,,selections ,,from ,,the ,,principles  
,,of ,,philosophy  ,,of  ,,rene         
,,descartes  7#aeif-afej7               
,,translated ,,by  ,,john ,,veitch1     
,,ll4 ,d4  ,,late ,,professor ,,of      
,,logic ,,and ,,rhetoric ,,in ,,the     
,,university ,,of ,,glasgow             
,from the ,publisher's ,preface4    ,the
 present volume contains a reprint of   
the preface and the first  part of the  
,principles of ,philosophy1 together    
with selections from  the second1 third 
and fourth parts of that work1          
corresponding to  the extracts in the   
,french edition of ,gamier1 are also    
given1 as  well as an appendix          
containing part of ,descartes' reply to 
the  ,second ,objections 7viz41 his     
formal demonstrations of the existence  
of ,deity74 ,the translation is based on
 the original ,latin edition of  the    
,principles1 published in #afdd4    ,the
 work had been translated into ,french  
during ,descartes' lifetime1  and       
personally revised and corrected by him1

 the ,french text is  evidently         
deserving of the same consideration as  
the ,latin  originals1 and consequently1
 the additions and variations of the    
,french version have also been          
given--the additions being put in       
square brackets in the text and the     
variations in the footnotes4    ,a copy 
of the title-page of the original       
edition1 as given in ,dr4 ,c4           
,guttler's work 7,munich3 ,c4 ,h4 ,beck4
 #aija71 are also reproduced in  the    
present volume4          ,,selections   
,,from ,,the ,,principles ,,of          
,,philosophy  ,,of ,,descartes          
,,translated ,,from ,,the ,,latin ,,and 
,,collated ,,with ,,the ,,french        
,,letter ,,of ,,the ,,author    ,,to    
,,the ,,french ,,translator ,,of ,,the  
,,principles ,,of ,,philosophy ,,serving
 ,,for  ,a ,,preface4    ,sir1--,the    
version of my principles which you have 
been at pains to  make1 is so elegant   
and finished as to lead me to expect    
that the  work will be more generally   

read in ,french than in ,latin1 and     
better  understood4 ,the only           
apprehension ,i entertain is lest the   
title  should deter some who have not   
been brought up to letters1 or with     
whom philosophy is in bad repute1       
because the kind they were taught  has  
proved unsatisfactory2 and this makes me
 think that it will be  useful to add a 
preface to it for the purpose of showing
 what the  ,,matter of the work is1 what
 ,,end ,i had in view in writing it1 and
  what ,,utility may be derived from it4
 ,but although it might be my  part to  
write a preface of this nature1 seeing  
,i ought to know those  particulars     
better than any other person1 ,i cannot 
nevertheless  prevail upon myself to do 
anything more than merely to give a     
summary of the chief points that fall1  
as ,i think1 to be discussed  in it3 and
 ,i leave it to your discretion to      
present to the public  such part of them
 as you shall judge proper4    ,i should
 have desired1 in the first place1 to   

explain in it what  philosophy is1 by   
commencing with the most common matters1
 as1 for  example1 that the word        
,,philosophy signifies the study of     
wisdom1 and  that by wisdom is to be    
understood not merely prudence in the   
management of affairs1 but a perfect    
knowledge of all that man can  know1 as 
well for the conduct of his life as for 
the preservation of  his health and the 
discovery of all the arts1 and that     
knowledge to  subserve these ends must  
necessarily be deduced from first       
causes2  so that in order to study the  
acquisition of it 7which is properly    
called philosophizing71 we must commence
 with the investigation of  those first 
causes which are called ,,principles4   
,now these principles  must possess     
,,two ,,conditions3 in the first place1 
they must be so  clear and evident that 
the human mind1 when it attentively     
considers  them1 cannot doubt of their  
truth2 in the second place1 the         
knowledge of other things must be so    

dependent on them as that  though the   
principles themselves may indeed be     
known apart from what  depends on them1 
the latter cannot nevertheless be known 
apart from  the former4 ,it will        
accordingly be necessary thereafter to  
endeavour  so to deduce from those      
principles the knowledge of the things  
that  depend on them1 as that there may 
be nothing in the whole series of       
deductions which is not perfectly       
manifest4 ,god is in truth the only     
being who is absolutely wise1 that is1  
who possesses a perfect  knowledge of   
all things2 but we may say that men are 
more or less  wise as their knowledge of
 the most important truths is greater or
  less4 ,and ,i am confident that there 
is nothing1 in what ,i have now  said1  
in which all the learned do not concur4 
,i should1 in the next place1 have      
proposed to consider the utility  of    
philosophy1 and at the same time have   
shown that1 since it  embraces all that 
the human mind can know1 we ought to    

believe that  it is by it we are        
distinguished from savages and          
barbarians1 and  that the civilisation  
and culture of a nation is regulated by 
the  degree in which true philosophy    
nourishes in it1 and1 accordingly1  that
 to contain true philosophers is the    
highest privilege a state  can enjoy4   
,besides this1 ,i should have shown     
that1 as regards  individuals1 it is not
 only useful for each man to have       
intercourse  with those who apply       
themselves to this study1 but that it is
  incomparably better he should himself 
direct his attention to it2  just as it 
is doubtless to be preferred that a man 
should make use  of his own eyes to     
direct his steps1 and enjoy by means of 
the same  the beauties of colour and    
light1 than that he should blindly      
follow  the guidance of another2 though 
the latter course is certainly  better  
than to have the eyes closed with no    
guide except one's self4  ,but to live  
without philosophizing is in truth the  

same as keeping  the eyes closed without
 attempting to open them2 and the       
pleasure of  seeing all that sight      
discloses is not to be compared with the
  satisfaction afforded by the          
discoveries of philosophy4 ,and1        
finally1 this study is more imperatively
 requisite for the  regulation of our   
manners1 and for conducting us through  
life1 than  is the use of our eyes for  
directing our steps4 ,the brutes1 which 
have only their bodies to conserve1 are 
continually occupied in  seeking sources
 of nourishment2 but men1 of whom the   
chief part is  the mind1 ought to make  
the search after wisdom their principal 
care1 for wisdom is the true nourishment
 of the mind2 and ,i feel  assured1     
moreover1 that there are very many who  
would not fail in  the search1 if they  
would but hope for success in it1 and   
knew the  degree of their capabilities  
for it4 ,there is no mind1 how ignoble  
soever it be1 which remains so firmly   
bound up in the objects of the  senses1 

as not sometime or other to turn itself 
away from them in  the aspiration after 
some higher good1 although not knowing  
frequently wherein that good consists4  
,the greatest favourites of             
fortune--those who have health1 honours1
 and riches in abundance--  are not more
 exempt from aspirations of this nature 
than others2  nay1 ,i am persuaded that 
these are the persons who sigh the most 
deeply after another good greater and   
more perfect still than any  they       
already possess4 ,but the supreme good1 
considered by natural  reason without   
the light of faith1 is nothing more than
 the  knowledge of truth through its    
first causes1 in other words1 the       
wisdom of which philosophy is the study4
 ,and1 as all these  particulars are    
indisputably true1 all that is required 
to gain  assent to their truth is that  
they be well stated4    ,but as one is  
restrained from assenting to these      
doctrines by  experience1 which shows   
that they who make pretensions to       

philosophy  are often less wise and     
reasonable than others who never applied
  themselves to the study1 ,i should    
have here shortly explained  wherein    
consists all the science we now possess1
 and what are the  degrees of wisdom at 
which we have arrived4 ,the first degree
  contains only notions so clear of     
themselves that they can be  acquired   
without meditation2 the second          
comprehends all that the  experience of 
the senses dictates2 the third1 that    
which the  conversation of other men    
teaches us2 to which may be added as the
  fourth1 the reading1 not of all books1
 but especially of such as  have been   
written by persons capable of conveying 
proper  instruction1 for it is a species
 of conversation we hold with their     
authors4 ,and it seems to me that all   
the wisdom we in ordinary  possess is   
acquired only in these four ways2 for ,i
 do not class  divine revelation among  
them1 because it does not conduct us by 
degrees1 but elevates us at once to an  

infallible faith4    ,there have been1  
indeed1 in all ages great minds who     
endeavoured to  find a fifth road to    
wisdom1 incomparably more sure and      
elevated  than the other four4 ,the path
 they essayed was the search of first   
causes and true principles1 from which  
might be deduced the reasons  of all    
that can be known by man2 and it is to  
them the appellation  of philosophers   
has been more especially accorded4 ,i am
 not aware  that there is any one of    
them up to the present who has succeeded
 in  this enterprise4 ,the first and    
chief whose writings we possess are     
,plato and ,aristotle1 between whom     
there was no difference1 except  that   
the former1 following in the footsteps  
of his master1 ,socrates1  ingenuously  
confessed that he had never yet been    
able to find  anything certain1 and that
 he was contented to write what seemed  
to  him probable1 imagining1 for this   
end1 certain principles by which  he    
endeavoured to account for the other    

things4 ,aristotle1 on the  other hand1 
characterised by less candour1 although 
for twenty years  the disciple of       
,plato1 and with no principles beyond   
those of his  master1 completely        
reversed his mode of putting them1 and  
proposed  as true and certain what it is
 probable he himself never esteemed as  
such4 ,but these two men had acquired   
much judgment and wisdom by the  four   
preceding means1 qualities which raised 
their authority very  high1 so much so  
that those who succeeded them were      
willing rather  to acquiesce in their   
opinions1 than to seek better for       
themselves4  ,the chief question among  
their disciples1 however1 was as to     
whether  we ought to doubt of all things
 or hold some as certain1--a dispute    
which led them on both sides into       
extravagant errors2 for a part of  those
 who were for doubt1 extended it even to
 the actions of life1  to the neglect of
 the most ordinary rules required for   
its conduct2  those1 on the other hand1 

who maintained the doctrine of          
certainty1  supposing that it must      
depend upon the senses1 trusted entirely
 to  them4 ,to such an extent was this  
carried by ,epicurus1 that it is  said  
he ventured to affirm1 contrary to all  
the reasonings of the  astronomers1 that
 the sun is no larger than it appears4  
,it is a fault we may remark in most    
disputes1 that1 as truth is the  mean   
between the two opinions that are       
upheld1 each disputant  departs from it 
in proportion to the degree in which he 
possesses  the spirit of contradiction4 
,but the error of those who leant too   
much to the side of doubt1 was not      
followed for any length of time1  and   
that of the opposite party has been to  
some extent corrected by  the doctrine  
that the senses are deceitful in many   
instances4  ,nevertheless1 ,i do not    
know that this error was wholly removed 
by  showing that certitude is not in the
 senses1 but in the  understanding alone
 when it has clear perceptions2 and that

 while we  only possess the knowledge   
which is acquired in the first four     
grades of wisdom1 we ought not to doubt 
of the things that appear to  be true in
 what regards the conduct of life1 nor  
esteem them as so  certain that we      
cannot change our opinions regarding    
them1 even  though constrained by the   
evidence of reason4    ,from ignorance  
of this truth1 or1 if there was any one 
to whom it  was known1 from neglect of  
it1 the majority of those who in these  
later ages aspired to be philosophers1  
blindly followed ,aristotle1  so that   
they frequently corrupted the sense of  
his writings1 and  attributed to him    
various opinions which he would not     
recognise as  his own were he now to    
return to the world2 and those who did  
not  follow him1 among whom are to be   
found many of the greatest minds1  did  
yet not escape being imbued with his    
opinions in their youth1 as  these form 
the staple of instruction in the        
schools2 and thus their  minds were so  

preoccupied that they could not rise to 
the knowledge  of true principles4 ,and 
though ,i hold all the philosophers in  
esteem1 and am unwilling to incur odium 
by my censure1 ,i can adduce  a proof of
 my assertion1 which ,i do not think any
 of them will  gainsay1 which is1 that  
they all laid down as a principle what  
they  did not perfectly know4 ,for      
example1 ,i know none of them who did   
not  suppose that there was gravity in  
terrestrial bodies2 but although        
experience shows us very clearly that   
bodies we call heavy descend  towards   
the center of the earth1 we do not1     
therefore1 know the  nature of gravity1 
that is1 the cause or principle in      
virtue of  which bodies descend1 and we 
must derive our knowledge of it from    
some other source4 ,the same may be said
 of a vacuum and atoms1 of  heat and    
cold1 of dryness and humidity1 and of   
salt1 sulphur1 and  mercury1 and the    
other things of this sort which some    
have adopted  as their principles4 ,but 

no conclusion deduced from a principle  
which is not clear can be evident1 even 
although the deduction be  formally     
valid2 and hence it follows that no     
reasonings based on  such principles    
could lead them to the certain knowledge
 of any one  thing1 nor consequently    
advance them one step in the search     
after  wisdom4 ,and if they did discover
 any truth1 this was due to one or      
other of the four means above mentioned4
 ,notwithstanding this1 ,i am  in no    
degree desirous to lessen the honour    
which each of them can  justly claim2 ,i
 am only constrained to say1 for the    
consolation of  those who have not given
 their attention to study1 that just as 
in  travelling1 when we turn our back   
upon the place to which we were  going1 
we recede the farther from it in        
proportion as we proceed in  the new    
direction for a greater length of time  
and with greater  speed1 so that1 though
 we may be afterwards brought back to   
the  right way1 we cannot nevertheless  

arrive at the destined place as  soon as
 if we had not moved backwards at all2  
so in philosophy1 when  we make use of  
false principles1 we depart the farther 
from the  knowledge of truth and wisdom 
exactly in proportion to the care with  
which we cultivate them1 and apply      
ourselves to the deduction of  diverse  
consequences from them1 thinking that we
 are philosophizing  well1 while we are 
only departing the farther from the     
truth2 from  which it must be inferred  
that they who have learned the least of 
all that has been hitherto distinguished
 by the name of philosophy  are the most
 fitted for the apprehension of truth4  
,after making those matters clear1 ,i   
should1 in the next place1 have  desired
 to set forth the grounds for holding   
that the true  principles by which we   
may reach that highest degree of wisdom 
wherein consists the sovereign good of  
human life1 are those ,i have  proposed 
in this work2 and two considerations    
alone are sufficient  to establish      

this--the first of which is1 that these 
principles are  very clear1 and the     
second1 that we can deduce all other    
truths from  them2 for it is only these 
two conditions that are required in true
  principles4 ,but ,i easily prove that 
they are very clear2 firstly1 by  a     
reference to the manner in which ,i     
found them1 namely1 by  rejecting all   
propositions that were in the least     
doubtful1 for it  is certain that such  
as could not be rejected by this test   
when they  were attentively considered1 
are the most evident and clear which    
the human mind can know4 ,thus by       
considering that he who strives to      
doubt of all is unable nevertheless to  
doubt that he is while he  doubts1 and  
that what reasons thus1 in not being    
able to doubt of  itself and doubting   
nevertheless of everything else1 is not 
that  which we call our body1 but what  
we name our mind or thought1 ,i have    
taken the existence of this thought for 
the first principle1 from  which ,i very

 clearly deduced the following truths1  
namely1 that  there is a ,god who is the
 author of all that is in the world1 and
  who1 being the source of all truth1   
cannot have created our  understanding  
of such a nature as to be deceived in   
the judgments it  forms of the things of
 which it possesses a very clear and    
distinct  perception4 ,those are all the
 principles of which ,i avail myself    
touching immaterial or metaphysical     
objects1 from which ,i most  clearly    
deduce these other principles of        
physical or corporeal  things1 namely1  
that there are bodies extended in       
length1 breadth1  and depth1 which are  
of diverse figures and are moved in a   
variety  of ways4 ,such are in sum the  
principles from which ,i deduce all     
other truths4 ,the second circumstance  
that proves the clearness of  these     
principles is1 that they have been known
 in all ages1 and even  received as true
 and indubitable by all men1 with the   
exception only  of the existence of     

,god1 which has been doubted by some1   
because  they attributed too much to the
 perceptions of the senses1 and ,god    
can neither be seen nor touched4        
,but1 though all the truths which ,i    
class among my principles were  known at
 all times1 and by all men1             
nevertheless1 there has been no  one up 
to the present1 who1 so far as ,i know1 
has adopted them as  principles of      
philosophy3 in other words1 as such that
 we can deduce  from them the knowledge 
of whatever else is in the world4 ,it   
accordingly now remains for me to prove 
that they are such2 and it  appears to  
me that ,i cannot better establish this 
than by the test  of experience3 in     
other words1 by inviting readers to     
peruse the  following work4 ,for1 though
 ,i have not treated in it of all       
matters-  -that being impossible--,i    
think ,i have so explained all of which 
,i  had occasion to treat1 that they who
 read it attentively will have  ground  
for the persuasion that it is           

unnecessary to seek for any  other      
principles than those ,i have given1 in 
order to arrive at the  most exalted    
knowledge of which the mind of man is   
capable2  especially if1 after the      
perusal of my writings1 they take the   
trouble to consider how many diverse    
questions are therein discussed  and    
explained1 and1 referring to the        
writings of others1 they see  how little
 probability there is in the reasons    
that are adduced in  explanation of the 
same questions by principles different  
from mine4  ,and that they may the more 
easily undertake this1 ,i might have    
said  that those imbued with my         
doctrines have much less difficulty in  
comprehending the writings of others1   
and estimating their true  value1 than  
those who have not been so imbued2 and  
this is precisely  the opposite of what 
,i before said of such as commenced with
 the  ancient philosophy1 namely1 that  
the more they have studied it the  less 
fit are they for rightly apprehending   

the truth4    ,i should also have added 
a word of advice regarding the manner of
  reading this work1 which is1 that ,i  
should wish the reader at first  to go  
over the whole of it1 as he would a     
romance1 without greatly  straining his 
attention1 or tarrying at the           
difficulties he may  perhaps meet with  
in it1 with the view simply of knowing  
in general  the matters of which ,i     
treat2 and that afterwards1 if they seem
 to  him to merit a more careful        
examination1 and he feel a desire to    
know their causes1 he may read it a     
second time1 in order to observe  the   
connection of my reasonings2 but that he
 must not then give it  up in despair1  
although he may not everywhere          
sufficiently discover  the connection of
 the proof1 or understand all the       
reasonings--it  being only necessary to 
mark with a pen the places where the    
difficulties occur1 and continue to read
 without interruption to the  end2 then1
 if he does not grudge to take up the   

book a third time1 ,i  am confident he  
will find in a fresh perusal the        
solution of most of  the difficulties he
 will have marked before2 and that1 if  
any still  remain1 their solution will  
in the end be found in another reading4 
,i have observed1 on examining the      
natural constitutions of different      
minds1 that there are hardly any so dull
 or slow of understanding as  to be     
incapable of apprehending good opinions1
 or even of acquiring  all the highest  
sciences1 if they be but conducted along
 the right  road4 ,and this can also be 
proved by reason2 for1 as the principles
  are clear1 and as nothing ought to be 
deduced from them1 unless most  manifest
 inferences1 no one is so devoid of     
intelligence as to be  unable to        
comprehend the conclusions that flow    
from them4 ,but1  besides the           
entanglement of prejudices1 from which  
no one is  entirely exempt1 although it 
is they who have been the most ardent   
students of the false sciences that     

receive the greatest detriment  from    
them1 it happens very generally that    
people of ordinary  capacity neglect to 
study from a conviction that they want  
ability1  and that others1 who are more 
ardent1 press on too rapidly3 whence  it
 comes to pass that they frequently     
admit principles far from  evident1 and 
draw doubtful inferences from them4 ,for
 this reason1 ,i  should wish to assure 
those who are too distrustful of their  
own  ability that there is nothing in my
 writings which they may not  entirely  
understand1 if they only take the       
trouble to examine them2  and ,i should 
wish1 at the same time1 to warn those of
 an opposite  tendency that even the    
most superior minds will have need of   
much  time and attention to remark all  
,i designed to embrace therein4         
,after this1 that ,i might lead men to  
understand the real design ,i  had in   
publishing them1 ,i should have wished  
here to explain the  order which it     
seems to me one ought to follow with the

 view of  instructing himself4 ,in the  
first place1 a man who has merely the   
vulgar and imperfect knowledge which can
 be acquired by the four  means above   
explained1 ought1 before all else1 to   
endeavour to form  for himself a code of
 morals1 sufficient to regulate the     
actions of  his life1 as well for the   
reason that this does not admit of delay
  as because it ought to be our first   
care to live well4 ,in the next  place1 
he ought to study ,logic1 not that of   
the schools1 for it is  only1 properly  
speaking1 a dialectic which teaches the 
mode of  expounding to others what we   
already know1 or even of speaking much1 
without judgment1 of what we do not     
know1 by which means it corrupts  rather
 than increases good sense--but the     
logic which teaches the  right conduct  
of the reason with the view of          
discovering the truths  of which we are 
ignorant2 and1 because it greatly       
depends on usage1  it is desirable he   
should exercise himself for a length of 

time in  practising its rules on easy   
and simple questions1 as those of the   
mathematics4 ,then1 when he has acquired
 some skill in discovering  the truth in
 these questions1 he should commence to 
apply himself in  earnest to true       
philosophy1 of which the first part is  
,metaphysics1  containing the principles
 of knowledge1 among which is the       
explication of the principal attributes 
of ,god1 of the immateriality  of the   
soul1 and of all the clear and simple   
notions that are in us2  the second is  
,physics1 in which1 after finding the   
true principles  of material things1 we 
examine1 in general1 how the whole      
universe  has been framed2 in the next  
place1 we consider1 in particular1 the  
nature of the earth1 and of all the     
bodies that are most generally  found   
upon it1 as air1 water1 fire1 the       
loadstone and other  minerals4 ,in the  
next place it is necessary also to      
examine singly  the nature of plants1 of
 animals1 and above all of man1 in order

  that we may thereafter be able to     
discover the other sciences that  are   
useful to us4 ,thus1 all ,philosophy is 
like a tree1 of which  ,metaphysics is  
the root1 ,physics the trunk1 and all   
the other  sciences the branches that   
grow out of this trunk1 which are       
reduced  to three principal1 namely1    
,medicine1 ,mechanics1 and ,ethics4 ,by 
the  science of ,morals1 ,i understand  
the highest and most perfect which1     
presupposing an entire knowledge of the 
other sciences1 is the last  degree of  
wisdom4    ,but as it is not from the   
roots or the trunks of trees that we    
gather the fruit1 but only from the     
extremities of their branches1  so the  
principal utility of philosophy depends 
on the separate uses  of its parts1     
which we can only learn last of all4    
,but1 though ,i am  ignorant of almost  
all these1 the zeal ,i have always felt 
in  endeavouring to be of service to the
 public1 was the reason why ,i          
published1 some ten or twelve years ago1

 certain ,essays on the  doctrines ,i   
thought ,i had acquired4 ,the first part
 of these ,essays  was a ,discourse on  
the ,method of rightly conducting the   
,reason1 and  seeking ,truth in the     
,sciences1 in which ,i gave a summary of
 the  principal rules of logic1 and also
 of an imperfect ethic1 which a  person 
may follow provisionally so long as he  
does not know any  better4 ,the other   
parts were three treatises3 the first of
  ,dioptrics1 the second of ,meteors1   
and the third of ,geometry4 ,in the     
,dioptrics1 ,i designed to show that we 
might proceed far enough in  philosophy 
as to arrive1 by its means1 at the      
knowledge of the arts  that are useful  
to life1 because the invention of the   
telescope1 of  which ,i there gave an   
explanation1 is one of the most         
difficult that  has ever been made4 ,in 
the treatise of ,meteors1 ,i desired to 
exhibit  the difference that subsists   
between the philosophy ,i cultivate and 
that taught in the schools1 in which the

 same matters are usually  discussed4   
,in fine1 in the ,geometry1 ,i professed
 to demonstrate that  ,i had discovered 
many things that were before unknown1   
and thus  afford ground for believing   
that we may still discover many others1 
with the view of thus stimulating all to
 the investigation of truth4  ,since    
that period1 anticipating the difficulty
 which many would  experience in        
apprehending the foundations of the     
,metaphysics1 ,i  endeavoured to explain
 the chief points of them in a book of  
,meditations1 which is not in itself    
large1 but the size of which has  been  
increased1 and the matter greatly       
illustrated1 by the  ,objections which  
several very learned persons sent to me 
on occasion  of it1 and by the ,replies 
which ,i made to them4 ,at length1 after
 it  appeared to me that those preceding
 treatises had sufficiently  prepared   
the minds of my readers for the         
,principles of ,philosophy1 ,i  also    
published it2 and ,i have divided this  

work into four parts1 the  first of     
which contains the principles of human  
knowledge1 and which  may be called the 
,first ,philosophy1 or ,metaphysics4    
,that this part1  accordingly1 may be   
properly understood1 it will be         
necessary to  read beforehand the book  
of ,meditations ,i wrote on the same    
subject4  ,the other three parts contain
 all that is most general in ,physics1  
namely1 the explication of the first    
laws or principles of nature1  and the  
way in which the heavens1 the fixed     
stars1 the planets1  comets1 and        
generally the whole universe1 were      
composed2 in the next  place1 the       
explication1 in particular1 of the      
nature of this earth1  the air1 water1  
fire1 the magnet1 which are the bodies  
we most  commonly find everywhere around
 it1 and of all the qualities we        
observe in these bodies1 as light1 heat1
 gravity1 and the like4 ,in  this way1  
it seems to me1 ,i have commenced the   
orderly explanation  of the whole of    

philosophy1 without omitting any of the 
matters that  ought to precede the last 
which ,i discussed4 ,but to bring this  
undertaking to its conclusion1 ,i ought 
hereafter to explain1 in the  same      
manner1 the nature of the other more    
particular bodies that are  on the      
earth1 namely1 minerals1 plants1        
animals1 and especially man2  finally1  
to treat thereafter with accuracy of    
,medicine1 ,ethics1 and  ,mechanics4 ,i 
should require to do this in order to   
give to the world  a complete body of   
philosophy2 and ,i do not yet feel      
myself so old1-  -,i do not so much     
distrust my strength1 nor do ,i find    
myself so far  removed from the         
knowledge of what remains1 as that ,i   
should not  dare to undertake to        
complete this design1 provided ,i were  
in a  position to make all the          
experiments which ,i should require for 
the  basis and verification of my       
reasonings4 ,but seeing that would      
demand a great expenditure1 to which the

 resources of a private  individual like
 myself would not be adequate1 unless   
aided by the  public1 and as ,i have no 
ground to expect this aid1 ,i believe   
that ,i  ought for the future to content
 myself with studying for my own        
instruction1 and posterity will excuse  
me if ,i fail hereafter to  labour for  
them4    ,meanwhile1 that it may be seen
 wherein ,i think ,i have already       
promoted the general good1 ,i will here 
mention the fruits that may  be gathered
 from my ,principles4 ,the first is the 
satisfaction which  the mind will       
experience on finding in the work many  
truths before  unknown2 for although    
frequently truth does not so greatly    
affect  our imagination as falsity and  
fiction1 because it seems less          
wonderful and is more simple1 yet the   
gratification it affords is  always more
 durable and solid4 ,the second fruit   
is1 that in studying  these principles  
we will become accustomed by degrees to 
judge  better of all the things we come 

in contact with1 and thus be made       
wiser1 in which respect the effect will 
be quite the opposite of the  common    
philosophy1 for we may easily remark in 
those we call pedants  that it renders  
them less capable of rightly exercising 
their reason  than they would have been 
if they had never known it4 ,the third  
is1  that the truths which they contain1
 being highly clear and certain1  will  
take away all ground of dispute1 and    
thus dispose men's minds  to gentleness 
and concord2 whereas the contrary is the
 effect of the  controversies of the    
schools1 which1 as they insensibly      
render those  who are exercised in them 
more wrangling and opinionative1 are    
perhaps the prime cause of the heresies 
and dissensions that now  harass the    
world4 ,the last and chief fruit of     
these ,principles is1  that one will be 
able1 by cultivating them1 to discover  
many truths  ,i myself have not         
unfolded1 and thus passing by degrees   
from one to  another1 to acquire in     

course of time a perfect knowledge of   
the  whole of philosophy1 and to rise to
 the highest degree of wisdom4  ,for    
just as all the arts1 though in their   
beginnings they are rude  and imperfect1
 are yet gradually perfected by         
practice1 from their  containing at     
first something true1 and whose effect  
experience  evinces2 so in philosophy1  
when we have true principles1 we cannot 
fail by following them to meet sometimes
 with other truths2 and we  could not   
better prove the falsity of those of    
,aristotle1 than by  saying that men    
made no progress in knowledge by their  
means during  the many ages they        
prosecuted them4    ,i well know that   
there are some men so precipitate and   
accustomed to  use so little            
circumspection in what they do1 that1   
even with the  most solid foundations1  
they could not rear a firm              
superstructure2  and as it is usually   
those who are the readiest to make      
books1 they  would in a short time mar  

all that ,i have done1 and introduce    
uncertainty and doubt into my manner of 
philosophizing1 from which ,i  have     
carefully endeavoured to banish them1 if
 people were to receive  their writings 
as mine1 or as representing my opinions4
 ,i had1 not  long ago1 some experience 
of this in one of those who were        
believed  desirous of following me the  
most closely1 ,footnote3 ,regius2 see   
,la  ,vie de ,m4 ,descartes1 reduite en 
abrege 7,baillet74 ,liv4 vii41 chap4    
vii4--,t4 and one too of whom ,i had    
somewhere said that ,i had such         
confidence in his genius as to believe  
that he adhered to no  opinions which ,i
 should not be ready to avow as mine2   
for he last  year published a book      
entitled ,fundamental ,physics1 in      
which1  although he seems to have       
written nothing on the subject of       
,physics  and ,medicine which he did not
 take from my writings1 as well from    
those ,i have published as from another 
still imperfect on the nature  of       

animals1 which fell into his hands2     
nevertheless1 because he has  copied    
them badly1 and changed the order1 and  
denied certain  metaphysical truths upon
 which all ,physics ought to be based1  
,i am  obliged wholly to disavow his    
work1 and here to request readers not   
to attribute to me any opinion unless   
they find it expressly stated  in my own
 writings1 and to receive no opinion as 
true1 whether in my  writings or        
elsewhere1 unless they see that it is   
very clearly  deduced from true         
principles4 ,i well know1 likewise1 that
 many ages  may elapse ere all the      
truths deducible from these principles  
are  evolved out of them1 as well       
because the greater number of such as   
remain to be discovered depend on       
certain particular experiments  that    
never occur by chance1 but which require
 to be investigated  with care and      
expense by men of the highest           
intelligence1 as because  it will hardly
 happen that the same persons who have  

the sagacity to  make a right use of    
them1 will possess also the means of    
making  them1 and also because the      
majority of the best minds have formed  
so  low an estimate of philosophy in    
general1 from the imperfections  they   
have remarked in the kind in vogue up to
 the present time1 that  they cannot    
apply themselves to the search after    
truth4    ,but1 in conclusion1 if the   
difference discernible between the      
principles in question and those of     
every other system1 and the  great array
 of truths deducible from them1 lead    
them to discern the  importance of      
continuing the search after these       
truths1 and to  observe the degree of   
wisdom1 the perfection and felicity of  
life1  to which they are fitted to      
conduct us1 ,i venture to believe that  
there will not be found one who is not  
ready to labour hard in so  profitable a
 study1 or at least to favour and aid   
with all his might  those who shall     
devote themselves to it with success4   

,the height of my wishes is1 that       
posterity may sometime behold the  happy
 issue of it1 etc4          ,,to ,,the  
,,most ,,serene ,,princess1             
,,elizabeth1 ,,eldest ,,daughter ,,of   
,,frederick1 ,,king ,,of ,,bohemia1     
,,count  ,,palatine1 ,,and ,,elector    
,,of ,,the ,,sacred ,,roman ,,empire4   
,,madam1--,the greatest advantage ,i    
have derived from the writings  which ,i
 have already published1 has arisen from
 my having1 through  means of them1     
become known to your ,highness1 and thus
 been  privileged to hold occasional    
converse with one in whom so many rare  
and estimable qualities are united1 as  
to lead me to believe ,i  should do     
service to the public by proposing them 
as an example to  posterity4 ,it would  
ill become me to flatter1 or to give    
expression  to anything of which ,i had 
no certain knowledge1 especially in the 
first pages of a work in which ,i aim at
 laying down the principles  of truth4  
,and the generous modesty that is       

conspicuous in all your  actions1       
assures me that the frank and simple    
judgment of a man who  only writes what 
he believes will be more agreeable to   
you than the  ornate laudations of those
 who have studied the art of compliment4
  ,for this reason1 ,i will give        
insertion to nothing in this letter for 
which ,i have not the certainty both of 
experience and reason2 and in  the      
exordium1 as in the rest of the work1 ,i
 will write only as  becomes a          
philosopher4 ,there is a vast difference
 between real and  apparent virtues2 and
 there is also a great discrepancy      
between  those real virtues that proceed
 from an accurate knowledge of the      
truth1 and such as are accompanied with 
ignorance or error4 ,the  virtues ,i    
call apparent are only1 properly        
speaking1 vices1 which1  as they are    
less frequent than the vices that are   
opposed to them1  and are farther       
removed from them than the intermediate 
virtues1 are  usually held in higher    

esteem than those virtues4 ,thus1       
because  those who fear dangers too much
 are more numerous than they who fear   
them too little1 temerity is frequently 
opposed to the vice of  timidity1 and   
taken for a virtue1 and is commonly more
 highly  esteemed than true fortitude4  
,thus1 also1 the prodigal are in        
ordinary more praised than the liberal2 
and none more easily acquire  a great   
reputation for piety than the           
superstitious and  hypocritical4 ,with  
regard to true virtues1 these do not all
 proceed  from true knowledge1 for there
 are some that likewise spring from     
defect or error2 thus1 simplicity is    
frequently the source of  goodness1 fear
 of devotion1 and despair of courage4   
,the virtues that  are thus accompanied 
with some imperfections differ from each
 other1  and have received diverse      
appellations4 ,but those pure and       
perfect  virtues that arise from the    
knowledge of good alone are all of the  
same nature1 and may be comprised under 

the single term wisdom4 ,for1  whoever  
owns the firm and constant resolution of
 always using his  reason as well as    
lies in his power1 and in all his       
actions of doing  what he judges to be  
best1 is truly wise1 as far as his      
nature  permits2 and by this alone he is
 just1 courageous1 temperate1 and       
possesses all the other virtues1 but so 
well balanced as that none  of them     
appears more prominent than another3 and
 for this reason1  although they are    
much more perfect than the virtues that 
blaze  forth through the mixture of some
 defect1 yet1 because the crowd  thus   
observes them less1 they are not usually
 extolled so highly4  ,besides1 of the  
two things that are requisite for the   
wisdom thus  described1 namely1 the     
perception of the understanding and the 
disposition of the will1 it is only that
 which lies in the will  which all men  
can possess equally1 inasmuch as the    
understanding of  some is inferior to   
that of others4 ,but although those who 

have only  an inferior understanding may
 be as perfectly wise as their nature   
permits1 and may render themselves      
highly acceptable to ,god by their      
virtue1 provided they preserve always a 
firm and constant resolution  to do all 
that they shall judge to be right1 and  
to omit nothing  that may lead them to  
the knowledge of the duties of which    
they are  ignorant2 nevertheless1 those 
who preserve a constant resolution of   
performing the right1 and are especially
 careful in instructing  themselves1 and
 who possess also a highly perspicacious
 intellect1  arrive doubtless at a      
higher degree of wisdom than others2 and
 ,i see  that these three particulars   
are found in great perfection in your   
,highness4 ,for1 in the first place1    
your desire of self-instruction  is     
manifest1 from the circumstance that    
neither the amusements of  the court1   
nor the accustomed mode of educating    
ladies1 which  ordinarily condemns them 
to ignorance1 have been sufficient to   

prevent you from studying with much care
 all that is best in the  arts and      
sciences2 and the incomparable          
perspicacity of your  intellect is      
evinced by this1 that you penetrated the
 secrets of the  sciences and acquired  
an accurate knowledge of them in a very 
short  period4 ,but of the vigour of    
your intellect ,i have a still stronger 
proof1 and one peculiar to myself1 in   
that ,i have never yet met any  one who 
understood so generally and so well as  
yourself all that is  contained in my   
writings4 ,for there are several1 even  
among men of  the highest intellect and 
learning1 who find them very obscure4   
,and  ,i remark1 in almost all those who
 are versant in ,metaphysics1 that  they
 are wholly disinclined from ,geometry2 
and1 on the other hand1  that the       
cultivators of ,geometry have no ability
 for the  investigations of the ,first  
,philosophy3 insomuch that ,i can say   
with  truth ,i know but one mind1 and   
that is your own1 to which both  studies

 are alike congenial1 and which ,i      
therefore1 with propriety1  designate   
incomparable4 ,but what most of all     
enhances my admiration  is1 that so     
accurate and varied an acquaintance with
 the whole  circle of the sciences is   
not found in some aged doctor who has   
employed many years in contemplation1   
but in a ,princess still young1  and    
whose countenance and years would more  
fitly represent one of  the ,graces than
 a ,muse or the sage ,minerva4 ,in      
conclusion1 ,i not  only remark in your 
,highness all that is requisite on the  
part of  the mind to perfect and sublime
 wisdom1 but also all that can be       
required on the part of the will or the 
manners1 in which benignity  and        
gentleness are so conjoined with majesty
 that1 though fortune  has attacked you 
with continued injustice1 it has failed 
either to  irritate or crush you4 ,and  
this constrains me to such veneration   
that ,i not only think this work due to 
you1 since it treats of  philosophy     

which is the study of wisdom1 but       
likewise feel not more  zeal for my     
reputation as a philosopher than        
pleasure in subscribing  myself1--      
,of your most ,serene ,highness1 ,the   
most devoted servant1    ,,descartes4   
,,part ,i4  ,,of ,,the ,,principles ,,of
 ,,human ,,knowledge4       ,i4 ,,that  
in order to seek truth1 it is necessary 
once in the course  of our life1 to     
doubt1 as far as possible1 of all       
things4    ,as we were at one time      
children1 and as we formed various      
judgments  regarding the objects        
presented to our senses1 when as yet we 
had  not the entire use of our reason1  
numerous prejudices stand in the  way of
 our arriving at the knowledge of truth2
 and of these it seems  impossible for  
us to rid ourselves1 unless we          
undertake1 once in our  lifetime1 to    
doubt of all those things in which we   
may discover even  the smallest         
suspicion of uncertainty4       ,,ii4   
,that we ought also to consider as false

 all that is doubtful4    ,moreover1 it 
will be useful likewise to esteem as    
false the things  of which we shall be  
able to doubt1 that we may with greater 
clearness discover what possesses most  
certainty and is the easiest  to know4  
,,iii4 ,that we ought not meanwhile to  
make use of doubt in the  conduct of    
life4    ,in the meantime1 it is to be  
observed that we are to avail ourselves 
of this general doubt only while engaged
 in the contemplation of  truth4 ,for1  
as far as concerns the conduct of life1 
we are very  frequently obliged to      
follow opinions merely probable1 or even
  sometimes1 though of two courses of   
action we may not perceive more         
probability in the one than in the      
other1 to choose one or other1  seeing  
the opportunity of acting would not     
unfrequently pass away  before we could 
free ourselves from our doubts4         
,,iv4 ,why we may doubt of sensible     
things4    ,accordingly1 since we now   
only design to apply ourselves to the   

investigation of truth1 we will doubt1  
first1 whether of all the  things that  
have ever fallen under our senses1 or   
which we have ever  imagined1 any one   
really exist2 in the first place1       
because we know  by experience that the 
senses sometimes err1 and it would be   
imprudent to trust too much to what has 
even once deceived us2  secondly1       
because in dreams we perpetually seem to
 perceive or  imagine innumerable       
objects which have no existence4 ,and to
 one who  has thus resolved upon a      
general doubt1 there appear no marks by 
which he can with certainty distinguish 
sleep from the waking state4       ,v4  
,why we may also doubt of mathematical  
demonstrations4    ,we will also doubt  
of the other things we have before held 
as most  certain1 even of the           
demonstrations of mathematics1 and of   
their  principles which we have hitherto
 deemed self-evident2 in the first      
place1 because we have sometimes seen   
men fall into error in such  matters1   

and admit as absolutely certain and self
 evident what to us  appeared false1 but
 chiefly because we have learnt that    
,god who  created us is all-powerful2   
for we do not yet know whether perhaps  
it was his will to create us so that we 
are always deceived1 even in  the things
 we think we know best3 since this does 
not appear more  impossible than our    
being occasionally deceived1 which1     
however1 as  observation teaches us1 is 
the case4 ,and if we suppose that an    
all-  powerful ,god is not the author of
 our being1 and that we exist of        
ourselves or by some other means1 still1
 the less powerful we  suppose our      
author to be1 the greater reason will we
 have for  believing that we are not so 
perfect as that we may not be           
continually deceived4       ,,vi4 ,that 
we possess a free-will1 by which we can 
withhold our  assent from what is       
doubtful1 and thus avoid error4    ,but 
meanwhile1 whoever in the end may be the
 author of our being1  and however      

powerful and deceitful he may be1 we are
 nevertheless  conscious of a freedom1  
by which we can refrain from admitting  
to a  place in our belief aught that is 
not manifestly certain and  undoubted1  
and thus guard against ever being       
deceived4       ,,vii4 ,that we cannot  
doubt of our existence while we doubt1  
and that  this is the first knowledge we
 acquire when we philosophize in  order4
    ,while we thus reject all of which  
we can entertain the smallest  doubt1   
and even imagine that it is false1 we   
easily indeed suppose  that there is    
neither ,god1 nor sky1 nor bodies1 and  
that we  ourselves even have neither    
hands nor feet1 nor1 finally1 a body2   
but we cannot in the same way suppose   
that we are not while we doubt  of the  
truth of these things2 for there is a   
repugnance in  conceiving that what     
thinks does not exist at the very time  
when it  thinks4 ,accordingly1 the      
knowledge1 ,i ,,think1 ,,therefore ,i   
,,am1 is  the first and most certain    

that occurs to one who philosophizes    
orderly4       ,,viii4 ,that we hence   
discover the distinction between the    
mind and  the body1 or between a        
thinking and corporeal thing4    ,and   
this is the best mode of discovering the
 nature of the mind1 and  its           
distinctness from the body3 for         
examining what we are1 while  supposing1
 as we now do1 that there is nothing    
really existing apart  from our thought1
 we clearly perceive that neither       
extension1 nor  figure1 nor local       
motion1,footnote3 ,instead of local     
motion1 the  ,french has existence in   
any place4 nor anything similar that can
  be attributed to body1 pertains to our
 nature1 and nothing save  thought      
alone2 and1 consequently1 that the      
notion we have of our  mind precedes    
that of any corporeal thing1 and is more
 certain1  seeing we still doubt whether
 there is any body in existence1 while  
we already perceive that we think4      
,,ix4 ,what thought 7,,cogitatio7 is4   

,by the word thought1 ,i understand all 
that which so takes place in  us that we
 of ourselves are immediately conscious 
of it2 and1  accordingly1 not only to   
understand 7,,intelligere1 ,,entendre71 
to will  7,,velle71 to imagine          
7,,imaginari71 but even to perceive     
7,,sentire1  ,,sentir71 are here the    
same as to think 7,,cogitare1 ,,penser74
 ,for if ,i  say1 ,i see1 or1 ,i walk1  
therefore ,i am2 and if ,i understand by
  vision or walking the act of my eyes  
or of my limbs1 which is the  work of   
the body1 the conclusion is not         
absolutely certain1 because1  as is     
often the case in dreams1 ,i may think  
that ,i see or walk1  although ,i do not
 open my eyes or move from my place1 and
 even1  perhaps1 although ,i have no    
body3 but1 if ,i mean the sensation     
itself1 or consciousness of seeing or   
walking1 the knowledge is  manifestly   
certain1 because it is then referred to 
the mind1 which  alone perceives or is  
conscious that it sees or walks4        

,footnote3 ,in  the ,french1 which alone
 has the power of perceiving1 or of     
being  conscious in any other way       
whatever4       ,x4 ,that the notions   
which are simplest and self-evident1 are
  obscured by logical definitions2 and  
that such are not to be  reckoned among 
the cognitions acquired by study1 but as
 born with  us4    ,i do not here       
explain several other terms which ,i    
have used1 or  design to use in the     
sequel1 because their meaning seems to  
me  sufficiently self-evident4 ,and ,i  
frequently remarked that  philosophers  
erred in attempting to explain1 by      
logical definitions1  such truths as are
 most simple and self-evident2 for they 
thus only  rendered them more obscure4  
,and when ,i said that the proposition1 
,i ,,think1 ,,therefore ,i ,,am1 is of  
all others the first and most  certain  
which occurs to one philosophizing      
orderly1 ,i did not  therefore deny that
 it was necessary to know what thought1 
existence1 and certitude are1 and the   

truth that1 in order to think  it is    
necessary to be1 and the like2 but1     
because these are the most  simple      
notions1 and such as of themselves      
afford the knowledge of  nothing        
existing1 ,i did not judge it proper    
there to enumerate them4       ,,xi4    
,how we can know our mind more clearly  
than our body4    ,but now that it may  
be discerned how the knowledge we have  
of the  mind not only precedes1 and has 
greater certainty1 but is even  clearer1
 than that we have of the body1 it must 
be remarked1 as a  matter that is highly
 manifest by the natural light1 that to 
nothing  no affections or qualities     
belong2 and1 accordingly1 that where we 
observe certain affections1 there a     
thing or substance to which  these      
pertain1 is necessarily found4 ,the same
 light also shows us  that we know a    
thing or substance more clearly in      
proportion as we  discover in it a      
greater number of qualities4 ,now1 it is
 manifest  that we remark a greater     

number of qualities in our mind than in 
any  other thing2 for there is no       
occasion on which we know anything      
whatever when we are not at the same    
time led with much greater  certainty to
 the knowledge of our own mind4 ,for    
example1 if ,i judge  that there is an  
earth because ,i touch or see it1 on the
 same  ground1 and with still greater   
reason1 ,i must be persuaded that my    
mind exists2 for it may be1 perhaps1    
that ,i think ,i touch the earth  while 
there is one in existence2 but it is not
 possible that ,i  should so judge1 and 
my mind which thus judges not exist2 and
 the  same holds good of whatever object
 is presented to our mind4       ,,xii4 
,how it happens that every one does not 
come equally to know  this4    ,those   
who have not philosophized in order have
 had other opinions on  this subject1   
because they never distinguished with   
sufficient care  the mind from the body4
 ,for1 although they had no difficulty  
in  believing that they themselves      

existed1 and that they had a higher     
assurance of this than of any other     
thing1 nevertheless1 as they did  not   
observe that by ,,themselves1 they ought
 here to understand their  ,,minds alone
 when the question related to           
metaphysical certainty2  and since1 on  
the contrary1 they rather meant their   
bodies which  they saw with their eyes1 
touched with their hands1 and to which  
they erroneously attributed the faculty 
of perception1 they were  prevented from
 distinctly apprehending the nature of  
the mind4       ,,xiii4 ,in what sense  
the knowledge of other things depends   
upon the  knowledge of ,god4    ,but    
when the mind1 which thus knows itself  
but is still in doubt as  to all other  
things1 looks around on all sides1 with 
a view to the  farther extension of its 
knowledge1 it first of all discovers    
within  itself the ideas of many things2
 and while it simply contemplates  them1
 and neither affirms nor denies that    
there is anything beyond  itself        

corresponding to them1 it is in no      
danger of erring4 ,the mind  also       
discovers certain common notions out of 
which it frames various  demonstrations 
that carry conviction to such a degree  
as to render  doubt of their truth      
impossible1 so long as we give attention
 to  them4 ,for example1 the mind has   
within itself ideas of numbers and      
figures1 and it has likewise among its  
common notions the principle  ,,that    
,,if ,,equals ,,be ,,added ,,to ,,equals
 ,,the ,,wholes ,,will ,,be ,,equal and 
the  like2 from which it is easy to     
demonstrate that the three angles of  a 
triangle are equal to two right angles1 
etc4 ,now1 so long as we  attend to the 
premises from which this conclusion and 
others similar  to it were deduced1 we  
feel assured of their truth2 but1 as the
 mind  cannot always think of these with
 attention1 when it has the  remembrance
 of a conclusion without recollecting   
the order of its  deduction1 and is     
uncertain whether the author of its     

being has  created it of a nature that  
is liable to be deceived1 even in what  
appears most evident1 it perceives that 
there is just ground to  distrust the   
truth of such conclusions1 and that it  
cannot possess  any certain knowledge   
until it has discovered its author4     
,,xiv4 ,that we may validly infer the   
existence of ,god from necessary        
existence being comprised in the concept
 we have of him4    ,when the mind      
afterwards reviews the different ideas  
that are in it1  it discovers what is by
 far the chief among them--that of a    
,being  omniscient1 all-powerful1 and   
absolutely perfect2 and it observes     
that in this idea there is contained not
 only possible and  contingent          
existence1 as in the ideas of all other 
things which it  clearly perceives1 but 
existence absolutely necessary and      
eternal4  ,and just as because1 for     
example1 the equality of its three      
angles  to two right angles is          
necessarily comprised in the idea of a  

triangle1 the mind is firmly persuaded  
that the three angles of a  triangle are
 equal to two right angles2 so1 from its
 perceiving  necessary and eternal      
existence to be comprised in the idea   
which it  has of an all-perfect ,being1 
it ought manifestly to conclude that    
this all-perfect ,being exists4         
,,xv4 ,that necessary existence is not  
in the same way comprised in  the       
notions which we have of other things1  
but merely contingent  existence4       
,the mind will be still more certain of 
the truth of this conclusion1  if it    
consider that it has no idea of any     
other thing in which it  can discover   
that necessary existence is contained2  
for1 from this  circumstance alone1 it  
will discern that the idea of an        
all-perfect  ,being has not been framed 
by itself1 and that it does not         
represent  a chimera1 but a true and    
immutable nature1 which must exist since
  it can only be conceived as           
necessarily existing4       ,,xvi4 ,that

 prejudices hinder many from clearly    
knowing the necessity  of the existence 
of ,god4    ,our mind would have no     
difficulty in assenting to this truth1  
if it  were1 first of all1 wholly free  
from prejudices2 but as we have been    
accustomed to distinguish1 in all other 
things1 essence from  existence1 and to 
imagine at will many ideas of things    
which neither  are nor have been1 it    
easily happens1 when we do not steadily 
fix  our thoughts on the contemplation  
of the all-perfect ,being1 that a  doubt
 arises as to whether the idea we have  
of him is not one of  those which we    
frame at pleasure1 or at least of that  
class to whose  essence existence does  
not pertain4       ,,xvii4 ,that the    
greater objective 7representative7      
perfection there  is in our idea of a   
thing1 the greater also must be the     
perfection  of its cause4    ,when we   
further reflect on the various ideas    
that are in us1 it is  easy to perceive 
that there is not much difference among 

them1 when  we consider them simply as  
certain modes of thinking1 but that they
  are widely different1 considered in   
reference to the objects they           
represent2 and that their causes must be
 so much the more perfect  according to 
the degree of objective perfection      
contained in them4  ,footnote3 as what  
they represent of their object has more 
perfection4--,,french4 ,for there is no 
difference between this and  the case of
 a person who has the idea of a machine1
 in the  construction of which great    
skill is displayed1 in which            
circumstances we have a right to inquire
 how he came by this idea1  whether1 for
 example1 he somewhere saw such a       
machine constructed by  another1 or     
whether he was so accurately taught the 
mechanical  sciences1 or is endowed with
 such force of genius1 that he was able 
of himself to invent it1 without having 
elsewhere seen anything like  it2 for   
all the ingenuity which is contained in 
the idea objectively  only1 or as it    

were in a picture1 must exist at least  
in its first  and chief cause1 whatever 
that may be1 not only objectively or    
representatively1 but in truth formally 
or eminently4       ,,xviii4 ,that the  
existence of ,god may be again inferred 
from the  above4    ,thus1 because we   
discover in our minds the idea of ,god1 
or of an  all-perfect ,being1 we have a 
right to inquire into the source whence 
we derive it2 and we will discover that 
the perfections it  represents are so   
immense as to render it quite certain   
that we  could only derive it from an   
all-perfect ,being2 that is1 from a ,god
  really existing4 ,for it is not only  
manifest by the natural light  that     
nothing cannot be the cause of anything 
whatever1 and that the  more perfect    
cannot arise from the less perfect1 so  
as to be thereby  produced as by its    
efficient and total cause1 but also that
 it is  impossible we can have the idea 
or representation of anything  whatever1
 unless there be somewhere1 either in us

 or out of us1 an  original which       
comprises1 in reality1 all the          
perfections that are  thus represented  
to us2 but1 as we do not in any way find
 in  ourselves those absolute           
perfections of which we have the idea1  
we  must conclude that they exist in    
some nature different from ours1  that  
is1 in ,god1 or at least that they were 
once in him2 and it most  manifestly    
follows from their infinity that they   
are still there4       ,,xix4 ,that1    
although we may not comprehend the      
nature of ,god1 there  is yet nothing   
which we know so clearly as his         
perfections4    ,this will appear       
sufficiently certain and manifest to    
those who have  been accustomed to      
contemplate the idea of ,god1 and to    
turn their  thoughts to his infinite    
perfections2 for1 although we may not   
comprehend them1 because it is of the   
nature of the infinite not to  be       
comprehended by what is finite1 we      
nevertheless conceive them  more clearly

 and distinctly than material objects1  
for this reason1  that1 being simple1   
and unobscured by limits1,footnote3     
,after  ,,limits1 what of them we do    
conceive is much less confused4 ,there  
is1 besides1 no speculation more        
calculated to aid in perfecting our     
understanding1 and which is more        
important than this1 inasmuch as  the   
consideration of an object that has no  
limits to its perfections  fills us with
 satisfaction and assurance4-,,french4  
they occupy our  mind more fully4       
,,xx4 ,that we are not the cause of     
ourselves1 but that this is ,god1  and  
consequently that there is a ,god4      
,but1 because every one has not observed
 this1 and because1 when we  have an    
idea of any machine in which great skill
 is displayed1 we  usually know with    
sufficient accuracy the manner in which 
we  obtained it1 and as we cannot even  
recollect when the idea we have  of a   
,god was communicated to us by him1     
seeing it was always in our  minds1 it  

is still necessary that we should       
continue our review1 and  make inquiry  
after our author1 possessing1 as we do1 
the idea of the  infinite perfections of
 a ,god3 for it is in the highest degree
  evident by the natural light1 that    
that which knows something more  perfect
 than itself1 is not the source of its  
own being1 since it  would thus have    
given to itself all the perfections     
which it knows2  and that1 consequently1
 it could draw its origin from no other 
being  than from him who possesses in   
himself all those perfections1 that  is1
 from ,god4       ,,xxi4 ,that the      
duration alone of our life is sufficient
 to  demonstrate the existence of ,god4 
,the truth of this demonstration will   
clearly appear1 provided we  consider   
the nature of time1 or the duration of  
things2 for this is  of such a kind that
 its parts are not mutually dependent1  
and never  co-existent2 and1            
accordingly1 from the fact that we now  
are1 it  does not necessarily follow    

that we shall be a moment afterwards1   
unless some cause1 viz41 that which     
first produced us1 shall1 as it  were1  
continually reproduce us1 that is1      
conserve us4 ,for we easily  understand 
that there is no power in us by which we
 can conserve  ourselves1 and that the  
being who has so much power as to       
conserve  us out of himself1 must also  
by so much the greater reason conserve  
himself1 or rather stand in need of     
being conserved by no one  whatever1    
and1 in fine1 be ,god4       ,,xxii4    
,that in knowing the existence of ,god1 
in the manner here  explained1 we       
likewise know all his attributes1 as far
 as they can  be known by the natural   
light alone4    ,there is the great     
advantage in proving the existence of   
,god in this  way1 viz41 by his idea1   
that we at the same time know what he   
is1 as  far as the weakness of our      
nature allows2 for1 reflecting on the   
idea we have of him which is born with  
us1 we perceive that he is  eternal1    

omniscient1 omnipotent1 the source of   
all goodness and  truth1 creator of all 
things1 and that1 in fine1 he has in    
himself  all that in which we can       
clearly discover any infinite perfection
 or  good that is not limited by any    
imperfection4       ,,xxiii4 ,that ,god 
is not corporeal1 and does not perceive 
by means of  senses as we do1 or will   
the evil of sin4    ,for there are      
indeed many things in the world that are
 to a certain  extent imperfect or      
limited1 though possessing also some    
perfection2  and it is accordingly      
impossible that any such can be in ,god4
 ,thus1  looking to corporeal           
nature1,footnote3 ,in the ,french1 since
  extension constitutes the nature of   
body4 since divisibility is  included in
 local extension1 and this indicates    
imperfection1 it is  certain that ,god  
is not body4 ,and although in men it is 
to some  degree a perfection to be      
capable of perceiving by means of the   
senses1 nevertheless since in every     

sense there is passivity  ,footnote3 ,in
 the ,french1 because our perceptions   
arise from  impressions made upon us    
from another source1 i4e41 than         
ourselves4 which indicates dependency1  
we must conclude that ,god is  in no    
manner possessed of senses1 and that he 
only understands and  wills1 not1       
however1 like us1 by acts in any way    
distinct1 but  always by an act that is 
one1 identical1 and the simplest        
possible1  understands1 wills1 and      
operates all1 that is1 all things that  
in  reality exist2 for he does not will 
the evil of sin1 seeing this is  but the
 negation of being4       ,,xxiv4 ,that 
in passing from the knowledge of ,god to
 the knowledge of  the creatures1 it is 
necessary to remember that our          
understanding is  finite1 and the power 
of ,god infinite4    ,but as we know    
that ,god alone is the true cause of all
 that is or  can be1 we will doubtless  
follow the best way of philosophizing1  
if1  from the knowledge we have of ,god 

himself1 we pass to the  explication of 
the things which he has created1 and    
essay to deduce  it from the notions    
that are naturally in our minds1 for we 
will  thus obtain the most perfect      
science1 that is1 the knowledge of      
effects through their causes4 ,but that 
we may be able to make this  attempt    
with sufficient security from error1 we 
must use the  precaution to bear in mind
 as much as possible that ,god1 who is  
the  author of things1 is infinite1     
while we are wholly finite4       ,,xxv4
 ,that we must believe all that ,god has
 revealed1 although it  may surpass the 
reach of our faculties4    ,thus1 if    
perhaps ,god reveal to us or others1    
matters concerning  himself which       
surpass the natural powers of our mind1 
such as the  mysteries of the           
incarnation and of the trinity1 we will 
not refuse  to believe them1 although we
 may not clearly understand them2 nor   
will we be in any way surprised to find 
in the immensity of his  nature1 or even

 in what he has created1 many things    
that exceed our  comprehension4         
,,xxvi4 ,that it is not needful to enter
 into disputes ,footnote3 to  essay to  
comprehend the infinite4--,,french4     
regarding the infinite1  but merely to  
hold all that in which we can find no   
limits as  indefinite1 such as the      
extension of the world1 the divisibility
 of  the parts of matter1 the number of 
the stars1 etc4    ,we will thus never  
embarrass ourselves by disputes about   
the  infinite1 seeing it would be absurd
 for us who are finite to  undertake to 
determine anything regarding it1 and    
thus as it were to  limit it by         
endeavouring to comprehend it4 ,we will 
accordingly give  ourselves no concern  
to reply to those who demand whether the
 half  of an infinite line is also      
infinite1 and whether an infinite number
  is even or odd1 and the like1 because 
it is only such as imagine  their minds 
to be infinite who seem bound to        
entertain questions of  this sort4 ,and1

 for our part1 looking to all those     
things in which  in certain senses1 we  
discover no limits1 we will not1        
therefore1  affirm that they are        
infinite1 but will regard them simply as
  indefinite4 ,thus1 because we cannot  
imagine extension so great that  we     
cannot still conceive greater1 we will  
say that the magnitude of  possible     
things is indefinite1 and because a body
 cannot be divided  into parts so small 
that each of these may not be conceived 
as again  divided into others still     
smaller1 let us regard quantity as      
divisible into parts whose number is    
indefinite2 and as we cannot  imagine so
 many stars that it would seem          
impossible for ,god to  create more1 let
 us suppose that their number is        
indefinite1 and so  in other instances4 
,,xxvii4 ,what difference there is      
between the indefinite and the          
infinite4    ,and we will call those    
things indefinite rather than infinite1 
with  the view of reserving to ,god     

alone the appellation of infinite2 in   
the first place1 because not only do we 
discover in him alone no  limits on any 
side1 but also because we positively    
conceive that he  admits of none2 and in
 the second place1 because we do not in 
the  same way positively conceive that  
other things are in every part          
unlimited1 but merely negatively admit  
that their limits1 if they  have any1   
cannot be discovered by us4             
,,xxviii4 ,that we must examine1 not the
 final1 but the efficient1  causes of   
created things4    ,likewise1 finally1  
we will not seek reasons of natural     
things from  the end which ,god or      
nature proposed to himself in their     
creation  7i4 e41 final causes71        
,footnote3 ,we will not stop to consider
 the  ends which ,god proposed to       
himself in the creation of the world1   
and  we will entirely reject from our   
philosophy the search of final          
causes6--,french4 for we ought not to   
presume so far as to think  that we are 

sharers in the counsels of ,deity1 but1 
considering him  as the efficient cause 
of all things1 let us endeavour to      
discover  by the natural light          
,footnote3 ,faculty of                  
reasoning4--,,french4  which he has     
planted in us1 applied to those of his  
attributes of  which he has been willing
 we should have some knowledge1 what    
must  be concluded regarding those      
effects we perceive by our senses2      
bearing in mind1 however1 what has been 
already said1 that we must  only confide
 in this natural light so long as       
nothing contrary to  its dictates is    
revealed by ,god himself4 ,footnote3    
,the last clause1  beginning bearing in 
mind4 is omitted in the ,french4        
,,xxix4 ,that ,god is not the cause of  
our errors4    ,the first attribute of  
,god which here falls to be considered1 
is  that he is absolutely veracious and 
the source of all light1 so that  it is 
plainly repugnant for him to deceive us1
 or to be properly and  positively the  

cause of the errors to which we are     
consciously  subject2 for although the  
address to deceive seems to be some mark
  of subtlety of mind among men1 yet    
without doubt the will to deceive  only 
proceeds from malice or from fear and   
weakness1 and  consequently cannot be   
attributed to ,god4       ,,xxx4 ,that  
consequently all which we clearly       
perceive is true1 and  that we are thus 
delivered from the doubts above         
proposed4    ,whence it follows1 that   
the light of nature1 or faculty of      
knowledge  given us by ,god1 can never  
compass any object which is not true1 in
  as far as it attains to a knowledge of
 it1 that is1 in as far as the  object  
is clearly and distinctly apprehended4  
,for ,god would have  merited the       
appellation of a deceiver if he had     
given us this  faculty perverted1 and   
such as might lead us to take falsity   
for  truth when we used it aright4 ,thus
 the highest doubt is removed1  which   
arose from our ignorance on the point as

 to whether perhaps  our nature was such
 that we might be deceived even in those
 things  that appear to us the most     
evident4 ,the same principle ought also 
to  be of avail against all the other   
grounds of doubting that have been      
already enumerated4 ,for mathematical   
truths ought now to be above  suspicion1
 since these are of the clearest4 ,and  
if we perceive  anything by our senses1 
whether while awake or asleep1 we will  
easily discover the truth provided we   
separate what there is of  clear and    
distinct in the knowledge from what is  
obscure and  confused4 ,there is no need
 that ,i should here say more on this   
subject1 since it has already received  
ample treatment in the  metaphysical    
,meditations2 and what follows will     
serve to explain it  still more         
accurately4       ,,xxxi4 ,that our     
errors are1 in respect of ,god1 merely  
negations1  but1 in respect of          
ourselves1 privations4    ,but as it    
happens that we frequently fall into    

error1 although ,god  is no deceiver1 if
 we desire to inquire into the origin   
and cause of  our errors1 with a view to
 guard against them1 it is necessary to 
observe that they depend less on our    
understanding than on our will1  and    
that they have no need of the actual    
concourse of ,god1 in order  to their   
production2 so that1 when considered in 
reference to ,god1  they are merely     
negations1 but in reference to          
ourselves1  privations4       ,,xxxii4  
,that there are only two modes of       
thinking in us1 viz41 the  perception of
 the understanding and the action of the
 will4    ,for all the modes of thinking
 of which we are conscious may be       
referred to two general classes1 the one
 of which is the perception  or         
operation of the understanding1 and the 
other the volition or  operation of the 
will4 ,thus1 to perceive by the senses  
7,,sentire71 to  imagine1 and to        
conceive things purely intelligible1 are
 only  different modes of perceiving    

7,,percip ,,iendi72 but to desire1 to be
  averse from1 to affirm1 to deny1 to   
doubt1 are different modes of  willing4 
,,xxxiii4 ,that we never err unless when
 we judge of something which  we do not 
sufficiently apprehend4    ,when we     
apprehend anything we are in no danger  
of error1 if we  refrain from judging of
 it in any way2 and even when we have   
formed  a judgment regarding it1 we     
would never fall into error1 provided we
  gave our assent only to what we       
clearly and distinctly perceived2  but  
the reason why we are usually deceived1 
is that we judge without  possessing an 
exact knowledge of that of which we     
judge4       ,,xxxiv4 ,that the will as 
well as the understanding is required   
for  judging4    ,i admit that the      
understanding is necessary for judging1 
there being  no room to suppose that we 
can judge of that which we in no way    
apprehend2 but the will also is required
 in order to our assenting  to what we  
have in any degree perceived4 ,it is not

 necessary1  however1 at least to form  
any judgment whatever1 that we have an  
entire and perfect apprehension of a    
thing2 for we may assent to  many things
 of which we have only a very obscure   
and confused  knowledge4       ,,xxxv4  
,that the will is of greater extension  
than the understanding1  and is thus the
 source of our errors4    ,further1 the 
perception of the intellect extends only
 to the few  things that are presented  
to it1 and is always very limited3 the  
will1 on the other hand1 may1 in a      
certain sense1 be said to be  infinite1 
because we observe nothing that can be  
the object of the  will of any other1   
even of the unlimited will of ,god1 to  
which ours  cannot also extend1 so that 
we easily carry it beyond the objects we
  clearly perceive2 and when we do this1
 it is not wonderful that we  happen to 
be deceived4       ,,xxxvi4 ,that our   
errors cannot be imputed to ,god4       
,but although ,god has not given us an  
omniscient understanding1 he is  not on 

this account to be considered in any    
wise the author of our  errors1 for it  
is of the nature of created intellect to
 be finite1  and of finite intellect not
 to embrace all things4       ,,xxxvii4 
,that the chief perfection of man is his
 being able to act  freely or by will1  
and that it is this which renders him   
worthy of  praise or blame4    ,that the
 will should be the more extensive is in
 harmony with its  nature3 and it is a  
high perfection in man to be able to act
 by  means of it1 that is1 freely2 and  
thus in a peculiar way to be the  master
 of his own actions1 and merit praise or
 blame4 ,for self-  acting machines are 
not commended because they perform with 
exactness all the movements for which   
they were adapted1 seeing  their motions
 are carried on necessarily2 but the    
maker of them is  praised on account of 
the exactness with which they were      
framed1  because he did not act of      
necessity1 but freely2 and1 on the same 
principle1 we must attribute to         

ourselves something more on this        
account1 that when we embrace truth1 we 
do so not of necessity1 but  freely4    
,,xxxviii4 ,that error is a defect in   
our mode of acting1 not in our  nature2 
and that the faults of their subjects   
may be frequently  attributed to other  
masters1 but never to ,god4    ,it is   
true1 that as often as we err1 there is 
some defect in our  mode of action or in
 the use of our liberty1 but not in our 
nature1  because this is always the     
same1 whether our judgments be true or  
false4 ,and although ,god could have    
given to us such perspicacity of        
intellect that we should never have     
erred1 we have1 notwithstanding1  no    
right to demand this of him2 for1       
although with us he who was  able to    
prevent evil and did not is held guilty 
of it1 ,god is not in  the same way to  
be reckoned responsible for our errors  
because he  had the power to prevent    
them1 inasmuch as the dominion which    
some  men possess over others has been  

instituted for the purpose of  enabling 
them to hinder those under them from    
doing evil1 whereas  the dominion which 
,god exercises over the universe is     
perfectly  absolute and free4 ,for this 
reason we ought to thank him for the    
goods he has given us1 and not complain 
that he has not blessed us  with all    
which we know it was in his power to    
impart4       ,,xxxix4 ,that the liberty
 of our will is self-evident4           
,finally1 it is so manifest that we     
possess a free will1 capable of  giving 
or withholding its assent1 that this    
truth must be reckoned  among the first 
and most common notions which are born  
with us4  ,this1 indeed1 has already    
very clearly appeared1 for when essaying
  to doubt of all things1 we went so far
 as to suppose even that he  who created
 us employed his limitless power in     
deceiving us in every  way1 we were     
conscious nevertheless of being free to 
abstain from  believing what was not in 
every respect certain and undoubted4    

,but  that of which we are unable to    
doubt at such a time is as self-        
evident and clear as any thing we can   
ever know4       ,,xl4 ,that it is      
likewise certain that ,god has          
fore-ordained all  things4    ,but      
because what we have already discovered 
of ,god1 gives us the  assurance that   
his power is so immense that we would   
sin in thinking  ourselves capable of   
ever doing anything which he had not    
ordained  beforehand1 we should soon be 
embarrassed in great difficulties if  we
 undertook to harmonise the             
pre-ordination of ,god with the freedom 
of our will1 and endeavoured to         
comprehend both truths at once4         
,,xli4 ,how the freedom of our will may 
be reconciled with the ,divine          
pre-ordination4    ,but1 in place of    
this1 we will be free from these        
embarrassments if  we recollect that our
 mind is limited1 while the power of    
,god1 by  which he not only knew from   
all eternity what is or can be1 but also

  willed and pre-ordained it1 is        
infinite4 ,it thus happens that we      
possess sufficient intelligence to know 
clearly and distinctly that  this power 
is in ,god1 but not enough to comprehend
 how he leaves the  free actions of men 
indeterminate and1 on the other hand1 we
 have  such consciousness of the liberty
 and indifference which exists in       
ourselves1 that there is nothing we more
 clearly or perfectly  comprehend3 so   
that the omnipotence of ,god ought not  
to keep us  from believing it4 ,for it  
would be absurd to doubt of that of     
which  we are fully conscious1 and which
 we experience as existing in           
ourselves1 because we do not comprehend 
another matter which1 from  its very    
nature1 we know to be incomprehensible4 
,,xlii4 ,how1 although we never will to 
err1 it is nevertheless by our  will    
that we do err4    ,but now since we    
know that all our errors depend upon our
 will1 and  as no one wishes to deceive 
himself1 it may seem wonderful that     

there is any error in our judgments at  
all4 ,it is necessary to  remark1       
however1 that there is a great          
difference between willing to  be       
deceived1 and willing to yield assent to
 opinions in which it  happens that     
error is found4 ,for though there is no 
one who  expressly wishes to fall into  
error1 we will yet hardly find any one  
who is not ready to assent to things in 
which1 unknown to himself1  error lurks2
 and it even frequently happens that it 
is the desire  itself of following after
 truth that leads those not fully aware 
of  the order in which it ought to be   
sought for1 to pass judgment on  matters
 of which they have no adequate         
knowledge1 and thus to fall  into error4
       ,,xliii4 ,that we shall never err
 if we give our assent only to what  we 
clearly and distinctly perceive4    ,but
 it is certain we will never admit      
falsity for truth1 so long as  we judge 
only of that which we clearly and       
distinctly perceive2  because1 as ,god  

is no deceiver1 the faculty of knowledge
 which he  has given us cannot be       
fallacious1 nor1 for the same reason1   
the  faculty of will1 when we do not    
extend it beyond the objects we  clearly
 know4 ,and even although this truth    
could not be established  by reasoning1 
the minds of all have been so impressed 
by nature as  spontaneously to assent to
 whatever is clearly perceived1 and to  
experience an impossibility to doubt of 
its truth4       ,,xliv4 ,that we       
uniformly judge improperly when we      
assent to what we  do not clearly       
perceive1 although our judgment may     
chance to be  true2 and that it is      
frequently our memory which deceives us 
by  leading us to believe that certain  
things were formerly sufficiently       
understood by us4    ,it is likewise    
certain that1 when we approve of any    
reason which we  do not apprehend1 we   
are either deceived1 or1 if we stumble  
on the  truth1 it is only by chance1 and
 thus we can never possess the          

assurance that we are not in error4 ,i  
confess it seldom happens that  we judge
 of a thing when we have observed we do 
not apprehend it1  because it is a      
dictate of the natural light never to   
judge of what  we do not know4 ,but we  
most frequently err in this1 that we    
presume  upon a past knowledge of much  
to which we give our assent1 as to      
something treasured up in the memory1   
and perfectly known to us2  whereas1 in 
truth1 we have no such knowledge4       
,,xlv4 ,what constitutes clear and      
distinct perception4    ,there are      
indeed a great many persons who1 through
 their whole  lifetime1 never perceive  
anything in a way necessary for judging 
of  it properly2 for the knowledge upon 
which we can establish a certain  and   
indubitable judgment must be not only   
clear1 but also1 distinct4  ,i call that
 clear which is present and manifest to 
the mind giving  attention to it1 just  
as we are said clearly to see objects   
when1  being present to the eye looking 

on1 they stimulate it with  sufficient  
force4 and it is disposed to regard     
them2 but the  distinct is that which is
 so precise and different from all other
  objects as to comprehend in itself    
only what is clear4 ,footnote3  what    
appears manifestly to him who considers 
it as he ought4--  ,,french4            
,,xlvi4 ,it is shown1 from the example  
of pain1 that a perception may  be clear
 without being distinct1 but that it    
cannot be distinct  unless it is clear4 
,for example1 when any one feels intense
 pain1 the knowledge which he  has of   
this pain is very clear1 but it is not  
always distinct2 for  men usually       
confound it with the obscure judgment   
they form  regarding its nature1 and    
think that there is in the suffering    
part  something similar to the sensation
 of pain of which they are alone        
conscious4 ,and thus perception may be  
clear without being distinct1  but it   
can never be distinct without likewise  
being clear4       ,,xlvii4 ,that1 to   

correct the prejudices of our early     
years1 we must  consider what is clear  
in each of our simple ,footnote3        
first4--  ,,french4 notions4    ,and1   
indeed1 in our early years1 the mind was
 so immersed in the  body1 that1        
although it perceived many things with  
sufficient  clearness1 it yet knew      
nothing distinctly2 and since even at   
that  time we exercised our judgment in 
many matters1 numerous prejudices  were 
thus contracted1 which1 by the majority1
 are never afterwards  laid aside4 ,but 
that we may now be in a position to get 
rid of  these1 ,i will here briefly     
enumerate all the simple notions of     
which  our thoughts are composed1 and   
distinguish in each what is clear  from 
what is obscure1 or fitted to lead into 
error4       ,,xlviii4 ,that all the    
objects of our knowledge are to be      
regarded  either 7#a7 as things or the  
affections of things3 or 7#b7 as eternal
  truths2 with the enumeration of       
things4    ,whatever objects fall under 

our knowledge we consider either as     
things or the affections of             
things1,footnote3 ,things and the       
affections of things are 7in the        
,french7 equivalent to what has  some   
7i4e41 a ,,real7 existence1 as opposed  
to the class of eternal  truths1 which  
have merely an ,,ideal existence4 or as 
eternal truths  possessing no existence 
beyond our thought4 ,of the first class 
the  most general are substance1        
duration1 order1 number1 and perhaps    
also some others1 which notions apply to
 all the kinds of things4 ,i  do not1   
however1 recognise more than two highest
 kinds 7,,summa  ,,genera7 of things2   
the first of intellectual things1 or    
such as have  the power of thinking1    
including mind or thinking substance and
 its  properties2 the second1 of        
material things1 embracing extended     
substance1 or body and its properties4  
,perception1 volition1 and all  modes as
 well of knowing as of willing1 are     
related to thinking  substance2 on the  

other hand1 to extended substance we    
refer  magnitude1 or extension in       
length1 breadth1 and depth1 figure1     
motion1 situation1 divisibility of parts
 themselves1 and the like4  ,there are1 
however1 besides these1 certain things  
of which we have  an internal experience
 that ought not to be referred either to
 the  mind of itself1 or to the body    
alone1 but to the close and intimate    
union between them1 as will hereafter be
 shown in its place4 ,of this  class are
 the appetites of hunger and thirst1    
etc41 and also the  emotions or passions
 of the mind which are not exclusively  
mental  affections1 as the emotions of  
anger1 joy1 sadness1 love1 etc42 and1   
finally1 all the sensations1 as of pain1
 titillation1 light and  colours1       
sounds1 smells1 tastes1 heat1 hardness1 
and the other  tactile qualities4       
,,xlix4 ,that the eternal truths cannot 
be thus enumerated1 but that  this is   
not necessary4    ,what ,i have already 
enumerated we are to regard as things1  

or the  qualities or modes of things4   
,we now come to speak of eternal        
truths4 ,when we apprehend that it is   
impossible a thing can arise  from      
nothing1 this proposition1 ,,ex ,,nihilo
 ,,nihil ,,fit1 is not  considered as   
somewhat existing1 or as the mode of a  
thing1 but as  an eternal truth having  
its seat in our mind1 and is called a   
common  notion or axiom4 ,of this class 
are the following3--,it is impossible   
the same thing can at once be and not   
be2 what is done cannot be  undone2 he  
who thinks must exist while he thinks2  
and innumerable  others1 the whole of   
which it is indeed difficult to         
enumerate1 but  this is not necessary1  
since1 if blinded by no prejudices1 we  
cannot  fail to know them when the      
occasion of thinking them occurs4       
,l4 ,that these truths are clearly      
perceived1 but not equally by all  men1 
on account of prejudices4    ,and1      
indeed1 with regard to these common     
notions1 it is not to be  doubted that  

they can be clearly and distinctly      
known1 for otherwise  they would not    
merit this appellation3 as1 in truth1   
some of them  are not1 with respect to  
all men1 equally deserving of the name1 
because they are not equally admitted by
 all3 not1 however1 from  this reason1  
as ,i think1 that the faculty of        
knowledge of one man  extends farther   
than that of another1 but rather because
 these  common notions are opposed to   
the prejudices of some1 who1 on this    
account1 are not able readily to embrace
 them1 even although others1  who are   
free from those prejudices1 apprehend   
them with the greatest  clearness4      
,,li4 ,what substance is1 and that the  
term is not applicable to ,god  and the 
creatures in the same sense4    ,but    
with regard to what we consider as      
things or the modes of  things1 it is   
worth while to examine each of them by  
itself4 ,by  substance we can conceive  
nothing else than a thing which exists  
in  such a way as to stand in need of   

nothing beyond itself in order to  its  
existence4 ,and1 in truth1 there can be 
conceived but one  substance which is   
absolutely independent1 and that is     
,god4 ,we  perceive that all other      
things can exist only by help of the    
concourse of ,god4 ,and1 accordingly1   
the term substance does not  apply to   
,god and the creatures ,,univocally1 to 
adopt a term familiar  in the schools2  
that is1 no signification of this word  
can be  distinctly understood which is  
common to ,god and them4       ,,lii4   
,that the term is applicable univocally 
to the mind and the  body1 and how      
substance itself is known4    ,created  
substances1 however1 whether corporeal  
or thinking1 may be  conceived under    
this common concept2 for these are      
things which1 in  order to their        
existence1 stand in need of nothing but 
the concourse  of ,god4 ,but yet        
substance cannot be first discovered    
merely from its  being a thing which    
exists independently1 for existence by  

itself is  not observed by us4 ,we      
easily1 however1 discover substance     
itself  from any attribute of it1 by    
this common notion1 that of nothing     
there are no attributes1 properties1 or 
qualities3 for1 from  perceiving that   
some attribute is present1 we infer that
 some  existing thing or substance to   
which it may be attributed is also of   
necessity present4       ,,liii4 ,that  
of every substance there is one         
principal attribute1 as  thinking of the
 mind1 extension of the body4    ,but1  
although any attribute is sufficient to 
lead us to the  knowledge of substance1 
there is1 however1 one principal        
property of  every substance1 which     
constitutes its nature or essence1 and  
upon  which all the others depend4      
,thus1 extension in length1 breadth1 and
  depth1 constitutes the nature of      
corporeal substance2 and thought  the   
nature of thinking substance4 ,for every
 other thing that can be  attributed to 
body1 presupposes extension1 and is only

 some mode of  an extended thing2 as all
 the properties we discover in the mind 
are  only diverse modes of thinking4    
,thus1 for example1 we cannot  conceive 
figure unless in something extended1 nor
 motion unless in  extended space1 nor  
imagination1 sensation1 or will1 unless 
in a  thinking thing4 ,but1 on the other
 hand1 we can conceive extension        
without figure or motion1 and thought   
without imagination or  sensation1 and  
so of the others2 as is clear to any one
 who attends  to these matters4         
,,liv4 ,how we may have clear and       
distinct notions of the substance  which
 thinks1 of that which is corporeal1 and
 of ,god4    ,and thus we may easily    
have two clear and distinct notions or  
ideas1  the one of created substance1   
which thinks1 the other of corporeal    
substance1 provided we carefully        
distinguish all the attributes of       
thought from those of extension4 ,we may
 also have a clear and  distinct idea of
 an uncreated and independent thinking  

substance1  that is1 of ,god1 provided  
we do not suppose that this idea        
adequately represents to us all that is 
in ,god1 and do not mix up  with it     
anything fictitious1 but attend simply  
to the characters  that are comprised in
 the notion we have of him1 and which we
  clearly know to belong to the nature  
of an absolutely perfect ,being4  ,for  
no one can deny that there is in us such
 an idea of ,god1 without  groundlessly 
supposing that there is no knowledge of 
,god at all in  the human mind4         
,,lv4 ,how duration1 order1 and number  
may be also distinctly  conceived4      
,we will also have most distinct        
conceptions of duration1 order1 and     
number1 if1 in place of mixing up with  
our notions of them that  which properly
 belongs to the concept of substance1 we
 merely think  that the duration of a   
thing is a mode under which we conceive 
this  thing1 in so far as it continues  
to exist2 and1 in like manner1 that     
order and number are not in reality     

different from things disposed  in order
 and numbered1 but only modes under     
which we diversely  consider these      
things4       ,,lvi4 ,what are modes1   
qualities1 attributes4    ,and1 indeed1 
we here understand by modes the same    
with what we  elsewhere designate       
attributes or qualities4 ,but when we   
consider  substance as affected or      
varied by them1 we use the term modes2  
when  from this variation it may be     
denominated of such a kind1 we adopt    
the term qualities to designate the     
different modes which cause it  to be so
 named2 and1 finally1 when we simply    
regard these modes as  in the substance1
 we call them attributes4 ,accordingly1 
since ,god  must be conceived as        
superior to change1 it is not proper to 
say  that there are modes or qualities  
in him1 but simply attributes2 and  even
 in created things that which is found  
in them always in the  same mode1 as    
existence and duration in the thing     
which exists and  endures1 ought to be  

called attribute and not mode or        
quality4       ,,lvii4 ,that some       
attributes exist in the things to which 
they are  attributed1 and others only in
 our thought2 and what duration and     
time are4    ,of these attributes or    
modes there are some which exist in the 
things themselves1 and others that have 
only an existence in our  thought2 thus1
 for example1 time1 which we distinguish
 from duration  taken in its generality1
 and call the measure of motion1 is only
 a  certain mode under which we think   
duration itself1 for we do not  indeed  
conceive the duration of things that are
 moved to be  different from the        
duration of things that are not moved3  
as is  evident from this1 that if two   
bodies are in motion for an hour1 the   
one moving quickly and the other slowly1
 we do not reckon more time  in the one 
than in the other1 although there may be
 much more motion  in the one of the    
bodies than in the other4 ,but that we  
may  comprehend the duration of all     

things under a common measure1 we       
compare their duration with that of the 
greatest and most regular  motions that 
give rise to years and days1 and which  
we call time2  hence what is so         
designated is nothing superadded to     
duration1 taken  in its generality1 but 
a mode of thinking4       ,,lviii4 ,that
 number and all universals are only     
modes of thought4    ,in the same way   
number1 when it is not considered as in 
created  things1 but merely in the      
abstract or in general1 is only a mode  
of  thinking2 and the same is true of   
all those general ideas we call         
universals4       ,,lix4 ,how universals
 are formed2 and what are the five      
common1 viz41  genus1 species1          
difference1 property1 and accident4     
,universals arise merely from our making
 use of one and the same idea  in       
thinking of all individual objects      
between which there subsists a  certain 
likeness2 and when we comprehend all the
 objects represented  by this idea under

 one name1 this term likewise becomes   
universal4  ,for example1 when we see   
two stones1 and do not regard their     
nature  farther than to remark that     
there are two of them1 we form the idea 
of a certain number1 which we call the  
binary2 and when we  afterwards see two 
birds or two trees1 and merely take     
notice of  them so far as to observe    
that there are two of them1 we again    
take  up the same idea as before1 which 
is1 accordingly1 universal2 and we      
likewise give to this number the same   
universal appellation of  binary4 ,in   
the same way1 when we consider a figure 
of three sides1  we form a certain idea1
 which we call the idea of a triangle1  
and we  afterwards make use of it as the
 universal to represent to our mind  all
 other figures of three sides4 ,but when
 we remark more  particularly that of   
figures of three sides1 some have a     
right angle  and others not1 we form the
 universal idea of a right-angled       
triangle1 which being related to the    

preceding as more general1 may  be      
called species2 and the right angle the 
universal difference by  which          
right-angled triangles are distinguished
 from all others2 and  farther1 because 
the square of the side which sustains   
the right  angle is equal to the squares
 of the other two sides1 and because    
this property belongs only to this      
species of triangles1 we may call  it   
the universal property of the species4  
,finally1 if we suppose  that of these  
triangles some are moved and others not1
 this will be  their universal accident2
 and1 accordingly1 we commonly reckon   
five  universals1 viz41 genus1 species1 
difference1 property1 accident4         
,,lx4 ,of distinctions2 and first of the
 real4    ,but number in things         
themselves arises from the distinction  
there is  between them3 and distinction 
is threefold1 viz41 real1 modal1 and  of
 reason4 ,the real properly subsists    
between two or more  substances2 and it 
is sufficient to assure us that two     

substances  are really mutually         
distinct1 if only we are able clearly   
and  distinctly to conceive the one of  
them without the other4 ,for the        
knowledge we have of ,god renders it    
certain that he can effect all  that of 
which we have a distinct idea3          
wherefore1 since we have now1  for      
example1 the idea of an extended and    
corporeal substance1 though  we as yet  
do not know with certainty whether any  
such thing is  really existent1         
nevertheless1 merely because we have the
 idea of  it1 we may be assured that    
such may exist2 and1 if it really       
exists1  that every part which we can   
determine by thought must be really     
distinct from the other parts of the    
same substance4 ,in the same  way1 since
 every one is conscious that he thinks1 
and that he in  thought can exclude from
 himself every other substance1 whether 
thinking or extended1 it is certain that
 each of us thus considered  is really  
distinct from every other thinking and  

corporeal  substance4 ,and although we  
suppose that ,god united a body to a    
soul  so closely that it was impossible 
to form a more intimate union1 and  thus
 made a composite whole1 the two        
substances would remain really          
distinct1 notwithstanding this union2   
for with whatever tie ,god  connected   
them1 he was not able to rid himself of 
the power he  possessed of separating   
them1 or of conserving the one apart    
from  the other1 and the things which   
,god can separate or conserve           
separately are really distinct4         
,,lxi4 ,of the modal distinction4       
,there are two kinds of modal           
distinctions1 viz41 that between the    
mode properly so-called and the         
substance of which it is a mode1 and    
that between two modes of the same      
substance4 ,of the former we have  an   
example in this1 that we can clearly    
apprehend substance apart  from the mode
 which we say differs from it2 while1 on
 the other  hand1 we cannot conceive    

this mode without conceiving the        
substance  itself4 ,there is1 for       
example1 a modal distinction between    
figure or  motion and corporeal         
substance in which both exist2 there is 
a  similar distinction between          
affirmation or recollection and the     
mind4 ,of the latter kind we have an    
illustration in our ability to          
recognise the one of two modes apart    
from the other1 as figure apart  from   
motion1 and motion apart from figure2   
though we cannot think of  either the   
one or the other without thinking of the
 common substance  in which they adhere4
 ,if1 for example1 a stone is moved1 and
 is  withal square1 we can1 indeed1     
conceive its square figure without  its 
motion1 and reciprocally its motion     
without its square figure2  but we can  
conceive neither this motion nor this   
figure apart from  the substance of the 
stone4 ,as for the distinction according
 to  which the mode of one substance is 
different from another substance1  or   

from the mode of another substance1 as  
the motion of one body is  different    
from another body or from the mind1 or  
as motion is  different from doubt1 it  
seems to me that it should be called    
real  rather than modal1 because these  
modes cannot be clearly conceived  apart
 from the really distinct substances of 
which they are the  modes4       ,,lxii4
 ,of the distinction of reason 7logical 
distinction74    ,finally1 the          
distinction of reason is that between a 
substance and  some one of its          
attributes1 without which it is         
impossible1 however1  we can have a     
distinct conception of the substance    
itself2 or  between two such attributes 
of a common substance1 the one of which 
we essay to think without the other4    
,this distinction is manifest  from our 
inability to form a clear and distinct  
idea of such  substance1 if we separate 
from it such attribute2 or to have a    
clear  perception of the one of two such
 attributes if we separate it from  the 

other4 ,for example1 because any        
substance which ceases to endure  ceases
 also to exist1 duration is not distinct
 from substance except  in thought      
7,,ratione72 and in general all the     
modes of thinking which  we consider as 
in objects differ only in thought1 as   
well from the  objects of which they are
 thought as from each other in a common 
object4,footnote3 and generally all the 
attributes that lead us to  entertain   
different thoughts of the same thing1   
such as1 for  example1 the extension of 
body and its property of divisibility1  
do  not differ from the body which is to
 us the object of them1 or from  each   
other1 unless as we sometimes confusedly
 think the one without  thinking the    
other4--,,french4 ,it occurs1 indeed1 to
 me that ,i have  elsewhere classed this
 kind of distinction with the modal     
7viz41  towards the end of the ,reply to
 the ,first ,objections to the          
,meditations on the ,first ,philosophy72
 but there it was only  necessary to    

treat of these distinctions generally1  
and it was  sufficient for my purpose at
 that time simply to distinguish both of
  them from the real4       ,,lxiii4    
,how thought and extension may be       
distinctly known1 as  constituting1 the 
one the nature of mind1 the other that  
of body4    ,thought and extension may  
be regarded as constituting the natures 
of  intelligent and corporeal substance2
 and then they must not be  otherwise   
conceived than as the thinking and      
extended substances  themselves1 that   
is1 as mind and body1 which in this way 
are  conceived with the greatest        
clearness and distinctness4 ,moreover1  
we  more easily conceive extended or    
thinking substance than substance  by   
itself1 or with the omission of its     
thinking or extension4 ,for  there is   
some difficulty in abstracting the      
notion of substance from  the notions of
 thinking and extension1 which1 in      
truth1 are only  diverse in thought     
itself 7i4e41 logically different72 and 

a concept  is not more distinct because 
it comprehends fewer properties1 but    
because we accurately distinguish what  
is comprehended in it from  all other   
notions4       ,,lxiv4 ,how these may   
likewise be distinctly conceived as     
modes of  substance4    ,thought and    
extension may be also considered as     
modes of substance2  in as far1 namely1 
as the same mind may have many different
  thoughts1 and the same body1 with its 
size unchanged1 may be  extended in     
several diverse ways1 at one time more  
in length and  less in breadth or depth1
 and at another time more in breadth and
  less in length2 and then they are     
modally distinguished from  substance1  
and can be conceived not less clearly   
and distinctly1  provided they be not   
regarded as substances or things        
separated from  others1 but simply as   
modes of things4 ,for by regarding them 
as in  the substances of which they are 
the modes1 we distinguish them from     
these substances1 and take them for what

 in truth they are3 whereas1  on the    
other hand1 if we wish to consider them 
apart from the  substances in which they
 are1 we should by this itself regard   
them  as self-subsisting things1 and    
thus confound the ideas of mode and     
substance4       ,,lxv4 ,how we may     
likewise know their modes4    ,in the   
same way we will best apprehend the     
diverse modes of thought1  as           
intellection1 imagination1 recollection1
 volition1 etc41 and also  the diverse  
modes of extension1 or those that belong
 to extension1  as all figures1 the     
situation of parts and their motions1   
provided  we consider them simply as    
modes of the things in which they are2  
and motion as far as it is concerned1   
provided we think merely of  locomotion1
 without seeking to know the force that 
produces it1 and  which nevertheless ,i 
will essay to explain in its own place4 
,,lxvi4 ,how our sensations1 affections1
 and appetites may be clearly  known1   
although we are frequently wrong in our 

judgments regarding  them4    ,there    
remain our sensations1 affections1 and  
appetites1 of which we  may also have a 
clear knowledge1 if we take care to     
comprehend in  the judgments we form of 
them only that which is precisely       
contained  in our perception of them1   
and of which we are immediately         
conscious4 ,there is1 however1 great    
difficulty in observing this1 at  least 
in respect of sensations2 because we    
have all1 without  exception1 from our  
youth judged that all the things we     
perceived by  our senses had an         
existence beyond our thought1 and that  
they were  entirely similar to the      
sensations1 that is1 perceptions1 we had
 of  them4 ,thus when1 for example1 we  
saw a certain colour1 we thought we  saw
 something occupying a place out of us1 
and which was entirely  similar to that 
idea of colour we were then conscious   
of2 and from  the habit of judging in   
this way1 we seemed to see this so      
clearly  and distinctly that we esteemed

 it 7i4e41 the externality of the       
colour7 certain and indubitable4        
,,lxvii4 ,that we are frequently        
deceived in our judgments regarding     
pain itself4    ,the same prejudice has 
place in all our other sensations1 even 
in  those of titillation and pain4 ,for 
though we are not in the habit of       
believing that there exist out of us    
objects that resemble  titillation and  
pain1 we do not nevertheless consider   
these  sensations as in the mind alone1 
or in our perception1 but as in the     
hand1 or foot1 or some other part of our
 body4 ,there is no reason1  however1 to
 constrain us to believe that the pain1 
for example1  which we feel1 as it were1
 in the foot is something out of the    
mind  existing in the foot1 or that the 
light which we see1 as it were1 in  the 
sun exists in the sun as it is in us4   
,both these beliefs are  prejudices of  
our early years1 as will clearly appear 
in the sequel4       ,,lxviii4 ,how in  
these things what we clearly conceive is

 to be  distinguished from that in which
 we may be deceived4    ,but that we may
 distinguish what is clear in our       
sensations from  what is obscure1 we    
ought most carefully to observe that we 
possess  a clear and distinct knowledge 
of pain1 colour1 and other things of    
this sort1 when we consider them simply 
as sensations or thoughts2  but that1   
when they are judged to be certain      
things subsisting  beyond our mind1 we  
are wholly unable to form any conception
 of  them4 ,indeed1 when any one tells  
us that he sees colour in a body or     
feels pain in one of his limbs1 this is 
exactly the same as if he  said that he 
there saw or felt something of the      
nature of which he  was entirely        
ignorant1 or that he did not know what  
he saw or felt4  ,for although1 when    
less attentively examining his thoughts1
 a person  may easily persuade himself  
that he has some knowledge of it1 since 
he supposes that there is something     
resembling that sensation of  colour or 

of pain of which he is conscious2 yet1  
if he reflects on  what the sensation of
 colour or pain represents to him as    
existing  in a coloured body or in a    
wounded member1 he will find that of    
such  he has absolutely no knowledge4   
,,lxix4 ,that magnitude1 figure1 etc41  
are known far differently from  colour1 
pain1 etc4    ,what we have said above  
will be more manifest2 especially if we 
consider that size in the body          
perceived1 figure1 motion 7at least     
local1 for philosophers by fancying     
other kinds of motion have  rendered its
 nature less intelligible to            
themselves71 the situation  of parts1   
duration1 number1 and those other       
properties which1 as we  have already   
said1 we clearly perceive in all bodies1
 are known by  us in a way altogether   
different from that in which we know    
what  colour is in the same body1 or    
pain1 smell1 taste1 or any other of     
those properties which ,i have said     
above must be referred to the  senses4  

,for although when we see a body we are 
not less assured of  its existence from 
its appearing figured than from its     
appearing  coloured1,footnote3 by the   
colour we perceive on occasion of it4-- 
,,french4 we yet know with far greater  
clearness its property of  figure than  
its colour4       ,,lxx4 ,that we may   
judge of sensible things in two ways1 by
 the one  of which we avoid error1 by   
the other fall into it4    ,it is thus  
manifest that to say we perceive colours
 in objects is in  reality equivalent to
 saying we perceive something in objects
 and  are yet ignorant of what it is1   
except as that which determines in  us a
 certain highly vivid and clear         
sensation1 which we call the  sensation 
of colours4 ,there is1 however1 very    
great diversity in the  manner of       
judging3 for so long as we simply judge 
that there is an  unknown something in  
objects 7that is1 in things such as they
 are1  from which the sensation reached 
us71 so far are we from falling  into   

error that1 on the contrary1 we thus    
rather provide against it1  for we are  
less apt to judge rashly of a thing     
which we observe we  do not know4 ,but  
when we think we perceive colours in    
objects1  although we are in reality    
ignorant of what we then denominate     
colour1 and are unable to conceive any  
resemblance between the  colour we      
suppose to be in objects1 and that of   
which we are  conscious in sensation1   
yet because we do not observe this1 or  
because there are in objects several    
properties1 as size1 figure1  number1   
etc41 which1 as we clearly know1 exist1 
or may exist in them  as they are       
perceived by our senses or conceived by 
our  understanding1 we easily glide into
 the error of holding that what  is     
called colour in objects is something   
entirely resembling the  colour we      
perceive1 and thereafter of supposing   
that we have a clear  perception of what
 is in no way perceived by us4          
,,lxxi4 ,that the chief cause of our    

errors is to be found in the  prejudices
 of our childhood4    ,and here we may  
notice the first and chief cause of our 
errors4 ,in  early life the mind was so 
closely bound to the body that it       
attended to nothing beyond the thoughts 
by which it perceived the  objects that 
made impression on the body2 nor as yet 
did it refer  these thoughts to anything
 existing beyond itself1 but simply felt
  pain when the body was hurt1 or       
pleasure when anything beneficial to    
the body occurred1 or if the body was so
 highly affected that it was  neither   
greatly benefited nor hurt1 the mind    
experienced the  sensations we call     
tastes1 smells1 sounds1 heat1 cold1     
light1  colours1 and the like1 which in 
truth are representative of nothing     
existing out of our mind1 and which vary
 according to the  diversities of the   
parts and modes in which the body is    
affected4  ,footnote3 which vary        
according to the diversities of the     
movements  that pass from all parts of  

our body to the part of the brain to    
which it 7the mind7 is closely joined   
and united4--,,french4 ,the  mind at the
 same time also perceived magnitudes1   
figures1 motions1  and the like1 which  
were not presented to it as sensations  
but as  things or the modes of things   
existing1 or at least capable of        
existing out of thought1 although it did
 not yet observe this  difference       
between these two kinds of perceptions4 
,and afterwards  when the machine of the
 body1 which has been so fabricated by  
nature  that it can of its own inherent 
power move itself in various ways1  by  
turning itself at random on every side1 
followed after what was  useful and     
avoided what was detrimental2 the mind1 
which was closely  connected with it1   
reflecting on the objects it pursued or 
avoided1  remarked1 for the first time1 
that they existed out of itself1 and    
not only attributed to them magnitudes1 
figures1 motions1 and the  like1 which  
it apprehended either as things or as   

the modes of  things1 but1 in addition1 
attributed to them tastes1 odours1 and  
the  other ideas of that sort1 the      
sensations of which were caused by      
itself2 ,footnote3 which it perceived on
 occasion of them 7i4e41  of external   
objects74--,,french4 and as it only     
considered other  objects in so far as  
they were useful to the body1 in which  
it was  immersed1 it judged that there  
was greater or less reality in each     
object1 according as the impressions it 
caused on the body were more  or less   
powerful4 ,hence arose the belief that  
there was more  substance or body in    
rocks and metals than in air or water1  
because  the mind perceived in them more
 hardness and weight4 ,moreover1 the    
air was thought to be merely nothing so 
long as we experienced no  agitation of 
it by the wind1 or did not feel it hot  
or cold4 ,and  because the stars gave   
hardly more light than the slender      
flames of  candles1 we supposed that    
each star was but of this size4 ,again1 

since the mind did not observe that the 
earth moved on its axis1 or  that its   
superficies was curved like that of a   
globe1 it was on that  account more     
ready to judge the earth immovable and  
its surface  flat4 ,and our mind has    
been imbued from our infancy with a     
thousand  other prejudices of the same  
sort which afterwards in our youth we   
forgot we had accepted without          
sufficient examination1 and admitted  as
 possessed of the highest truth and     
clearness1 as if they had been  known by
 means of our senses1 or implanted in us
 by nature4       ,,lxxii4 ,that the    
second cause of our errors is that we   
cannot forget  these prejudices4    ,and
 although now in our mature years1 when 
the mind1 being no longer  wholly       
subject to the body1 is not in the habit
 of referring all  things to it1 but    
also seeks to discover the truth of     
things  considered in themselves1 we    
observe the falsehood of a great many   
of the judgments we had before formed2  

yet we experience a  difficulty in      
expunging them from our memory1 and1 so 
long as they  remain there1 they give   
rise to various errors4 ,thus1 for      
example1  since from our earliest years 
we imagined the stars to be of very     
small size1 we find it highly difficult 
to rid ourselves of this  imagination1  
although assured by plain astronomical  
reasons that  they are of the           
greatest1--so prevailing is the power of
  preconceived opinion4       ,,lxxiii4 
,the third cause is1 that we become     
fatigued by attending to  those objects 
which are not present to the senses2 and
 that we are  thus accustomed to judge  
of these not from present perception but
  from pre-conceived opinion4           
,besides1 our mind cannot attend to any 
object without at length  experiencing  
some pain and fatigue2 and of all       
objects it has the  greatest difficulty 
in attending to those which are present 
neither  to the senses nor to the       
imagination3 whether for the reason that

  this is natural to it from its union  
with the body1 or because in  our early 
years1 being occupied merely with       
perceptions and  imaginations1 it has   
become more familiar with1 and acquired 
greater  facility in thinking in those  
modes than in any other4 ,hence it also 
happens that many are unable to conceive
 any substance except what  is          
imaginable and corporeal1 and even      
sensible4 ,for they are  ignorant of the
 circumstance1 that those objects alone 
are  imaginable which consist in        
extension1 motion1 and figure1 while    
there are many others besides these that
 are intelligible2 and they  persuade   
themselves that nothing can subsist but 
body1 and1 finally1  that there is no   
body which is not sensible4 ,and since  
in truth we  perceive no object such as 
it is by sense alone but only by our    
reason exercised upon sensible objects1 
as will hereafter be  clearly shown1 it 
thus happens that the majority during   
life  perceive nothing unless in a      

confused way4       ,,lxxiv4 ,the fourth
 source of our errors is1 that we attach
 our  thoughts to words which do not    
express them with accuracy4    ,finally1
 since for the use of speech we attach  
all our conceptions  to words by which  
to express them1 and commit to memory   
our thoughts  in connection with these  
terms1 and as we afterwards find it more
  easy to recall the words than the     
things signified by them1 we can        
scarcely conceive anything with such    
distinctness as to separate  entirely   
what we conceive from the words that    
were selected to  express it4 ,on this  
account the majority attend to words    
rather than  to things2 and thus very   
frequently assent to terms without      
attaching to them any meaning1 either   
because they think they once  understood
 them1 or imagine they received them    
from others by whom  they were correctly
 understood4 ,this1 however1 is not the 
place to  treat of this matter in       
detail1 seeing the nature of the human  

body  has not yet been expounded1 nor   
the existence even of body  established2
 enough1 nevertheless1 appears to have  
been said to  enable one to distinguish 
such of our conceptions as are clear and
  distinct from those that are obscure  
and confused4       ,,lxxv4 ,summary of 
what must be observed in order to       
philosophize  correctly4    ,wherefore  
if we would philosophize in earnest1 and
 give ourselves to  the search after all
 the truths we are capable of knowing1  
we must1  in the first place1 lay aside 
our prejudices2 in other words1 we  must
 take care scrupulously to withhold our 
assent from the opinions  we have       
formerly admitted1 until upon new       
examination we discover  that they are  
true4 ,we must1 in the next place1 make 
an orderly  review of the notions we    
have in our minds1 and hold as true all 
and  only those which we will clearly   
and distinctly apprehend4 ,in this  way 
we will observe1 first of all1 that we  
exist in so far as it is  our nature to 

think1 and at the same time that there  
is a ,god upon  whom we depend2 and     
after considering his attributes we will
 be able  to investigate the truth of   
all other things1 since ,god is the     
cause  of them4 ,besides the notions we 
have of ,god and of our mind1 we will   
likewise find that we possess the       
knowledge of many propositions  which   
are eternally true1 as1 for example1    
that nothing cannot be  the cause of    
anything1 etc4 ,we will farther discover
 in our minds  the knowledge of a       
corporeal or extended nature that may be
 moved1  divided1 etc41 and also of     
certain sensations that affect us1 as of
  pain1 colours1 tastes1 etc41 although 
we do not yet know the cause  of our    
being so affected2 and1 comparing what  
we have now learne'd1  by examining     
those things in their order1 with our   
former confused  knowledge of them1 we  
will acquire the habit of forming clear 
and  distinct conceptions of all the    
objects we are capable of knowing4  ,in 

these few precepts seem to me to be     
comprised the most general  and         
important principles of human knowledge4
       ,,lxxvi4 ,that we ought to prefer
 the ,divine authority to our           
perception2 ,footnote3                  
reasonings4--,,french4 but that1 apart  
from  things revealed1 we ought to      
assent to nothing that we do not        
clearly apprehend4    ,above all1 we    
must impress on our memory the          
infallible rule1 that  what ,god has    
revealed is incomparably more certain   
than anything  else2 and that1 we ought 
to submit our belief to the ,divine     
authority rather than to our own        
judgment1 even although perhaps the     
light of reason should1 with the        
greatest clearness and evidence1  appear
 to suggest to us something contrary to 
what is revealed4 ,but  in things       
regarding which there is no revelation1 
it is by no means  consistent with the  
character of a philosopher to accept as 
true  what he has not ascertained to be 

such1 and to trust more to the  senses1 
in other words1 to the inconsiderate    
judgments of childhood  than to the     
dictates of mature reason4              
,,part ,,ii4  ,,of ,,the ,,principles   
,,of ,,material ,,things4      ,i4 ,the 
grounds on which the existence of       
material things may be  known with      
certainty4    ,although we are all      
sufficiently persuaded of the existence 
of  material things1 yet1 since this was
 before called in question by  us1 and  
since we reckoned the persuasion of     
their existence as among  the prejudices
 of our childhood1 it is now necessary  
for us to  investigate the grounds on   
which this truth may be known with      
certainty4 ,in the first place1 then1 it
 cannot be doubted that every           
perception we have comes to us from some
 object different from our  mind2 for it
 is not in our power to cause ourselves 
to experience  one perception rather    
than another1 the perception being      
entirely  dependent on the object which 

affects our senses4 ,it may1 indeed1 be 
matter of inquiry whether that object be
 ,god1 or something different  from     
,god2 but because we perceive1 or       
rather1 stimulated by sense1  clearly   
and distinctly apprehend1 certain matter
 extended in length1  breadth1 and      
thickness1 the various parts of which   
have different  figures and motions1 and
 give rise to the sensation we have of  
colours1 smells1 pain1 etc41 ,god would1
 without question1 deserve to  be       
regarded as a deceiver1 if he directly  
and of himself presented  to our mind   
the idea of this extended matter1 or    
merely caused it to  be presented to us 
by some object which possessed neither  
extension1  figure1 nor motion4 ,for we 
clearly conceive this matter as entirely
  distinct from ,god1 and from          
ourselves1 or our mind2 and appear even 
clearly to discern that the idea of it  
is formed in us on occasion  of objects 
existing out of our minds1 to which it  
is in every  respect similar4 ,but since

 ,god cannot deceive us1 for this is    
repugnant to his nature1 as has been    
already remarked1 we must               
unhesitatingly conclude that there      
exists a certain object extended  in    
length1 breadth1 and thickness1 and     
possessing all those  properties which  
we clearly apprehend to belong to what  
is extended4  ,and this extended        
substance is what we call body or       
matter4       ,,ii4 ,how we likewise    
know that the human body is closely     
connected  with the mind4    ,we ought  
also to conclude that a certain body is 
more closely united  to our mind than   
any other1 because we clearly observe   
that pain and  other sensations affect  
us without our foreseeing them2 and     
these1  the mind is conscious1 do not   
arise from itself alone1 nor pertain  to
 it1 in so far as it is a thing which   
thinks1 but only in so far  as it is    
united to another thing extended and    
movable1 which is  called the human     
body4 ,but this is not the place to     

treat in detail  of this matter4        
,,iii4 ,that the perceptions of the     
senses do not teach us what is in       
reality in things1 but what is          
beneficial of hurtful to the  composite 
whole of mind and body4    ,it will be  
sufficient to remark that the           
perceptions of the senses  are merely to
 be referred to this intimate union of  
the human body  and mind1 and that they 
usually make us aware of what1 in       
external  objects1 may be useful or     
adverse to this union1 but do not       
present  to us these objects as they are
 in themselves1 unless occasionally  and
 by accident4 ,for1 after this          
observation1 we will without  difficulty
 lay aside the prejudices of the senses1
 and will have  recourse to our         
understanding alone on this question by 
reflecting  carefully on the ideas      
implanted in it by nature4       ,,iv4  
,that the nature of body consists not in
 weight hardness1 colour  and the like1 
but in extension alone4    ,in this way 

we will discern that the nature of      
matter or body1  considered in general1 
does not consist in its being hard1 or  
ponderous1 or coloured1 or that which   
affects our senses in any  other way1   
but simply in its being a substance     
extended in length1  breadth1 and depth4
 ,for with respect to hardness1 we know 
nothing of  it by sense farther than    
that the parts of hard bodies resist the
  motion of our hands on coming into    
contact with them2 but if every  time   
our hands moved towards any part1 all   
the bodies in that place  receded as    
quickly as our hands approached1 we     
should never feel  hardness2 and yet we 
have no reason to believe that bodies   
which  might thus recede would on this  
account lose that which makes them      
bodies4 ,the nature of body does not1   
therefore1 consist in hardness4  ,in the
 same way1 it may be shown that weight1 
colour1 and all the  other qualities of 
this sort1 which are perceived in       
corporeal  matter1 may be taken from it1

 itself meanwhile remaining entire3 it  
thus follows that the nature of body    
depends on none of these4       ,v4     
,that the truth regarding the nature of 
body is obscured by the  opinions       
respecting rarefaction and a vacuum with
 which we are pre-  occupied4    ,there 
still remain two causes to prevent its  
being fully admitted  that the true     
nature of body consists in extension    
alone4 ,the first  is the prevalent     
opinion1 that most bodies admit of being
 so  rarefied and condensed that1 when  
rarefied1 they have greater  extension  
than when condensed2 and some even have 
subtilized to such  a degree as to make 
a distinction between the substance of  
body and  its quantity1 and between     
quantity itself and extension4 ,the     
second  cause is this1 that where we    
conceive only extension in length1      
breadth1 and depth1 we are not in the   
habit of saying that body is  there1 but
 only space and further void space1     
which the generality  believe to be a   

mere negation4       ,,vi4 ,in what way 
rarefaction takes place4    ,but with   
regard to rarefaction and condensation1 
whoever gives his  attention to his own 
thoughts1 and admits nothing of which he
 is not  clearly conscious1 will not    
suppose that there is anything in those 
processes further than a change of      
figure in the body rarefied or          
condensed3 so that1 in other words1 rare
 bodies are those between  the parts of 
which there are numerous distances      
filled with other  bodies2 and dense    
bodies1 on the other hand1 those whose  
parts  approaching each other1 either   
diminish these distances or take them   
wholly away1 in the latter of which     
cases the body is rendered  absolutely  
dense4 ,the body1 however1 when         
condensed1 has not1  therefore1 less    
extension than when the parts embrace a 
greater  space1 owing to their removal  
from each other1 and their dispersion   
into branches4 ,for we ought not to     
attribute to it the extension of  the   

pores or distances which its parts do   
not occupy when it is  rarefied1 but to 
the other bodies that fill these        
interstices2 just  as when we see a     
sponge full of water or any other       
liquid1 we do not  suppose that each    
part of the sponge has on this account  
greater  extension than when compressed 
and dry1 but only that its pores are    
wider1 and therefore that the body is   
diffused over a larger space4           
,,vii4 ,that rarefaction cannot be      
intelligibly explained unless in  the   
way here proposed4    ,and indeed ,i am 
unable to discover the force of the     
reasons which  have induced some to say 
that rarefaction is the result of the   
augmentation of the quantity of body1   
rather than to explain it on  the       
principle exemplified in the case of a  
sponge4 ,for although when  air or water
 is rarefied we do not see any of the   
pores that are  rendered large1 or the  
new body that is added to occupy them1  
it is  yet less agreeable to reason to  

suppose something that is               
unintelligible for the purpose of giving
 a verbal and merely  apparent          
explanation of the rarefaction of       
bodies1 than to conclude1  because of   
their rarefaction1 that there are pores 
or distances  between the parts which   
are increased in size1 and filled with  
some  new body4 ,nor ought we to refrain
 from assenting to this  explanation1   
because we perceive this new body by    
none of our  senses1 for there is no    
reason which obliges us to believe that 
we  should perceive by our senses all   
the bodies in existence4 ,and we  see   
that it is very easy to explain         
rarefaction in this manner1 but         
impossible in any other2 for1 in fine1  
there would be1 as appears to  me1 a    
manifest contradiction in supposing that
 any body was  increased by a quantity  
or extension which it had not before1   
without the addition to it of a new     
extended substance1 in other  words1 of 
another body1 because it is impossible  

to conceive any  addition of extension  
or quantity to a thing without supposing
 the  addition of a substance having    
quantity or extension1 as will more     
clearly appear from what follows4       
,,viii4 ,that quantity and number differ
 only in thought 7,,ratione7  from that 
which has quantity and is numbered4     
,for quantity differs from extended     
substance1 and number from what  is     
numbered1 not in reality but merely in  
our thought2 so that1 for  example1 we  
may consider the whole nature of a      
corporeal substance  which is comprised 
in a space of ten feet1 although we do  
not attend  to this measure of ten feet1
 for the obvious reason that the thing  
conceived is of the same nature in any  
part of that space as in the  whole2    
and1 on the other hand1 we can conceive 
the number ten1 as  also a continuous   
quantity of ten feet1 without thinking  
of this  determinate substance1 because 
the concept of the number ten is        
manifestly the same whether we consider 

a number of ten feet or ten  of anything
 else2 and we can conceive a continuous 
quantity of ten  feet without thinking  
of this or that determinate substance1  
although we cannot conceive it without  
some extended substance of  which it is 
the quantity4 ,it is in reality1        
however1 impossible that  any1 even the 
least part1 of such quantity or         
extension1 can be  taken away1 without  
the retrenchment at the same time of as 
much of  the substance1 nor1 on the     
other hand1 can we lessen the substance1
  without at the same time taking as    
much from the quantity or  extension4   
,,ix4 ,that corporeal substance1 when   
distinguished from its quantity1  is    
confusedly conceived as something       
incorporeal4    ,although perhaps some  
express themselves otherwise on this    
matter1 ,i  am nevertheless convinced   
that they do not think differently from 
what ,i have now said3 for when they    
distinguish 7corporeal7  substance from 
extension or quantity1 they either mean 

nothing by  the word 7corporeal7        
substance1 or they form in their minds  
merely a  confused idea of incorporeal  
substance1 which they falsely attribute 
to corporeal1 and leave to extension the
 true idea of this corporeal  substance2
 which extension they call an accident1 
but with such  impropriety as to make it
 easy to discover that their words are  
not  in harmony with their thoughts4    
,x4 ,what space or internal place is4   
,space or internal place1 and the       
corporeal substance which is  comprised 
in it1 are not different in reality1 but
 merely in the  mode in which they are  
wont to be conceived by us4 ,for1 in    
truth1  the same extension in length1   
breadth1 and depth1 which constitutes   
space1 constitutes body2 and the        
difference between them lies only  in   
this1 that in body we consider extension
 as particular1 and  conceive it to     
change with the body2 whereas in space  
we attribute  to extension a generic    
unity1 so that after taking from a      

certain  space the body which occupied  
it1 we do not suppose that we have at   
the same time removed the extension of  
the space1 because it appears  to us    
that the same extension remains there so
 long as it is of the  same magnitude   
and figure1 and preserves the same      
situation in  respect to certain bodies 
around it1 by means of which we         
determine  this space4       ,,xi4 ,how 
space is not in reality different from  
corporeal substance4    ,and indeed it  
will be easy to discern that it is the  
same extension  which constitutes the   
nature of body as of space1 and that    
these two  things are mutually diverse  
only as the nature of the genus and     
species differs from that of the        
individual1 provided we reflect on  the 
idea we have of any body1 taking a stone
 for example1 and reject  all that is   
not essential to the nature of body4 ,in
 the first place1  then1 hardness may be
 rejected1 because if the stone were    
liquefied  or reduced to powder1 it     

would no longer possess hardness1 and   
yet  would not cease to be a body2      
colour also may be thrown out of        
account1 because we have frequently seen
 stones so transparent as to  have no   
colour2 again1 we may reject weight1    
because we have the  case of fire1      
which1 though very light1 is still a    
body2 and1  finally1 we may reject cold1
 heat1 and all the other qualities of   
this sort1 either because they are not  
considered as in the stone1  or because1
 with the change of these qualities1 the
 stone is not  supposed to have lost the
 nature of body4 ,after this examination
 we  will find that nothing remains in  
the idea of body1 except that it  is    
something extended in length1 breadth1  
and depth2 and this  something is       
comprised in our idea of space1 not only
 of that which  is full of body1 but    
even of what is called void space4      
,,xii4 ,how space differs from body in  
our mode of conceiving it4    ,there is1
 however1 some difference between them  

in the mode of  conception2 for if we   
remove a stone from the space or place  
in  which it was1 we conceive that its  
extension also is taken away1  because  
we regard this as particular1 and       
inseparable from the stone  itself3 but 
meanwhile we suppose that the same      
extension of place in  which this stone 
was remains1 although the place of the  
stone be  occupied by wood1 water1 air1 
or by any other body1 or be even        
supposed vacant1 because we now consider
 extension in general1 and  think that  
the same is common to stones1 wood1     
water1 air1 and other  bodies1 and even 
to a vacuum itself1 if there is any such
 thing1  provided it be of the same     
magnitude and figure as before1 and     
preserve the same situation among the   
external bodies which  determine this   
space4       ,,xiii4 ,what external     
place is4    ,the reason of which is1   
that the words place and space signify  
nothing really different from body which
 is said to be in place1 but  merely    

designate its magnitude1 figure1 and    
situation among other  bodies4 ,for it  
is necessary1 in order to determine this
 situation1  to regard certain other    
bodies which we consider as immovable2  
and1  according as we look to different 
bodies1 we may see that the same  thing 
at the same time does and does not      
change place4 ,for example1  when a     
vessel is being carried out to sea1 a   
person sitting at the  stern may be said
 to remain always in one place1 if we   
look to the  parts of the vessel1 since 
with respect to these he preserves the  
same situation2 and on the other hand1  
if regard be had to the  neighbouring   
shores1 the same person will seem to be 
perpetually  changing place1 seeing he  
is constantly receding from one shore   
and  approaching another4 ,and besides1 
if we suppose that the earth  moves1 and
 that it makes precisely as much way    
from west to east as  the vessel from   
east to west1 we will again say that the
 person at  the stern does not change   

his place1 because this place will be   
determined by certain immovable points  
which we imagine to be in the  heavens4 
,but if at length we are persuaded that 
there are no points  really immovable in
 the universe1 as will hereafter be     
shown to be  probable1 we will thence   
conclude that nothing has a permanent   
place  unless in so far as it is fixed  
by our thought4       ,,xiv4 ,wherein   
place and space differ4    ,the terms   
place and space1 however1 differ in     
signification1 because  place more      
expressly designates situation than     
magnitude or figure1  while1 on the     
other hand1 we think of the latter when 
we speak of  space4 ,for we frequently  
say that a thing succeeds to the place  
of  another1 although it be not exactly 
of the same magnitude or figure2  but we
 do not therefore admit that it occupies
 the same space as the  other2 and when 
the situation is changed we say that the
 place also  is changed1 although there 
are the same magnitude and figure as    

before3 so that when we say that a thing
 is in a particular place1  we mean     
merely that it is situated in a         
determinate way in respect  of certain  
other objects2 and when we add that it  
occupies such a  space or place1 we     
understand besides that it is of such   
determinate  magnitude and figure as    
exactly to fill this space4       ,,xv4 
,how external place is rightly taken for
 the superficies of the  surrounding    
body4    ,and thus we never indeed      
distinguish space from extension in     
length1  breadth1 and depth2 we         
sometimes1 however1 consider place as in
 the  thing placed1 and at other times  
as out of it4 ,internal place indeed    
differs in no way from space2 but       
external place may be taken for  the    
superficies that immediately surrounds  
the thing placed4 ,it  ought to be      
remarked that by superficies we do not  
here understand  any part of the        
surrounding body1 but only the boundary 
between the  surrounding and surrounded 

bodies1 which is nothing more than a    
mode2 or at least that we speak of      
superficies in general which is  no part
 of one body rather than another1 but is
 always considered  the same1 provided  
it retain the same magnitude and figure4
 ,for  although the whole surrounding   
body with its superficies were  changed1
 it would not be supposed that the body 
which was surrounded  by it had         
therefore changed its place1 if it      
meanwhile preserved the  same situation 
with respect to the other bodies that   
are regarded as  immovable4 ,thus1 if we
 suppose that a boat is carried in one  
direction by the current of a stream1   
and impelled by the wind in  the        
opposite with an equal force1 so that   
its situation with respect  to the banks
 is not changed1 we will readily admit  
that it remains  in the same place1     
although the whole superficies which    
surrounds it  is incessantly changing4  
,,xvi4 ,that a vacuum or space in which 
there is absolutely no body is          

repugnant to reason4    ,with regard to 
a vacuum1 in the philosophical sense of 
the term1  that is1 a space in which    
there is no substance1 it is evident    
that  such does not exist1 seeing the   
extension of space or internal place  is
 not different from that of body4 ,for  
since from this alone1 that  a body has 
extension in length1 breadth1 and depth1
 we have reason  to conclude that it is 
a substance1 it being absolutely        
contradictory that nothing should       
possess extension1 we ought to  form a  
similar inference regarding the space   
which is supposed void1  viz41 that     
since there is extension in it there is 
necessarily also  substance4            
,,xvii4 ,that a vacuum in the ordinary  
use of the term does not  exclude all   
body4    ,and1 in truth1 by the term    
vacuum in its common use1 we do not mean
  a place or space in which there is    
absolutely nothing1 but only a  place in
 which there is none of those things we 
presume ought to be  there4 ,thus1      

because a pitcher is made to hold water1
 it is said to  be empty when it is     
merely filled with air2 or if there are 
no fish  in a fish-pond1 we say there is
 nothing in it1 although it be full  of 
water2 thus a vessel is said to be      
empty1 when1 in place of the            
merchandise which it was designed to    
carry1 it is loaded with sand  only1 to 
enable it to resist the violence of the 
wind2 and1 finally1  it is in the same  
sense that we say space is void when it 
contains  nothing sensible1 although it 
contain created and self-subsisting     
matter2 for we are not in the habit of  
considering the bodies near  us1 unless 
in so far as they cause in our organs of
 sense1  impressions strong enough to   
enable us to perceive them4 ,and if1 in 
place of keeping in mind what ought to  
be understood by these terms  a vacuum  
and nothing1 we afterwards suppose that 
in the space we  called a vacuum1 there 
is not only no sensible object1 but no  
object  at all1 we will fall into the   

same error as if1 because a pitcher in  
which there is nothing but air1 is1 in  
common speech1 said to be  empty1 we    
were therefore to judge that the air    
contained in it is  not a substance     
7,,res ,,subsistens74       ,,xviii4    
,how the prejudice of an absolute vacuum
 is to be corrected4    ,we have almost 
all fallen into this error from the     
earliest age1  for1 observing that there
 is no necessary connection between a   
vessel and the body it contains1 we     
thought that ,god at least could  take  
from a vessel the body which occupied   
it1 without it being  necessary that any
 other should be put in the place of the
 one  removed4 ,but that we may be able 
now to correct this false opinion1  it  
is necessary to remark that there is in 
truth no connection  between the vessel 
and the particular body which it        
contains1 but  that there is an         
absolutely necessary connection between 
the concave  figure of the vessel and   
the extension considered generally which

  must be comprised in this cavity2 so  
that it is not more  contradictory to   
conceive a mountain without a valley    
than such a  cavity without the         
extension it contains1 or this extension
 apart  from an extended substance1 for1
 as we have often said1 of nothing      
there can be no extension4 ,and         
accordingly1 if it be asked what  would 
happen were ,god to remove from a vessel
 all the body contained  in it1 without 
permitting another body to occupy its   
place1 the  answer must be that the     
sides of the vessel would thus come into
  proximity with each other4 ,for two   
bodies must touch each other when  there
 is nothing between them1 and it is     
manifestly contradictory  for two bodies
 to be apart1 in other words1 that there
 should be a  distance between them1 and
 this distance yet be nothing2 for all  
distance is a mode of extension1 and    
cannot therefore exist without  an      
extended substance4       ,,xix4 ,that  
this confirms what was said of          

rarefaction4    ,after we have thus     
remarked that the nature of corporeal   
substance  consists only in its being an
 extended thing1 and that its extension 
is not different from that which we     
attribute to space1 however  empty1 it  
is easy to discover the impossibility of
 any one of its  parts in any way       
whatsoever occupying more space at one  
time than at  another1 and thus of being
 otherwise rarefied than in the way     
explained above2 and it is easy to      
perceive also that there cannot  be more
 matter or body in a vessel when it is  
filled with lead or  gold1 or any other 
body however heavy and hard1 than when  
it but  contains air and is supposed to 
be empty3 for the quantity of the  parts
 of which a body is composed does not   
depend on their weight or  hardness1 but
 only on the extension1 which is always 
equal in the  same vase4       ,,xx4    
,that from this the non-existence of    
atoms may likewise be  demonstrated4    
,we likewise discover that there cannot 

exist any atoms or parts of  matter that
 are of their own nature indivisible4   
,for however small  we suppose these    
parts to be1 yet because they are       
necessarily  extended1 we are always    
able in thought to divide any one of    
them  into two or more smaller parts1   
and may accordingly admit their         
divisibility4 ,for there is nothing we  
can divide in thought which we  do not  
thereby recognize to be divisible2 and1 
therefore1 were we to  judge it         
indivisible our judgment would not be in
 harmony with the  knowledge we have of 
the thing2 and although we should even  
suppose  that ,god had reduced any      
particle of matter to a smallness so    
extreme that it did not admit of being  
further divided1 it would  nevertheless 
be improperly styled indivisible1 for   
though ,god had  rendered the particle  
so small that it was not in the power of
 any  creature to divide it1 he could   
not however deprive himself of the      
ability to do so1 since it is absolutely

 impossible for him to  lessen his own  
omnipotence1 as was before observed4    
,wherefore1  absolutely speaking1 the   
smallest extended particle is always    
divisible1 since it is such of its very 
nature4       ,,xxi4 ,it is thus also   
demonstrated that the extension of the  
world  is indefinite4    ,we further    
discover that this world or the whole   
7universitas7 of  corporeal substance1  
is extended without limit1 for wherever 
we fix  a limit1 we still not only      
imagine beyond it spaces indefinitely   
extended1 but perceive these to be truly
 imaginable1 in other words1  to be in  
reality such as we imagine them2 so that
 they contain in  them corporeal        
substance indefinitely extended1 for1 as
 has been  already shown at length1 the 
idea of extension which we conceive in  
any space whatever is plainly identical 
with the idea of corporeal  substance4  
,,xxii4 ,it also follows that the matter
 of the heavens and earth is  the same1 
and that there cannot be a plurality of 

worlds4    ,and it may also be easily   
inferred from all this that the earth   
and  heavens are made of the same       
matter2 and that even although there    
were an infinity of worlds1 they would  
all be composed of this  matter2 from   
which it follows that a plurality of    
worlds is  impossible1 because we       
clearly conceive that the matter whose  
nature  consists only in its being an   
extended substance1 already wholly      
occupies all the imaginable spaces where
 these other worlds could  alone be1 and
 we cannot find in ourselves the idea of
 any other  matter4       ,,xxiii4 ,that
 all the variety of matter1 or the      
diversity of its  forms1 depends on     
motion4    ,there is therefore but one  
kind of matter in the whole universe1   
and  this we know only by its being     
extended4 ,all the properties we        
distinctly perceive to belong to it are 
reducible to its capacity of  being     
divided and moved according to its      
parts2 and accordingly it  is capable of

 all those affections which we perceive 
can arise from  the motion of its parts4
 ,for the partition of matter in thought
  makes no change in it2 but all        
variation of it1 or diversity of  form1 
depends on motion4 ,the philosophers    
even seem universally to  have observed 
this1 for they said that nature was the 
principle of  motion and rest1 and by   
nature they understood that by which all
  corporeal things become such as they  
are found in experience4       ,,xxiv4  
,what motion is1 taking the term in its 
common use4    ,but motion 7viz41 local1
 for ,i can conceive no other kind of   
motion1  and therefore ,i do not think  
we ought to suppose there is any other  
in nature71 in the ordinary sense of the
 term1 is nothing more than  the action 
by which a body passes from one place to
 another4 ,and  just as we have remarked
 above that the same thing may be said  
to  change and not to change place at   
the same time1 so also we may say  that 
the same thing is at the same time moved

 and not moved4 ,thus1  for example1 a  
person seated in a vessel which is      
setting sail1  thinks he is in motion if
 he look to the shore that he has left1 
and  consider it as fixed2 but not if he
 regard the ship itself1 among  the     
parts of which he preserves always the  
same situation4 ,moreover1  because we  
are accustomed to suppose that there is 
no motion without  action1 and that in  
rest there is the cessation of action1  
the  person thus seated is more properly
 said to be at rest than in  motion1    
seeing he is not conscious of being in  
action4       ,,xxv4 ,what motion is    
properly so called4    ,but if1 instead 
of occupying ourselves with that which  
has no  foundation1 unless in ordinary  
usage1 we desire to know what ought  to 
be understood by motion according to the
 truth of the thing1 we  may say1 in    
order to give it a determinate nature1  
that it is ,,the  ,,transporting ,,of   
,,one ,,part ,,of ,,matter ,,or ,,of    
,,one ,,body ,,from ,,the ,,vicinity    

,,of ,,those ,,bodies ,,that ,,are ,,in 
,,immediate ,,contact ,,with ,,it1 ,,or 
,,which ,,we  ,,regard ,,as ,,at ,,rest1
 to the vicinity of other bodies4 ,by a 
body as a  part of matter1 ,i understand
 all that which is transferred together1
  although it be perhaps composed of    
several parts1 which in  themselves have
 other motions2 and ,i say that it is   
the transporting  and not the force or  
action which transports1 with the view  
of  showing that motion is always in the
 movable thing1 not in that  which      
moves2 for it seems to me that we are   
not accustomed to  distinguish these two
 things with sufficient accuracy4       
,farther1 ,i  understand that it is a   
mode of the movable thing1 and not a    
substance1 just as figure is a property 
of the thing figured1 and  repose of    
that which is at rest4          ,,part  
,,iii4  ,,of ,,the ,,visible ,,world4   
,i4 ,that we cannot think too highly of 
the works of ,god4    ,having now       
ascertained certain principles of       

material things1 which  were sought1 not
 by the prejudices of the senses1 but by
 the light  of reason1 and which thus   
possess so great evidence that we cannot
  doubt of their truth1 it remains for  
us to consider whether from  these alone
 we can deduce the explication of all   
the phenomena of  nature4 ,we will      
commence with those phenomena that are  
of the  greatest generality1 and upon   
which the others depend1 as1 for        
example1 with the general structure of  
this whole visible world4 ,but  in order
 to our philosophizing aright regarding 
this1 two things are  first of all to be
 observed4 ,the first is1 that we should
 ever bear  in mind the infinity of the 
power and goodness of ,god1 that we may 
not fear falling into error by imagining
 his works to be too great1  beautiful1 
and perfect1 but that we may1 on the    
contrary1 take care  lest1 by supposing 
limits to them of which we have no      
certain  knowledge1 we appear to think  
less highly than we ought of the power  

of ,god4     ,,ii4 ,that we ought to    
beware lest1 in our presumption1 we     
imagine  that the ends which ,god       
proposed to himself in the creation of  
the  world are understood by us4    ,the
 second is1 that we should beware of    
presuming too highly of  ourselves1 as  
it seems we should do if we supposed    
certain limits to  the world1 without   
being assured of their existence either 
by  natural reasons or by divine        
revelation1 as if the power of our      
thought extended beyond what ,god has in
 reality made2 but likewise  still more 
if we persuaded ourselves that all      
things were created by  ,god for us     
only1 or if we merely supposed that we  
could comprehend  by the power of our   
intellect the ends which ,god proposed  
to himself  in creating the universe4   
,,iii4 ,in what sense it may be said    
that all things were created for  the   
sake of man4    ,for although1 as far as
 regards morals1 it may be a pious      
thought to  believe that ,god made all  

things for us1 seeing we may thus be    
incited to greater gratitude and love   
toward him2 and although it is  even in 
some sense true1 because there is no    
created thing of which  we cannot make  
some use1 if it be only that of         
exercising our mind  in considering it1 
and honouring ,god on account of it1 it 
is yet by  no means probable that all   
things were created for us in this way  
that ,god had no other end in their     
creation2 and this supposition  would be
 plainly ridiculous and inept in        
physical reasoning1 for we  do not doubt
 but that many things exist1 or formerly
 existed and  have now ceased to be1    
which were never seen or known by man1  
and  were never of use to him4          
,,part ,,iv4  ,,of ,,the ,,earth4       
,,clxxxviii4 ,of what is to be borrowed 
from disquisitions on animals  and man  
to advance the knowledge of material    
objects4    ,i should add nothing       
farther to this the ,fourth ,part of the
  ,principles of ,philosophy1 did ,i    

purpose carrying out my original  design
 of writing a ,fifth and ,sixth ,part1  
the one treating of things  possessed of
 life1 that is1 animals and plants1 and 
the other of  man4 ,but because ,i have 
not yet acquired sufficient knowledge of
 all  the matters of which ,i should    
desire to treat in these two last       
parts1 and do not know whether ,i shall 
ever have sufficient leisure  to finish 
them1 ,i will here subjoin a few things 
regarding the  objects of our senses1   
that ,i may not1 for the sake of the    
latter1  delay too long the publication 
of the former parts1 or of what may  be 
desiderated in them1 which ,i might have
 reserved for explanation  in those     
others3 for ,i have hitherto described  
this earth1 and  generally the whole    
visible world1 as if it were merely a   
machine in  which there was nothing at  
all to consider except the figures and  
motions of its parts1 whereas our senses
 present to us many other  things1 for  
example colours1 smells1 sounds1 and the

 like1 of which1  if ,i did not speak at
 all1 it would be thought ,i had omitted
 the  explication of the majority of the
 objects that are in nature4            
,,clxxxix4 ,what perception 7,,sensus7  
is1 and how we perceive4    ,we must    
know1 therefore1 that although the human
 soul is united to  the whole body1 it  
has1 nevertheless1 its principal seat in
 the  brain1 where alone it not only    
understands and imagines1 but also      
perceives2 and this by the medium of the
 nerves1 which are extended  like       
threads from the brain to all the other 
members1 with which  they are so        
connected that we can hardly touch any  
one of them  without moving the         
extremities of some of the nerves spread
 over it2  and this motion passes to the
 other extremities of those nerves      
which are collected in the brain round  
the seat of the soul1  ,footnote3 999999
 ,,footnote ,,not ,,visible ,,in ,,page 
,,image 7#ih1 ,text p #aie7  as ,i have 
already explained with sufficient       

minuteness in the fourth  chapter of the
 ,dioptrics4 ,but the movements which   
are thus excited  in the brain by the   
nerves variously affect the soul or     
mind1 which  is intimately conjoined    
with the brain1 according to the        
diversity  of the motions themselves4   
,and the diverse affections of the mind 
or  thoughts that immediately arise from
 these motions1 are called  perceptions 
of the senses 7,,sensuum                
,,perceptiones71 or1 as we commonly     
speak1 sensations 7,,sensus74           
,,cxc4 ,of the distinction of the       
senses2 and1 first1 of the internal1    
that is1 of the affections of the mind  
7passions71 and the natural  appetites4 
,the varieties of these sensations      
depend1 firstly1 on the diversity  of   
the nerves themselves1 and1 secondly1 of
 the movements that are  made in each   
nerve4 ,we have not1 however1 as many   
different senses  as there are nerves4  
,we can distinguish but seven principal 
classes  of nerves1 of which two belong 

to the internal1 and the other five  to 
the external senses4 ,the nerves which  
extend to the stomach1 the  oesophagus1 
the fauces1 and the other internal parts
 that are  subservient to our natural   
wants1 constitute one of our internal   
senses4 ,this is called the natural     
appetite 7,,appetitus ,,naturalis74     
,the other internal sense1 which        
embraces all the emotions               
7,,commotiones7 of the mind or passions1
 and affections1 as joy1  sadness1 love1
 hate1 and the like1 depends upon the   
nerves which  extend to the heart and   
the parts about the heart1 and are      
exceedingly small2 for1 by way of       
example1 when the blood happens to  be  
pure and well tempered1 so that it      
dilates in the heart more  readily and  
strongly than usual1 this so enlarges   
and moves the  small nerves scattered   
around the orifices1 that there is      
thence a  corresponding movement in the 
brain1 which affects the mind with a    
certain natural feeling of joy2 and as  

often as these same nerves  are moved in
 the same way1 although this is by other
 causes1 they  excite in our mind the   
same feeling 7sensus1 sentiment74 ,thus1
 the  imagination of the enjoyment of a 
good does not contain in itself  the    
feeling of joy1 but it causes the animal
 spirits to pass from  the brain to the 
muscles in which these nerves are       
inserted2 and  thus dilating the        
orifices of the heart1 it also causes   
these small  nerves to move in the way  
appointed by nature to afford the       
sensation of joy4 ,thus1 when we receive
 news1 the mind first of all  judges of 
it1 and if the news be good1 it rejoices
 with that  intellectual joy 7,,gaudium 
,,intellectuale7 which is independent of
 any  emotion 7,,commotio7 of the body1 
and which the ,stoics did not deny to   
their wise man although they supposed   
him exempt from all passion4  ,but as   
soon as this joy passes from the        
understanding to the  imagination1 the  
spirits flow from the brain to the      

muscles that are  about the heart1 and  
there excite the motion of the small    
nerves1 by  means of which another      
motion is caused in the brain1 which    
affects  the mind with the sensation of 
animal joy 7,,laetitia ,,animalis74 ,on 
the same principle1 when the blood is so
 thick that it flows but  sparingly into
 the ventricles of the heart1 and is not
 there  sufficiently dilated1 it excites
 in the same nerves a motion quite      
different from the preceding1 which1    
communicated to the brain1  gives to the
 mind the sensation of sadness1 although
 the mind itself  is perhaps ignorant of
 the cause of its sadness4 ,and all the 
other  causes which move these nerves in
 the same way may also give to the  mind
 the same sensation4 ,but the other     
movements of the same nerves  produce   
other effects1 as the feelings of love1 
hate1 fear1 anger1  etc41 as far as they
 are merely affections or passions of   
the mind2  in other words1 as far as    
they are confused thoughts which the    

mind  has not from itself alone1 but    
from its being closely joined to the    
body1 from which it receives            
impressions2 for there is the widest    
difference between these passions and   
the distinct thoughts which we  have of 
what ought to be loved1 or chosen1 or   
shunned1 etc41  although these are often
 enough found together4 ,the natural    
appetites1 as hunger1 thirst1 and the   
others1 are likewise  sensations excited
 in the mind by means of the nerves of  
the  stomach1 fauces1 and other parts1  
and are entirely different from  the    
will which we have to eat1 drink1 and to
 do all that which we  think proper for 
the conservation of our body2 but1      
because this  will or appetition almost 
always accompanies them1 they are       
therefore named appetites4       ,,cxci4
 ,of the external senses2 and first of  
touch4    ,we commonly reckon the       
external senses five in number1 because 
there  are as many different kinds of   
objects which move the nerves and  their

 organs1 and an equal number of kinds of
 confused thoughts  excited in the soul 
by these emotions4 ,in the first place1 
the  nerves terminating in the skin of  
the whole body can be touched  through  
this medium by any terrene objects      
whatever1 and moved by  these wholes1 in
 one way by their hardness1 in another  
by their  gravity1 in a third by their  
heat1 in a fourth by their humidity1    
etc4--and in as many diverse modes as   
they are either moved or  hindered from 
their ordinary motion1 to that extent   
are diverse  sensations excited in the  
mind1 from which a corresponding number 
of  tactile qualities derive their      
appellations4 ,besides this1 when  these
 nerves are moved a little more         
powerfully than usual1 but not          
nevertheless to the degree by which our 
body is in any way hurt1  there thus    
arises a sensation of titillation1 which
 is naturally  agreeable to the mind1   
because it testifies to it of the powers
 of  the body with which it is joined1  

in that the latter can suffer the       
action causing this titillation1 without
 being hurt4 ,but if this  action be    
strong enough to hurt our body in any   
way1 this gives to  our mind the        
sensation of pain4 ,and we thus see why 
corporeal  pleasure and pain1 although  
sensations of quite an opposite         
character1 arise nevertheless from      
causes nearly alike4       ,,cxcii4 ,of 
taste4    ,in the second place1 the     
other nerves scattered over the tongue  
and  the parts in its vicinity are      
diversely moved by the particles of  the
 same bodies1 separated from each other 
and floating in the  saliva in the      
mouth1 and thus cause sensations of     
diverse tastes  according to the        
diversity of figure in these particles4 
,footnote3  ,in the ,french this section
 begins1 ,taste1 after touch the        
grossest  of the senses1 etc4           
,,cxciii4 ,of smell4    ,thirdly1 two   
nerves also or appendages of the brain1 
for they do not  go beyond the limits of

 the skull1 are moved by the particles  
of  terrestrial bodies1 separated and   
flying in the air1 not indeed by  all   
particles indifferently1 but by those   
only that are sufficiently  subtle and  
penetrating to enter the pores of the   
bone we call the  spongy1 when drawn    
into the nostrils1 and thus to reach the
 nerves4  ,from the different motions of
 these particles arise the sensations   
of the different smells4       ,,cxciv4 
,of hearing4    ,fourthly1 there are two
 nerves within the ears1 so attached to 
three  small bones that are mutually    
sustaining1 and the first of which      
rests on the small membrane that covers 
the cavity we call the  tympanum of the 
ear1 that all the diverse vibrations    
which the  surrounding air communicates 
to this membrane are transmitted to the 
mind by these nerves1 and these         
vibrations give rise1 according to      
their diversity1 to the sensations of   
the different sounds4       ,,cxcv4 ,of 
sight4    ,finally1 the extremities of  

the optic nerves1 composing the coat in 
the eyes called the retina1 are not     
moved by the air nor by any  terrestrial
 object1 but only by the globules of the
 second element1  whence we have the    
sense of light and colours3 as ,i have  
already at  sufficient length explained 
in the ,dioptrics and treatise of       
,meteors4 ,footnote3 ,in the ,french    
this section begins1 ,finally1  sight is
 the most subtle of all the senses1 etc4
       ,,cxcvi4 ,that the soul perceives
 only in so far as it is in the  brain4 
,it is clearly established1 however1    
that the soul does not perceive  in so  
far as it is in each member of the body1
 but only in so far as  it is in the    
brain1 where the nerves by their        
movements convey to it  the diverse     
actions of the external objects that    
touch the parts of  the body in which   
they are inserted4 ,for1 in the first   
place1 there  are various maladies1     
which1 though they affect the brain     
alone1 yet  bring disorder upon1 or     

deprive us altogether of the use of1 our
  senses1 just as sleep1 which affects  
the brain only1 and yet takes  from us  
daily during a great part of our time   
the faculty of  perception1 which       
afterwards in our waking state is       
restored to us4  ,the second proof is1  
that though there be no disease in the  
brain1  or in the members in which the  
organs of the external senses are1  it  
is nevertheless sufficient to take away 
sensation from the part  of the body    
where the nerves terminate1 if only the 
movement of one  of the nerves that     
extend from the brain to these members  
be  obstructed in any part of the       
distance that is between the two4 ,and  
the last proof is1 that we sometimes    
feel pain as if in certain of  our      
members1 the cause of which1 however1 is
 not in these members  where it is felt1
 but somewhere nearer the brain1 through
 which the  nerves pass that give to the
 mind the sensation of it4 ,i could     
establish this fact by innumerable      

experiments2 ,i will here1  however1    
merely refer to one of them4 ,a girl    
suffering from a bad  ulcer in the hand1
 had her eyes bandaged whenever the     
surgeon came  to visit her1 not being   
able to bear the sight of the dressing  
of  the sore2 and1 the gangrene having  
spread1 after the expiry of a few  days 
the arm was amputated from the elbow    
without the girl's  knowledge2 linen    
cloths tied one above the other were    
substituted  in place of the part       
amputated1 so that she remained for some
 time  without knowing that the         
operation had been performed1 and       
meanwhile  she complained of feeling    
various pains1 sometimes in one finger  
of  the hand that was cut off1 and      
sometimes in another4 ,the only         
explanation of this is1 that the nerves 
which before stretched  downwards from  
the brain to the hand1 and then         
terminated in the arm  close to the     
elbow1 were there moved in the same way 
as they  required to be moved before in 

the hand for the purpose of  impressing 
on the mind residing in the brain the   
sensation of pain  in this or that      
finger4 ,and this clearly shows that the
 pain of the  hand is not felt by the   
mind in so far as it is in the hand1 but
 in  so far as it is in the brain4      
,,cxcvii4 ,that the nature of the mind  
is such that from the motion  alone of  
body the various sensations can be      
excited in it4    ,in the next place1 it
 can be proved that our mind is of such 
a  nature that the motions of the body  
alone are sufficient to excite  in it   
all sorts of thoughts1 without it being 
necessary that these  should in any way 
resemble the motions which give rise to 
them1 and  especially that these motions
 can excite in it those confused        
thoughts called sensations 7,,sensus1   
,,sensationes74 ,for we see that  words1
 whether uttered by the voice or merely 
written1 excite in our  minds all kinds 
of thoughts and emotions4 ,on the same  
paper1 with  the same pen and ink1 by   

merely moving the point of the pen over 
the  paper in a particular way1 we can  
trace letters that will raise in  the   
minds of our readers the thoughts of    
combats1 tempests1 or the  furies1 and  
the passions of indignation and sorrow2 
in place of  which1 if the pen be moved 
in another way hardly different from the
  former1 this slight change will cause 
thoughts widely different from  the     
above1 such as those of repose1 peace1  
pleasantness1 and the  quite opposite   
passions of love and joy4 ,some one will
 perhaps  object that writing and speech
 do not immediately excite in the mind  
any passions1 or imaginations of things 
different from the letters  and sounds1 
but afford simply the knowledge of      
these1 on occasion of  which the mind1  
understanding the signification of the  
words1  afterwards excites in itself the
 imaginations and passions that         
correspond to the words4 ,but what will 
be said of the sensations of  pain and  
titillation8 ,the motion merely of a    

sword cutting a part of  our skin causes
 pain1 but does not on that account make
 us aware of  the motion or figure of   
the sword4 ,and it is certain that this 
sensation of pain is not less different 
from the motion that causes  it1 or from
 that of the part of our body which the 
sword cuts1 than  are the sensations we 
have of colour1 sound1 odour1 or taste4 
,on  this ground we may conclude that   
our mind is of such a nature that  the  
motions alone of certain bodies can also
 easily excite in it all  the other     
sensations1 as the motion of a sword    
excites in it the  sensation of pain4   
,,cxcviii4 ,that by our senses we know  
nothing of external objects  beyond     
their figure or situation1 magnitude1   
and motion4    ,besides1 we observe no  
such difference between the nerves as to
 lead  us to judge that one set of them 
convey to the brain from the organs  of 
the external senses anything different  
from another1 or that  anything at all  
reaches the brain besides the local     

motion of the  nerves themselves4 ,and  
we see that local motion alone causes in
 us  not only the sensation of          
titillation and of pain1 but also of    
light  and sounds4 ,for if we receive a 
blow on the eye of sufficient force  to 
cause the vibration of the stroke to    
reach the retina1 we see  numerous      
sparks of fire1 which1 nevertheless1 are
 not out of our  eye2 and when we stop  
our ear with our finger1 we hear a      
humming  sound1 the cause of which can  
only proceed from the agitation of the  
air that is shut up within it4 ,finally1
 we frequently observe that  heat       
hardness1 weight1 and the other sensible
 qualities1 as far as  they are in      
objects1 and also the forms of those    
bodies that are  purely material1 as1   
for example1 the forms of fire1 are     
produced in  them by the motion of      
certain other bodies1 and that these in 
their  turn likewise produce other      
motions in other bodies4 ,and we can    
easily conceive how the motion of one   

body may be caused by that of  another1 
and diversified by the size1 figure1 and
 situation of its  parts1 but we are    
wholly unable to conceive how these same
 things  7viz41 size1 figure1 and       
motion71 can produce something else of a
  nature entirely different from        
themselves1 as1 for example1 those      
substantial forms and real qualities    
which many philosophers suppose  to be  
in bodies2 nor likewise can we conceive 
how these qualities or  forms possess   
force to cause motions in other bodies4 
,but since we  know1 from the nature of 
our soul1 that the diverse motions of   
body  are sufficient to produce in it   
all the sensations which it has1 and    
since we learn from experience that     
several of its sensations are in        
reality caused by such motions1 while we
 do not discover that  anything besides 
these motions ever passes from the      
organs of the  external senses to the   
brain1 we have reason to conclude that  
we in  no way likewise apprehend that in

 external objects1 which we call  light1
 colour1 smell1 taste1 sound1 heat or   
cold1 and the other  tactile qualities1 
or that which we call their substantial 
forms1  unless as the various           
dispositions of these objects which have
 the  power of moving our nerves in     
various ways4 ,footnote3 the diverse    
figures1 situations1 magnitudes1 and    
motions of their parts4--  ,french4     
,,cxcix4 ,that there is no phenomenon of
 nature whose explanation has  been     
omitted in this treatise4    ,and thus  
it may be gathered1 from an enumeration 
that is easily  made1 that there is no  
phenomenon of nature whose explanation  
has  been omitted in this treatise2 for 
beyond what is perceived by the  senses1
 there is nothing that can be considered
 a phenomenon of  nature4 ,but leaving  
out of account motion1 magnitude1       
figure1 and  the situation of the parts 
of each body1 which ,i have explained as
  they exist in body1 we perceive       
nothing out of us by our senses  except 

light1 colours1 smells1 tastes1 sounds1 
and the tactile  qualities2 and these ,i
 have recently shown to be nothing more1
 at  least so far as they are known to  
us1 than certain dispositions of  the   
objects1 consisting in magnitude1       
figure1 and motion4       ,,cc4 ,that   
this treatise contains no principles    
which are not  universally received2 and
 that this philosophy is not new1 but of
  all others the most ancient and       
common4    ,but ,i am desirous also that
 it should be observed that1 though ,i  
have here endeavoured to give an        
explanation of the whole nature of      
material things1 ,i have nevertheless   
made use of no principle which  was not 
received and approved by ,aristotle1 and
 by the other  philosophers of all ages2
 so that this philosophy1 so far from   
being  new1 is of all others the most   
ancient and common3 for ,i have in      
truth merely considered the figure1     
motion1 and magnitude of bodies1  and   
examined what must follow from their    

mutual concourse on the  principles of  
mechanics1 which are confirmed by       
certain and daily  experience4 ,but no  
one ever doubted that bodies are moved1 
and that  they are of various sizes and 
figures1 according to the diversity of  
which their motions also vary1 and that 
from mutual collision those  somewhat   
greater than others are divided into    
many smaller1 and thus  change figure4  
,we have experience of the truth of     
this1 not merely  by a single sense1 but
 by several1 as touch1 sight1 and       
hearing3 we  also distinctly imagine and
 understand it4 ,this cannot be said of 
any of the other things that fall under 
our senses1 as colours1  sounds1 and the
 like2 for each of these affects but one
 of our  senses1 and merely impresses   
upon our imagination a confused image   
of itself1 affording our understanding  
no distinct knowledge of what  it is4   
,,cci4 ,that sensible bodies are        
composed of insensible particles4       
,but ,i allow many particles in each    

body that are perceived by none  of our 
senses1 and this will not perhaps be    
approved of by those who  take the      
senses for the measure of the knowable4 
,we greatly wrong  human reason1        
however1 as appears to me1 if we suppose
 that it does  not go beyond the        
eye-sight2 for no one can doubt that    
there are  bodies so small as not to be 
perceptible by any of our senses1       
provided he only consider what is each  
moment added to those bodies  that are  
being increased little by little1 and   
what is taken from  those that are      
diminished in the same way4 ,a tree     
increases daily1  and it is impossible  
to conceive how it becomes greater than 
it was  before1 unless we at the same   
time conceive that some body is added   
to it4 ,but who ever observed by the    
senses those small bodies that  are in  
one day added to a tree while growing8  
,among the philosophers  at least1 those
 who hold that quantity is indefinitely 
divisible1  ought to admit that in the  

division the parts may become so small  
as  to be wholly imperceptible4 ,and    
indeed it ought not to be a matter  of  
surprise1 that we are unable to perceive
 very minute bodies2 for  the nerves    
that must be moved by objects to cause  
perception are not  themselves very     
minute1 but are like small cords1 being 
composed of  a quantity of smaller      
fibres1 and thus the most minute bodies 
are  not capable of moving them4 ,nor do
 ,i think that any one who makes  use of
 his reason will deny that we           
philosophize with much greater  truth   
when we judge of what takes place in    
those small bodies which  are           
imperceptible from their minuteness     
only1 after the analogy of  what we see 
occurring in those we do perceive1 and  
in this way  explain all that is in     
nature1 as ,i have essayed to do in this
  treatise1 than when we give an        
explanation of the same things by       
inventing ,i know not what novelties1   
that have no relation to the  things we 

actually perceive1 as first matter1     
substantial forms1  and all that grand  
array of qualities which many are in the
 habit of  supposing1 each of which is  
more difficult to comprehend than all   
that is professed to be explained by    
means of them4       ,,ccii4 ,that the  
philosophy of ,democritus is not less   
different from  ours than from the      
common4 ,footnote3 that of ,aristotle or
 the  others4--,french4    ,but it may  
be said that ,democritus also supposed  
certain corpuscles  that were of various
 figures1 sizes1 and motions1 from the  
heaping  together and mutual concourse  
of which all sensible bodies arose2     
and1 nevertheless1 his mode of          
philosophizing is commonly rejected  by 
all4 ,to this ,i reply that the         
philosophy of ,democritus was never     
rejected by any one1 because he allowed 
the existence of bodies  smaller than   
those we perceive1 and attributed to    
them diverse  sizes1 figures1 and       
motions1 for no one can doubt that there

 are in  reality such1 as we have       
already shown2 but it was rejected1 in  
the  first place1 because he supposed   
that these corpuscles were  indivisible1
 on which ground ,i also reject it2 in  
the second place1  because he imagined  
there was a vacuum about them1 which ,i 
show to  be impossible2 thirdly1 because
 he attributed gravity to these  bodies1
 of which ,i deny the existence in any  
body1 in so far as a  body is considered
 by itself1 because it is a quality that
 depends  on the relations of situation 
and motion which several bodies bear  to
 each other2 and1 finally1 because he   
has not explained in  particular how all
 things arose from the concourse of     
corpuscles  alone1 or1 if he gave this  
explanation with regard to a few of     
them1  his whole reasoning was far from 
being coherent1 or such as would        
warrant us in extending the same        
explanation to the whole of  nature4    
,this1 at least1 is the verdict we must 
give regarding his  philosophy1 if we   

may judge of his opinions from what has 
been  handed down to us in writing4 ,i  
leave it to others to determine  whether
 the philosophy ,i profess possesses a  
valid coherency1 and  whether on its    
principles we can make the requisite    
number of  deductions2 and1 inasmuch as 
the consideration of figure1 magnitude1 
and motion has been admitted by         
,aristotle and by all the others1 as    
well as by ,democritus1 and since ,i    
reject all that the latter has          
supposed1 with this single exception1   
while ,i reject generally all  that has 
been supposed by the others1 it is plain
 that this mode of  philosophizing has  
no more affinity with that of           
,democritus than of  any other          
particular sect4       ,,cciii4 ,how we 
may arrive at the knowledge of the      
figures1  magnitudes1 and motions of the
 insensible particles of bodies4        
,but1 since ,i assign determinate       
figures1 magnitudes1 and motions to  the
 insensible particles of bodies1 as if  

,i had seen them1 whereas ,i  admit that
 they do not fall under the senses1 some
 one will perhaps  demand how ,i have   
come by my knowledge of them4 ,to this  
,i reply1  that ,i first considered in  
general all the clear and distinct      
notions of material things that are to  
be found in our  understanding1 and     
that1 finding no others except those of 
figures1  magnitudes1 and motions1 and  
of the rules according to which these   
three things can be diversified by each 
other1 which rules are the  principles  
of geometry and mechanics1 ,i judged    
that all the  knowledge man can have of 
nature must of necessity be drawn from  
this source2 because all the other      
notions we have of sensible  things1 as 
confused and obscure1 can be of no avail
 in affording us  the knowledge of      
anything out of ourselves1 but must     
serve rather to  impede it4 ,thereupon1 
taking as my ground of inference the    
simplest  and best known of the         
principles that have been implanted in  

our  minds by nature1 ,i considered the 
chief differences that could  possibly  
subsist between the magnitudes1 and     
figures1 and situations  of bodies      
insensible on account of their smallness
 alone1 and what  sensible effects could
 be produced by their various modes of  
coming  into contact2 and afterwards1   
when ,i found like effects in the       
bodies that we perceive by our senses1  
,i judged that they could have  been    
thus produced1 especially since no other
 mode of explaining  them could be      
devised4 ,and in this matter the example
 of several  bodies made by art was of  
great service to me3 for ,i recognize no
  difference between these and natural  
bodies beyond this1 that the  effects of
 machines depend for the most part on   
the agency of  certain instruments1     
which1 as they must bear some proportion
 to the  hands of those who make them1  
are always so large that their figures  
and motions can be seen2 in place of    
which1 the effects of natural  bodies   

almost always depend upon certain organs
 so minute as to  escape our senses4    
,and it is certain that all the rules of
 mechanics  belong also to physics1 of  
which it is a part or species1 so that  
all that is artificial is withal        
natural3 for it is not less  natural for
 a clock1 made of the requisite number  
of wheels1 to mark  the hours1 than for 
a tree1 which has sprung from this or   
that seed1  to produce the fruit        
peculiar to it4 ,accordingly1 just as   
those who  are familiar with automata1  
when they are informed of the use of a  
machine1 and see some of its parts1     
easily infer from these the way  in     
which the others1 that are not seen by  
them1 are made2 so from  considering the
 sensible effects and parts of natural  
bodies1 ,i have  essayed to determine   
the character of their causes and       
insensible  parts4       ,,cciv4 ,that1 
touching the things which our senses do 
not perceive1  it is sufficient to      
explain how they can be1 and that this  

is all  that ,aristotle has essayed4    
,but here some one will perhaps reply1  
that although ,i have supposed  causes  
which could produce all natural objects1
 we ought not on this  account to       
conclude that they were produced by     
these causes2 for1  just as the same    
artisan can make two clocks1 which1     
though they  both equally well indicate 
the time1 and are not different in      
outward appearance1 have nevertheless   
nothing resembling in the  composition  
of their wheels2 so doubtless the       
,supreme ,maker of  things has an       
infinity of diverse means at his        
disposal1 by each of  which he could    
have made all the things of this world  
to appear as  we see them1 without it   
being possible for the human mind to    
know  which of all these means he chose 
to employ4 ,i most freely concede  this2
 and ,i believe that ,i have done all   
that was required1 if the  causes ,i    
have assigned are such that their       
effects accurately  correspond to all   

the phenomena of nature1 without        
determining  whether it is by these or  
by others that they are actually        
produced4  ,and it will be sufficient   
for the use of life to know the causes  
thus imagined1 for medicine1 mechanics1 
and in general all the arts  to which   
the knowledge of physics is of service1 
have for their end  only those effects  
that are sensible1 and that are         
accordingly to be  reckoned among the   
phenomena of nature4 ,footnote3 have for
 their  end only to apply certain       
sensible bodies to each other in such a 
way that1 in the course of natural      
causes1 certain sensible effects  may be
 produced2 and we will be able to       
accomplish this quite as  well by       
considering the series of certain causes
 thus imagined1  although false1 as if  
they were the true1 since this series is
  supposed similar as far as regards    
sensible effects4-,french4    ,and lest 
it should be supposed that ,aristotle   
did1 or professed to  do1 anything more 

than this1 it ought to be remembered    
that he  himself expressly says1 at the 
commencement of the seventh chapter  of 
the first book of the ,meteorologies1   
that1 with regard to things  which are  
not manifest to the senses1 he thinks to
 adduce sufficient  reasons and         
demonstrations of them1 if he only shows
 that they may  be such as he explains  
them4 ,footnote3 words in ,greek        
,,ccv4 ,that nevertheless there is a    
moral certainty that all the  things of 
this world are such as has been here    
shown they may be4    ,but nevertheless1
 that ,i may not wrong the truth by     
supposing it  less certain than it is1  
,i will here distinguish two kinds of   
certitude4 ,the first is called moral1  
that is1 a certainty  sufficient for the
 conduct of life1 though1 if we look to 
the  absolute power of ,god1 what is    
morally certain may be false4 ,thus1    
those who never visited ,rome do not    
doubt that it is a city of  ,italy1     
though it might be that all from whom   

they got their  information were        
deceived4 ,again1 if any one1 wishing to
 decipher a  letter written in ,latin   
characters that are not placed in       
regular  order1 bethinks himself of     
reading a ,b wherever an ,a is found1   
and a  ,c wherever there is a ,b1 and   
thus of substituting in place of each   
letter the one which follows it in the  
order of the alphabet1 and if  by this  
means he finds that there are certain   
,latin words composed  of these1 he will
 not doubt that the true meaning of the 
writing is  contained in these words1   
although he may discover this only by   
conjecture1 and although it is possible 
that the writer of it did  not arrange  
the letters on this principle of        
alphabetical order1 but  on some other1 
and thus concealed another meaning in   
it3 for this is  so improbable          
especially when the cipher contains a   
number of  words as to seem incredible4 
,but they who observe how many things   
regarding the magnet1 fire1 and the     

fabric of the whole world1 are  here    
deduced from a very small number of     
principles1 though they  deemed that ,i 
had taken them up at random and without 
grounds1 will  yet perhaps acknowledge  
that it could hardly happen that so many
  things should cohere if these         
principles were false4       ,,ccvi4    
,that we possess even more than a moral 
certainty of it4    ,besides1 there are 
some1 even among natural1 things which  
we judge  to be absolutely certain4     
,absolute certainty arises when we judge
  that it is impossible a thing can be  
otherwise than as we think it4  ,this   
certainty is founded on the metaphysical
 ground1 that1 as ,god  is supremely    
good and the source of all truth1 the   
faculty of  distinguishing truth from   
error which he gave us1 cannot be       
fallacious so long as we use it aright1 
and distinctly perceive  anything by it4
 ,of this character are the             
demonstrations of  mathematics1 the     
knowledge that material things exist1   

and the clear  reasonings that are      
formed regarding them4 ,the results ,i  
have given  in this treatise will       
perhaps be admitted to a place in the   
class of  truths that are absolutely    
certain1 if it be considered that they  
are deduced in a continuous series from 
the first and most  elementary          
principles of human knowledge2          
especially if it be  sufficiently       
understood that we can perceive no      
external objects  unless some local     
motion be caused by them in our nerves1 
and that  such motion cannot be caused  
by the fixed stars1 owing to their      
great distance from us1 unless a motion 
be also produced in them and  in the    
whole heavens lying between them and us3
 for these points  being admitted1 all  
the others1 at least the more general   
doctrines  which ,i have advanced       
regarding the world or earth e4 g41 the 
fluidity of the heavens1 ,part ,,iii41  
,section ,,xlvi41 will appear to  be    
almost the only possible explanations of

 the phenomena they  present4           
,,ccvii4 ,that1 however1 ,i submit all  
my opinions to the authority of  the    
church4    ,nevertheless1 lest ,i should
 presume too far1 ,i affirm nothing1 but
  submit all these my opinions to the   
authority of the church and the         
judgment of the more sage2 and ,i desire
 no one to believe anything ,i  may have
 said1 unless he is constrained to admit
 it by the force and  evidence of       
reason4