,a ,discourse   ,,of ,a   ,,method      
,for the well guiding of   ,,reason1    
,and the ,discovery of ,truth   ,in the 
,,sciences4    ,illustration            
,,london1   ,printed by ,thomas         
,newcombe4   ,,mdcxlix4     ,to the     
,understanding ,,reader4  ,the ,great   
,,descartes 7who may justly challenge   
the first place amongst the             
,philosophers of this ,age7 is the      
,author of this ,discourse2 which in the
 ,originall was so well known1 ,that it 
could be no mans but his own1 that his  
,name was not affix'd to it3 ,i need say
 no more either of ,him or ,it2 ,he is  
best made known by ,himself1 and his    
,writings want nothing but thy reading  
to commend them4 ,but as those who      
cannot compasse the ,originals of       
,titian and ,van-,dyke1 are glad to     
adorne their ,cabinets with the ,copies 
of them2 ,so be pleased favourably to   
receive his ,picture from my hand1      
copied after his own ,designe3 ,you may 
therein observe the lines of a well     

form'd ,minde1 ,the hightnings of       
,truth1 ,the sweetnings and shadowings  
of ,probabilities1 ,the falls and depths
 of ,falshood2 all which serve to       
perfect this ,masterpiece4 ,now although
 my after-draught be rude and           
unpolished1 and that perhaps ,i have    
touch'd it too boldly1 ,the thoughts of 
so clear a ,minde1 being so extremely   
fine1 ,that as the choisest words are   
too grosse1 and fall short fully to     
expresse such sublime ,notions2 ,so it  
cannot be1 but being transvested1 it    
must necessarily lose very much of its  
native ,lustre3 ,nay1 although ,i am    
conscious 7notwithstanding the care ,i  
have taken neither to wrong the         
,authours ,sense1 nor offend the        
,readers ,ear7 of many escapes which ,i 
have made2 yet ,i so little doubt of    
being excused1 ,that ,i am confident1 my
 endeavour cannot but be gratefull to   
all ,lovers of ,learning2 for whose     
benefit ,i have ,englished1 and to whom 
,i addresse this ,essay1 which contains 

a ,method1 by the ,rules whereof we may 
,shape our better part1 ,rectifie our   
,reason1 ,form our ,manners and ,square 
our ,actions1 ,adorn our ,mindes1 and   
making a diligent ,enquiry into ,nature1
 wee may attain to the ,knowledge of the
 ,truth1 which is the most desirable    
union in the ,world4  ,our ,authour also
 invites all letterd men to his         
assistance in the prosecution of this   
,search2 ,that for the good of          
,mankinde1 ,they would practise and     
communicate ,experiments1 for the use of
 all those who labour for the perfection
 of ,arts and ,sciences3 ,every man now 
being obliged to the furtherance of so  
beneficiall an ,undertaking1 ,i could   
not but lend my hand to open the        
,curtain1 and discover this ,new ,model 
of ,philosophy2 which ,i now publish1   
neither to humour the present1 nor      
disgust former times2 but rather that it
 may serve for an innocent              
,divertisement to those1 who would      
rather ,reform themselves1 then the rest

 of the world2 and who1 having the same 
seeds and grounds1 and knowing ,that    
there is nothing ,new under the ,sun2   
,that ,novelty is but ,oblivion1 and    
that ,knowledge is but ,remembrance1    
will study to finde out in themselves1  
and restore to ,posterity those lost    
,arts1 which render ,antiquity so       
venerable2 and strive 7if it be         
possible7 to go beyond them in other    
things1 as well as ,time3 ,who minde not
 those things which are above1 beyond1  
or without them2 but would rather limit 
their desires by their power1 then      
change the ,course of ,nature2 ,who seek
 the knowledge1 and labour for the      
,conquest of themselves2 ,who have      
,vertue enough to make their own        
,fortune2 ,and who prefer the ,culture  
of the ,minde before the ,adorning of   
the ,body2 ,to such as these ,i present 
this ,discourse 7whose pardon ,i beg1   
for having so long detain'd them from so
 desirable a ,conversation27 and        
conclude with this ,advice of the       

,divine ,plato3      ,cogita in te1     
praeter ,animum1 nihil esse mirabile4   
,a ,,discourse ,,of ,a ,,method1 ,for   
the wel-guiding of ,reason2 ,,and ,the  
discovery of ,truth in the ,,sciences4  
,if this ,discourse seem too long to be 
read at once1 it may be divided into six
 parts4 ,in the first1 are divers       
,considerations touching the ,sciences4 
,in the second1 the principall ,rules of
 that ,method which the ,author hath    
studyed4 ,in the third1 some of those in
 morality1 which he hath drawn from this
 ,method4 ,in the fourth1 the reasons   
whereby the existence of ,god and of the
 humane ,soul is proved2 which are the  
grounds of his ,metaphysicks4 ,in the   
fift1 the order of these ,physicall     
questions1 which he hath examined1 and  
particularly the explication of the     
hearts motion2 with some other          
difficulties relating to ,physick2 as   
also the difference between our ,souls  
and those of beasts4 ,in the last1 what 
he conceives requisit to make a further 

inquiry into ,nature1 then hath hitherto
 been made4 ,and what reasons induc'd   
him to write4     ,,part4 ,i4   ,right  
understanding is the most equally       
divided thing in the ,world2 for every  
one beleevs himself so well stor'd with 
it1 that even those who in all other    
things are the hardest to be pleas'd1   
seldom desire more of it then they have2
 wherein it is not likely that all ,men 
are deceived3 ,but it rather witnesseth1
 ,that the faculty of right-judging and 
distinguishing truth from falshood      
7which is properly call'd1              
,understanding or ,reason7 is naturally 
equal in all ,men4 ,and as the diversity
 of our ,opinions1 is not1 because some 
are more reasonable then others2 but    
only that we direct our thoughts several
 ways1 neither do we consider the same  
things4 ,for 'tis not enough to have    
good faculties1 but the principal is1 to
 apply them well4 ,the greatest ,souls  
are as capable of the greatest ,vices1  
as of the most eminent ,vertues3 ,and   

those who move but very slowly1 may     
advance much farther1 if they always    
follow the right way2 then those who run
 and straggle from it4  ,for my part1 ,i
 never presum'd that my ,minde was more 
perfect in any thing then an ordinary   
,mans2 nay1 ,i have often wish'd to have
 had my thoughts as quick1 my           
imagination as clear and distinct1 and  
my memory as large and as ready as some 
other ,men have had4 ,and ,i know no    
,qualities which serve more then those  
to the perfection of the ,minde2 for as 
for ,reason or ,understanding1 forasmuch
 as it is the only thing which makes us 
,men1 and distinguisheth us from beasts1
 ,i will beleeve it to be entire in     
every ,one1 and follow herein the common
 opinion of the ,philosophers1 who say1 
,that there is only more or less among  
the ,accidents1 and not amongst the     
,forms or nature of the ,individuals of 
one species4  ,but ,i shall not stick to
 say1 ,that ,i beleeve my self very     
happy1 in having encountred from my     

youth with certain ways which have led  
me to considerations and ,maximes1 from 
which ,i have found a ,method2 whereby  
methinks1 ,i have the means by degrees  
to augment my knowledg1 and by little   
and little to raise it up to the highest
 pitch1 whereto the meaness of my       
capacity1  the short course of my life  
can permit it to attain4 ,for ,i have   
already reaped such fruits from it1 that
 although in the judgment ,i make of my 
self1 ,i endevour always rather to      
incline to mistrust1 then to            
presumption4 ,and looking on the divers 
actions and undertakings of all ,men1   
with the eye of a ,philosopher1 there is
 almost none which to me seems not vain 
and useless4 ,yet ,i am extremely       
satisfied with the ,progress1 which 7as 
it seems to me7 ,i have already made in 
the search of ,truth1 and do conceive   
such hopes for the future1 ,that if     
among the employments of ,men1 purely   
,men1 there is any solidly good1 and of 
importance1 ,i dare beleeve it is that  

which ,i have chosen3 ,yet it may be    
that ,i deceive my self1 and perhaps it 
is but a little ,copper and ,glass which
 ,i take for ,gold and ,diamonds4 ,i    
know how subject we are to mistake in   
those things which concern us1 and how  
jealous we ought to be of the judgment  
of our friends1 when it is in our favor4
 ,but ,i should willingly in this       
,discourse1 trace out unto you the ways 
which ,i have followed1 and represent   
therein my life1 as in a ,picture1 to   
the end1 that every one may judge       
thereof2 and that learning from common  
,fame1 what mens opinions are of it1 ,i 
may finde a new means of instructing my 
self2 which ,i shall add to those which 
,i customarily make use of4  ,neither is
 it my design to teach a ,method which  
every ,man ought to follow1 for the good
 conduct of his reason2 but only to shew
 after what manner ,i have endevoured to
 order mine own4 ,those who undertake to
 give precepts1 ought to esteem         
themselves more able1 then those to whom

 they give them1 and are blame-worthy1  
if they fail in the least4 ,but         
proposing this but as a ,history1 or if 
you will have it so1 but as a ,fable2   
wherein amongst other examples1 which   
may be imitated1 we may perhaps find    
divers others which we may have reason  
to decline3 ,i hope it will be          
profitable to some1 without being       
hurtfull to any2 and that the liberty ,i
 take will be gratefull to all4  ,i have
 been bred up to ,letters from mine     
infancy2  because ,i was perswaded1 that
 by their means a man might acquire a   
clear and certain knowledg of all that's
 usefull for this life1 ,i was extremely
 desirous to learn them3 ,but as soon as
 ,i had finish'd all the course of my   
,studies1 at the end whereof ,men are   
usually receiv'd amongst the rank of the
 learned4 ,i wholly changed my opinion1 
for ,i found my self intangled in so    
many doubts and errors1 that me thought 
,i had made no other profit in seeking  
to instruct my self1 but that ,i had the

 more discovered mine own ignorance4    
,yet ,i was in one of the most famous   
,schools in ,europe2 where ,i thought1  
if there were any on earth1 there ought 
to have been learned ,men4 ,i had learnt
 all what others had learnt2 even       
unsatisfied with the ,sciences which    
were taught us1 ,i had read over all    
,books 7which ,i could possibly procure7
 treating of such as are held to be the 
rarest and the most curious4 ,withall1  
,i knew the judgment others made of me2 
and ,i perceiv'd that ,i was no less    
esteem'd then my fellow ,students1      
although there were some amongst them   
that were destin'd to fill our ,masters 
rooms4 ,and in fine1 our age seem'd to  
me as flourishing and as fertile of good
 ,wits1 as any of the preceding1 which  
made me take the liberty to judg of all 
other men by my self1 and to think1     
,that there was no such learning in the 
world1 as formerly ,i had been made     
beleeve4  ,yet did ,i continue the      
esteem ,i had of those exercises which  

are the employments of the ,schools3 ,i 
knew that ,languages which are there    
learnt1 are necessary for the           
understanding of ancient ,writers1 ,that
 the quaintness of ,fables awakens the  
,minde2 ,that the memorable actions in  
,history raise it up1 and that being    
read with discretion1 they help to form 
the judgment4 ,that the reading of good 
books1 is like the conversation with the
 honestest persons of the past age1 who 
were the ,authors of them1 and even a   
studyed conversation1 wherein they      
discover to us the best only of their   
thoughts4 ,that eloquence hath forces   
beauties which are incomparable4 ,that  
,poetry hath delicacies and sweets      
extremly ravishing2 ,that the           
,mathematicks hath most subtile         
inventions1 which very much conduce     
aswel to content the curious1 as to     
facilitate all arts1 and to lessen the  
labour of ,men3 ,that those writings    
which treat of manners contain divers   
instructions1 and exhortations to       

vertue1 which are very usefull4 ,that   
,theology teacheth the way to heaven2   
,that ,philosophy affords us the means  
to speake of all things with            
probability1 and makes her self admir'd1
 by the least knowing ,men4 ,that ,law1 
,physick and other sciences bring honor 
and riches to those who practice them2  
,finally that its good to have examin'd 
them all even the falsest and the most  
superstitious1 that we may discover     
their just value1 and preserve our      
selves from their cheats4  ,but ,i      
thought ,i had spent time enough in the 
languages1 and even also in the lecture 
of ancient books1 their histories and   
their fables4 ,for 'tis even the same   
thing to converse with those of former  
ages1 as to travel4 ,its good to know   
something of the manners of severall    
,nations1 that we may not think that all
 things against our ,mode are ridiculous
 or unreasonable1 as those are wont to  
do1 who have seen ,nothing4 ,but when we
 employ too long time in travell1 we at 

last become strangers to our own        
,country1 and when we are too curious of
 those things1 which we practised in    
former times1 we commonly remain        
ignorant of those which are now in use4 
,besides1 ,fables make us imagine divers
 events possible1 which are not so3 ,and
 that even the most faithfull           
,histories1 if they neither change or   
augment the value of things1 to render  
them the more worthy to be read1 at     
least1 they always omit the basest and  
less remarkable circumstances2 whence it
 is1 that the rest seems not as it is2  
and that those who form their ,manners  
by the examples they thence derive1 are 
subject to fall into the extravagancies 
of the ,paladins of our ,romances1 and  
to conceive designes beyond their       
abilities4  ,i highly priz'd ,eloquence1
 and was in love with ,poetry2 but ,i   
esteem'd both the one and the other1    
rather gifts of the ,minde1 then the    
fruits of study4 ,those who have the    
strongest reasoning faculties1 and who  

best digest their thoughts1 to render   
them the more clear and intelligible1   
may always the better perswade what they
 propose1 although they should speak but
 a corrupt dialect1 and had never learnt
 ,rhetorick3 ,and those whose inventions
 are most pleasing1 and can express them
 with most ornament and sweetness1 will 
still be the best ,poets2 although      
ignorant of the ,art of ,poetry4        
,beyond all1 ,i was most pleas'd with   
the ,mathematicks1 for the certainty and
 evidence of the reasons thereof2 but ,i
 did not yet observe their true use1 and
 thinking that it served only for       
,mechanick ,arts2 ,i wondred1 that since
 the grounds thereof were so firm and   
solid1 that nothing more sublime had    
been built thereon4 ,as on the contrary1
 ,i compar'd the writings of the        
,ancient heathen which treated of       
,manner1 to most proud and stately      
,palaces which were built only on sand  
and mire1 they raise the vertues very   
high1 and make them appear estimable    

above all the things in the world2 but  
they doe not sufficiently instruct us in
 the knowledg of them1 and often what   
they call by that fair ,name1 is but a  
stupidness1 or an act of pride1 or of   
despair1 or a paricide4  ,i reverenc'd  
our ,theology1 and pretended to heaven  
as much as any2 ,but having learnt as a 
most certain ,truth1 that the way to it1
 is no less open to the most ignorant1  
then to the most learned2 and that those
 revealed truths which led thither1 were
 beyond our understanding1 ,i durst not 
submit to the weakness of my            
ratiocination4 ,and ,i thought1 that to 
undertake to examine them1 and to       
succeed in it1 requir'd some            
extraordinary assistance from heaven1   
and somewhat more then ,man4 ,i shall   
say nothing of ,philosophy1 but that    
seeing it hath been cultivated by the   
most excellent wits1 which have liv'd   
these many ages1 and that yet there is  
nothing which is undisputed1 and by     
consequence1 which is not doubtfull4 ,i 

could not presume so far1 as to hope to 
succeed better then others4 ,and        
considering how many different opinions 
there may be on the same thing1         
maintain'd by learned ,men1 and yet that
 there never can be but one only ,truth1
 ,i reputed almost all false1 which had 
no more then probability in it4  ,as for
 other ,sciences1 since they borrow     
their ,principles from ,philosophy1 ,i  
judg'd that nothing which was solid     
could be built upon such unsound        
foundations2 and neither honour nor     
wealth were sufficient to invite me to  
the study of them4 ,for 7,i thank ,god7 
,i found not my self in a condition     
which obliged me to make a ,trade of    
,letters for the relief of my fortune4  
,and although ,i made it not my         
profession to despise glory with the    
,cynick2 yet did ,i little value that   
which ,i could not acquire but by false 
pretences4 ,and lastly1 for             
unwarrantable ,studies1 ,i thought ,i   
already too well understood what they   

were1 to be any more subject to be      
deceived1 either by the promises of an  
,alchymist1 or by the predictions of an 
,astrologer1 or by the impostures of a  
,magician1 or by the artifice or brags  
of those who profess to know more then  
they do4  ,by reason whereof1 as soon as
 my years freed me from the subjection  
of my ,tutors1 ,i wholly gave over the  
study of ,letters1 and resolving to seek
 no other knowledge but what ,i could   
finde in my self1 or in the great book  
of the ,world1 ,i imployed the rest of  
my youth in ,travell1 to see ,courts and
 ,armies1 to frequent people of severall
 humors and conditions1 to gain         
experience1 to hazard my self in those  
encounters of fortune which should      
occurr2 and every-where to make such a  
reflection on those things which        
presented themselves to me1 that ,i     
might draw profit from them4 ,for 7me   
thought7 ,i could meet with far more    
truth in the discourses which every man 
makes touching those affairs which      

concern him1 whose event would quickly  
condemn him1 if he had judg'd amisse2   
then amongst those which letter'd ,men  
make in their closets touching          
speculations1 which produce no effect1  
and are of no consequence to them1 but  
that perhaps they may gain so much the  
more vanity1 as they are farther        
different from the common understanding3
 ,forasmuch as he must have imployed the
 more wit and subtilty in endeavouring  
to render them probable4 ,and ,i had    
always an extreme desire to learn to    
distinguish ,truth from ,falshood1 that 
,i might see cleerly into my actions1   
and passe this life with assurance4     
,its true1 that whiles ,i did but       
consider the ,manners of other men1 ,i  
found little or nothing wherein ,i might
 confirm my self3 ,and ,i observ'd in   
them even as much diversity as ,i had   
found before in the opinions of the     
,philosophers3 ,so that the greatest    
profit ,i could reap from them was1 that
 seeing divers things1 which although   

they seem to us very extravagant and    
ridiculous1 are nevertheless commonly   
received and approved by other great    
,nations1 ,i learn'd to beleeve nothing 
too firmly1 of what had been onely      
perswaded me by example or by custom1   
and so by little and little ,i freed my 
self from many errors1 which might      
eclipse our naturall light1 and render  
us lesse able to comprehend reason4 ,but
 after ,i had imployed some years in    
thus studying the ,book of the ,world1  
and endeavouring to get experience1 ,i  
took one day a resolution to study also 
within my self1 and to employ all the   
forces of my minde in the choice of the 
way ,i was to follow3 which 7me thought7
 succeeded much better1 then if ,i had  
never estranged my self from my         
,country1 or from my ,books4     ,,part4
 ,,ii4   ,i was then in ,germany1       
whither the occasion of the ,wars 7which
 are not yet finished7 call'd me2 and as
 ,i return'd from the ,emperors         
,coronation towards the ,army1 the      

beginning of ,winter stopt me in a      
place1 where finding no conversation to 
divert me and on the other sides having 
by good fortune no cares nor passions   
which troubled me1 ,i stayd alone the   
whole day1 shut up in my ,stove1 where  
,i had leasure enough to entertain my   
self with my thoughts4 ,among which one 
of the first was that ,i betook my self 
to consider1 ,that oft times there is   
not so much perfection in works compos'd
 of divers peeces1 and made by the hands
 of severall masters1 as in those that  
were wrought by one only3 ,so we may    
observe that those buildings which were 
undertaken and finished by one onely1   
are commonly fairer and better ordered  
then those which divers have laboured to
 patch up1 making use of old wals1 which
 were built for other purposes2 ,so     
those ancient ,cities which of boroughs1
 became in a succession of time great   
,towns1 are commonly so ill girt in     
comparison of other regular ,places1    
which were design'd on a flatt according

 to the fancy of an ,engeneer2 and      
although considering their buildings    
severally1 we often find as much or more
 art1 then in those of other places2    
,yet to see how they are rank'd here a  
great one1 there a little one1 and how  
they make the streets crooked and       
uneven1 ,one would say1 ,that it was    
rather ,fortune1 then the will of ,men  
indued with reason1 that had so disposed
 them4 ,and if we consider1 that there  
hath always been certain ,officers1     
whose charge it was1 to take care of    
private buildings1 to make them serve   
for the publique ornament2 ,we may well 
perceive1 that it's very difficult1     
working on the works of others1 to make 
things compleat4 ,so also did ,i        
imagine1 that those people who formerly 
had been half wilde1 and civiliz'd but  
by degrees1 made their laws but         
according to the incommodities which    
their crimes and their quarrels         
constrain'd them to1 could not be so wel
 pollic'd1 as those who from the        

beginning of their association1 observ'd
 the constitutions of some prudent      
,legislator4 ,as it is very certain1    
that the state of the true ,religion1   
whose ,ordinances ,god alone hath made1 
must be incomparably better regulated   
then all others4 ,and to speak of humane
 things1 ,i beleeve that if ,sparta hath
 formerly been most flourishing1 it was 
not by reason of the goodness of every  
of their laws in particular1 many of    
them being very strange1 and even       
contrary to good manners1 but because   
they were invented by one only1 ,they   
all tended to ,one ,end4 ,and so ,i     
thought the sciences in ,books1 at least
 those whose reasons are but probable1  
and which have no demonstrations1 having
 been compos'd of1 and by little and    
little enlarg'd with1 the opinions of   
divers persons1 come not so near the    
,truth1 as those simple reasonings which
 an understanding ,man can naturally    
make1 touching those things which       
occurr4 ,and ,i thought besides also1   

,that since we have all been children1  
before we were ,men2 and that we must   
have been a long time govern'd by our   
appetites1 and by our ,tutors1 who were 
often contrary to one another1 and      
neither of which alwayes counsel'd us   
for the best2 ,it's almost impossible   
that our judgment could be so clear or  
so solid1 as it might have been1 had we 
had the intire use of our reason from   
the time of our birth1 and been always  
guided by it alone4  ,its true1 we doe  
not see the houses of a whole ,town     
pull'd down purposely to re build them  
of another fashion2 and to make the     
streets the fairer2 ,but we often see1  
that divers pull their own down to set  
them up again1 and that even sometimes  
they are forc'd thereunto1 when they are
 in danger to fall of themselves1 and   
that their foundations are not sure4 ,by
 which example ,i perswaded my self1    
that there was no sense for a particular
 person1 to design the ,reformation of a
 ,state1 changing all from the very     

foundations1 and subverting all to      
redress it again3 ,nor even also to     
reform the bodies of ,sciences1 or the  
,orders already established in the      
,schools for teaching them4 ,but as for 
all the ,opinions which ,i had till then
 receiv'd into my beleef1 ,i could not  
doe better then to undertake to expunge 
them once for all1 that afterwards ,i   
might place in their stead1 either      
others which were better1 or the same   
again1 as soon as ,i should have        
adjusted them to the rule of reason4    
,and ,i did confidently beleeve1 that by
 that means ,i should succeed much      
better in the conduct of my life1 then  
if ,i built but on old foundations1 and 
only relyed on those principles1 which  
,i suffer'd my self to be perswaded to  
in my youth1 without ever examining the 
,truth of them4 ,for although ,i        
observ'd herein divers difficulties1 yet
 were they not without cure1 nor        
comparable to those which occurr in the 
reformation of the least things         

belonging to the publick3 these great   
bodies are too unweldy to be rais'd2    
being cast down1 or to be held up when  
they are shaken1 neither can their falls
 be but the heavyest4  ,as for their    
imperfections1 if they have any1 as the 
only diversity which is amongst them1 is
 sufficient to assure us that many have4
 ,custome hath 7without doubt7 much     
sweetned them1 and even it hath made    
others wave1 or insensibly correct a    
many1 whereto we could not so well by   
prudence have given a remedy4 ,and in   
fine1 ,they are alwayes more            
supportable1 then their change can be1  
,even1 as the great ,roads1 which       
winding by little and little betwixt    
mountains1 become so plain and          
commodious1 with being often frequented1
 that it's much better to follow them1  
then to undertake to goe in a strait    
line by climbing over the rocks1 and    
descending to the bottom of precipices4 
,wherefore ,i can by no means approve of
 those turbulent and unquiet humors1 who

 being neither call'd by birth or       
fortune to the managing of publique     
affairs1 yet are alwayes forming in     
,idea1 some new ,reformation4 ,and did  
,i think there were the least thing in  
this ,discourse1 which might render me  
suspected of that folly1 ,i should be   
extremely sorry to suffer it to be      
published2 ,i never had any designe     
which intended farther then to reform my
 own thoughts and to build on a         
foundation which was wholly mine4 ,but  
though ,i present you here with a       
,modell of my work1 because it hath     
sufficiently pleased me2 ,i would not   
therefore counsell any one to imitate   
it4 ,those whom ,god hath better endued 
with his graces1 may perhaps have more  
elevated designes2 but ,i fear me1 lest 
already this be too bold for some4 ,the 
resolution only of quitting all those   
opinions which we have formerly receiv'd
 into our belief1 is not an example to  
be followed by every ,one2 and the world
 is almost compos'd but of two sorts of 

,men1 to whom it's no wayes convenient1 
to wit1 of those1 who beleeving         
themselves more able then they are1     
cannot with-hold themselves from        
precipitating their judgments1 nor have 
patience enough to steer all their      
thoughts in an orderly course4 ,whence  
it happens1 that if they should once    
take the liberty to doubt of those      
principles which they have already      
received1 and to stray from the common  
road1 they could never keep the path    
which leads strait forwards1 and so1    
would straggle all their lives4 ,and of 
such who having reason and modesty      
enough to judg that they are less able  
to distinguish truth from falshood then 
others1 from whom they may receive      
instruction1 ought much rather to be    
content to follow other ,mens opinions1 
rather then to seek after better        
themselves4  ,and for my part1 ,i had   
undoubtedly been of the number of those 
latter1 had ,i never had but one        
,master1 or had ,i not known the        

disputes which have alwayes hapned      
amongst the most learned4 ,for having   
learnt from the very ,school1 ,that one 
can imagin nothing so strange or        
incredible1 which had not been said by  
some one of the ,philosophers2 ,and     
having since observ'd in my travails1   
,that all those whose opinions are      
contrary to ours1 are not therefore     
barbarous or savage1 but that many use  
as much or more reason then we2 and     
having consider'd how much one ,man with
 his own understanding1 bred up from his
 childhood among the ,french or the     
,dutch1 becomes different from what he  
would be1 had he alwayes liv'd amongst  
the ,chineses1 or the ,cannibals3 ,and  
how even in the fashion of our ,clothes1
 the same thing which pleas'd ten years 
since1 and which perhaps wil please ten 
years hence1 seems now to us ridiculous 
and extravagant4 ,so that it's much more
 ,custome and ,example which perswades  
us1 then any assured knowledg2 and      
notwithstanding that plurality of voices

 is a proof of no validity1 in those    
truths which are hard to be discovered2 
for that it's much more likely for one  
man alone to have met with them1 then a 
whole ,nation2 ,i could choose no ,man  
whose opinion was to be preferr'd before
 anothers3 ,and ,i found my self even   
constrain'd to undertake the conduct of 
my self4  ,but as a man that walks      
alone1 and in the dark1 ,i resolv'd to  
goe so softly1 and use so much          
circumspection in all things1 that      
though ,i advanc'd little1 ,i would yet 
save my self from falling4 ,neither     
would ,i begin quite to reject1 some    
opinions1 which formerly had crept into 
my belief1 without the consent of my    
reason1 before ,i had employed time     
enough to form the project of the work  
,i undertook1 and to seek the true      
,method to bring me to the knowledg of  
all those things1 of which my           
understanding was capable4  ,i had a    
little studyed1 being young1 of the     
parts of ,philosophy1 ,logick1 and of   

the ,mathematicks1 the ,analysis of the 
,geometricians1 and ,algebra3 ,three    
arts or sciences which seem'd to        
contribute somewhat conducing to my     
designe3 ,but examining them1 ,i        
observ'd1 ,that as for ,logick1 its     
,sylogisms1 and the greatest part of its
 other ,rules1 serve rather to expound  
to another the things they know1 or even
 as ,lullies art1 to speak with judgment
 of the things we are ignorant of1 then 
to learn them4 ,and although in effect  
it contain divers most true and good    
precepts1 yet there are so many others  
mixed amongst them1 either hurtfull or  
superfluous1 ,that it's even as         
difficult to extract them1 as 'tis to   
draw a ,diana or a ,mercury out of a    
lump of ,marble1 which is not yet       
rough-hewn2 as for the ,analysis of the 
,ancients1 and the ,algebra of the      
,moderns2 besides that1 they extend only
 to matters very abstract1 and which    
seem to be of no use2 ,the first being  
alwayes so tyed to the consideration of 

figures1 ,that it cannot exercise the   
understanding1 without very much tiring 
the imagination4 ,and in the latter they
 have so subjected themselves to certain
 ,rules and cyphers1 that they have made
 a confus'd and obscure art which       
perplexeth the minde1 in stead of a     
,science to instruct it4 ,for this      
reason1 ,i thought ,i ought to seek some
 other ,method1 which comprehending the 
advantages of these1 they might be      
exempt from their defects4 ,and as the  
multitude of ,laws often furnisheth     
excuses for vice2 so a ,state is fair   
better polic'd1 when having but a few1  
they are very strictly observ'd therein3
 ,so1 instead of the great many precepts
 whereof ,logick is compos'd1 ,i thought
 these four following would be          
sufficient for me1 if ,i took but a firm
 and constant resolution not once to    
fail in the observation of them4  ,the  
first was1 never to receive any thing   
for true1 but what ,i evidently knew to 
be so2 that's to say1 ,carefully to     

avoid ,precipitation and ,prevention1   
and to admit nothing more into my       
judgment1 but what should so clearly and
 distinctly present it self to my minde1
 that ,i could have no reason to doubt  
of it4  ,the second1 to divide every    
,one of these difficulties1 which ,i was
 to examine into as many parcels as     
could be1 and1 as was requisite the     
better to resolve them4  ,the third1 to 
lead my thoughts in order1 beginning by 
the most simple objects1 and the easiest
 to be known2 to rise by little and     
little1 as by steps1 even to the        
knowledg of the most mixt2 and even     
supposing an ,order among those which   
naturally doe not precede one the other4
  ,and the last1 to make every where    
such exact calculations1 and such       
generall reviews1 ,that ,i might be     
confident to have omitted ,nothing4     
,those long chains of reasons1 7though  
simple and easie7 which the             
,geometricians commonly use to lead us  
to their most difficult demonstrations1 

gave me occasion to imagine1 ,that all  
things which may fall under the knowledg
 of ,men1 follow one the other in the   
same manner1 and so we doe only abstain 
from receiving any one for true1 which  
is not so1 and observe alwayes the right
 order of deducing them one from the    
other1 there can be none so remote1 to  
which at last we shall not attain2 nor  
so hid1 which we shall not discover4    
,neither was ,i much troubled to seek by
 which it behooved me to begin1 for ,i  
already knew1 that it was by the most   
simple1 and the easiest to be discern'd4
 ,but considering1 that amongst all     
those who formerly have sought the      
,truth in ,learning1 none but the       
,mathematicians only could finde any    
demonstrations1 that's to say1 any      
certain and evident reasons4 ,i doubted 
not1 but that it was by the same that   
they have examin'd2 although ,i did hope
 for no other profit1 but only that they
 would accustome my ,minde to nourish it
 self with ,truths1 and not content it  

self with false ,reasons4 ,but for all  
this1 ,i never intended to endevour to  
learn all those particular ,sciences    
which we commonly call'd ,mathematicall2
 ,and perceiving1 that although their   
objects were different1 yet did they    
nevertheless agree altogether1 in that  
they consider no other thing1 but the   
divers relations or proportions which   
are found therein2 ,i thought it        
therefore better to examine those       
proportions in generall1 and without    
supporting them but in those subjects1  
which might the more easily serve to    
bring me to the knowledg of them4 ,but  
withall1 without any wayes limiting     
them1 ,that ,i might afterwards the     
better sit them to all others whereto   
they might be applyed4 ,having also     
observ'd1 ,that to know them1 it would  
be sometimes needfull for me to consider
 every one in particular1 or sometimes  
only to restrain them1 or comprehend    
many together2 ,i thought1 that to      
consider them the better in particular  

,i ought to suppose them in lines1 for  
as much as ,i find nothing more simple1 
nor which ,i could more distinctly      
represent to my imagination1 and to my  
sences2 ,but to hold or comprehend many 
in one1 ,i was oblig'd to explain them  
by certain ,cyphers the shortest ,i     
possibly could1 and that ,i should      
thereby borrow the best of the          
,geometricall ,analysis1 and of         
,algebra1  so correct all the defects of
 the one by the other4  ,as in effect ,i
 dare say1 ,that the exact observation  
of those few precepts ,i had chosen1    
gave me such a facility to resolve all  
the questions whereto these two sciences
 extend2 ,that in two or three months   
space which ,i employed in the          
examination of them1 having begun by the
 most simple and most generall1 and     
every ,truth which ,i found being a rule
 which afterwards served me to discover 
others2 ,i did not only compasse divers 
truths which ,i had formerly judged most
 difficult1 ,but me thought also that   

towards the end ,i could determin even  
in those which ,i was ignorant of1 by   
what means and how farr it was possible 
to resolve them4 ,wherein perhaps ,i    
shall not appear to be very vain if you 
consider1 ,that there being but one     
truth of every thing1 who ever finds it1
 knows as much of it as one can know2   
,and that for example a child instructed
 in ,arithmatick having made an addition
 according to his rules1 may be sure to 
have found1 touching the sum he         
examined1 all what the wit of man could 
finde out4 ,in a word the method which  
teacheth to folow a right order1 and    
exactly to enumerate all the            
circumstances of what we seek1 contains1
 whatsoever ascertains the rules of     
,arithmatick4  ,but that which pleas'd  
me most in this ,method was the         
assurance ,i had1 wholly to use my      
reason1 if not perfectly1 at least as   
much as it was in my power2 ,besides    
this1 ,i perceived in the practice of   
it1 my minde by little and little       

accustom'd it self to conceive its      
objects more clearly and distinctly2 and
 having not subjected it to any         
particular matter1 ,i promised my self  
to apply it also as profitable to the   
difficulties1 of other sciences as ,i   
had to ,algebra3 ,not that ,i therefore 
durst at first undertake to examine all 
which might present themselves1 for that
 were contrary to the order it          
prescribes4 ,but having observ'd that   
all their principles were to be borrowed
 from ,philosophy1 in which ,i had yet  
found none that were certain1 ,i thought
 it were needfull for me in the first   
place to endevor to establish some1 and 
that this being the most important thing
 in the world1 wherein precipitation and
 prevention were the most to be feared1 
,i should not undertake to performe it1 
till ,i had attain'd to a riper ,age    
then ,,xxiii4 which was then mine4      
,before ,i had formerly employed a long 
time in preparing my self thereunto1    
aswel in rooting out of my minde all the

 ill opinions ,i had before that time   
received1 as in getting a stock of      
experience to serve afterwards for the  
subject of my reasonings1 and in        
exercising my self always in the ,method
 ,i had prescribed4 ,that ,i might the  
more and more confine my self therein4  
,,part4 ,,iii4   ,but as it is not      
enough to pull down the house where we  
dwell1 before we begin to re-edify it1  
and to make provision of materials and  
architects1 or performe that office our 
selves2 nor yet to have carefully laid  
the design of it2 but we must also have 
provided our selves of some other place 
of abode during the time of the         
rebuilding3 ,so that ,i might not remain
 irresolute in my actions1 while reason 
would oblige me to be so in my          
judgments1 and that ,i might continue to
 live the most happily ,i could1 ,i     
form'd for my own use in the interim a  
,moral1 which consisted but of three or 
four ,maximes1 which ,i shall           
communicate unto you4  ,the first was to

 obey the lawes and customes of my      
,country1 constantly adhaering to that  
,religion wherein by the grace of ,god  
,i had from mine infancy bin bred4 ,and 
in all other things behaving my self    
according to the most moderate opinions 
and those which were farthest from      
excesse1 which were commonly received in
 practice by the most judicious ,men1   
amongst whom ,i was to live3 ,for       
beginning from that very time1 to reckon
 mine own for nothing1 because ,i could 
bring them all to the test1 ,i was      
confident ,i could not do better then   
follow those of the deepest sense2 and  
although perhaps there are as           
understanding men amongst the ,persians 
or ,chineses as amongst us1 yet ,i      
thought it was more fit to regulate my  
self by those with whom ,i was to live1 
and that ,i might truly know what their 
opinions were1 ,i was rather to observe 
what they practic'd1 then what they     
taught4 ,not only by reason of the      
corruption of our manners1 there are but

 few who will say1 all they beleeve1 but
 also because divers are themselves     
ignorant of it2 for the act of the      
thought by which we beleeve a thing1    
being different from that whereby we    
know that we believe it1 the one often  
is without the other4 ,and amongst      
divers opinions equally receiv'd1 ,i    
made choise of the most moderate only1  
as well because they are always the most
 fit for practice1 and probably the     
best1 all excess being commonly ill2 ,as
 also that ,i might less err from the   
right way1 if ,i should perhaps miss it1
 then if having chosen one of the       
extremes1 it might prove to be the      
other1 which ,i should have followed4   
,and particularly ,i plac'd amongst     
extremities1 all those promises by which
 we somwhat restrain our liberty4 ,not  
that ,i disapproved the laws1 which to  
cure the inconstancy of weak minds1     
permit us when we have any good design1 
or else for the preservation of         
,commerce1 one that is but indifferent1 

to make vows or contracts1 which oblige 
us to persevere in them3 ,but because ,i
 saw nothing in the world remain always 
in the same state2 and forming own      
particular1 promised my self to perfect 
more and more my judgment1 and not to   
impair it1 ,i should have thought my    
self guilty of a great fault against    
right understanding1 if because ,i then 
approved any thing1 ,i were also        
afterwards oblig'd to take it for good1 
when perhaps it ceased to be so1 or that
 ,i had ceased to esteem it so4  ,my    
second ,maxime was1 ,to be the most     
constant and resolute in my actions that
 ,i could2 and to follow with no less   
perseverance the most doubtfull         
opinions1 when ,i had once determined   
them1 then if they had been the most    
certain4 ,imitating herein ,travellers1 
who having lost their way in a ,forrest1
 ought not to wander1 turning now this  
way1 and then that1 and less to abide in
 one place2 but stil advance straight   
forwards1 towards one way1 and not to   

change on slight occasions1 although    
perhaps at first ,chance only mov'd them
 to determine that choice3 ,for by that 
means1 if they do not go directly       
whither they desire1 they will at least 
arrive somewhere where they will        
probably be better then in the midst of 
a ,forrest4 ,so the actions of this life
 admitting often of no delay1 its a most
 certain ,truth1 ,that when it is not in
 our power to discern the truest        
opinions1 we are to follow the most     
probable3 ,yea1 although we finde no    
more probability in the one then in the 
other1 we yet ought to determine some   
way1 considering them afterwards no more
 as doubtful in what they relate to     
practice2 but as most true and certain2 
forasmuch as the reason was so1 which   
made us determine it4 ,and this was     
sufficient for that time to free me from
 all the remorse and repentance which   
useth to perplex the consciences of     
those weak and staggering minds1 which  
inconstantly suffer themselves to passe 

to the practice of those things as good1
 which they afterwards judge evill4  ,my
 third ,maxime was1 ,to endevour always 
rather to conquer my self then ,fortune2
 and to change my desires1 rather then  
the order of the world3 and generally to
 accustome my self to beleeve1 ,that    
there is nothing wholly in our power but
 our thoughts2 so that after we have    
done our best1 touching things which are
 without us1 all whats wanting of       
success in respect of us is absolutely  
impossible4 ,and this alone seem'd      
sufficient to hinder me from desiring   
any thing which ,i could not acquire1   
and so to render me content4 ,for our   
will naturally moving us to desire      
nothing1 but those things which our     
understanding presents in some manner as
 possible1 certain it is1 that if we    
consider all the good which is without  
us1 as equally distant from our power1  
we should have no more regret for the   
want of those which seem due to our     
births1 when without any fault of ours  

we shall be deprived of them1 then we   
have in wanting the possessions of the  
,kingdoms of ,china or ,mexico4 ,and    
making 7as we say7 vertue of necessity1 
we should no more desire to be in health
 being sick1 or free being in prison1   
then we now do1 to have bodies of as    
incorruptible a matter as diamonds1 or  
wings to fly like birds4 ,but ,i        
confess1 that a long exercise1 and an   
often reiterated meditation1 is         
necessary to accustom us to look on all 
things with that byass3 ,and ,i beleeve1
 in this principally consists1 the      
secret of those ,philosophers who       
formerly could snatch themselves from   
the ,empire of ,fortune1 and in spight  
of pains and poverty1 dispute felicity  
with their ,gods1 for imploying         
themselves incessantly in considering   
the bounds which ,nature had prescribed 
them1 they so perfectly perswaded       
themselves1 ,that nothing was in their  
power but their thoughts1 that1 that    
onely was enough to hinder them from    

having any affection for other things4  
,and they disposed so absolutely of     
them1 that therein they had some reason 
to esteem themselves more rich and      
powerfull1 more free and happy then any 
other men2 who wanting this ,philosophy1
 though they were never so much favoured
 by ,nature and ,fortune1 could never   
dispose of all things so well as they   
desired4  ,lastly1 ,to conclude these   
,morals1 ,i thought fit to make a review
 of mens severall imployments in this   
life1 that ,i might endeavour to make   
choice of the best1 and without         
prejudice to other mens1 ,i thought ,i  
could not do better then to continue in 
the same wherein ,i was1 that is1 to    
imploy all my life in cultivating my    
,reason1 and advancing my self1 as far  
as ,i could in the knowledge of ,truth1 
following the ,method ,i had prescribed 
myself4 ,i was sensible of such extreme 
contentment since ,i began to use this  
,method1 that ,i thought none could in  
this life be capable of any more sweet  

and innocent3 and daily discovering by  
means thereof1 some ,truths which seemed
 to me of importance1 and commonly such 
as other men were ignorant of1 the      
satisfaction ,i thereby received did so 
possesse my minde1 as if all things else
 concern'd me not4 ,besides1 that the   
three preceding ,maximes were grounded  
only on the designe ,i had1 to continue 
the instruction of my self4 ,for ,god   
having given to every one of us a light 
to discern truth from falsehood1 ,i     
could not beleeve ,i ought to content my
 self one moment with the opinions of   
others1 unlesse ,i had proposed to my   
self in due time to imploy my judgment  
in the examination of them4 ,neither    
could ,i have exempted my self from     
scruple in following them1 had ,i not   
hoped to lose no occasion of finding out
 better1 if there were any4  ,but to    
conclude1 ,i could not have bounded my  
desires1 nor have been content1 had ,i  
not followed a way1 whereby thinking my 
self assured to acquire all the         

knowledge ,i could be capable of3 ,i    
thought ,i might by the same means      
attain to all that was truly good1 which
 should ever be within my power2        
forasmuch as our ,will inclining it self
 to follow1 or fly nothing but what our 
,understanding proposeth good or ill1 to
 judge well is sufficient to do well1   
and to judge the best we can1 to do also
 what's best2 to wit1 to acquire all    
vertues1 and with them all acquirable   
goods3 and whosoever is sure of that1 he
 can never fail of being content4       
,after ,i had thus confirmed my self    
with these ,maximes1 and laid them up   
with the ,articles of ,faith1 which     
always had the first place in my        
,belief1 ,i judg'd that ,i might freely 
undertake to expell all the rest of my  
opinions4 ,and forasmuch as ,i did hope 
to bring it the better to passe by      
conversing with men1 then by staying any
 longer in my stove1 where ,i had had   
all these thoughts3 before the ,winter  
was fully ended1 ,i returned to my      

travels2 and in all the nine following  
yeers ,i did nothing but rowl here and  
there about the world1 endeavouring     
rather to be a spectator1 then an actor 
in all those ,comedies which were acted 
therein3 and reflecting particularly on 
every subject which might render it     
suspected1 or afford any occasion       
mistake4 ,in the mean time ,i rooted out
 of my minde all those errours which    
formerly had crept in4 ,not that ,i     
therein imitated the ,scepticks1 who    
doubt onely to the end they may doubt1  
and affect to be always unresolved3 ,for
 on the contrary1 all my designe tended 
onely to fix my self1 and to avoid      
quick-mires and sands1 that ,i might    
finde rock and clay3 which 7me thought7 
succeeded well enough2 forasmuch as1    
seeking to discover the falshood or     
uncertainty of those propositions ,i    
examined1 7not by weak conjectures1 but 
by clear and certain ratiocinations7 ,i 
met with none so doubtfull1 but ,i      
thence drew some conclusion certain     

enough1 were it but onely this1 ,that it
 contained nothing that was certain4    
,and as in pulling down an old house1   
commonly those materials are reserved   
which may serve to build a new one2 so  
in destroying all those my opinions     
which ,i judg'd ill grounded1 ,i made   
divers observations1 and got severall   
experiences which served me since to    
establish more certain ones4 ,and       
besides ,i continued to exercise my self
 in the ,method ,i had prescribed4  ,for
 ,i was not only carefull to direct all 
my thoughts in generall according to its
 rules1 but ,i from time to time        
reserv'd some houres1 which ,i          
particularly employd to practice it in  
difficulties belonging to the           
,mathematicks1 loosening from all the   
principles of other ,sciences1 which ,i 
found not stable enough1 as you may see 
,i have done in divers explain'd in my  
other following discourses4 ,and thus   
not living in appearance otherwise then 
those who having no other business then 

to lead a sweet and innocent life1 study
 to separate pleasures from vices1 and  
use honest recreations to enjoy their   
ease without wearinesse2 ,i did not     
forbear to pursue my design1 and advance
 in the knowledg of truth1 perhaps more1
 then if ,i had done nothing but read   
books or frequent learned men4  ,yet    
these nine years were vanished1 before  
,i had engaged my self in those         
difficulties which use to be disputed   
amongst the learned2 or begun to seek   
the grounds of any more certain         
,philosophy then the ,vulgar3 ,and the  
example of divers excellent ,men who    
formerly having had the same designe1   
seem'd not to me to have succeeded      
therein1 made me imagine so much        
difficulty1 that ,i had not perhaps     
dar'd so quickly to have undertaken it1 
had ,i not perceiv'd that some already  
had given it out that ,i had already    
accomplished it4 ,i know not whereupon  
they grounded this opinion1 and if ,i   
have contributed any thing thereto by my

 discourse1 it must have been by        
confessing more ingeniously what ,i was 
ignorant of1 then those are wont to do  
who have a little studyed1 and perhaps  
also by comunicating those reasons1 ,i  
had to doubt of many things which others
 esteem'd most eminent1 rather then that
 ,i bragg'd of any learning4 ,but having
 integrity enough1 not to desire to be  
taken for what ,i was not1 ,i thought   
that ,i ought to endeavour by all means 
to render my self worthy of the         
reputation which was given me4 ,and 'tis
 now eight years since this desire made 
me resolve to estrange my self from all 
places where ,i might have any          
acquaintance1 and so retire my self     
hither in a ,country where the long     
continuance of the warre hath           
established such orders1 that the       
,armies which are intertain'd there1    
seem to serve onely to make the         
inhabitants enjoy the fruits of peace   
with so much the more security2 and     
where amongst the croud of a great      

people more active and solicitous for   
their own affaires1 then curious of     
other mens1 not wanting any of those    
necessaries which are in the most       
frequented ,towns1 ,i could live as     
solitary and retired as in the most     
remote deserts4     ,part4 ,,iiii4   ,i 
,know not whether ,i ought to entertain 
you with the first ,meditations which ,i
 had there1 for they are so             
,metaphysicall and so little common1    
that perhaps they will not be relished  
by all men3 ,and yet that you may judge 
whether the foundations ,i have laid are
 firm enough1 ,i find my self in a      
manner oblig'd to discourse them2 ,i had
 long since observed that as for        
manners1 it was somtimes necessary to   
follow those opinions which we know to  
be very uncertain1 as much as if they   
were indubitable1 as is beforesaid3 ,but
 because that then ,i desired onely to  
intend the search of truth1 ,i thought  
,i ought to doe the contrary1 and reject
 as absolutely false all wherein ,i     

could imagine the least doubt1 to the   
end ,i might see if afterwards any thing
 might remain in my belief1 not at all  
subject to doubt4 ,thus because our     
senses sometimes deceive us1 ,i would   
suppose that there was nothing which was
 such as they represented it to us4 ,and
 because there are men who mistake      
themselves in reasoning1 even in the    
most simple matters of ,geometry1 and   
make therein ,paralogismes1 judging that
 ,i was as subject to fail as any other 
,man1 ,i rejected as false all those    
reasons1 which ,i had before taken for  
,demonstrations4 ,and considering1 that 
the same thoughts which we have waking1 
may also happen to us sleeping1 when as 
not any one of them is true4 ,i resolv'd
 to faign1 that all those things which  
ever entred into my ,minde1 were no more
 true1 then the illusions of my dreams4 
,but presently after ,i observ'd1 that  
whilst ,i would think that all was      
false1 it must necessarily follow1 that 
,i who thought it1 must be something4   

,and perceiving that this ,truth1 ,i    
think1 therefore1 ,i am1 was so firm and
 certain1 that all the most extravagant 
suppositions of the ,scepticks was not  
able to shake it1 ,i judg'd that ,i     
might receive it without scruple for the
 first principle of the ,philosophy ,i  
sought4  ,examining carefully afterwards
 what ,i was2 and seeing that ,i could  
suppose that ,i had no body1 and that   
there was no ,world1 nor any place where
 ,i was3 but for all this1 ,i could not 
feign that ,i was not2 and that even    
contrary thereto1 thinking to doubt the 
truth of other things1 it most evidently
 and certainly followed1 ,that ,i was3  
whereas1 if ,i had ceas'd to think1     
although all the rest of what-ever ,i   
had imagined were true1 ,i had no reason
 to beleeve that ,i had been4 ,i knew   
then that ,i was a substance1 whose     
whole essence or nature is1 but to      
think1 and who to be1 hath need of no   
place1 nor depends on any materiall     
thing4 ,so that this ,me1 to wit1 my    

,soul1 by which ,i am what ,i am1 is    
wholly distinct from the ,body1 and more
 easie to be known then it2 and although
 that were not1 it would not therefore  
cease to be what it is4  ,after this ,i 
considered in generall what is requisite
 in a ,proposition to make it true and  
certain3 for since ,i had found out one 
which ,i knew to be so1 ,i thought ,i   
ought also to consider wherein that     
certainty consisted3 and having         
observed1 ,that there is nothing at all 
in this1 ,i think1 therefore ,i am1     
which assures me that ,i speak the      
truth1 except this1 that ,i see most    
cleerly1 ,that to think1 one must have a
 being2 ,i judg'd that ,i might take for
 a generall rule1 ,that those things    
which we conceive cleerly and           
distinctly1 are all true2 and that the  
onely difficulty is punctually to       
observe what those are which we         
distinctly conceive4  ,in pursuance     
whereof1 reflecting on what ,i doubted1 
and that consequently my being was not  

perfect2 for ,i clearly perceived1 that 
it was a greater perfection to know1    
then to doubt1 ,i advised in my self to 
seek from whence ,i had learnt to think 
on something which was more perfect then
 ,i2 and ,i knew evidently that it must 
be of some nature which was indeed more 
perfect4 ,as for what concerns the      
thoughts ,i had of divers other things  
without my self1 as of heaven1 earth1   
light1 heat1 and a thousand more1 ,i was
 not so much troubled to know whence    
they came1 for that ,i observed nothing 
in them which seemed to render them     
superiour to me2 ,i might beleeve1 that 
if they were true1 they were            
dependancies from my nature1 as far     
forth as it had any perfection2 and if  
they were not1 ,i made no accompt of    
them2 that is to say1 ,that they were in
 me1 because ,i had something deficient4
 ,but it could not be the same with the 
,idea of a being more perfect then mine3
 ,for to esteem of it as of nothing1 was
 a thing manifestly impossible4 ,and    

because there is no lesse repugnancy    
that the more perfect should succeed    
from and depend upon the less perfect1  
then for something to proceed from      
nothing1 ,i could no more hold it from  
my self3 ,so as it followed1 that it    
must have bin put into me by a ,nature  
which was truly more perfect then ,i1   
and even which had in it all the        
perfections whereof ,i could have an    
,idea2 to wit1 7to explain my self in   
one word7 ,god4 ,whereto ,i added1 that 
since ,i knew some perfections which ,i 
had not1 ,i was not the onely ,being    
which had an existence1 7,i shall1 under
 favour1 use here freely the terms of   
the ,schools7 but that of necessity     
there must be some other more perfect   
whereon ,i depended1 and from whom ,i   
had gotten all what ,i had3 ,for had ,i 
been alone1 and depending upon no other 
thing1 so that ,i had had of my self all
 that little which ,i participated of a 
perfect ,being1 ,i might have had by the
 same reason from my self1 all the      

remainder which ,i knew ,i wanted1 and  
so have been my self infinite1 eternall1
 immutable1 all-knowing1 almighty2 and  
lastly1 have had all those perfections  
which ,i have observed to be in ,god4   
,for according to the way of reasoning  
,i have now followed1 to know the nature
 of ,god1 as far as mine own was capable
 of it1 ,i was onely to consider of     
those things of which ,i found an ,idea 
in me1 whether the possessing of them   
were a perfection or no2 and ,i was     
sure1 that any of those which had any   
imperfections were not in him1 but that 
all others were4 ,i saw that            
doubtfulness1 inconstancy1 sorrow and   
the like1 could not be in him1 seeing ,i
 could my self have wish'd to have been 
exempted from them4 ,besides this1 ,i   
had the ,ideas of divers sensible and   
corporeall things2 for although ,i      
supposed that ,i doted1 and that all    
that ,i saw or imagined was false2 yet  
could ,i not deny but that these ,ideas 
were truly in my thoughts4 ,but because 

,i had most evidently known in my self1 
,that the understanding ,nature is      
distinct from the corporeall1           
considering that all composition        
witnesseth a dependency1 and that       
dependency is manifestly a defect1 ,i   
thence judged that it could not be a    
perfection in ,god to be composed of    
those two ,natures2 and that by         
consequence he was not so composed4 ,but
 that if there were any ,bodies in the  
world1 or els any intelligences1 or     
other ,natures which were not wholly    
perfect1 their being must depend from   
his power in such a manner1 that they   
could not subsist one moment without    
him4  ,thence ,i went in search of other
 ,truths2 and having proposed ,geometry 
for my object1 which ,i conceived as a  
continued ,body1 or a space indefinitely
 spred in length1 bredth1 height or     
depth1 divisible into divers parts1     
which might take severall figures and   
bignesses1 and be moved and transposed  
every way4 ,for the ,geometricians      

suppose all this in their object4 ,i    
past through some of their most simple  
demonstrations2 and having observed that
 this great certaintie1 which all the   
world grants them1 is founded only on   
this1 that men evidently conceived them1
 following the rule ,i already          
mentioned4 ,i observed also that there  
was nothing at all in them which        
ascertain'd me of the existence of their
 object4 ,as for example1 ,i well       
perceive1 that supposing a ,triangle1   
three angles necessarily must be equall 
to two right ones3 but yet nevertheless 
,i saw nothing which assured me that    
there was a ,triangle in the world4     
,whereas returning to examine the ,idea 
which ,i had of a perfect ,being1 ,i    
found its existence comprised in it1 in 
the same manner as it was comprised in  
that of a ,triangle1 where the three    
angles are equall to two right ones2 or 
in that of a sphere1 where all the parts
 are equally distant from the center4   
,or even yet more evidently1 and that by

 consequence1 it is at least as certain 
that ,god1 who is that perfect ,being1  
is1 or exists1 as any demonstration in  
,geometry can be4  ,but that which makes
 many perswade themselves that there is 
difficulty in knowing it1 as also to    
know what their ,soul is1 'tis that they
 never raise their thoughts beyond      
sensible things1 and that they are so   
accustomed to consider nothing but by   
imagination1 which is a particular      
manner of thinking on materiall things1 
that whatsoever is not imaginable seems 
to them not intelligible4 ,which is     
manifest enough from this1 that even the
 ,philosophers hold for a ,maxime in the
 ,schools1 ,that there is nothing in the
 understanding which was not first in   
the sense2 where notwithstanding its    
certain1 that the ,ideas of ,god and of 
the ,soul never were4 ,and 7me thinks7  
those who use their imagination to      
comprehend them1 are just as those1 who 
to hear sounds1 or smell odours1 would  
make use of their eys2 save that there  

is yet this difference1 ,that the sense 
of seeing assures us no lesse of the    
truth of its objects1 then those of     
smelling or hearing do3 whereas neither 
our imagination1 nor our senses1 can    
ever assure us of any thing1 if our     
understanding intervenes not4  ,to be   
short1 if there remain any who are not  
enough perswaded of the existence of    
,god1 and of their soul1 from the       
reasons ,i have produc'd1 ,i would have 
them know1 that all other things1       
whereof perhaps they think themselves   
more assured1 as to have a body1 and    
that there are ,stars1 and an earth1 and
 the like1 are less certain4 ,for       
although we had such a morall assurance 
of these things1 that without being     
extravagant we could not doubt of them4 
,however1 unless we be unreasonable when
 a metaphysicall certainty is in        
question1 we cannot deny but we have    
cause enough not to be wholly confirmed 
in them1 when we consider that in the   
same manner we may imagine being asleep1

 we have other bodies1 and that we see  
other ,stars1 and another earth1 though 
there be no such thing4 ,for how doe we 
know that those thoughts which we have  
in our dreams1 are rather false then the
 others1 seeing often they are no less  
lively and significant1 and let the     
ablest men study it as long as they     
please1 ,i beleeve they can give no     
sufficient reason to remove this doubt1 
unless they presuppose the existence of 
,god4 ,for first of all1 that which ,i  
even now took for a rule1 to wit1 that  
those things which were most clearly and
 distinctly conceived1 are all true1 is 
certain1 only by reason1 that ,god is or
 exists1 and that he is a perfect being1
 and that all which we have comes from  
him4 ,whence it follows1 that our       
,idea's or notions1 being reall things1 
and which come from ,god in all wherein 
they are clear and distinct1 cannot     
therein be but true4 ,so that if we have
 very often any which contain falshood1 
they cannot be but of such things which 

are somewhat confus'd and obscure1      
because that therein they signifie      
nothing to us1 that's to say1 that they 
are thus confus'd in us only1 because we
 are not wholly perfect4 ,and it's      
evident that there is no less           
contrariety that falshood and           
imperfection should proceed from ,god1  
as such1 then there is in this1 that    
truth and falshood proceed from nothing4
 ,but if we know not that whatsoever was
 true and reall in us comes from a      
perfect and infinite being1 how clear   
and distinct soever our ,idea's were1 we
 should have no reason to assure us1    
that they had the perfection to be true4
  ,now after that the knowledge of ,god1
 and of the ,soul hath rendred us thus  
certain of this rule1 it's easie to     
know2 that the extravaganceys which we  
imagin in our sleep1 ought no way to    
make us doubt of the truth of those     
thoughts which we have being awake3 ,for
 if it should happen1 that even sleeping
 we should have a very distinct ,idea2  

as for example1 ,a ,geometritian should 
invent some new demonstration1 his      
sleeping would not hinder it to be true4
 ,and for the most ordinary error of our
 dreames1 which consists in that they   
represent unto us severall objects in   
the same manner as our exterior senses  
doe1 it matters not though it give us   
occasion to mistrust the truth of those 
,ideas1 because that they may also often
 enough cozen us when we doe not sleep2 
,as when to those who have the          
,jaundies1 all they see seems yellow2   
or1 as the ,stars or other bodies at a  
distance1 appear much less then they    
are4 ,for in fine1 whether we sleep or  
wake1 we ought never to suffer our      
selves to be perswaded but by the       
evidence of our ,reason2 ,i say1 7which 
is observable7 ,of our ,reason1 and not 
of our imagination1 or of our senses4   
,as although we see the ,sun most       
clearly1 we are not therefore to judge  
him to be of the bigness we see him of2 
and we may well distinctly imagine the  

head of a ,lion1 set on the body of a   
,goat1 but therefore we ought not to    
conclude that there is a ,chimera in the
 world4 ,for reason doth not dictate to 
us1 that what we see or imagine so1 is  
true3 ,but it dictates1 that all our    
,idea's or notions ought to have some   
grounds of truth2 ,for it were not      
possible1 that ,god who is all perfect1 
and all truth1 should have put them in  
us without that3 ,and because that our  
reasonings are never so evident1 nor so 
entire while we sleep1 as when we wake1 
although sometimes our imaginations be  
then as much or more lively and express4
 ,it also dictates to us1 that our      
thoughts1 seeing they cannot be all true
 by reason that we are not wholly       
perfect2 what they have of truth1 ought 
infallibly to occur in those which we   
have being awake1 rather then in our    
dreams4     ,part4 ,v4   ,i should be   
glad to pursue this ,discourse1 and shew
 you the whole ,series of the following 
,truths1 which ,i have drawn from the   

former3 ,but because for this purpose1  
it were now necessary for me to treat of
 severall questions1 which are          
controverted by the learned1 with whom  
,i have no desire to imbroil my self1 ,i
 beleeve it better for me to abstain    
from it2 and so in generall onely to    
discover what they are1 that ,i may     
leave the wisest to judge whether it    
were profitable to inform the publick   
more particularly of them4 ,i alwayes   
remained constant to my resolution1 to  
suppose no other ,principle but that    
which ,i now made use of1 for the       
demonstration of the ,existence of ,god1
 and of the ,soul2 and to receive       
nothing for true1 which did not seem to 
me more clear and more certain then the 
demonstrations of ,geometry had formerly
 done4 ,and yet ,i dare say1 that ,i    
have not onely found out the means to   
satisfie my self1 in a short time1      
concerning all the principall           
difficulties which are usually treated  
in ,philosophy4 ,but that also ,i have  

observed certain ,laws which ,god hath  
so established in ,nature1 and of which 
he hath imprinted such notions in our   
,souls1 that when we shall have made    
sufficient reflections upon them we     
cannot doubt but that they are exactly  
observed in whatsoever either is1 or is 
done in the ,world4 ,then considering   
the connexion of these ,laws1 me thinks1
 ,i have discovercd divers ,truths1 more
 usefull and important then whatever ,i 
learn'd before1 or ever hop'd to learn4 
,but because ,i have endeavoured to lay 
open the principall of them in a        
,treatise1 which some considerations    
hinder me from publishing2 ,i can no way
 better make them known1 then by        
relating summarily what it contains4  ,i
 had a designe to comprehend all what ,i
 thought ,i knew1 before ,i would write 
it1 touching the nature of material     
things4 ,but even as ,painters1 not     
being able equally well to represent    
upon a flat all the severall facies of a
 solid body1 chuse the principall of    

them1 which they place towards the      
light2 and shadowing the others1 make   
them appear no more then they do to our 
sight3 ,so1 fearing lest ,i should not  
bring into this ,discourse all which was
 in my thoughts1 ,i onely undertook to  
set forth at large my conceptions       
touching the light2 and upon that       
occasion to add somewhat of the ,sun1   
and of the fix'd ,stars1 by reason that 
it proceeds almost all from thence2 of  
the ,heavens1 because they transmit it2 
of the ,planets1 of the ,comets1 and of 
the ,earth1 because they cause it to    
reflect2 and in particular1 of all      
,bodies which are on the earth1 whether 
for that they are either coloured1 or   
transparent1 or luminous2 and last of   
all1 of ,man1 because he is the         
,spectator thereof4 ,as also1 in some   
manner to shadow out all these things1  
and that ,i might the more freely speak 
what ,i judg'd1 without being obliged to
 follow1 or to refute the opinions which
 are received amongst the ,learned1 ,i  

resolved to leave all this world here to
 their disputes1 and to speak onely of  
what would happen in a new one1 if ,god 
now created some where in those         
imaginary spaces matter enough to       
compose it1 and that he diversly and    
without order agitated the severall     
parts of this matter1 so as to compose a
 ,chaos of it as confused as the ,poets 
could feign one3 and that afterwards he 
did nothing but lend his ordinary       
concurrence to ,nature1 and leave her to
 work according to the ,laws he hath    
established4  ,thus first of all ,i     
described this ,matter1 and endevoured  
to represent it such1 that me thinks    
there is nothing in the world more      
clear1 or more intelligible1 except what
 was beforesaid of ,god1 and of the     
,soul4 ,for even ,i expresly supposed   
that there was in it none of those forms
 and qualities which are disputed in the
 ,schools2 nor generally any thing but  
that the knowledge thereof was so       
naturall to our understandings1 that we 

could not even feigne to be ignorant of 
it4 ,besides1 ,i made known what the    
,laws of ,nature were2 and without      
grounding my reasons on any other       
principles1 but on the infinite         
perfections of ,god1 ,i did endeavour to
 demonstrate all those which might be   
questioned1 and to make them appear to  
be such1 that although ,god had created 
divers worlds1 there could have been    
none where they were not observed4      
,afterwards ,i shewed how the greater   
part of the ,matter of this ,chaos      
ought1 according to those ,laws1 to     
dispose and order it self in a certain  
manner1 which would make it like our    
,heavens3 ,and how some of these parts  
were to compose an ,earth1 and some     
,planets and ,commets1 some others a    
,sun and fix'd ,starrs4 ,and here       
enlarging my self on the subject of     
,light1 ,i at length explain'd what that
 light was1 which was to be in the ,sun 
and ,stars2 and thence how it travers'd 
in an instant the immense spaces of the 

,heavens1 and how it reflected it self  
from ,planets and ,commets towards the  
,earth4 ,i added also divers things     
touching the substance1 situation1 the  
motions1 and all the several qualities  
of these heavens and these stars3 ,so   
that ,i thought ,i had said enough to   
make known1 ,that there is nothing      
remarkable in those of this world1 which
 ought not1 or at least could not appear
 altogether like to these of that world 
which ,i described4  ,thence ,i came to 
speak particularly of the ,earth2 how1  
although ,i had expresly supposed1 that 
,god had placed no weight in the ,matter
 whereof it was composed2 yet all its   
parts exactly tended towards its center3
 ,how that there being water and air    
upon its superficies1 the disposition of
 the ,heavens1 and of the ,starrs1 and  
chiefly of the ,moon1 ought to cause a  
floud and an ebb1 which in all          
circumstances was like to that which we 
observe in our ,seas2 ,and besides1 a   
certain course aswel of the water1 as of

 the air1 from ,east to ,west1 as is    
also observed between the ,tropicks3    
,how the ,mountains1 the ,seas1 the     
,springs and ,rivers might naturally be 
form'd therein1 and ,metals run in the  
mines1 and ,plants grow in the ,fields1 
and generally all bodies be therein     
engendered which are call'd mixt or     
composed4  ,and amongst other things1   
because that next the ,stars1 ,i know   
nothing in the world but ,fire1 which   
produceth light1 ,i studied to make all 
clearly understood which belongs to its 
nature2 how it's made1 how it's fed1 how
 sometimes it hath heat onely without   
light1 and sometimes onely light without
 heat2 how it can introduce several     
colours into several bodies1 and divers 
other qualities2 how it dissolves some1 
and hardens others2 how it can consume  
almost all1 or convert them into ashes  
and smoak3 and last of all1 how of those
 ashes1 by the only violence of its     
action1 it forms glass4 ,for this       
transmutation of ashes into glass1      

seeming to me to be as admirable as any 
other operation in ,nature1 ,i          
particularly took pleasure to describe  
it4  ,yet would ,i not inferre from all 
these things1 that this ,world was      
created after the manner ,i had         
proposed4 ,for it is more probable that 
,god made it such as it was to be1 from 
the beginning4 ,but it's certain1 and   
'tis an opinion commonly received       
amongst the ,divines1 ,that the action  
whereby he now preserveth it1 is the    
same with that by which he created it4  
,so that1 although at the beginning he  
had given it no other form but that of a
 ,chaos 7provided1 that having          
established the ,laws of ,nature1 he had
 afforded his concurrence to it1 to work
 as it used to do7 we may beleeve       
7without doing wrong to the miracle of  
the ,creation7 that by that alone all   
things which are purely material might  
in time have rendred themselves such as 
we now see them3 and their nature is far
 easier to conceive1 when by little and 

little we see them brought forth so1    
then when we consider them quite form'd 
all at once4  ,from the description of  
inanimate ,bodies and ,plants1 ,i pass'd
 to that of ,animals1 and particularly  
to that of ,men4 ,but because ,i had not
 yet knowledge enough to speak of them  
in the same stile as of the others2 to  
wit1 in demonstrating effects by their  
causes1 and shewing from what seeds1 and
 in what manner ,nature ought to produce
 them2 ,i contented my self to suppose1 
,that ,god form'd the body of a ,man    
altogether like one of ours2 aswel the  
exteriour figure of its members1 as in  
the interiour conformity of its organs2 
without framing it of other matter then 
of that which ,i had described2 and     
without putting in it at the beginning  
any reasonable soul1 or any other thing 
to serve therein for a vegetative or    
sensitive soul2 unless he stirr'd up in 
his heart one of those fires without    
light which ,i had already discovered2  
and that ,i conceiv'd of no other nature

 but that which heats hay when its      
housed before it be dry1 or which causes
 new ,wines to boyl when it works upon  
the grape3 ,for examining the functions 
which might be consequently in this     
body1 ,i exactly found all those which  
may be in us1 without our thinking of   
them2 and to which our soul 7that is to 
say1 that distinct part from our bodies1
 whose nature 7as hath been said before7
 is onely to think7 consequently doth   
not contribute1 and which are all the   
same wherein we may say unreasonable    
creatures resemble us4 ,yet could ,i not
 finde any1 of those which depending    
from the thought1 are the onely ones    
which belong unto us as ,men2 whereas ,i
 found them all afterwards1 having      
supposed that ,god created a reasonable 
soul1 and that he joyn'd it to this     
body1 after a certain manner which ,i   
describ'd4  ,but that you might see how 
,i treated this matter1 ,i shall here   
present you with the explication of the 
motion of the heart1 and of the         

arteries1 which being the first and most
 general 7which is observed in animals7 
we may thereby easily judge what we     
ought to think of all the rest4 ,and    
that we may have the less difficulty to 
understand what ,i shall say thereof1 ,i
 wish those who are not versed in       
,anatomy1 would take the pains1 before  
they read this1 to cause the heart of   
some great animal which hath lungs1 to  
be dissected2 for in all of them its    
very like that of a ,man3 and that they 
may have shewn them the two cels or     
concavities which are there3 ,first that
 on the right side1 whereto two large   
conduits answer1 to wit1 the vena cava1 
which is the principal receptacle of    
bloud1 and as the body of a tree1       
whereof all the other veins of the body 
are branches2 and the arterious vein1   
which was so mis-call'd1 because that in
 effect its an artery1 which taking its 
origine from the heart1 divides it self 
after being come forth1 into divers     
branches1 which every way spred         

themselves through the lungs4 ,then the 
other which is on the left side1        
whereunto in the same manner two pipes  
answer1 which are as large1 or larger   
then the former2 to wit1 the veinous    
artery1 which was also il named1        
forasmuch as its nothing else but a vein
 which comes from the lungs1 where its  
divided into several branches interlaid 
with those of the arterious vein1 and   
those of that pipe which is called the  
,whistle1 by which the breath enters4   
,and the great artery1 which proceeding 
from the heart1 disperseth its branches 
thorow all the body4 ,i would also that 
they would carefully observe the eleven 
little skins1 which1 as so many little  
doors1 open and shut the four openings  
which are in these two concavities2 to  
wit1 three at the entry of the vena     
cava1 where they are so disposed1 that  
they can no wayes hinder the bloud which
 it contains from running into the right
 concavity of the heart2 and yet        
altogether hinder it from coming out4   

,three at the entry of the arterious    
vein2 which being disposed quite        
contrary1 permit only the bloud which is
 in that concavity to pass to the lungs2
 but not that which is in the lungs to  
return thither4 ,and then two others at 
the entry of the veinous artery1 which  
permits the bloud to run to the left    
concavity of the heart1 but opposeth its
 return4 ,and three at the entry of the 
great artery1 which permit it to go from
 the heart1 but hinder its return       
thither4 ,neither need we seek any other
 reason for the number of these skins1  
save only that the opening of the       
veinous artery1 being oval-wise1 by     
reason of its situation1 may be fitly   
shut with two2 whereas the other1 being 
round1 may the better be clos'd with    
three4 ,besides1 ,i would have them     
consider1 that the great artery and the 
arterious vein are of a composition much
 stronger then the veinous artery or the
 vena cava4 ,and that these two later   
grow larger before they enter into the  

heart1 and make 7as it were7 two purses1
 call'd the ears of the heart1 which are
 composed of a flesh like it2 and that  
there is always more heat in the heart  
then in any other part of the body4 ,and
 in fine1 that if any drop of bloud     
enter into these concavities1 this heat 
is able to make it presently swell and  
dilate it self1 as generally all liquors
 do1 when drop by drop we let them fall 
into a very hot vessel4  ,for after this
 ,i need say no more for to unfold the  
motion of the heart1 but that when these
 concavities are not full of bloud1     
necessarily there runs some from the    
vena cava into the right1 and from the  
veinous artery into the left2 for that  
these two vessels are always full of it1
 and that their openings which are      
towards the heart cannot then be shut3  
,but that assoon as there is thus but   
two drops of bloud entred1 one in either
 of these concavities1 these drops1     
which cannot but be very big1 by reason 
that their openings whereby they enter  

are very large1 and the vessels whence  
they come very full of bloud1 are       
rarified and dilated because of the heat
 which they find therein4 ,by means     
whereof1 causing all the heart to swel1 
they drive and shut the five little     
doors which are at the entry of the two 
vessels whence they come1 hindering     
thereby any more bloud to fall down into
 the heart1 and continuing more and more
 to rarifie themselves1 they drive and  
open the six other little doors which   
are at the entry of the other two       
vessels whence they issue1 causing by   
that means all the branches of the      
arterious vein1 and of the great artery1
 to swel 7as it were7 at the same time  
with the heart3 which presently after   
fals1 as those arteries also do1 by     
reason that the bloud which is entred   
therein grows colder1 and their six     
little doors shut up again1 and those   
five of the vena cava1 and of the       
veinous artery open again1 and give way 
to two other drops of bloud1 which again

 swell the heart and the arteries in the
 same manner as the preceding did4 ,and 
because the bloud which thus enters into
 the heart1 passeth thorow those two    
purses1 which are call'd the ears2      
thence it comes1 that their motion is   
contrary to the heart's1 and that they  
fall when that swels4  ,lastly1 ,that   
they who know not the force of          
,mathematical demonstrations1 and are   
not accustomed to distinguish true      
reasons from probable ones1 may not     
venture to deny this without examining  
it1 ,i shall advertise them1 that this  
motion which ,i have now discovered1 as 
necessarily follows from the onely      
disposition of the organs 7which may    
plainly be seen in the heart17 and from 
the heat 7which we may feel with our    
fingers17 and from the nature of the    
bloud 7which we may know by experience17
 as the motions of a clock doth by the  
force1 situation and figure of its      
weight and wheels4  ,but if it be asked1
 how it comes that the bloud of the     

veins is not exhausted1 running so      
continually into the heart2 and how that
 the arteries are not too full1 since   
all that which passeth thorow the heart 
dischargeth it self into them3 ,i need  
answer nothing thereto but what hath    
been already writ by an ,english        
,physician1 to whom this praise must be 
given1 to have broken the ice in this   
place1 and to be the first who taught   
us1 ,that there are several little      
passages in the extremity of the        
arteries whereby the bloud which they   
receive from the heart1 enters the      
little branches of the veins2 whence    
again it sends it self back towards the 
heart3 so that its course is no other   
thing but a perpetuall circulation4     
,which he very wel proves by the        
ordinary experience of ,chirurgians1 who
 having bound the arm indifferently hard
 above the the place where they open the
 vein1 which causeth the bloud to issue 
more abundantly1 then if it had not been
 bound4 ,and the contrary would happen1 

were it bound underneath1 between the   
hand and the incision1 or bound very    
hard above4 ,for its manifest1 that the 
band indifferently tyed1 being able to  
hinder the bloud which is already in the
 arm to return towards the heart by the 
veins2 yet it therefore hinders not the 
new from coming always by the arteries1 
by reason they are placed under the     
veins1 and that their skin being        
thicker1 are less easie to be press'd1  
as also that the bloud which comes from 
the heart1 seeks more forcibly to passe 
by them towards the hand1 then it doth  
to return from thence towards the heart 
by the veins4 ,and since this bloud     
which issues from the arm by the        
incision made in one of the veins1 must 
necessarily have some passage under the 
bond1 to wit1 towards the extremities of
 the arm1 whereby it may come thither by
 the arteries1 he also proves very well 
what he sayes of the course of the bloud
 through certain little skins1 which are
 so disposed in divers places along the 

veins1 which permit it not to pass from 
the middle towards the extremities1 but 
onely to return from the extremities    
towards the heart4 ,and besides this1   
experience shews1 ,that all the bloud   
which is in the body may in a very      
little time run out by one onely        
artery's being cut1 although it were    
even bound very neer the heart1 and cut 
betwixt it and the ligature3 ,so that we
 could have no reason to imagine that   
the bloud which issued thence could come
 from any other part4  ,but there are   
divers other things which witness1 that 
the true cause of this motion of the    
bloud is that which ,i have related4 ,as
 first1 ,the difference observed between
 that which issues out of the veins1 and
 that which comes out of the arteries1  
cannot proceed but from its being       
rarified and 7as it were7 distilled by  
passing thorow the heart3 its more      
subtil1 more lively1 and more hot       
presently after it comes out2 that is to
 say1 being in the arteries1 then it is 

a little before it enters them1 that is 
to say1 in the veins4 ,and if you       
observe1 you will finde1 that this      
difference appears not well but about   
the heart2 and not so much in those     
places which are farther off4 ,next1 the
 hardnesse of the skin of which the     
artery vein and the great artery are    
composed1 sheweth sufficiently1 that the
 bloud beats against them more forcibly 
then against the veins4 ,and why should 
the left concavity of the heart1 and the
 great artery be more large and ample   
then the right concavity1 and the       
arterious vein2 unless it were that the 
bloud of the veinous artery1 having bin 
but onely in the lungs since its passage
 thorow the heart1 is more subtil1 and  
is rarified with more force and ease    
then the bloud which immediately comes  
from the vena cava4 ,and what can the   
,physicians divine by feeling of the    
pulse1 unlesse they know1 that according
 as the bloud changeth its nature1 it   
may by the heat of the heart be rarified

 to be more or lesse strong1 and more or
 lesse quick then before4 ,and if we    
examine how this heat is communicated to
 the other members1 must we not avow    
that 'tis by means of the bloud1 which  
passing the heart1 reheats it self      
there1 and thence disperseth it self    
thorow the whole body3 whence it        
happens1 that if you take away the bloud
 from any part1 the heat by the same    
means also is taken a way4 ,and although
 the heart were as burning as hot iron1 
it were not sufficient to warm the feet 
and the hands so often as it doth1 did  
it not continue to furnish them with new
 bloud4  ,besides1 from thence we know  
also that the true use of respiration is
 to bring fresh air enough to the lungs1
 to cause that bloud which comes from   
the right concavity of the heart1 where 
it was rarified1 and 7as it were7       
chang'd into vapours1 there to thicken1 
and convert it self into bloud again1   
before it fall again into the left1     
without which it would not be fit to    

serve for the nourishment of the fire   
which is there4 ,which is confirm'd1 for
 that its seen1 that animals which have 
no lungs have but one onely concavity in
 the heart2 and that children1 who can  
make no use of them when they are in    
their mothers bellies1 have an opening1 
by which the bloud of the vena cava runs
 to the left concavity of the heart1 and
 a conduit by which it comes from the   
arterious vein into the great artery    
without passing the lungs4  ,next1 ,how 
would the concoction be made in the     
stomach1 unlesse the heart sent heat by 
the arteries1 and therewithall some of  
the most fluid parts of the bloud1 which
 help to dissolve the meat receiv'd     
therein8 and is not the act which       
converts the juice of these meats into  
bloud easie to be known1 if we consider1
 that it is distill'd by passing and    
repassing the heart1 perhaps more then  
one or two hundred times a day8 ,and    
what need we ought else to explain the  
nutrition and the production of divers  

humours which are in the body1 but to   
say1 that the force wherewith the bloud 
in rarifying it self1 passeth from the  
heart towards the extremities or the    
arteries1 causeth some of its parts to  
stay amongst those of the members where 
they are1 and there take the place of   
some others1 which they drive from      
thence8 ,and that according to the      
situation1 or the figure1 or the        
smalnesse of the pores which they meet1 
some arrive sooner in one place then    
others4 ,in the same manner as we may   
have seen in severall sieves1 which     
being diversly pierc'd1 serve to sever  
divers grains one from the other4 ,and  
briefly1 that which is most remarkable  
herein1 is the generation of the animal 
spirits1 which are as a most subtil     
wind1 or rather1 as a most pure and     
lively flame1 which continually rising  
in great abundance from the heart to the
 brain1 dischargeth it self thence by   
the nerves into the muscles1 and gives  
motion to all the members2 without      

imagining any other reason which might  
cause these parts of the bloud1 which   
being most mov'd1 and the most          
penetrating1 are the most fit to form   
these spirits1 tend rather towards the  
brain1 then to any other part4 ,save    
onely that the arteries which carry them
 thither1 are those which come from the 
heart in the most direct line of all3   
,and that according to the rules of the 
,mechanicks1 which are the same with    
those of ,nature1 when divers things    
together strive to move one way1 where  
there is not room enough for all2 so    
those parts of bloud which issue from   
the left concavity of the heart tend    
towards the brain1 the weaker and less  
agitated are expell'd by the stronger1  
who by that means arrive there alone4   
,i had particularly enough expounded all
 these things in a ,treatise which ,i   
formerly had design'd to publish3 ,in   
pursuit whereof1 ,i had therein shewed  
what ought to be the fabrick of the     
nerves and muscles of an humane body1 to

 cause those animall spirits which were 
in them1 to have the power to move those
 members4 ,as we see that heads a while 
after they are cut off1 yet move of     
themselves1 and bite the ground1        
although they are not then animated4    
,what changes ought to be made in the   
brain to cause waking1 sleeping1 and    
dreaming3 how light1 sounds1 smels1     
tasts1 heat1 and all other qualities of 
exteriour objects1 might imprint        
severall ,ideas by means of the senses4 
,how hunger and thirst1 and the other   
interiour passions might also send      
theirs thither4 ,what ought to be taken 
therein for common sense1 where these   
,ideas are received2 for memory which   
preserves them2 and for fancy1 which can
 diversly change them1 and form new ones
 of them2 and by the same means1        
distributing the animal spirits into the
 muscles1 make the members of the body  
move in so many severall fashions1 and  
as fitly to those objects which present 
themselves to its senses2 and to the    

interiour passions which are in them1 as
 ours may move themselves without the   
consent of the ,wil4 ,which wil seem    
nothing strange to those1 who knowing   
how many ,automatas or moving ,machines 
the industry of men can make1 imploying 
but very few pieces1 in comparison of   
the great abundance of bones1 muscles1  
nerves1 arteries1 veins1 and all the    
other parts which are in the body of    
every ,animal1 will consider this body  
as a fabrick1 which having been made by 
the hands of ,god1 is incomparably      
better ordered1 and hath more admirable 
motions in it then any of those which   
can be invented by men4 ,and herein ,i  
particularly insisted1 to make it       
appear1 that if there were such         
,machines which had organs1 and the     
exteriour figure of an ,ape1 or of any  
other unreasonable creature1 we should  
finde no means of knowing them not to be
 altogether of the same nature as those 
,animals3 whereas1 if there were any    
which resembled our bodies1 and imitated

 our actions as much as morally it were 
possible1 we should always have two most
 certain ways to know1 that for all that
 they were not reall men3 ,the first of 
which is1 that they could never have the
 use of speech1 nor of other signes in  
framing it1 as we have1 to declare our  
thoughts to others3 for we may well     
conceive1 that a ,machine may be so     
made1 that it may utter words1 and even 
some proper to the corporal actions1    
which may cause some change in its      
organs2 as if we touch it in some part1 
and it should ask what we would say2 or 
so as it might cry out that one hurts   
it1 and the like3 but not that they can 
diversifie them to answer sensibly to   
all what shall be spoken in its         
presence1 as the dullest men may do4    
,and the second is1 ,that although they 
did divers things aswel1 or perhaps     
better1 then any of us1 they must       
infallibly fail in some others1 whereby 
we might discover that they act not with
 knowledge1 but onely by the disposition

 of their organs3 for whereas ,reason is
 an universal instrument which may serve
 in all kinde of encounters1 these      
organs have need of some particular     
disposition for every particular action3
 whence it is1 that its morally         
impossible for one ,machine to have     
severall organs enough to make it move  
in all the occurrences of this life1 in 
the same manner as our ,reason makes us 
move4 ,now by these two means we may    
also know the difference which is       
between ,men and ,beasts3 ,for 'tis a   
very remarkable thing1 that there are no
 men so dull and so stupid1 without     
excepting those who are out of their    
wits1 but are capable to rank severall  
words together1 and of them to compose a
 ,discourse1 by which they make known   
their thoughts3 and that on the         
contrary1 there is no other creature1   
how perfect or happily soever brought   
forth1 which can do the like4 ,the which
 happens1 not because they want organs2 
for we know1 that ,pyes and ,parrots can

 utter words even as we can1 and yet    
cannot speak like us2 that is to say1   
with evidence that they think what they 
say4 ,whereas ,men1 being born deaf and 
dumb1 and deprived of those organs which
 seem to make others speak1 as much or  
more then beasts1 usually invent of     
themselves to be understood by those1   
who commonly being with them1 have the  
leisure to learn their expressions4 ,and
 this not onely witnesseth1 that ,beasts
 have lesse reason than men1 but that   
they have none at all4 ,for we see there
 needs not much to learn to speak3 and  
forasmuch as we observe inequality      
amongst ,beasts of the same kind1 aswell
 as amongst men1 and that some are more 
easily managed then others2 'tis not to 
be believed1 but that an ,ape or a      
,parrot which were the most perfect of  
its kinde1 should therein equall the    
most stupid child1 or at least a child  
of a distracted brain1 if their souls   
were not of a nature wholly different   
from ours4 ,and we ought not to confound

 words with naturall motions1 which     
witness passions1 and may be imitated by
 ,machines aswell as by ,animals2 nor   
think 7as some of the ,ancients7 that   
beasts speak1 although we do not        
understand their language3 for if it    
were true1 since they have divers organs
 which relate to ours1 they could aswell
 make themselves understood by us1 as by
 their like4 ,its likewise very         
remarkable that although there are      
divers creatures which express more     
industry then we in some one of their   
actions2 yet we may well perceive1 that 
the same shew none at all in many       
others3 ,so that what they do better    
then we1 proves not at all that they    
have reason2 for by that reckoning they 
would have more then any of us1 and     
would do better in all other things2 but
 rather1 that they have none at all1 and
 that its ,nature onely which works in  
them according to the disposition of    
their organs4 ,as wee see a ,clock1     
which is onely composed of wheels and   

springs1 can reckon the hours1 and      
measure the times more exactly then we  
can with all our prudence4  ,after this 
,i had described the reasonable ,soul1  
and made it appear1 that it could no way
 be drawn from the power of the ,matter1
 as other things whereof ,i had spoken2 
but that it ought to have been expresly 
created3 ,and how it suffiseth not for  
it to be lodg'd in our humane body as a 
,pilot in his ship1 to move its members 
onely2 but also that its necessary it be
 joyned and united more strongly        
therewith to have thoughts and appetites
 like ours1 and so make a reall man4  ,i
 have here dilated my self a little on  
the subject of the ,soul1 by reason 'tis
 of most importance2 for1 next the      
errour of those who deny ,god1 which ,i 
think ,i have already sufficiently      
confuted1 there is none which sooner    
estrangeth feeble minds from the right  
way of vertue1 then to imagine that the 
soul of beasts is of the same nature as 
ours1 and that consequently we have     

nothing to fear nor hope after this     
life1 no more then flies or ants4       
,whereas1 when we know how different    
they are1 we comprehend much better the 
reasons which prove that ours is of a   
nature wholly independing from the body1
 and consequently that it is not subject
 to die with it4 ,and that when we see  
no other cause which destroys it1 we are
 naturally thence moved to judge that   
it's immortall4     ,,part4 ,,vi4   ,its
 now three years since ,i ended the     
,treatise which contains all these      
things1 and that ,i began to review it1 
to send it afterwards to the ,presse1   
when ,i understood1 that persons to whom
 ,i submit1 and whose authority can no  
lesse command my actions1 then my own   
,reason doth my thoughts1 had           
disapproved an opinion in ,physicks1    
published a little before by another2 of
 which ,i will not say that ,i was1 but 
that indeed ,i had observed nothing     
therein1 before their censure1 which ,i 
could have imagined prejudiciall either 

to ,religion or the ,state2 or          
consequently1 which might have hindred  
me from writing the same1 had my ,reason
 perswaded mee thereto4 ,and this made  
me fear1 lest in the same manner there  
might be found some one amongst mine1 in
 which ,i might have been mistaken2     
notwithstanding the great care ,i always
 had to admit no new ones into my       
belief1 of which ,i had not most certain
 demonstrations2 and not to write such  
as might turn to the disadvantage of any
 body4 ,which was sufficient to oblige  
me to change my resolution of publishing
 them4 ,for although the reasons for    
which ,i had first of all taken it1 were
 very strong2 yet my inclination1 which 
alwayes made me hate the trade of       
,book-making1 presently found me out    
others enough to excuse my self from it4
 ,and these reasons on the one and other
 side are such1 that ,i am not only     
somewhat concern'd to speak them2 but   
happily the ,publick also to know them4 
,i never did much esteem those things   

which proceeded from mine own brain2 and
 so long as ,i have gathered no other   
fruits from the ,method ,i use1 but     
onely that ,i have satisfied my self in 
some difficulties which belong to       
speculative ,sciences1 or at least      
endeavoured to regulate my ,manners by  
the reasons it taught me1 ,i thought my 
self not obliged to write any thing of  
them4 ,for1 as for what concerns        
,manners1 every one abounds so much in  
his own sense1 ,that we may finde as    
many ,reformers as heads1 were it       
permitted to others1 besides those whom 
,god hath established as ,soveraigns    
over his people1 or at least1 to whom he
 hath dispensed grace and zeal enough to
 be ,prophets1 to undertake the change  
of any thing therein4 ,and although my  
,speculations did very much please me1  
,i did beleeve that other men also had  
some1 which perhaps pleas'd them more4  
,but as soon as ,i had acquired some    
generall notions touching naturall      
,philosophy1 and beginning to prove them

 in divers particular difficulties1 ,i  
observed how far they might lead a man1 
and how far different they were from the
 principles which to this day are in    
use2 ,i judg'd1 that ,i could not keep  
them hid without highly sinning against 
the ,law1 which obligeth us to procure1 
as much as in us lies1 the general good 
of all men4 ,for they made it appear to 
me1 that it was possible to attain to   
points of knowledge1 which may be very  
profitable for this life3 and that in   
stead of this speculative ,philosophy   
which is taught in the ,schools1 we     
might finde out a practicall one1 by    
which knowing the force and workings of 
,fire1 ,water1 ,air1 of the ,starrs1 of 
the ,heavens1 and of all other ,bodies  
which environ us1 distinctly1 as we know
 the several trades of our ,handicrafts1
 we might in the same manner employ them
 to all uses to which they are fit1 and 
so become masters and possessours of    
,nature4 ,which is not onely to be      
desired for the invention of very many  

expedients of ,arts1 which without      
trouble might make us enjoy the fruits  
of the earth1 and all the conveniences  
which are to be found therein3 ,but     
chiefly also for the preservation of    
health1 which 7without doubt7 is the    
first good1 and the foundation of all   
other good things in this life4 ,for    
even the minde depends so much on the   
temper and disposition of the organs of 
the body1 that if it be possible to     
finde any way of making men in the      
generall wiser1 and more able then      
formerly they were1 ,i beleeve it ought 
to be sought in ,physick4 ,true it is1  
that which is now in use contains but   
few things1 whose benefit is very       
remarkable3 ,but 7without any designe of
 slighting of it7 ,i assure my self1    
there is none1 even of their own        
profession1 but will consent1 that      
whatsoever is known therein1 is almost  
nothing in companion of what remains to 
be known4 ,and that we might be freed   
from very many diseases1 aswell of the  

body as of the mind1 and even also      
perhaps from the weaknesses of old age1 
had we but knowledge enough of their    
,causes1 and of all the ,remedies       
wherewith ,nature hath furnished us4    
,now having a designe to employ all my  
life in the enquiry of so necessary a   
,science2 and having found a way1 the   
following of which me thinks might      
infallibly lead us to it1 unless we be  
hindred by the shortness of life1 or by 
defect of experiments4 ,i judg'd that   
there was no better ,remedie against    
those two impediments1 but faithfully to
 communicate to the publique1 all that  
little ,i should discover1 and to invite
 all good ,wits to endevour to advance  
farther in contributing every one1      
according to his inclination and power1 
to those ,experiments which are to be   
made1 and communicating also to the     
publique all the things they should     
learn2 so that the last1 beginning where
 the precedent ended1 and so joyning the
 lives and labors of many in one1 we    

might all together advance further then 
any particular ,man could do4  ,i also  
observ'd touching ,experiments1 that    
they are still so much the more         
necessary1 as we are more advanc'd in   
knowledg4 ,for in the beginning it's    
better to use those only which of       
themselves are presented to our senses1 
and which we cannot be ignorant of1 if  
we do but make the least reflections    
upon them1 then to seek out the rarest  
and most studied ones4 ,the reason      
whereof is1 that those which are rarest1
 doe often deceive1 when we seldome know
 the same of the most common ones1 and  
that the circumstances on which they    
depend1 are1 as it were1 always so      
particular1 and so small1 that it's very
 uneasie to finde them out4 ,but the    
order ,i observed herein was this4      
,first1 ,i endevoured to finde in       
generall the ,principles or first       
,causes of whatsoever is or may be in   
the world1 without considering any thing
 for this end1 but ,god alone who       

created it1 or drawing them elsewhere1  
then from certain seeds of ,truth which 
naturally are in our souls4 ,after this1
 ,i examined what were the first and    
most ordinary ,effects which might be   
deduced from these ,causes3 ,and me     
thinks that thereby ,i found out        
,heavens1 ,starrs1 an ,earth2 and even  
on the ,earth1 ,water1 ,air and ,fire1  
,minerals1 and some other such like     
things1 which are the most common1 and  
the most simple of all1 and consequently
 the most easie to be understood4       
,afterwards1 when ,i would descend to   
those which were more particular1 there 
were so many severall ones presented    
themselves to me1 that ,i did beleeve it
 impossible for a humane understanding  
to distinguish the forms and species of 
,bodies which are on the earth1 from an 
infinite number of others which might be
 there1 had it been the will of ,god so 
to place them3 ,nor by consequence to   
apply them to our use1 unless we set the
 ,effects before the ,causes1 and make  

use of divers particular experiments2   
,in relation to which1 revolving in my  
minde all those objects which ever were 
presented to my senses1 ,i dare boldly  
say1 ,i observed nothing which ,i could 
not fitly enough explain by the         
principles ,i had found4 ,but ,i must   
also confesse that the power of ,nature 
is so ample and vast1 and these         
principles are so simple and generall1  
that ,i can observe almost no particular
 ,effect1 but that ,i presently know it 
might be deduced from thence in many    
severall ways3 and that commonly my     
greatest difficulty is to finde in which
 of these ways it depends thereon2 for  
,i know no other expedient for that1 but
 again to seek some experiments1 which  
may be such1 that their event may not be
 the same1 if it be in one of those ways
 which is to be exprest1 as if it were  
in another4 ,in fine1 ,i am gotten so   
far1 ,that 7me thinks7 ,i see well      
enough what course we ought to hold to  
make the most part of those experiments 

which may tend to this effect4 ,but ,i  
also see they are such1 and of so great 
a number1 that neither my hands nor my  
estate 7though ,i had a thousand times  
more then ,i have7 could ever suffice   
for all4 ,so that according as ,i shall 
hereafter have conveniency to make more 
or fewer of them1 ,i shall also advance 
more or lesse in the knowledge of       
,nature1 which ,i hop'd ,i should make  
known by the ,treatise which ,i had     
written2 and therein so clearly shew the
 benefit which the ,publick may receive 
thereby1 that ,i should oblige all those
 in general who desire the good of      
,mankinde2 that is to say1 all those who
 are indeed vertuous1 7and not so       
seemingly1 or by opinion only7 aswell to
 communicate such experiments as they   
have already made1 as to help me in the 
enquiry of those which are to be made4  
,but since that time1 other reasons have
 made me alter my opinion1 and think    
that ,i truly ought to continue to write
 of all those things which ,i judg'd of 

any importance1 according as ,i should  
discover the truth of them1 and take the
 same care1 as if ,i were to print them2
 as well that ,i might have so much the 
more occasion throughly to examine them2
 as without doubt1 we always look more  
narrowly to what we offer to the publick
 view1 then to what we compose onely for
 our own use3 and oftentimes the same   
things which seemed true to me when ,i  
first conceived them1 appear'd          
afterwards false to me1 when ,i was     
committing them to paper3 as also that  
,i might lose no occasion of benefiting 
the ,publick1 if ,i were able1 and that 
if my ,writings were of any value1 those
 to whose hands they should come after  
my death1 might to make what use of them
 they think fit4  ,but that ,i ought not
 any wayes to consent that they should  
be published during my life2 ,that      
neither the opposition and              
controversies1 whereto perhaps they     
might be obnoxious1 nor even the        
reputation whatsoever it were1 which    

they might acquire me1 might give me any
 occasion of mispending the time ,i had 
design'd to employ for my instruction2  
for although it be true that every ,man 
is oblig'd to procure1 as much as in him
 lies1 the good of others2 and that to  
be profitable to no body1 is properly to
 be good for nothing3 ,yet it's as true1
 that our care ought to reach beyond the
 present time2 and that it were good to 
omit those things which might perhaps   
conduce to the benefit of those who are 
alive1 when our designe is1 to doe      
others which shall prove farr more      
advantagious to our posterity2 ,as      
indeed ,i desire it may be known that   
the little ,i have learnt hitherto1 is  
almost nothing in comparison of what ,i 
am ignorant of2 and ,i doe not despair  
to be able to learn3 ,for it's even the 
same with those1 who by little and      
little discover the truth in ,learning2 
as with those who beginning to grow     
rich1 are less troubled to make great   
purchases1 then they were before when   

they were poorer1 to make little ones4  
,or else one may compare them to        
,generals of ,armies1 whose ,forces     
usually encrease porportionably to their
 ,victories2 and who have need of more  
conduct to maintain themselves after the
 loss of a battail1 then after the      
gaining one1 to take ,towns and         
,provinces4 ,for to endeavour to        
overcome all the difficulties and       
errours which hinder us to come to the  
knowledg of the ,truth1 is truly to     
fight battails4 ,and to receive any     
false opinion touching a generall or    
weighty matter1 is as much as to lose   
one2 there is far more dexterity        
required to recover our former          
condition1 then to make great progresses
 where our ,principles are already      
certain4 ,for my part1 if ,i formerly   
have discovered some ,truths in         
,learning1 as ,i hope my ,discourse will
 make it appear ,i have1 ,i may say1    
they are but the products and           
dependances of five or six principall   

difficulties which ,i have overcome1 and
 which ,i reckon for so many won        
,battails on my side4 ,neither will ,i  
forbear to say2 ,that ,i think1 ,it's   
only necessary for me to win two or     
three more such1 wholly to perfect my   
design4 ,and that ,i am not so old1 but 
according to the ordinary course of     
,nature1 ,i may have time enough to     
effect it4 ,but ,i beleeve ,i am so much
 the more obliged to husband the rest of
 my time1 as ,i have more hopes to      
employ it well2 without doubt1 ,i should
 have divers occasions of impeding it1  
should ,i publish the grounds of my     
,physicks4 ,for although they are almost
 all so evident1 that to beleeve them1  
it's needfull onely to understand them2 
and that there is none whereof ,i think 
my self unable to give demonstration4   
,yet because it's impossible that they  
should agree with all the severall      
opinions of other men1 ,i foresee ,i    
should often be diverted by the         
opposition they would occasion4  ,it may

 be objected1 ,these oppositions might  
be profitable1 as well to make me know  
my faults1 as if any thing of mine were 
good to make others by that means come  
to a better understanding thereof2 and  
as many may see more then one man1      
beginning from this time to make use of 
my grounds1 they might also help me with
 their invention4 ,but although ,i know 
my self extremely subject to fail1 and  
do never almost trust my first thoughts2
 yet the experience ,i have of the      
objections which may be made unto me1   
hinder me from hoping for any profit    
from them2 ,for ,i have often tried the 
judgments as well of those whom ,i      
esteem'd my friends1 as of others whom  
,i thought indifferent1 and even also of
 some1 whose malignity and envie did    
sufficiently discover what the affection
 of my friends might hide4 ,but it      
seldom happened that any thing was      
objected against me1 which ,i had not   
altogether foreseen1 unless it were very
 remote from my ,subject3 ,so that ,i   

never almost met with any ,censurer of  
my opinions1 that seemed unto me either 
less rigorous1 or less equitable then my
 self4 ,neither did ,i ever observe1    
that by the disputations practiced in   
the ,schools any ,truth which was       
formerly unknown1 was ever discovered4  
,for whilest every one seeks to         
overcome1 men strive more to maintain   
probabilities1 then to weigh the reasons
 on both sides2 and those who for a long
 time have been good ,advocates1 are not
 therefore the better ,judges           
afterwards4  ,as for the benefit which  
others may receive from the             
communication of my thoughts1 it cannot 
also be very great1 forasmuch as ,i have
 not yet perfected them1 but that it is 
necessary to add many things thereunto1 
before a usefull application can be made
 of them4 ,and ,i think ,i may say      
without vanity1 ,that if there be any   
one capable thereof1 it must be my self1
 rather then any other4 ,not but that   
there may be divers wits in the world   

incomparably better then mine2 but      
because men cannot so well conceive a   
thing and make it their own1 when they  
learn it of another1 as when they invent
 it themselves3 which is so true in this
 ,subject1 that although ,i have often  
explain'd some of my opinions to very   
understanding men1 and who1 whilest ,i  
spake to them1 seem'd very distinctly to
 conceive them2 yet when they repeated  
them1 ,i observ'd1 that they chang'd    
them almost always in such a manner1    
that ,i could no longer own them for    
mine4 ,upon which occasion1 ,i shall    
gladly here desire those who come after 
me1 never to beleeve those things which 
may be delivered to them for mine1 when 
,i have not published them my self4 ,and
 ,i do not at all wonder at the         
extravagancies which are attributed to  
all those ancient ,philosophers1 whose  
,writings we have not2 neither do ,i    
thereby judge1 that their thoughts were 
very irrationall1 seeing they were the  
best ,wits of their time2 but onely that

 they have been ill convey'd to us3 as  
it appears also1 that never any of their
 followers surpass'd them4 ,and ,i      
assure my self1 that the most passionate
 of those1 who now follow ,aristotle1   
would beleeve himself happy1 had he but 
as much knowledge of ,nature as he had1 
although it were on condition that he   
never might have more3 ,they are like   
the ivie1 which seeks to climb no higher
 then the trees which support it1 and   
ever after tends downwards again when it
 hath attain'd to the height thereof3   
for1 me thinks also1 that such men sink 
downwards2 that is to say1 render       
themselves in some manner lesse knowing1
 then if they did abstain from studying2
 who being not content to know all which
 is intelligibly set down in their      
,authour1 will besides that1 finde out  
the solution of divers difficulties of  
which he says nothing1 and perhaps never
 thought of them3 yet their way of      
,philosophy is very fit for those who   
have but mean capacities3 ,for the      

obscurity of the distinctions and       
principles which they use causeth them  
to speak of all things as boldly1 as if 
they knew them1 and maintain all which  
they say1 against the most subtill and  
most able2 so that there is no means    
left to convince them4 ,wherein they    
seem like to a blinde man1 who1 to fight
 without disadvantage against one that  
sees1 should challenge him down into the
 bottom of a very dark cellar3 ,and ,i  
may say1 that it is these mens interest1
 that ,i should abstain from publishing 
the principles of the ,philosophy ,i    
use1 for being most simple and most     
evident1 as they are1 ,i should even do 
the same in publishing of them1 as if ,i
 opened some windows1 to let the day    
into this cellar1 into which they go    
down to fight4 ,but even the best ,wits 
have no reason to wish for the knowledge
 of them3 for if they will be able to   
speak of all things1 and acquire the    
reputation of being learned1 they will  
easily attain to it by contenting       

themselves with probability1 which      
without much trouble may be found in all
 kinde of matters2 then in seeking the  
,truth1 which discovers it self but by  
little and little1 in some few things2  
and which1 when we are to speak of      
others1 oblige us freely to confesse our
 ignorance of them4 ,but if they prefer 
the knowledge of some few truths to the 
vanity of seeming to be ignorant of     
nothing1 as without doubt they ought to 
do1 and will undertake a designe like   
mine1 ,i need not tell them any more for
 this purpose1 but what ,i have already 
said in this ,discourse3 ,for if they   
have a capacity to advance farther then 
,i have done1 they may with greater     
consequence finde out of themselves     
whatsoever ,i think ,i have found2      
,forasmuch as having never examined any 
thing but by order1 it's certain1 that  
what remains yet for me to discover1 is 
in it self more difficult and more hid1 
then what ,i have already here before   
met with2 and they would receive much   

less satisfaction in learning it from   
me1 then from themselves4 ,besides that1
 the habit which they would get by      
seeking first of all the easie things1  
and passing by degrees to others more   
difficult1 will be more usefull to them1
 then all my instructions4 ,as ,i for my
 part am perswaded1 that had ,i been    
taught from my youth all the ,truths    
whose demonstrations ,i have discovered 
since1 and had taken no pains to learn  
them1 perhaps ,i should never have known
 any other1 or at least1 ,i should never
 have acquired that habit1 and that     
faculty which ,i think ,i have1 still to
 finde out new ones1 as ,i apply my self
 to the search of them4 ,and in a word1 
if there be in the world any work which 
cannot be so well ended by any other1 as
 by the same who began it1 it's that    
which ,i am now about4  ,it's true1     
,that one man will not be sufficient to 
make all the experiments which may      
conduce thereunto3 ,but withall1 he     
cannot profitably imploy other hands    

then his own1 unlesse it be those of    
,artists1 or others whom he hires1 and  
whom the hope of profit 7which is a very
 powerfull motive7 might cause exactly  
to do all those things he should appoint
 them3 ,for as for voluntary persons1   
who by curiosity or a desire to learn1  
would perhaps offer themselves to his   
help1 besides that commonly they promise
 more then they perform1 and make onely 
fair propositions1 whereof none ever    
succeeds1 they would infallibly be paid 
by the solution of some difficulties1 or
 at least by complements and            
unprofitable entertainments1 which could
 not cost him so little of his time1 but
 he would be a loser thereby4 ,and for  
the ,experiments which others have      
already made1 although they would even  
communicate them to him 7which those who
 call them ,secrets would never do17    
they are for the most part composed of  
so many circumstances1 or superfluous   
ingredients1 that it would be very hard 
for him to decypher the truth of them3  

,besides1 he would find them all so ill 
exprest1 or else so false1 by reason    
that those who made them have laboured  
to make them appear conformable to their
 principles2 that if there were any     
which served their turn1 they could not 
at least be worth the while which must  
be imployed in the choice of them4 ,so  
that1 if there were any in the world    
that were certainly known to be capable 
of finding out the greatest things1 and 
the most profitable for the ,publick    
which could be1 and that other men would
 therefore labour alwayes to assist him 
to accomplish his ,designes2 ,i do not  
conceive that they could do more for    
him1 then furnish the expence of the    
experiments whereof he stood in need2   
and besides1 take care only that he may 
not be by any body hindred of his time4 
,but besides that1 ,i do not presume so 
much of my ,self1 as to promise any     
thing extraordinary1 neither do ,i feed 
my self with such vain hopes1 as to     
imagine that the ,publick should much   

interesse it self in my designes2 ,i    
have not so base a minde1 as to accept  
of any favour whatsoever1 which might be
 thought ,i had not deserved4  ,all     
these considerations joyned together1   
were the cause three years since why ,i 
would not divulge the ,treatise ,i had  
in hand2 and which is more1 that ,i     
resolved to publish none whilest ,i     
lived1 which might be so general1 as    
that the ,grounds of my ,philosophy     
might be understood thereby4 ,but since1
 there hath been two other reasons have 
obliged me to put forth some particular 
,essays1 and to give the ,publick some  
account of my ,actions and ,designes4   
,the first was1 that if ,i failed       
therein1 divers who knew the intention  
,i formerly had to print some of my     
,writings1 might imagine that the causes
 for which ,i forbore it1 might be more 
to my disadvantage then they are4 ,for  
although ,i do not affect glory in      
excess2 or even1 7if ,i may so speak7   
that ,i hate it1 as far as ,i judge it  

contrary to my rest1 which ,i esteem    
above all things3 ,yet also did ,i never
 seek to hide my actions as crimes1     
neither have ,i been very wary to keep  
my self unknown2 as well because ,i     
thought ,i might wrong my self1 as that 
it might in some manner disquiet me1    
which would again have been contrary to 
the perfect repose of my minde which ,i 
seek4 ,and because having alwayes kept  
my self indifferent1 caring not whether 
,i were known or no1 ,i could not chuse 
but get some kinde of reputation1 ,i    
thought that ,i ought to do my best to  
hinder it at least from being ill4 ,the 
other reason which obliged me to write  
this1 is1 that observing every day more 
and more the designe ,i have to instruct
 my self1 retarded by reason of an      
infinite number of experiments which are
 needful to me1 and which its impossible
 for me to make without the help of     
others2 although ,i do not so much      
flatter my self1 as to hope that the    
,publick1 shares much in my             

concernments2 yet will ,i not also be so
 much wanting to my self1 as to give any
 cause to those who shall survive me1 to
 reproach this1 one day to me1 ,that ,i 
could have left them divers things far  
beyond what ,i have done1 had ,i not too
 much neglected to make them understand 
wherein they might contribute to my     
designe4  ,and ,i thought it easie for  
me to choose some matters1 which being  
not subject to many ,controversies1 nor 
obliging me to declare any more of my   
,principles then ,i would willingly1    
would neverthelesse expresse clearly    
enough1 what my abilities or defects are
 in the ,sciences4 ,wherein ,i cannot   
say whether ,i have succeeded or no2    
neither will ,i prevent the judgment of 
any man by speaking of my own ,writings3
 but ,i should be glad they might be    
examin'd2 and to that end ,i beseech all
 those who have any objections to make1 
to take the pains to send them to my    
,stationer1 that ,i being advertised by 
him1 may endeavour at the same time to  

adjoyn my ,answer thereunto3 and by that
 means1 the ,reader seeing both the one 
and the other1 may the more easily judge
 of the ,truth4 ,for ,i promise1 that ,i
 will never make any long ,answers1 but 
only very freely confesse my own faults1
 if ,i find them2 or if ,i cannot       
discover them1 plainly say what ,i shal 
think requisite in defence of what ,i   
have writ1 without adding the           
explanation of any new matter1 that ,i  
may not endlesly engage my self out of  
one into another4  ,now if there be any 
whereof ,i have spoken in the beginning1
 of the ,opticks and of the ,meteors1   
which at first jarr1 by reason that ,i  
call them ,suppositions1 and that ,i    
seem not willing to prove them2 let a   
man have but the patience to read the   
whole attentively1 and ,i hope he will  
rest satisfied3 ,for 7me thinks7 the    
reasons follow each other so closely1   
that as the later are demonstrated by   
the former1 which are their ,causes2 the
 former are reciprocally proved by the  

later1 which are their ,effects4 ,and no
 man can imagine that ,i herein commit  
the fault which the ,logicians call a   
,circle2 for experience rendring the    
greatest part of these effects most     
certain1 the causes whence ,i deduce    
them serve not so much to prove1 as to  
explain them2 but on the contrary1 they 
are those which are proved by them4     
,neither named ,i them ,suppositions1   
that it might be known that ,i conceive 
my self able to deduce them from those  
first ,truths which ,i have before      
discovered3 ,but that ,i would not      
expresly do it to crosse certain        
spirits1 who imagine that they know in a
 day al what another may have thought in
 twenty yeers1 as soon as he hath told  
them but two or three words2 and who are
 so much the more subject to erre1 and  
less capable of the ,truth1 7as they are
 more quick and penetrating7 from taking
 occasion of erecting some extravagant  
,philosophy on what they may beleeve to 
be my ,principles1 and lest the fault   

should be attributed to me4 ,for as for 
those opinions which are wholly mine1 ,i
 excuse them not as being new1 because  
that if the reasons of them be seriously
 considered1 ,i assure my self1 they    
will be found so plain1 and so agreeable
 to common sense1 that they will seem   
less extraordinary and strange then any 
other which may be held on the same     
,subjects4 ,neither do ,i boast that ,i 
am the first ,inventor of any of them2  
but of this indeed1 that ,i never       
admitted any of them1 neither because   
they had1 or had not been said by       
others1 but only because ,reason        
perswaded me to them4  ,if ,mechanicks  
cannot so soon put in practise the      
,invention which is set forth in the    
,opticks1 ,i beleeve that therefore men 
ought not to condemn it2 forasmuch as   
skill and practice are necessary for the
 making and compleating the ,machines ,i
 have described2 so that no circumstance
 should be wanting4 ,i should no less   
wonder if they should succeed at first  

triall1 then if a man should learn in a 
day to play excellently well on a ,lute1
 by having an exact piece set before    
him4 ,and if ,i write in ,french1 which 
is the language of my ,country1 rather  
then in ,latin1 which is that of my     
,tutors1 'tis because ,i hope such who  
use their meer naturall reason1 wil     
better judge of my opinions1 then those 
who only beleeve in old ,books4 ,and for
 those who joyn a right understanding   
with study1 7who ,i only wish for my    
,judges7 ,i assure my self1 they will   
not be so partiall to the ,latin1 as to 
refuse to read my reasons because ,i    
expresse them in a vulgar tongue4  ,to  
conclude1 ,i will not speak here in     
particular of the progresse ,i hoped to 
make hereafter in ,learning2 ,nor engage
 my self by any promise to the ,publick1
 which ,i am not certain to perform4    
,but ,i shall onely say1 ,that ,i am    
resolved to employ the remainder of my  
life in no other thing but the study to 
acquire some such knowledge of ,nature  

as may furnish us with more certain     
rules in ,physick then we hitherto have 
had3 ,and that my inclination drives me 
so strongly from all other kind of      
designes1 chiefly from those which      
cannot be profitable to any1 but by     
prejudicing others2 that if any occasion
 obliged me to spend my time therein1 ,i
 should beleeve ,i should never succeed 
therein3 which ,i here declare1 though  
,i well know it conduceth not to make me
 considerable in the world2 neither is  
it my ambition to be so4 ,and ,i shall  
esteem my self always more obliged to   
those by whose favour ,i shal without   
disturbance enjoy my ease1 then to them 
who should proffer me the most          
honourable imployment of the earth4     
,,finis4                                
----------------------------------------
----------------------                  
,transcriber's ,notes and ,errata       
,one instance each of what-ever and     
whatever were found       in the        
orignal4                                

,the following typographical errors were
 corrected3                             
,error         ,correction              
or            our                       
,phpsick       ,physick                 
moreworthy    more worthy               
examinanation examination               
mnner         manner                    
propable      probable                  
rape          grape                     
veuture       venture                   
circumstrance circumstance              
----------------------------------------
----------------------