs and the coats of the          
blood-vessels between the blood and the 
air4 ,it is necessary1 however1 that    
there should be a substance in the blood
 with which the oxygen of the air may   
immediately combine2 otherwise instead  
of passing into the blood1 it would     
permeate the whole organism3 and it is  
necessary that the carbonic acid1 as it 
is formed in the capillaries1 should    
also find a substance in the blood with 
which it can combine2 otherwise it would

 leave the body at all points1 instead  
of being discharged through the lungs4  
#e4 ,the following is a deduction which 
confirms1 by explaining1 the old but not
 undisputed empirical generalization1   
that soda powders weaken the human      
system4 ,these powders1 consisting of a 
mixture of tartaric acid with           
bicarbonate of soda1 from which the     
carbonic acid is set free1 must pass    
into the stomach as tartrate of soda4   
,now1 neutral tartrates1 citrates1 and  
acetates of the alkalis are found1 in   
their passage through the system1 to be 
changed into carbonates2 and to convert 
a tartrate into a carbonate requires an 
additional quantity of oxygen1 the      
abstraction of which must lessen the    
oxygen destined for assimilation with   
the blood1 on the quantity of which the 
vigorous action of the human system     
partly depends4  ,the instances of new  
theories agreeing with and explaining   
old empiricisms1 are innumerable4 ,all  
the just remarks made by experienced    

persons on human character and conduct1 
are so many special laws1 which the     
general laws of the human mind explain  
and resolve4 ,the empirical             
generalizations on which the operations 
of the arts have usually been founded1  
are continually justified and confirmed 
on the one hand1 or corrected and       
improved on the other1 by the discovery 
of the simpler scientific laws on which 
the efficacy of those operations        
depends4 ,the effects of the rotation of
 crops1 of the various manures1 and     
other processes of improved agriculture1
 have been for the first time resolved  
in our own day into known laws of       
chemical and organic action1 by ,davy1  
,liebig1 and others4 ,the processes of  
the medical art are even now mostly     
empirical3 their efficacy is concluded1 
in each instance1 from a special and    
most precarious experimental            
generalization3 but as science advances 
in discovering the simple laws of       
chemistry and physiology1 progress is   

made in ascertaining the intermediate   
links in the series of phenomena1 and   
the more general laws on which they     
depend2 and thus1 while the old         
processes are either exploded1 or their 
efficacy1 in so far as real1 explained1 
better processes1 founded on the        
knowledge of proximate causes1 are      
continually suggested and brought into  
use4#dh ,many even of the truths of     
geometry were generalizations from      
experience before they were deduced from
 first principles4 ,the quadrature of   
the cycloid is said to have been first  
effected by measurement1 or rather by   
weighing a cycloidal card1 and comparing
 its weight with that of a piece of     
similar card of known dimensions4    #f4
 ,to the foregoing examples from        
physical science1 let us add another    
from mental4 ,the following is one of   
the simple laws of mind3 ,ideas of a    
pleasurable or painful character form   
associations more easily and strongly   
than other ideas1 that is1 they become  

associated after fewer repetitions1 and 
the association is more durable4 ,this  
is an experimental law1 grounded on the 
,method of ,difference4 ,by deduction   
from this law1 many of the more special 
laws which experience shows to exist    
among particular mental phenomena may be
 demonstrated and explained3--the ease  
and rapidity1 for instance1 with which  
thoughts connected with our passions or 
our more cherished interests are        
excited1 and the firm hold which the    
facts relating to them have on our      
memory2 the vivid recollection we retain
 of minute circumstances which          
accompanied any object or event that    
deeply interested us1 and of the times  
and places in which we have been very   
happy or very miserable2 the horror with
 which we view the accidental instrument
 of any occurrence which shocked us1 or 
the locality where it took place1 and   
the pleasure we derive from any memorial
 of past enjoyment2 all these effects   
being proportional to the sensibility of

 the individual mind1 and to the        
consequent intensity of the pain or     
pleasure from which the association     
originated4 ,it has been suggested by   
the able writer of a biographical sketch
 of ,dr4 ,priestley in a monthly        
periodical1#di that the same elementary 
law of our mental constitution1 suitably
 followed out1 would explain a variety  
of mental phenomena previously          
inexplicable1 and in particular some of 
the fundamental diversities of human    
character and genius4 ,associations     
being of two sorts1 either between      
synchronous1 or between successive      
impressions2 and the influence of the   
law which renders associations stronger 
in proportion to the pleasurable or     
painful character of the impressions1   
being felt with peculiar force in the   
synchronous class of associations2 it is
 remarked by the writer referred to1    
that in minds of strong organic         
sensibility synchronous associations    
will be likely to predominate1 producing

 a tendency to conceive things in       
pictures and in the concrete1 richly    
clothed in attributes and circumstances1
 a mental habit which is commonly called
 ,imagination1 and is one of the        
peculiarities of the painter and the    
poet2 while persons of more moderate    
susceptibility to pleasure and pain will
 have a tendency to associate facts     
chiefly in the order of their           
succession1 and such persons1 if they   
possess mental superiority1 will addict 
themselves to history or science rather 
than to creative art4 ,this interesting 
speculation the author of the present   
work has endeavoured1 on another        
occasion1 to pursue farther1 and to     
examine how far it will avail towards   
explaining the peculiarities of the     
poetical temperament4#ej ,it is at least
 an example which may serve1 instead of 
many others1 to show the extensive scope
 which exists for deductive             
investigation in the important and      
hitherto so imperfect ,science of ,mind4

    #g4 ,the copiousness with which the 
discovery and explanation of special    
laws of phenomena by deduction from     
simpler and more general ones has here  
been exemplified1 was prompted by a     
desire to characterize clearly1 and     
place in its due position of importance1
 the ,deductive ,method2 which1 in the  
present state of knowledge1 is destined 
henceforth irrevocably to predominate in
 the course of scientific investigation4
 ,a revolution is peaceably and         
progressively effecting itself in       
philosophy1 the reverse of that to which
 ,bacon has attached his name4 ,that    
great man changed the method of the     
sciences from deductive to experimental1
 and it is now rapidly reverting from   
experimental to deductive4 ,but the     
deductions which ,bacon abolished were  
from premises hastily snatched up1 or   
arbitrarily assumed4 ,the principles    
were neither established by legitimate  
canons of experimental inquiry1 nor the 
results tested by that indispensable    

element of a rational ,deductive        
,method1 verification by specific       
experience4 ,between the primitive      
method of ,deduction and that which ,i  
have attempted to characterize1 there is
 all the difference which exists between
 the ,aristotelian physics and the      
,newtonian theory of the heavens4  ,it  
would1 however1 be a mistake to expect  
that those great generalizations1 from  
which the subordinate truths of the more
 backward sciences will probably at some
 future period be deduced by reasoning  
7as the truths of astronomy are deduced 
from the generalities of the ,newtonian 
theory71 will be found1 in all1 or even 
in most cases1 among truths now known   
and admitted4 ,we may rest assured1 that
 many of the most general laws of nature
 are as yet entirely unthought of2 and  
that many others1 destined hereafter to 
assume the same character1 are known1 if
 at all1 only as laws or properties of  
some limited class of phenomena2 just as
 electricity1 now recognised as one of  

the most universal of natural agencies1 
was once known only as a curious        
property which certain substances       
acquired by friction1 of first          
attracting and then repelling light     
bodies4 ,if the theories of heat1       
cohesion1 crystallization1 and chemical 
action1 are destined1 as there can be   
little doubt that they are1 to become   
deductive1 the truths which will then be
 regarded as the principia of those     
sciences would probably1 if now         
announced1 appear quite as novel#ea as  
the law of gravitation appeared to the  
cotemporaries of ,newton2 possibly even 
more so1 since ,newton's law1 after all1
 was but an extension of the law of     
weight--that is1 of a generalization    
familiar from of old1 and which already 
comprehended a not inconsiderable body  
of natural phenomena4 ,the general laws 
of a similarly commanding character1    
which we still look forward to the      
discovery of1 may not always find so    
much of their foundations already laid4 

,these general truths will doubtless    
make their first appearance in the      
character of hypotheses2 not proved1 nor
 even admitting of proof1 in the first  
instance1 but assumed as premises for   
the purpose of deducing from them the   
known laws of concrete phenomena4 ,but  
this1 though their initial1 cannot be   
their final state4 ,to entitle an       
hypothesis to be received as one of the 
truths of nature1 and not as a mere     
technical help to the human faculties1  
it must be capable of being tested by   
the canons of legitimate induction1 and 
must actually have been submitted to    
that test4 ,when this shall have been   
done1 and done successfully1 premises   
will have been obtained from which all  
the other propositions of the science   
will thenceforth be presented as        
conclusions1 and the science will1 by   
means of a new and unexpected           
,induction1 be rendered ,deductive4     
,,footnotes3  #a ,dr4 ,whewell thinks it
 improper to apply the term ,induction  

to any operation not terminating in the 
establishment of a general truth4       
,induction1 he says 7,philosophy of     
,discovery1 p4 #bde71 is not the same   
thing as experience and observation4    
,induction is experience or observation 
consciously looked at in a general form4
 ,this consciousness and generality are 
necessary parts of that knowledge which 
is science4 ,and he objects 7p4 #bda7 to
 the mode in which the word ,induction  
is employed in this work1 as an undue   
extension of that term not only to the  
cases in which the general induction is 
consciously applied to a particular     
instance1 but to the cases in which the 
particular instance is dealt with by    
means of experience in that rude sense  
in which experience can be asserted of  
brutes1 and in which of course we can in
 no way imagine that the law is         
possessed or understood as a general    
proposition4 ,this use of the term he   
deems a confusion of knowledge with     
practical tendencies4  ,i disclaim1 as  

strongly as ,dr4 ,whewell can do1 the   
application of such terms as induction1 
inference1 or reasoning1 to operations  
performed by mere instinct1 that is1    
from an animal impulse1 without the     
exertion of any intelligence4 ,but ,i   
perceive no ground for confining the use
 of those terms to cases in which the   
inference is drawn in the forms and with
 the precautions required by scientific 
propriety4 ,to the idea of ,science1 an 
express recognition and distinct        
apprehension of general laws as such1 is
 essential3 but nine-tenths of the      
conclusions drawn from experience in the
 course of practical life1 are drawn    
without any such recognition3 they are  
direct inferences from known cases1 to a
 case supposed to be similar4 ,i have   
endeavoured to show that this is not    
only as legitimate an operation1 but    
substantially the same operation1 as    
that of ascending from known cases to a 
general proposition2 except that the    
latter process has one great security   

for correctness which the former does   
not possess4 ,in ,science1 the inference
 must necessarily pass through the      
intermediate stage of a general         
proposition1 because ,science wants its 
conclusions for record1 and not for     
instantaneous use4 ,but the inferences  
drawn for the guidance of practical     
affairs1 by persons who would often be  
quite incapable of expressing in        
unexceptionable terms the corresponding 
generalizations1 may and frequently do  
exhibit intellectual powers quite equal 
to any which have ever been displayed in
 ,science3 and if these inferences are  
not inductive1 what are they8 ,the      
limitation imposed on the term by ,dr4  
,whewell seems perfectly arbitrary2     
neither justified by any fundamental    
distinction between what he includes and
 what he desires to exclude1 nor        
sanctioned by usage1 at least from the  
time of ,reid and ,stewart1 the         
principal legislators 7as far as the    
,english language is concerned7 of      

modern metaphysical terminology4  #b    
,supra1 p4 #bad4  #c ,novum ,organum    
,renovatum1 pp4 #gb1 #gc4  #d ,novum    
,organum ,renovatum1 p4 #cb4  #e ,cours 
de ,philosophie ,positive1 vol4 ii4 p4  
#bjb4  #f ,dr4 ,whewell1 in his reply1  
contests the distinction here drawn1 and
 maintains1 that not only different     
descriptions1 but different explanations
 of a phenomenon1 may all be true4 ,of  
the three theories respecting the       
motions of the heavenly bodies1 he says 
7,philosophy of ,discovery1 p4 #bca73   
,undoubtedly all these explanations may 
be true and consistent with each other1 
and would be so if each had been        
followed out so as to show in what      
manner it could be made consistent with 
the facts4 ,and this was1 in reality1 in
 a great measure done4 ,the doctrine    
that the heavenly bodies were moved by  
vortices was successfully modified1 so  
that it came to coincide in its results 
with the doctrine of an                 
inverse-quadratic centripetal force4444 

,when this point was reached1 the vortex
 was merely a machinery1 well or ill    
devised1 for producing such a           
centripetal force1 and therefore did not
 contradict the doctrine of a           
centripetal force4 ,newton himself does 
not appear to have been averse to       
explaining gravity by impulse4 ,so      
little is it true that if one theory be 
true the other must be false4 ,the      
attempt to explain gravity by the       
impulse of streams of particles flowing 
through the universe in all directions1 
which ,i have mentioned in the          
,philosophy1 is so far from being       
inconsistent with the ,newtonian theory1
 that it is founded entirely upon it4   
,and even with regard to the doctrine1  
that the heavenly bodies move by an     
inherent virtue2 if this doctrine had   
been maintained in any such way that it 
was brought to agree with the facts1 the
 inherent virtue must have had its laws 
determined2 and then it would have been 
found that the virtue had a reference to

 the central body2 and so1 the 'inherent
 virtue' must have coincided in its     
effect with the ,newtonian force2 and   
then1 the two explanations would agree1 
except so far as the word 'inherent' was
 concerned4 ,and if such a part of an   
earlier theory as this word inherent    
indicates1 is found to be untenable1 it 
is of course rejected in the transition 
to later and more exact theories1 in    
,inductions of this kind1 as well as in 
what ,mr4 ,mill calls ,descriptions4    
,there is1 therefore1 still no validity 
discoverable in the distinction which   
,mr4 ,mill attempts to draw between     
descriptions like ,kepler's law of      
elliptical orbits1 and other examples of
 induction4  ,if the doctrine of        
vortices had meant1 not that vortices   
existed1 but only that the planets moved
 in the same manner as if they had been 
whirled by vortices2 if the hypothesis  
had been merely a mode of representing  
the facts1 not an attempt to account for
 them2 if1 in short1 it had been only a 

,description2 it would1 no doubt1 have  
been reconcileable with the ,newtonian  
theory4 ,the vortices1 however1 were not
 a mere aid to conceiving the motions of
 the planets1 but a supposed physical   
agent1 actively impelling them2 a       
material fact1 which might be true or   
not true1 but could not be both true and
 not true4 ,according to ,descartes'    
theory it was true1 according to        
,newton's it was not true4 ,dr4 ,whewell
 probably means that since the phrases1 
centripetal and projectile force1 do not
 declare the nature but only the        
direction of the forces1 the ,newtonian 
theory does not absolutely contradict   
any hypothesis which may be framed      
respecting the mode of their production4
 ,the ,newtonian theory1 regarded as a  
mere description of the planetary       
motions1 does not2 but the ,newtonian   
theory as an explanation of them does4  
,for in what does the explanation       
consist8 ,in ascribing those motions to 
a general law which obtains between all 

particles of matter1 and in identifying 
this with the law by which bodies fall  
to the ground4 ,if the planets are kept 
in their orbits by a force which draws  
the particles composing them towards    
every other particle of matter in the   
solar system1 they are not kept in those
 orbits by the impulsive force of       
certain streams of matter which whirl   
them round4 ,the one explanation        
absolutely excludes the other4 ,either  
the planets are not moved by vortices1  
or they do not move by a law common to  
all matter4 ,it is impossible that both 
opinions can be true4 ,as well might it 
be said that there is no contradiction  
between the assertions1 that a man died 
because somebody killed him1 and that he
 died a natural death4  ,so1 again1 the 
theory that the planets move by a virtue
 inherent in their celestial nature1 is 
incompatible with either of the two     
others3 either that of their being moved
 by vortices1 or that which regards them
 as moving by a property which they have

 in common with the earth and all       
terrestrial bodies4 ,dr4 ,whewell says  
that the theory of an inherent virtue   
agrees with ,newton's when the word     
inherent is left out1 which of course it
 would be 7he says7 if found to be      
untenable4 ,but leave that out1 and     
where is the theory8 ,the word inherent 
is the theory4 ,when that is omitted1   
there remains nothing except that the   
heavenly bodies move by a virtue1 i4e4  
by a power of some sort2 or by virtue of
 their celestial nature1 which directly 
contradicts the doctrine that           
terrestrial bodies fall by the same law4
  ,if ,dr4 ,whewell is not yet          
satisfied1 any other subject will serve 
equally well to test his doctrine4 ,he  
will hardly say that there is no        
contradiction between the emission      
theory and the undulatory theory of     
light2 or that there can be both one and
 two electricities2 or that the         
hypothesis of the production of the     
higher organic forms by development from

 the lower1 and the supposition of      
separate and successive acts of         
creation1 are quite reconcileable2 or   
that the theory that volcanoes are fed  
from a central fire1 and the doctrines  
which ascribe them to chemical action at
 a comparatively small depth below the  
earth's surface1 are consistent with one
 another1 and all true as far as they   
go4  ,if different explanations of the  
same fact cannot both be true1 still    
less1 surely1 can different predictions4
 ,dr4 ,whewell quarrels 7on what ground 
it is not necessary here to consider7   
with the example ,i had chosen on this  
point1 and thinks an objection to an    
illustration a sufficient answer to a   
theory4 ,examples not liable to his     
objection are easily found1 if the      
proposition that conflicting predictions
 cannot both be true1 can be made       
clearer by any examples4 ,suppose the   
phenomenon to be a newly-discovered     
comet1 and that one astronomer predicts 
its return once in every #cjj           

years--another once in every #djj3 can  
they both be right8 ,when ,columbus     
predicted that by sailing constantly    
westward he should in time return to the
 point from which he set out1 while     
others asserted that he could never do  
so except by turning back1 were both he 
and his opponents true prophets8 ,were  
the predictions which foretold the      
wonders of railways and steamships1 and 
those which averred that the ,atlantic  
could never be crossed by steam         
navigation1 nor a railway train         
propelled ten miles an hour1 both 7in   
,dr4 ,whewell's words7 true1 and        
consistent with one another8  ,dr4      
,whewell sees no distinction between    
holding contradictory opinions on a     
question of fact1 and merely employing  
different analogies to facilitate the   
conception of the same fact4 ,the case  
of different ,inductions belongs to the 
former class1 that of different         
,descriptions to the latter4  #g ,phil4 
of ,discov4 p4 #bef4  #h ,essays on the 

,pursuit of ,truth4  #i ,in the first   
edition a note was appended at this     
place1 containing some criticism on     
,archbishop ,whately's mode of          
conceiving the relation between         
,syllogism and ,induction4 ,in a        
subsequent issue of his ,logic1 the     
,archbishop made a reply to the         
criticism1 which induced me to cancel   
part of the note1 incorporating the     
remainder in the text4 ,in a still later
 edition1 the ,archbishop observes in a 
tone of something like disapprobation1  
that the objections1 doubtless from     
their being fully answered and found    
untenable1 were silently suppressed1 and
 that hence he might appear to some of  
his readers to be combating a shadow4   
,on this latter point1 the ,archbishop  
need give himself no uneasiness4 ,his   
readers1 ,i make bold to say1 will fully
 credit his mere affirmation that the   
objections have actually been made4     
,but as he seems to think that what he  
terms the suppression of the objections 

ought not to have been made silently1 ,i
 now break that silence1 and state      
exactly what it is that ,i suppressed1  
and why4 ,i suppressed that alone which 
might be regarded as personal criticism 
on the ,archbishop4 ,i had imputed to   
him the having omitted to ask himself a 
particular question4 ,i found that he   
had asked himself the question1 and     
could give it an answer consistent with 
his own theory4 ,i had also1 within the 
compass of a parenthesis1 hazarded some 
remarks on certain general              
characteristics of ,archbishop ,whately 
as a philosopher4 ,these remarks1 though
 their tone1 ,i hope1 was neither       
disrespectful nor arrogant1 ,i felt1 on 
reconsideration1 that ,i was hardly     
entitled to make2 least of all1 when the
 instance which ,i had regarded as an   
illustration of them1 failed1 as ,i now 
saw1 to bear them out4 ,the real matter 
at the bottom of the whole dispute1 the 
different view we take of the function  
of the major premise1 remains exactly   

where it was2 and so far was ,i from    
thinking that my opinion had been fully 
answered and was untenable1 that in the 
same edition in which ,i cancelled the  
note1 ,i not only enforced the opinion  
by further arguments1 but answered      
7though without naming him7 those of the
 ,archbishop4  ,for not having made this
 statement before1 ,i do not think it   
needful to apologize4 ,it would be      
attaching very great importance to one's
 smallest sayings1 to think a formal    
retractation requisite every time that  
one commits an error4 ,nor is           
,archbishop ,whately's well-earned fame 
of so tender a quality as to require1   
that in withdrawing a slight criticism  
on him ,i should have been bound to     
offer a public amende for having made   
it4  #aj ,but though it is a condition  
of the validity of every induction that 
there be uniformity in the course of    
nature1 it is not a necessary condition 
that the uniformity should pervade all  
nature4 ,it is enough that it pervades  

the particular class of phenomena to    
which the induction relates4 ,an        
induction concerning the motions of the 
planets1 or the properties of the       
magnet1 would not be vitiated though we 
were to suppose that wind and weather   
are the sport of chance1 provided it be 
assumed that astronomical and magnetic  
phenomena are under the dominion of     
general laws4 ,otherwise the early      
experience of mankind would have rested 
on a very weak foundation2 for in the   
infancy of science it could not be known
 that all phenomena are regular in their
 course4  ,neither would it be correct  
to say that every induction by which we 
infer any truth1 implies the general    
fact of uniformity as foreknown1 even in
 reference to the kind of phenomena     
concerned4 ,it implies1 either that this
 general fact is already known1 or that 
we may now know it3 as the conclusion1  
the ,duke of ,wellington is mortal1     
drawn from the instances ,a1 ,b1 and ,c1
 implies either that we have already    

concluded all men to be mortal1 or that 
we are now entitled to do so from the   
same evidence4 ,a vast amount of        
confusion and paralogism respecting the 
grounds of ,induction would be dispelled
 by keeping in view these simple        
considerations4  #aa ,infra1 chap4 xxi4 
#ab ,infra1 chap4 xxi4 xxii4  #ac ,dr4  
,whewell 7,phil4 of ,discov4 p4 #bdf7   
will not allow these and similar        
erroneous judgments to be called        
inductions2 inasmuch as such            
superstitious fancies were not collected
 from the facts by seeking a law of     
their occurrence1 but were suggested by 
an imagination of the anger of superior 
powers1 shown by such deviations from   
the ordinary course of nature4 ,i       
conceive the question to be1 not in what
 manner these notions were at first     
suggested1 but by what evidence they    
have1 from time to time1 been supposed  
to be substantiated4 ,if the believers  
in these erroneous opinions had been put
 on their defence1 they would have      

referred to experience3 to the comet    
which preceded the assassination of     
,julius ,csar1 or to oracles and other  
prophecies known to have been fulfilled4
 ,it is by such appeals to facts that   
all analogous superstitions1 even in our
 day1 attempt to justify themselves2 the
 supposed evidence of experience is     
necessary to their hold on the mind4 ,i 
quite admit that the influence of such  
coincidences would not be what it is1 if
 strength were not lent to it by an     
antecedent presumption2 but this is not 
peculiar to such cases2 preconceived    
notions of probability form part of the 
explanation of many other cases of      
belief on insufficient evidence4 ,the   
priori prejudice does not prevent the   
erroneous opinion from being sincerely  
regarded as a legitimate conclusion from
 experience2 though it improperly       
predisposes the mind to that            
interpretation of experience4  ,thus    
much in defence of the sort of examples 
objected to4 ,but it would be easy to   

produce instances1 equally adapted to   
the purpose1 and in which no antecedent 
prejudice is at all concerned4 ,for many
 ages1 says ,archbishop ,whately1 all   
farmers and gardeners were firmly       
convinced--and convinced of their       
knowing it by experience--that the crops
 would never turn out good unless the   
seed were sown during the increase of   
the moon4 ,this was induction1 but bad  
induction3 just as a vicious syllogism  
is reasoning1 but bad reasoning4  #ad   
,the assertion1 that any and every one  
of the conditions of a phenomenon may be
 and is1 on some occasions and for some 
purposes1 spoken of as the cause1 has   
been disputed by an intelligent reviewer
 of this work in the ,prospective       
,review 7the predecessor of the justly  
esteemed ,national ,review71 who        
maintains that we always apply the word 
cause rather to that element in the     
antecedents which exercises force1 and  
which would tend at all times to produce
 the same or a similar effect to that   

which1 under certain conditions1 it     
would actually produce4 ,and he says1   
that every one would feel the           
expression1 that the cause of a surprise
 was the sentinel's being off his post1 
to be incorrect2 but that the allurement
 or force which drew him off his post1  
might be so called1 because in doing so 
it removed a resisting power which would
 have prevented the surprise4 ,i cannot 
think that it would be wrong to say1    
that the event took place because the   
sentinel was absent1 and yet right to   
say that it took place because he was   
bribed to be absent4 ,since the only    
direct effect of the bribe was his      
absence1 the bribe could be called the  
remote cause of the surprise1 only on   
the supposition that the absence was the
 proximate cause2 nor does it seem to me
 that any one 7who had not a theory to  
support7 would use the one expression   
and reject the other4  ,the reviewer    
observes1 that when a person dies of    
poison1 his possession of bodily organs 

is a necessary condition1 but that no   
one would ever speak of it as the cause4
 ,i admit the fact2 but ,i believe the  
reason to be1 that the occasion could   
never arise for so speaking of it2 for  
when in the inaccuracy of common        
discourse we are led to speak of some   
one condition of a phenomenon as its    
cause1 the condition so spoken of is    
always one which it is at least possible
 that the hearer may require to be      
informed of4 ,the possession of bodily  
organs is a known condition1 and to give
 that as the answer1 when asked the     
cause of a person's death1 would not    
supply the information sought4 ,once    
conceive that a doubt could exist as to 
his having bodily organs1 or that he    
were to be compared with some being who 
had them not1 and cases may be imagined 
in which it might be said that his      
possession of them was the cause of his 
death4 ,if ,faust and ,mephistopheles   
together took poison1 it might be said  
that ,faust died because he was a human 

being1 and had a body1 while            
,mephistopheles survived because he was 
a spirit4  ,it is for the same reason   
that no one 7as the reviewer remarks7   
calls the cause of a leap1 the muscles  
or sinews of the body1 though they are  
necessary conditions2 nor the cause of a
 self-sacrifice1 the knowledge which was
 necessary for it2 nor the cause of     
writing a book1 that a man has time for 
it1 which is a necessary condition4     
,these conditions 7besides that they are
 antecedent states1 and not proximate   
antecedent events1 and are therefore    
never the conditions in closest apparent
 proximity to the effect7 are all of    
them so obviously implied1 that it is   
hardly possible there should exist that 
necessity for insisting on them1 which  
alone gives occasion for speaking of a  
single condition as if it were the      
cause4 ,wherever this necessity exists  
in regard to some one condition1 and    
does not exist in regard to any other1  
,i conceive that it is consistent with  

usage1 when scientific accuracy is not  
aimed at1 to apply the name cause to    
that one condition4 ,if the only        
condition which can be supposed to be   
unknown is a negative condition1 the    
negative condition may be spoken of as  
the cause4 ,it might be said that a     
person died for want of medical advice3 
though this would not be likely to be   
said1 unless the person was already     
understood to be ill1 and in order to   
indicate that this negative circumstance
 was what made the illness fatal1 and   
not the weakness of his constitution1 or
 the original virulence of the disease4 
,it might be said that a person was     
drowned because he could not swim2 the  
positive condition1 namely1 that he fell
 into the water1 being already implied  
in the word drowned4 ,and here let me   
remark1 that his falling into the water 
is in this case the only positive       
condition3 all the conditions not       
expressly or virtually included in this 
7as that he could not swim1 that nobody 

helped him1 and so forth7 are negative4 
,yet1 if it were simply said that the   
cause of a man's death was falling into 
the water1 there would be quite as great
 a sense of impropriety in the          
expression1 as there would be if it were
 said that the cause was his inability  
to swim2 because1 though the one        
condition is positive and the other     
negative1 it would be felt that neither 
of them was sufficient1 without the     
other1 to produce death4  ,with regard  
to the assertion that nothing is termed 
the cause1 except the element which     
exerts active force2 ,i wave the        
question as to the meaning of active    
force1 and accepting the phrase in its  
popular sense1 ,i revert to a former    
example1 and ,i ask1 would it be more   
agreeable to custom to say that a man   
fell because his foot slipped in        
climbing a ladder1 or that he fell      
because of his weight8 for his weight1  
and not the motion of his foot1 was the 
active force which determined his fall4 

,if a person walking out in a frosty    
day1 stumbled and fell1 it might be said
 that he stumbled because the ground was
 slippery1 or because he was not        
sufficiently careful2 but few people1 ,i
 suppose1 would say1 that he stumbled   
because he walked4 ,yet the only active 
force concerned was that which he       
exerted in walking3 the others were mere
 negative conditions2 but they happened 
to be the only ones which there could be
 any necessity to state2 for he walked1 
most likely1 in exactly his usual       
manner1 and the negative conditions made
 all the difference4 ,again1 if a person
 were asked why the army of ,xerxes     
defeated that of ,leonidas1 he would    
probably say1 because they were a       
thousand times the number2 but ,i do not
 think he would say1 it was because they
 fought1 though that was the element of 
active force4 ,to borrow another        
example1 used by ,mr4 ,grove and by ,mr4
 ,baden ,powell1 the opening of         
floodgates is said to be the cause of   

the flow of water2 yet the active force 
is exerted by the water itself1 and     
opening the floodgates merely supplies a
 negative condition4 ,the reviewer adds1
 there are some conditions absolutely   
passive1 and yet absolutely necessary to
 physical phenomena1 viz4 the relations 
of space and time2 and to these no one  
ever applies the word cause without     
being immediately arrested by those who 
hear him4 ,even from this statement ,i  
am compelled to dissent4 ,few persons   
would feel it incongruous to say 7for   
example7 that a secret became known     
because it was spoken of when ,a4 ,b4   
was within hearing2 which is a condition
 of space3 or that the cause why one of 
two particular trees is taller than the 
other1 is that it has been longer       
planted2 which is a condition of time4  
#ae ,there are a few exceptions2 for    
there are some properties of objects    
which seem to be purely preventive2 as  
the property of opaque bodies1 by which 
they intercept the passage of light4    

,this1 as far as we are able to         
understand it1 appears an instance not  
of one cause counteracting another by   
the same law whereby it produces its own
 effects1 but of an agency which        
manifests itself in no other way than in
 defeating the effects of another       
agency4 ,if we knew on what other       
relations to light1 or on what          
peculiarities of structure1 opacity     
depends1 we might find that this is only
 an apparent1 not a real1 exception to  
the general proposition in the text4 ,in
 any case it needs not affect the       
practical application4 ,the formula     
which includes all the negative         
conditions of an effect in the single   
one of the absence of counteracting     
causes1 is not violated by such cases as
 this2 though1 if all counteracting     
agencies were of this description1 there
 would be no purpose served by employing
 the formula1 since we should still have
 to enumerate specially the negative    
conditions of each phenomenon1 instead  

of regarding them as implicitly         
contained in the positive laws of the   
various other agencies in nature4  #af  
,i mean by this expression1 the ultimate
 laws of nature 7whatever they may be7  
as distinguished from the derivative    
laws and from the collocations4 ,the    
diurnal revolution of the earth 7for    
example7 is not a part of the           
constitution of things1 because nothing 
can be so called which might possibly be
 terminated or altered by natural       
causes4  #ag ,i use the words straight  
line for brevity and simplicity4 ,in    
reality the line in question is not     
exactly straight1 for1 from the effect  
of refraction1 we actually see the sun  
for a short interval during which the   
opaque mass of the earth is interposed  
in a direct line between the sun and our
 eyes2 thus realizing1 though but to a  
limited extent1 the coveted desideratum 
of seeing round a corner4  #ah ,second  
,burnett ,prize ,essay1 by ,principal   
,tulloch1 p4 #be4  #ai ,letters on the  

,philosophy of the ,human ,mind1 ,first 
,series1 p4 #bai4  #bj ,essays1 pp4     
#bjf-bjh4  #ba ,to the universality     
which mankind are agreed in ascribing to
 the ,law of ,causation1 there is one   
claim of exception1 one disputed case1  
that of the ,human ,will2 the           
determinations of which1 a large class  
of metaphysicians are not willing to    
regard as following the causes called   
motives1 according to as strict laws as 
those which they suppose to exist in the
 world of mere matter4 ,this            
controverted point will undergo a       
special examination when we come to     
treat particularly of the ,logic of the 
,moral ,sciences 7,book vi4 ch4 #b74 ,in
 the mean time ,i may remark that these 
metaphysicians1 who1 it must be         
observed1 ground the main part of their 
objection on the supposed repugnance of 
the doctrine in question to our         
consciousness1 seem to me to mistake the
 fact which consciousness testifies     
against4 ,what is really in             

contradiction to consciousness1 they    
would1 ,i think1 on strict              
self-examination1 find to be1 the       
application to human actions and        
volitions of the ideas involved in the  
common use of the term ,necessity2 which
 ,i agree with them in objecting to4    
,but if they would consider that by     
saying that a person's actions          
necessarily follow from his character1  
all that is really meant 7for no more is
 meant in any case whatever of          
causation7 is that he invariably does   
act in conformity to his character1 and 
that any one who thoroughly knew his    
character would certainly predict how he
 would act in any supposable case2 they 
probably would not find this doctrine   
either contrary to their experience or  
revolting to their feelings4 ,and no    
more than this is contended for by any  
one but an ,asiatic fatalist4  #bb      
,lectures on ,metaphysics1 vol4 ii4     
,lect4 xxxix4 pp4 #cia-b4  ,i regret    
that ,i cannot invoke the authority of  

,sir ,william ,hamilton in favour of my 
own opinions on ,causation1 as ,i can   
against the particular theory which ,i  
am now combating4 ,but that acute       
thinker has a theory of ,causation      
peculiar to himself1 which has never    
yet1 as far as ,i know1 been            
analytically examined1 but which1 ,i    
venture to think1 admits of as complete 
refutation as any one of the false or   
insufficient psychological theories     
which strew the ground in such numbers  
under his potent metaphysical scythe4   
7,since examined and controverted in the
 sixteenth chapter of ,an ,examination  
of ,sir ,william ,hamilton's            
,philosophy74  #bc ,unless we are to    
consider as such the following          
statement1 by one of the writers quoted 
in the text3 ,in the case of mental     
exertion1 the result to be accomplished 
is preconsidered or meditated1 and is   
therefore known  priori1 or before      
experience4--7,bowen's ,lowell ,lectures
 on the ,application of ,metaphysical   

and ,ethical ,science to the ,evidence  
of ,religion1 ,boston1 #ahdi47 ,this is 
merely saying that when we will a thing 
we have an idea of it4 ,but to have an  
idea of what we wish to happen1 does not
 imply a prophetic knowledge that it    
will happen4 ,perhaps it will be said   
that the first time we exerted our will1
 when we had of course no experience of 
any of the powers residing in us1 we    
nevertheless must already have known    
that we possessed them1 since we cannot 
will that which we do not believe to be 
in our power4 ,but the impossibility is 
perhaps in the words only1 and not in   
the facts2 for we may desire what we do 
not know to be in our power2 and finding
 by experience that our bodies move     
according to our desire1 we may then1   
and only then1 pass into the more       
complicated mental state which is termed
 will4  ,after all1 even if we had an   
instinctive knowledge that our actions  
would follow our will1 this1 as ,brown  
remarks1 would prove nothing as to the  

nature of ,causation4 ,our knowing1     
previous to experience1 that an         
antecedent will be followed by a certain
 consequent1 would not prove the        
relation between them to be anything    
more than antecedence and consequence4  
#bd ,reid's ,essays on the ,active      
,powers1 ,essay iv4 ch4 #c4  #be        
,prospective ,review for ,february      
#ahej4  #bf ,vide supra1 p4 #bgj1 note4 
#bg ,westminster ,review for ,october   
#ahee4  #bh ,see the whole doctrine in  
,aristotle de ,anim3 where the ,greek3  
threptik psych is treated as exactly    
equivalent to ,greek3 threptik dynamis4 
#bi ,it deserves notice that the parts  
of nature1 which ,aristotle regards as  
presenting evidence of design1 are the  
,uniformities3 the phenomena in so far  
as reducible to law4 ,greek3 ,tych and  
,greek3 to automaton satisfy him as     
explanations of the variable element in 
phenomena1 but their occurring according
 to a fixed rule can only1 to his       
conceptions1 be accounted for by an     

,intelligent ,will4 ,the common1 or what
 may be called the instinctive1         
religious interpretation of nature1 is  
the reverse of this4 ,the events in     
which men spontaneously see the hand of 
a supernatural being1 are those which   
cannot1 as they think1 be reduced to a  
physical law4 ,what they can distinctly 
connect with physical causes1 and       
especially what they can predict1 though
 of course ascribed to an ,author of    
,nature if they already recognise such  
an author1 might be conceived1 they     
think1 to arise from a blind fatality1  
and in any case do not appear to them to
 bear so obviously the mark of a divine 
will4 ,and this distinction has been    
countenanced by eminent writers on      
,natural ,theology1 in particular by    
,dr4 ,chalmers3 who thinks that though  
design is present everywhere1 the       
irresistible evidence of it is to be    
found not in the laws of nature but in  
the collocations1 i4e4 in the part of   
nature in which it is impossible to     

trace any law4 ,a few properties of dead
 matter might1 he thinks1 conceivably   
account for the regular and invariable  
succession of effects and causes2 but   
that the different kinds of matter have 
been so placed as to promote beneficent 
ends1 is what he regards as the proof of
 a ,divine ,providence4 ,mr4 ,baden     
,powell1 in his ,essay entitled         
,philosophy of ,creation1 has returned  
to the point of view of ,aristotle and  
the ancients1 and vigorously reasserts  
the doctrine that the indication of     
design in the universe is not special   
adaptations1 but ,uniformity and ,law1  
these being the evidences of mind1 and  
not what appears to us to be a provision
 for our uses4 ,while ,i decline to     
express any opinion here on this vexata 
qustio1 ,i ought not to mention ,mr4    
,powell's volume without the            
acknowledgment due to the philosophic   
spirit which pervades generally the     
three ,essays composing it1 forming in  
the case of one of them 7the ,unity of  

,worlds7 an honourable contrast with the
 other dissertations1 so far as they    
have come under my notice1 which have   
appeared on either side of that         
controversy4  #cj ,in the words of      
,fontenelle1 another celebrated         
,cartesian1 les philosophes aussi bien  
que le peuple avaient cru que l'me et le
 corps agissaient rellement et          
physiquement l'un sur l'autre4          
,descartes vint1 qui prouva que leur    
nature ne permettait point cette sorte  
de communication vritable1 et qu'ils    
n'en pouvaient avoir qu'une apparente1  
dont ,dieu tait le ,mdiateur4--,oeuvres 
de ,fontenelle1 ed4 #agfg1 tom4 v4 p4   
#ecd4  #ca ,i omit1 for simplicity1 to  
take into account the effect1 in this   
latter case1 of the diminution of       
pressure1 in diminishing the flow of    
water through the drain2 which evidently
 in no way affects the truth or         
applicability of the principle1 since   
when the two causes act simultaneously  
the conditions of that diminution of    

pressure do not arise4  #cb ,unless1    
indeed1 the consequent was generated not
 by the antecedent1 but by the means    
employed to produce the antecedent4 ,as1
 however1 these means are under our     
power1 there is so far a probability    
that they are also sufficiently within  
our knowledge1 to enable us to judge    
whether that could be the case or not4  
#cc ,discourse on the ,study of ,natural
 ,philosophy1 p4 #agi4  #cd ,for this   
speculation1 as for many other of my    
scientific illustrations1 ,i am indebted
 to ,professor ,bain1 of ,aberdeen1 who 
has since1 in his profound treatises    
entitled ,the ,senses and the           
,intellect1 and ,the ,emotions and the  
,will1 carried the analytic             
investigation of the mental phenomena   
according to the methods of physical    
science1 to the most advanced point     
which it has yet reached1 and has       
worthily inscribed his name among the   
successive constructors of an edifice to
 which ,hartley1 ,brown1 and ,james     

,mill had each contributed their part4  
#ce ,this view of the necessary         
coexistence of opposite excitements     
involves a great extension of the       
original doctrine of two electricities4 
,the early theorists assumed that1 when 
amber was rubbed1 the amber was made    
positive and the rubber negative to the 
same degree2 but it never occurred to   
them to suppose that the existence of   
the amber charge was dependent on an    
opposite charge in the bodies with which
 the amber was contiguous1 while the    
existence of the negative charge on the 
rubber was equally dependent on a       
contrary state of the surfaces that     
might accidentally be confronted with   
it2 that1 in fact1 in a case of         
electrical excitement by friction1 four 
charges were the minimum that could     
exist4 ,but this double electrical      
action is essentially implied in the    
explanation now universally adopted in  
regard to the phenomena of the common   
electric machine4  #cf ,pp4 #aei-afb4   

#cg ,infra1 book iv4 ch4 ii4 ,on        
,abstraction4  #ch ,i must1 however1    
remark1 that this example1 which seems  
to militate against the assertion we    
made of the comparative inapplicability 
of the ,method of ,difference to cases  
of pure observation1 is really one of   
those exceptions which1 according to a  
proverbial expression1 prove the general
 rule4 ,for in this case1 in which      
,nature1 in her experiment1 seems to    
have imitated the type of the           
experiments made by man1 she has only   
succeeded in producing the likeness of  
man's most imperfect experiments2       
namely1 those in which1 though he       
succeeds in producing the phenomenon1 he
 does so by employing complex means1    
which he is unable perfectly to analyse1
 and can form therefore no sufficient   
judgment what portion of the effects may
 be due1 not to the supposed cause1 but 
to some unknown agency of the means by  
which that cause was produced4 ,in the  
natural experiment which we are speaking

 of1 the means used was the clearing off
 a canopy of clouds2 and we certainly do
 not know sufficiently in what this     
process consists1 or on what it depends1
 to be certain  priori that it might not
 operate upon the deposition of dew     
independently of any thermometric effect
 at the earth's surface4 ,even1         
therefore1 in a case so favourable as   
this to ,nature's experimental talents1 
her experiment is of little value except
 in corroboration of a conclusion       
already attained through other means4   
#ci ,in his subsequent work1 ,outlines  
of ,astronomy 7 #egj71 ,sir ,john       
,herschel suggests another possible     
explanation of the acceleration of the  
revolution of a comet4  #dj ,discourse1 
pp4 #aef-h1 and #aga4  #da ,outlines of 
,astronomy1  #hef4  #db ,philosophy of  
,discovery1 pp4 #bfc1 #bfd4  #dc ,see1  
on this point1 the second chapter of the
 present ,book4  #dd ,ante1 ch4 vii4    
#a4  #de ,it seems hardly necessary to  
say that the word impinge1 as a general 

term to express collision of forces1 is 
here used by a figure of speech1 and not
 as expressive of any theory respecting 
the nature of force4  #df ,essays on    
some ,unsettled ,questions of ,political
 ,economy1 ,essay ,v4  #dg ,vide ,memoir
 by ,thomas ,graham1 ,f4,r4,s41 ,master 
of the ,mint1 ,on ,liquid ,diffusion    
,applied to ,analysis1 in the           
,philosophical ,transactions for #ahfb1 
reprinted in the ,journal of the        
,chemical ,society1 and also separately 
as a pamphlet4  #dh ,it was an old      
generalization in surgery1 that tight   
bandaging had a tendency to prevent or  
dissipate local inflammation4 ,this     
sequence1 being1 in the progress of     
physiological knowledge1 resolved into  
more general laws1 led to the important 
surgical invention made by ,dr4 ,arnott1
 the treatment of local inflammation and
 tumours by means of an equable         
pressure1 produced by a bladder         
partially filled with air4 ,the         
pressure1 by keeping back the blood from

 the part1 prevents the inflammation1 or
 the tumour1 from being nourished3 in   
the case of inflammation1 it removes the
 stimulus1 which the organ is unfit to  
receive2 in the case of tumours1 by     
keeping back the nutritive fluid1 it    
causes the absorption of matter to      
exceed the supply1 and the diseased mass
 is gradually absorbed and disappears4  
#di ,since acknowledged and reprinted in
 ,mr4 ,martineau's ,miscellanies4  #ej  
,dissertations and ,discussions1 vol4   
i41 fourth paper4  #ea ,written before  
the rise of the new views respecting the
 relation of heat to mechanical force2  
but confirmed rather than contradicted  
by them4   ,,end ,,of ,,vol4 ,i4        
,,london3   ,,savill1 ,,edwards ,,and   
,,co41 ,,printers1 ,,chandos ,,street1  
,,covent ,,garden4     ,transcriber's   
,notes   ,spelling irregularities where 
there was no obviously preferred version
 were left as is4 ,variants include3    
alkalies and alkalis2 apprise and       
apprize2 coexistent and co-existent     

7along with derivatives72 coextensive   
and co-extensive2 e4 g4 and e4g42       
encumbered and incumbered2 formul and   
formulas2 i4 e4 and i4e42 nonentity and 
non-entity2 recal and recall 7and       
derivatives72 rectilinear and           
rectilineal2 stopt and stopped4         
,changed #c to #d on page xiii3 #d4     
--and from descriptions4  ,inserted     
missing page number1 #afg1 for ,chapter 
,,viii1 section #g on page xiii4  ,moved
 the semi-colon inside the quotation    
marks in the footnote on page #ad3 the  
,science of the ,formal ,laws of        
,thought24  ,changed sub-divisions to   
subdivisions on page #ei3 three         
subdivisions4  ,changed pre-supposed to 
presupposed on page #ge3 they are       
presupposed4  ,in the footnote to page  
#abb1 changed the ,greek character      
upsilon with dasia and oxia to upsilon  
with psili and oxia1 making the         
transliteration deuterai ousiai4        
,changed he to be on page #ahi3 to which
 it may be reduced4  ,changed cb4 to ch4

 in footnote on page #bbg3 ,theory of   
,reasoning1 ch4 iv4  ,changed           
reconcilable to reconcileable on page   
#bdj3 not easily reconcileable4         
,preserved the hyphen in counter-acting 
on page #bhj4 ,usually this is spelled  
without the hyphen1 but this instance is
 in a quotation4  ,moved parenthesis    
that was after to to before it on page  
#cba3 7to return to a former example74  
,put i4e4 in italics on page #cce3 i4e4 
by a power of some sort4  ,changed      
paralyzed to paralysed on page #chi3    
nerves of motion were paralysed4  ,the  
footnote from page #cif refers to the   
footnote on page #bgj4 ,there is no such
 footnote4 ,the intent may be to refer  
to the footnote on page #bfh4 ,however1 
the text was not changed4  ,added the   
dropped w in which on page #dbj3 which  
the progress of the inquiry4  ,changed  
developes to develops on page #def3 the 
prime conductor develops4  ,removed the 
additional period at the end of the     
footnote on page #deg3 ,pp4 #aei-afb4   

,added the dropped l to essential on    
page #eae3 an essential requisite4      
,removed extra opening quotation mark   
before gum on page #ecb3 vegetable gum  
is not digested4  ,in the ,latin-#a text
 version1 the oe-ligature was replaced  
by the two characters1 oe 7or ,oe when  
capitalized74