[pg/etext93/dcart10.txt]

This work is one of the most influential in history.  The famous
phrase, "COGITO ERGO SUM" (I think, therefore I am) is a central
theme.  Descartes' beliefs on that dual nature of mind and body,
and his emphasis on the role of doubt in all inquiry, formed the
basis for centuries of science and social thought.

This etext was created by Ilana and Greg Newby.  They used a Mac
IIci and Apple One Flatbed Scanner donated by Apple.  Caere text
scanning and character recognition software (OmniPage) was used.
Greg is a professor in the U. of Illinois at Urbana-Champaign in
the Grad. School of Library and Information Science.  Ilana is a
reference librarian at the Urbana Free Library.  Thanks to Apple
and Caere for their donations and to the Computer Service Office
of the University of Illinois for their unofficial support.



        DISCOURSE ON THE METHOD OF RIGHTLY CONDUCTING THE REASON,
                   AND SEEKING TRUTH IN THE SCIENCES

                           by Rene Descartes



PREFATORY NOTE BY THE AUTHOR

If this Discourse appear too long to be read at once, it may be divided
into six Parts:  and, in the first, will be found various considerations
touching the Sciences; in the second, the principal rules of the Method
which the Author has discovered, in the third, certain of the rules of
Morals which he has deduced from this Method; in the fourth, the
reasonings by which he establishes the existence of God and of the Human
Soul, which are the foundations of his Metaphysic; in the fifth, the order
of the Physical questions which he has investigated, and, in particular,
the explication of the motion of the heart and of some other difficulties
pertaining to Medicine, as also the difference between the soul of man and
that of the brutes; and, in the last, what the Author believes to be
required in order to greater advancement in the investigation of Nature
than has yet been made, with the reasons that have induced him to write.



PART 1

Good sense is, of all things among men, the most equally distributed; for
every one thinks himself so abundantly provided with it, that those even
who are the most difficult to satisfy in everything else, do not usually
desire a larger measure of this quality than they already possess.  And in
this it is not likely that all are mistaken the conviction is rather to be
held as testifying that the power of judging aright and of distinguishing
truth from error, which is properly what is called  good sense or reason,
is by nature equal in all men; and that the diversity of our opinions,
consequently, does not arise from some being endowed with a larger share
of reason than others, but solely from this, that we conduct our thoughts
along different ways, and do not fix our attention on the same objects.
For to be possessed of a vigorous mind is not enough; the prime requisite
is rightly to apply it.  The greatest minds, as they are capable of the
highest excellences, are open likewise to the greatest aberrations; and
those who travel very slowly may yet make far greater progress, provided
they keep always to the straight road, than those who, while they run,
forsake it.

For myself, I have never fancied my mind to be in any respect more perfect
than those of the generality; on the contrary, I have often wished that I
were equal to some others in promptitude of thought, or in clearness and
distinctness of imagination, or in fullness and readiness of memory.  And
besides these, I know of no other qualities that contribute to the
perfection of the mind; for as to the reason or sense, inasmuch as it is
that alone which constitutes us men, and distinguishes us from the brutes,
I am disposed to believe that it is to be found complete in each
individual; and on this point to adopt the common opinion of philosophers,
who say that the difference of greater and less holds only among the
accidents, and not among the forms or natures of individuals of the same
species.

I will not hesitate, however, to avow my belief that it has been my
singular good  fortune to have very early in life fallen in with certain
tracks which have conducted me to considerations and maxims, of which I
have formed a method that gives me the means, as I think, of gradually
augmenting my knowledge, and of raising it by little and little to the
highest point which the mediocrity of my talents and the brief duration of
my life will permit me to reach.  For I have already reaped from it such
fruits that, although I have been accustomed to think lowly enough of
myself, and although when I look with the eye of a philosopher at the
varied courses and pursuits of mankind at large, I find scarcely one which
does not appear in vain and useless, I nevertheless derive the highest
satisfaction from the progress I conceive myself to have already made in
the search after truth, and cannot help entertaining such expectations of
the future as to believe that if, among the occupations of men as men, there
is any one really excellent and important, it is that which I have chosen.

After all, it is possible I may be mistaken; and it is but a little
copper and glass, perhaps, that I take for gold and diamonds.  I know how
very liable we are to delusion in what relates to ourselves, and also how
much the judgments of our friends are to be suspected when given in our
favor.  But I shall endeavor in this discourse to describe the paths I
have followed, and to delineate my life as in a picture, in order that
each one may also be able to judge of them for himself, and that in the
general opinion entertained of them, as gathered from current report, I
myself may have a new help towards instruction to be added to those I have
been in the habit of employing.

My present design, then, is not to teach the method which each ought to
follow for the right conduct of his reason, but solely to describe the way
in which I have endeavored to conduct my own.  They who set themselves to
give precepts must of course regard themselves as possessed of greater skill
than those to whom they prescribe; and if they err in the slightest particular,
they subject themselves to censure.  But as this tract is put forth merely
as a history, or, if you will, as a tale, in which, amid some examples worthy
of imitation, there will be found, perhaps, as many more which it were
advisable not to follow, I hope it will prove useful to some without being
hurtful to any, and that my openness will find some favor with all.

From my childhood, I have been familiar with letters; and as I was given
to believe that by their help a clear and certain knowledge of all that is
useful in life might be acquired, I was ardently desirous of instruction.
But as soon as I had finished the entire course of study, at the close of
which it is customary to be admitted into the order of the learned, I
completely changed my opinion.  For I found myself involved in so many
doubts and errors, that I was convinced I had advanced no farther in all
my attempts at learning, than the discovery at every turn of my own
ignorance.  And yet I was studying in one of the most celebrated schools in
Europe, in which I thought there must be learned men,  if such were
anywhere to be found.  I had been taught all that others learned there;
and not contented with the sciences actually taught us, I had, in
addition, read all the books that had fallen into my hands, treating of
such branches as are esteemed the most curious and rare.  I knew the
judgment which others had formed of me; and I did not find that I was
considered inferior to my fellows, although there were among them some who
were already marked out to fill the places of our instructors.  And, in
fine, our age appeared to me as flourishing, and as fertile in powerful
minds as any preceding one.  I was thus led to take the liberty of judging
of all other men by myself, and of concluding that there was no science in
existence that was of such a nature as I had previously been given to believe.

I still continued, however, to hold in esteem the studies of the schools.
I was aware that the languages taught in them are necessary to the
understanding of the writings of the ancients; that the grace of fable
stirs the mind; that the memorable deeds of history elevate it; and, if
read with discretion, aid in forming the judgment; that the perusal of all
excellent books is,  as it were, to interview with the noblest men of past
ages, who have written them, and even a studied interview, in which are
discovered to us only their choicest thoughts; that eloquence has
incomparable force and beauty; that poesy has its ravishing graces and
delights; that in the mathematics there are many refined discoveries
eminently suited to gratify the inquisitive, as well as further all the
arts an lessen the labour of man; that numerous highly useful precepts and
exhortations to virtue are contained in treatises on morals; that theology
points out the path to heaven; that philosophy affords the means of
discoursing with an appearance of truth on all matters, and commands the
admiration of the more simple; that jurisprudence, medicine, and the other
sciences, secure for their cultivators honors and riches; and, in fine,
that it is useful to bestow some attention upon all, even upon those
abounding the most in superstition and error, that we may be in a position
to determine their real value, and guard against being deceived.

But I believed that I had already given sufficient time to languages, and
likewise to the reading of the writings of the ancients, to their
histories and fables.   For to hold converse with those of other ages and
to travel, are almost the same thing.  It is useful to know something of
the manners of different nations, that we may be enabled  to form a more
correct judgment regarding our own, and be prevented from thinking that
everything contrary to our customs is ridiculous and irrational, a
conclusion usually come to by those whose experience has been limited to
their own country.  On the other hand, when too much time is occupied in
traveling, we become strangers to our native country; and the over
curious in the customs of the past are generally ignorant of those of the
present.  Besides, fictitious narratives lead us to imagine the possibility
of many events that are impossible; and even the most faithful histories,
if they do not wholly misrepresent matters, or exaggerate their importance
to render the account of them more worthy of perusal, omit, at least, almost
always the meanest and least striking of the attendant circumstances; hence
it happens that the remainder does not represent the truth, and that such as
regulate their conduct by examples drawn from this source, are apt to fall
into the extravagances of the knight-errants of romance, and to entertain
projects that exceed their powers.

I esteemed eloquence highly, and was in raptures with poesy; but I thought
that both were gifts of nature rather than fruits of study.  Those in whom
the faculty of reason is predominant, and who most skillfully dispose their
thoughts with a view to render them clear and intelligible, are always the
best able to persuade others of the truth of what they lay down, though
they should speak only in the language of Lower Brittany, and be wholly
ignorant of the rules of rhetoric; and those whose minds are stored with
the most agreeable fancies, and who can give expression to them with the
greatest embellishment and harmony, are still the best poets, though
unacquainted with the art of poetry.

I was especially delighted with the mathematics, on account of the
certitude and evidence of their reasonings;  but I had not as yet a
precise knowledge of their true use; and thinking that they but
contributed to the advancement of the mechanical arts, I was astonished
that foundations, so strong and solid, should have had no loftier
superstructure reared on them.  On the other hand, I compared the
disquisitions of the ancient moralists to very towering and magnificent
palaces with no better foundation than sand and mud:  they laud the virtues
very highly, and exhibit them as estimable far above anything on earth;
but they give us no adequate criterion of virtue, and frequently that
which they designate with so fine a name is but apathy, or pride,
or despair, or parricide.

I revered our theology, and aspired as much as any one to reach heaven:
but being given assuredly to understand that the way is not less open to
the most ignorant than to the most learned, and that the revealed truths
which lead to heaven are above our comprehension, I did not presume to
subject them to the impotency of my reason; and I thought that in order
competently to undertake their examination, there was need of some special
help from heaven, and of being more than man.

Of philosophy I will say nothing, except that when I saw that it had been
cultivated for many ages by the most distinguished men, and that yet there
is not a single matter within its sphere which is not still in dispute,
and nothing, therefore, which is above doubt, I did not presume to
anticipate that my success would be greater in it than that of others; and
further, when I considered the number of conflicting opinions touching a
single matter that may be upheld by learned men, while there can be but
one true, I reckoned as well-nigh false all that was only probable.

As to the other sciences, inasmuch as these borrow their principles from
philosophy, I judged that no solid superstructures could be reared on
foundations so infirm; and neither the honor nor the gain held out by them
was sufficient to determine me to their cultivation:  for I was not, thank
Heaven, in a condition which compelled me to make merchandise of science
for the bettering of my fortune; and though I might not profess to scorn
glory as a cynic, I yet made very slight account of that honor which I
hoped to acquire only through fictitious titles.  And, in fine, of false
sciences I thought I knew the worth sufficiently to escape being deceived
by the professions of an alchemist, the predictions of an astrologer, the
impostures of a magician, or by the artifices and boasting of any of those
who profess to know things of which they are ignorant.

For these reasons, as soon as my age permitted me to pass from under the
control of my instructors, I entire y abandoned the study of letters, and
resolved no longer to seek any other science than the knowledge of myself,
or of the great book of the world.  I spent the remainder of my youth in
traveling, in visiting courts and armies, in holding intercourse with men
of different dispositions and ranks, in collecting varied experience, in
proving myself in the different situations into which fortune threw me,
and, above all, in making such reflection on the matter of my experience
as to secure my improvement.  For it occurred to me that I should find
much more truth in the reasonings of each individual with reference to the
affairs in which he is personally interested, and the issue of which must
presently punish him if he has judged amiss, than in those conducted by a
man of letters in his study, regarding speculative matters that are of no
practical moment, and followed by no consequences to himself, farther,
perhaps, than that they foster his vanity the better the more remote they
are from common sense; requiring, as they must in this case, the exercise
of greater ingenuity and art to render them probable.  In addition, I had
always a most earnest desire to know how to distinguish the true from the
false, in order that I might be able clearly to discriminate the right
path in life, and proceed in it with confidence.

It is true that, while busied only in considering the manners of other
men, I found here, too, scarce any ground for settled conviction, and
remarked hardly less contradiction among them than in the opinions of the
philosophers.  So that the greatest advantage I derived from the study
consisted in this, that, observing many things which, however extravagant
and ridiculous to our apprehension, are yet by common consent received and
approved by other great nations, I learned to entertain too decided a
belief in regard to nothing of the truth of which I had been persuaded
merely by example and custom; and thus I gradually extricated myself from
many errors powerful enough to darken our natural intelligence, and
incapacitate us in great measure from listening to reason.  But after I had
been occupied several years in thus studying the book of the world, and in
essaying to gather some experience, I at length resolved to make myself an
object of study, and to employ all the powers of my mind in choosing the
paths I ought to follow, an undertaking which was accompanied with greater
success than it would have been had I never quitted my country or my books.



PART II

I was then in Germany, attracted thither by the wars in that country,
which have not yet been brought to a termination; and as I was returning
to the army from the coronation of the emperor, the setting in of winter
arrested me in a locality where, as I found no society to interest me, and
was besides fortunately undisturbed by any cares or passions, I remained
the whole day in seclusion, with full opportunity to occupy my attention
with my own thoughts.  Of these one of the very first that occurred to me
was, that there is seldom so much perfection in works composed of many
separate parts, upon which different hands had been employed, as in those
completed by a single master.   Thus it is observable that the buildings
which a single architect has planned and executed, are generally more
elegant and commodious than those which several have attempted to improve,
by making old walls serve for purposes for which they were not originally
built.  Thus also, those ancient cities which, from being at first only
villages, have become, in course of time, large towns, are usually but ill
laid out compared with the regularity constructed towns which a
professional architect has freely planned on an open plain; so that
although the several buildings of the former may often equal or surpass in
beauty those of the latter, yet when one observes their indiscriminate
juxtaposition, there a large one and here a small, and the consequent
crookedness and irregularity of the streets, one is disposed to allege
that chance rather than any human will guided by reason must have led to
such an arrangement.  And if we consider that nevertheless there have been
at all times certain officers whose duty it was to see that private
buildings contributed to public ornament, the difficulty of reaching high
perfection with but the materials of others to operate on, will be readily
acknowledged.  In the same way I fancied that those nations which, starting
from a semi-barbarous state and advancing to civilization by slow degrees,
have had their laws successively determined, and, as it were, forced upon
them simply by experience of the hurtfulness of particular crimes and
disputes, would by this process come to be possessed of less perfect
institutions than those which, from the commencement of their association
as communities, have followed the appointments of some wise legislator.  It
is thus quite certain that the constitution of the true religion, the
ordinances of which are derived from God, must be incomparably superior to
that of every other.  And, to speak of human affairs, I believe that the
pre-eminence of Sparta was due not to the goodness of each of its laws in
particular, for many of these were very strange, and even opposed to good
morals, but to the circumstance that, originated by a single individual,
they all tended to a single end.  In the same way I thought that the
sciences contained in books (such of them at least as are made up of
probable reasonings, without demonstrations), composed as they are of the
opinions of many different individuals massed together, are farther
removed from truth than the simple inferences which a man of good sense
using his natural and unprejudiced judgment draws respecting the matters
of his experience.  And because we have all to pass through a state of
infancy to manhood, and have been of necessity, for a length of time,
governed by our desires and preceptors (whose dictates were frequently
conflicting, while neither perhaps always counseled us for the best), I
farther concluded that it is almost impossible that our judgments can be
so correct or solid as they would have been, had our reason been mature
from the moment of our birth, and had we always been guided by it alone.

It is true, however, that it is not customary to pull down all the houses
of a town with the single design of rebuilding them differently, and
thereby rendering the streets more handsome; but it often happens that a
private individual takes down his own with the view of erecting it anew,
and that people are even sometimes constrained to this when their houses
are in danger of falling from age, or when the foundations are insecure.
With this before me by way of example, I was persuaded that it would
indeed be preposterous for a private individual to think of reforming a
state by fundamentally changing it throughout, and overturning it in order
to set it up amended; and the same I thought was true of any similar
project for reforming the body of the sciences, or the order of teaching
them established in the schools:  but as for the opinions which up to that
time I had embraced, I thought that I could not do better than resolve at
once to sweep them wholly away, that I might afterwards be in a position
to admit either others more correct, or even perhaps the same when they
had undergone the scrutiny of reason.  I firmly believed that in this way I
should much better succeed in the conduct of my life, than if I built only
upon old foundations, and leaned upon principles which, in my youth, I had
taken upon trust.  For although I recognized various difficulties in this
undertaking, these were not, however, without remedy, nor once to be
compared with such as attend the slightest reformation in public affairs.
Large bodies, if once overthrown, are with great difficulty set up again,
or even kept erect when once seriously shaken, and the fall of such is
always disastrous.  Then if there are any imperfections in the
constitutions of states (and that many such exist the diversity of
constitutions is alone sufficient to assure us), custom has without doubt
materially smoothed their inconveniences, and has even managed to steer
altogether clear of, or insensibly corrected a number which sagacity could
not have provided against with equal effect; and, in fine, the defects are
almost always more tolerable than the change necessary for their removal;
in the same manner that highways which wind among mountains, by being much
frequented, become gradually so smooth and commodious, that it is much
better to follow them than to seek a straighter path by climbing over the
tops of rocks and descending to the bottoms of precipices.

Hence it is that I cannot in any degree approve of those restless and busy
meddlers who, called neither by birth nor fortune to take part in the
management of public affairs, are yet always projecting reforms; and if I
thought that this tract contained aught which might justify the suspicion
that I was a victim of such folly, I would by no means permit its
publication.  I have never contemplated anything higher than the
reformation of my own opinions, and basing them on a foundation wholly my
own.  And although my own satisfaction with my work has led me to present
here a draft of it, I do not by any means therefore recommend to every one
else to make a similar attempt.  Those whom God has endowed with a larger
measure of genius will entertain, perhaps, designs still more exalted; but
for the many I am much afraid lest even the present undertaking be more
than they can safely venture to imitate.  The single design to strip one's
self of all past beliefs is one that ought not to be taken by every one.
The majority of men is composed of two classes, for neither of which would
this be at all a befitting resolution:  in the first place, of those who
with more than a due confidence in their own powers, are precipitate in
their judgments and want the patience requisite for orderly and
circumspect thinking; whence it happens, that if men of this class once
take the liberty to doubt of their accustomed opinions, and quit the
beaten highway, they will never be able to thread the byway that would
lead them by a shorter course, and will lose themselves and continue to
wander for life; in the second place, of those who, possessed of
sufficient sense or modesty to determine that there are others who excel
them in the power of discriminating between truth and error, and by whom
they may be instructed, ought rather to content themselves with the
opinions of such than trust for more correct to their own reason.

For my own part, I should doubtless have belonged to the latter class, had
I received instruction from but one master, or had I never known the
diversities of opinion that from time immemorial have prevailed among men
of the greatest learning.  But I had become aware, even so early as during
my college life, that no opinion, however absurd and incredible, can be
imagined, which has not been maintained by some on of the philosophers;
and afterwards in the course of my travels I remarked that all those whose
opinions are decidedly repugnant to ours are not in that account
barbarians and savages, but on the contrary that many of these nations
make an equally good, if not better, use of their reason than we do.  I
took into account also the very different character which a person brought
up from infancy in France or Germany exhibits, from that which, with the
same mind originally, this individual would have possessed had he lived
always among the Chinese or with savages, and the circumstance that in
dress itself the fashion which pleased us ten years ago, and which may
again, perhaps, be received into favor before ten years have gone,
appears to us at this moment extravagant and ridiculous.  I was thus led
to infer that the ground of our opinions is far more custom and example
than any certain knowledge.  And, finally, although such be the ground of
our opinions, I remarked that a plurality of suffrages is no guarantee of
truth where it is at all of difficult discovery, as in such cases it is
much more likely that it will be found by one than by many.  I could,
however, select from the crowd no one whose opinions seemed worthy of
preference, and thus I found myself constrained, as it were, to use my own
reason in the conduct of my life.

But like one walking alone and in the dark, I resolved to proceed so
slowly and with such circumspection, that if I did not advance far, I
would at least guard against falling.  I did not even choose to dismiss
summarily any of the opinions that had crept into my belief without having
been introduced by reason, but first of all took sufficient time carefully
to satisfy myself of the general nature of the task I was setting myself,
and ascertain the true method by which to arrive at the knowledge of
whatever lay within the compass of my powers.

Among the branches of philosophy, I had, at an earlier period, given some
attention to logic, and among those of the mathematics to geometrical
analysis and algebra, -- three arts or sciences which ought, as I
conceived, to contribute something to my design.  But, on examination, I
found that, as for logic, its syllogisms and the majority of its other
precepts are of avail- rather in the communication of what we already
know, or even as the art of Lully, in speaking without judgment of things
of which we are ignorant, than in the investigation of the unknown; and
although this science contains indeed a number of correct and very
excellent precepts, there are, nevertheless, so many others, and these
either injurious or superfluous, mingled with the former, that it is
almost quite as difficult to effect a severance of the true from the false
as it is to extract a Diana or a Minerva from a rough block of marble.
Then as to the analysis of the ancients and the algebra of the moderns,
besides that they embrace only matters highly abstract, and, to
appearance, of no use, the former is so exclusively restricted to the
consideration of figures, that it can exercise the understanding only on
condition of greatly fatiguing the imagination; and, in the latter, there
is so complete a subjection to certain rules and formulas, that there
results an art full of confusion and obscurity calculated to embarrass,
instead of a science fitted to cultivate the mind.  By these considerations
I was induced to seek some other method which would comprise the
advantages of the three and be exempt from their defects.  And as a
multitude of laws often only hampers justice, so that a state is best
governed when, with few laws, these are rigidly administered; in like
manner, instead of the great number of precepts of which logic is
composed, I believed that the four following would prove perfectly
sufficient for me, provided I took the firm and unwavering resolution
never in a single instance to fail in observing them.

The first was never to accept anything for true which I did not clearly know
to be such; that is to say, carefully to avoid precipitancy and prejudice,
and to comprise nothing more in my judgement than what was presented to
my mind so clearly and distinctly as to exclude all ground of doubt.

The second, to divide each of the difficulties under examination into as many
parts as possible, and as might be necessary for its adequate solution.

The third, to conduct my thoughts in such order that, by commencing with
objects the simplest and easiest to know, I might ascend by little and
little, and, as it were, step by step, to the knowledge of the more complex;
assigning in thought a certain order even to those objects which in their
own nature do not stand in a relation of antecedence and sequence.

And the last, in every case to make enumerations so complete, and reviews
so general, that I might be assured that nothing was omitted.

The long chains of simple and easy reasonings by means of which
geometers are accustomed to reach the conclusions of their most
difficult demonstrations, had led me to imagine that all things,
to the knowledge of which man is competent, are mutually connected
in the same way, and that there is nothing so far removed from us
as to be beyond our reach, or so hidden that we cannot discover it,
provided only we abstain from accepting the false for the true, and
always preserve in our thoughts the order necessary for the deduction
of one truth from another.  And I had little difficulty in determining
the objects with which it was necessary to commence, for I was already
persuaded that it must be with the simplest and easiest to know, and,
considering that of all those who have hitherto sought truth in the sciences,
the mathematicians alone have been able to find any demonstrations, that is,
any certain and evident reasons, I did not doubt but that such must have been
the rule of their investigations.  I resolved to commence, therefore, with the
examination of the simplest objects, not anticipating, however, from this any
other advantage than that to be found in accustoming my mind to the love and
nourishment of truth, and to a distaste for all such reasonings as were
unsound.  But I had no intention on that account of attempting to master all
the particular sciences commonly denominated mathematics:  but observing that,
however different their objects, they all agree in considering only the
various relations or proportions subsisting among those objects, I thought
it best for my purpose to consider these proportions in the most general
form possible, without referring them to any objects in particular, except
such as would most facilitate the knowledge of them, and without by any
means restricting them to these, that afterwards I might thus be the
better able to apply them to every other class of objects to which they
are legitimately applicable.  Perceiving further, that in order to
understand these relations I should sometimes have to consider them one by
one and sometimes only to bear them in mind, or embrace them in the
aggregate, I thought that, in order the better to consider them
individually, I should view them as subsisting between straight lines,
than which I could find no objects more simple, or capable of being more
distinctly represented to my imagination and senses; and on the other
hand, that in order to retain them in the memory or embrace an aggregate
of many, I should express them by certain characters the briefest
possible.  In this way I believed that I could borrow all that was best
both in geometrical analysis and in algebra, and correct all the defects
of the one by help of the other.

And, in point of fact, the accurate observance of these few precepts gave me,
I take the liberty of saying, such ease in unraveling all the questions
embraced in these two sciences, that in the two or three months
I devoted to their examination, not only did I reach solutions of
questions I had formerly deemed exceedingly difficult but even as regards
questions of the solution of which I continued ignorant, I was enabled, as
it appeared to me, to determine the means whereby, and the extent to which
a solution was possible; results attributable to the circumstance that I
commenced with the simplest and most general truths, and that thus each
truth discovered was a rule available in the discovery of subsequent ones
Nor in this perhaps shall I appear too vain, if it be considered that, as
the truth on any particular point is one whoever apprehends the truth,
knows all that on that  point can be known.  The child, for example, who
has been instructed in the elements of arithmetic, and has made a
particular addition, according to rule, may be assured that he has found,
with respect to the sum of the numbers before him, and that in this
instance is within the reach of human genius.  Now, in conclusion, the
method which teaches adherence to the true order, and an exact enumeration
of all the conditions of the thing .sought includes all that gives
certitude to the rules of arithmetic.

But the chief ground of my satisfaction with thus method, was the
assurance I had of thereby exercising my reason in all matters, if not
with absolute perfection, at least with the greatest attainable by me:
besides, I was conscious that by its use my mind was becoming gradually
habituated to clearer and more distinct conceptions of its objects; and I
hoped also, from not having restricted this method to any particular
matter, to apply it to the difficulties of the other sciences, with not
less success than to those of algebra.  I should not, however, on this
account have ventured at once on the examination of all the difficulties
of the sciences which presented themselves to me, for this would have been
contrary to the order prescribed in the method, but observing that the
knowledge of such is dependent on principles borrowed from philosophy, in
which I found nothing certain, I thought it necessary first of all to
endeavor to establish its principles.  .And because I observed, besides,
that an inquiry of this kind was of all others of the greatest moment, and
one in which precipitancy and anticipation in judgment were most to be
dreaded, I thought that I ought not to approach it till I had reached a
more mature age (being at that time but twenty-three), and had first of
all employed much of my time in preparation for the work, as well by
eradicating from my mind all the erroneous opinions I had up to that
moment accepted, as by amassing variety of experience to afford materials
for my reasonings, and by continually exercising myself in my chosen
method with a view to increased skill in its application.



PART III

And finally, as it is not enough, before commencing to rebuild the house
in which we live, that it be pulled down, and materials and builders
provided, or that we engage in the work ourselves, according to a plan
which we have beforehand carefully drawn out, but as it is likewise
necessary that we be furnished with some other house in which we may live
commodiously during the operations, so that I might not remain irresolute
in my actions, while my reason compelled me to suspend my judgement, and
that I might not be prevented from living thenceforward in the greatest
possible felicity, I formed a provisory code of morals, composed of three
or four maxims, with which I am desirous to make you acquainted.

The first was to obey the laws and customs of my country, adhering firmly
to the faith in which, by the grace of God, I had been educated from my
childhood and regulating my conduct in every other matter according to the
most moderate opinions, and the farthest removed from extremes, which
should happen to be adopted in practice with general consent of the most
judicious of those among whom I might be living.  For as I had from that
time begun to hold my own opinions for nought because I wished to subject
them all to examination, I was convinced that I could not do better than
follow in the meantime the opinions of the most judicious; and although
there are some perhaps among the Persians and Chinese as judicious as
among ourselves, expediency seemed to dictate that I should regulate my
practice conformably to the opinions of those with whom I should have to
live; and it appeared to me that, in order to ascertain the real opinions
of such, I ought rather to take cognizance of what they practised than of
what they said, not only because, in the corruption of our manners, there
are few disposed to speak exactly as they believe, but also because very
many are not aware of what it is that they really believe; for, as the act
of mind by which a thing is believed is different from that by which we
know that we believe it, the one act is often found without the other.
Also, amid many opinions held in equal repute, I chose always the most
moderate, as much for the reason that these are always the most convenient
for practice, and probably the best (for all excess is generally vicious),
as that, in the event of my falling into error, I might be at less
distance from the truth than if, having chosen one of the extremes, it
should turn out to be the other which I ought to have adopted.  And I
placed in the class of extremes especially all promises by which somewhat
of our freedom is abridged; not that I disapproved of the laws which, to
provide against the instability of men of feeble resolution, when what is
sought to be accomplished is some good, permit engagements by vows and
contracts binding the parties to persevere in it, or even, for the
security of commerce, sanction similar engagements where the purpose
sought to be realized is indifferent:  but because I did not find anything
on earth which was wholly superior to change, and because, for myself in
particular, I hoped gradually to perfect my judgments, and not to suffer
them to deteriorate, I would have deemed it a grave sin against good
sense, if, for the reason that I approved of something at a particular
time, I therefore bound myself to hold it for good at a subsequent time,
when perhaps it had ceased to be so, or I had ceased to esteem it such.

My second maxim was to be as firm and resolute in my actions as I was
able, and not to adhere less steadfastly to the most doubtful opinions,
when once adopted, than if they had been highly certain; imitating in this
the example of travelers who, when they have lost their way in a forest,
ought not to wander from side to side, far less remain in one place, but
proceed constantly towards the same side in as straight a line as
possible, without changing their direction for slight reasons, although
perhaps it might be chance alone which at first determined the selection;
for in this way, if they do not exactly reach the point they desire, they
will come at least in the end to some place that will probably be
preferable to the middle of a forest.  In the same way, since in action it
frequently happens that no delay is permissible, it is very certain that,
when it is not in our power to determine what is true, we ought to act
according to what is most probable; and even although we should not remark
a greater probability in one opinion than in another, we ought
notwithstanding to choose one or the other, and afterwards consider it, in
so far as it relates to practice, as no longer dubious, but manifestly
true and certain,  since the reason by which our choice has been
determined  is itself possessed of these qualities.  This principle was
sufficient thenceforward to rid me of all those repentings and pangs of
remorse that usually disturb the consciences of such feeble and uncertain
minds as, destitute of any clear and determinate principle of choice,
allow themselves one day to adopt a course of action as the best, which
they abandon the next, as the opposite.

My third maxim was to endeavor always to conquer myself rather than
fortune, and change my desires rather than the order of the world, and in
general, accustom  myself to the persuasion that, except our own thoughts,
there is nothing absolutely in our power; so that when we have done our
best in things external to us, all wherein we fail of success is to be
held, as regards us, absolutely impossible:  and this single principle
seemed to me sufficient to prevent me from desiring for the future
anything which I could not obtain, and thus render me contented; for since
our will naturally seeks those objects alone which the understanding
represents as in some way possible of attainment, it is plain, that if we
consider all external goods as equally beyond our power, we shall no more
regret the absence of such goods as seem due to our birth, when deprived
of them without any fault of ours,  than our not possessing the kingdoms
of China or Mexico, and thus making, so to speak, a virtue of necessity,
we shall no more desire health in disease, or freedom in imprisonment,
than we now do bodies incorruptible as diamonds, or the wings of birds to
fly with.  But I confess there is need of prolonged discipline and
frequently repeated meditation to accustom the mind to view all objects in
this light; and I believe that in this chiefly consisted the secret of the
power of such philosophers as in former times were enabled to rise
superior to the influence of fortune, and, amid suffering and poverty,
enjoy a happiness which their gods might have envied.  For, occupied
incessantly with the consideration of the limits prescribed to their power
by nature, they became so entirely convinced that nothing was at their
disposal except their own thoughts, that this conviction was of itself
sufficient to prevent their entertaining any desire of other objects; and
over their thoughts they acquired a sway so absolute, that they had some
ground on this account for esteeming themselves more rich and more
powerful, more free and more happy, than other men who, whatever be the
favors heaped on them by nature and fortune, if destitute of this
philosophy, can never command the realization of all their desires.

In fine, to conclude this code of morals, I thought of reviewing the
different occupations of men in this life, with the view of making choice
of the best.  And, without wishing to offer any remarks on the employments
of others, I may state that it was my conviction that I could not do
better than continue in that in which I was engaged, viz., in devoting my
whole life to the culture of my reason, and in making the greatest
progress I was able in the knowledge of truth, on the principles of the
method which I had prescribed to myself.  This method, from the time I had
begun to apply it, had been to me the source of satisfaction so intense as
to lead me to, believe that more perfect or more innocent could not be
enjoyed in this life; and as by its means I daily discovered truths that
appeared to me of some importance, and of which other men were generally
ignorant, the gratification thence arising so occupied my mind that I was
wholly indifferent to every other object.  Besides, the three preceding
maxims were founded singly on the design of continuing the work of self-
instruction.  For since God has endowed each of us with some light of
reason by which to distinguish truth from error, I could not have believed
that I ought for a single moment to rest satisfied with the opinions of
another, unless I had resolved to exercise my own judgment in examining
these whenever I should be duly qualified for the task.  Nor could I have
proceeded on such opinions without scruple, had I supposed that I should
thereby forfeit any advantage for attaining still more accurate, should
such exist.  And, in fine, I could not have restrained my desires, nor
remained satisfied had I not followed a path in which I thought myself
certain of attaining all the knowledge to the acquisition of which I was
competent, as well as the largest amount of what is truly good which I
could ever hope to secure Inasmuch as we neither seek nor shun any object
except in so far as our understanding represents it as good or bad, all
that is necessary to right action is right judgment, and to the best
action the most correct judgment, that is, to the acquisition of all the
virtues with all else that is truly valuable and within our reach; and the
assurance of such an acquisition cannot fail to render us contented.

Having thus provided myself with these maxims, and having placed them in
reserve along with the truths of  faith, which have ever occupied the
first place in my  belief, I came to the conclusion that I might with
freedom set about ridding myself of what remained of my opinions.  And,
inasmuch as I hoped to be better able successfully to accomplish this work
by holding intercourse with mankind, than by remaining longer shut up in
the retirement where these thoughts had occurred to me, I betook me again
to traveling before the winter was well ended.  And, during the nine
subsequent years, I did nothing but roam from one place to another,
desirous of being a  spectator rather than an actor in the plays exhibited
on the theater of the world; and, as I made it my business in each matter
to reflect particularly upon what might fairly be doubted and prove a
source of error, I gradually rooted out from my mind all the errors which
had hitherto crept into it.  Not that in this I imitated the sceptics who
doubt only that they may doubt, and seek nothing beyond uncertainty
itself; for, on the contrary, my design  was singly to find ground of
assurance, and cast aside the  loose earth and sand, that I might reach
the rock or the clay.  In this, as appears to me, I was successful enough;
for, since I endeavored to discover the falsehood or incertitude of the
propositions I examined, not by feeble conjectures, but by clear and
certain reasonings, I met with nothing so doubtful as not to yield some
conclusion of adequate certainty, although this were merely the inference,
that the matter in question contained nothing certain.  And, just as in
pulling down an old house, we usually reserve the ruins to contribute
towards the erection, so, in destroying such of my opinions as I judged to
be Ill-founded, I made a variety of observations and acquired an amount of
experience of which I availed myself in the establishment of more certain.
And further, I continued to exercise myself in the method I had
prescribed; for, besides taking care in general to conduct all my thoughts
according to its rules, I reserved some hours from time to time which I
expressly devoted to the employment of the method in the solution of
mathematical difficulties, or even in the solution likewise of some
questions belonging to other sciences, but which, by my having detached
them from such principles of these sciences as were of inadequate
certainty, were rendered almost mathematical:  the truth of this will be
manifest from the numerous examples contained in this volume.  And thus,
without in appearance living otherwise than those who, with no other
occupation than that of spending their lives agreeably and innocently,
study to sever pleasure from vice, and who, that they may enjoy their
leisure without ennui, have recourse to such pursuits as are honorable, I
was nevertheless prosecuting my design, and making greater progress in the
knowledge of truth, than I might, perhaps, have made had I been engaged in
the perusal of books merely, or in holding converse with men of letters.

These nine years passed away, however, before I had come to any
determinate judgment respecting the difficulties which form matter of
dispute among the learned, or had commenced to seek the principles of any
philosophy more certain than the vulgar.  And the examples of many men of
the highest genius, who had, in former times, engaged in this inquiry,
but, as appeared to me, without success, led me to imagine it to be a work
of so much difficulty, that I would not perhaps have ventured on it so
soon had I not heard it currently  rumored that I had already completed
the inquiry.  I know not what were the grounds of this opinion; and, if my
conversation contributed in any measure to its rise, this must have
happened rather from my having confessed my Ignorance with greater freedom
than those are accustomed to do who have studied a little, and expounded
perhaps, the reasons that led me to doubt of many of those things that by
others are esteemed certain, than from my having boasted of any system of
philosophy.  But, as I am of a disposition that makes me unwilling to be
esteemed different from what I really am, I thought it necessary to
endeavor by all means to render myself worthy of the reputation accorded
to me; and it is now exactly eight years since this desire constrained me
to remove from all those places where interruption from any of my
acquaintances was possible, and betake myself to this country, in which
the long duration of the war has led to the establishment of such
discipline, that the armies maintained seem to be of use only in enabling
the inhabitants to enjoy more securely the blessings of peace and where,
in the midst of a great crowd actively engaged in business, and more
careful of their own affairs than curious about those of others, I have
been enabled to live without being deprived of any of the conveniences to
be had in the most populous cities, and yet as solitary and as retired as
in the midst of the most remote deserts.



PART IV

I am in doubt as to the propriety of making my first meditations in the
place above mentioned matter of discourse; for these are so metaphysical,
and so uncommon, as not, perhaps, to be acceptable to every one.  And yet,
that it may be determined whether the foundations that I have laid are
sufficiently secure, I find myself in a measure constrained to advert to
them.  I had long before remarked that, in relation to practice, it is
sometimes necessary to adopt, as if above doubt, opinions which we discern
to be highly uncertain, as has been already said; but as I then desired to
give my attention solely to the search after truth, I thought that a
procedure exactly the opposite was called for, and that I ought to reject
as absolutely false all opinions in regard to which I could suppose the
least ground for doubt, in order to ascertain whether after that there
remained aught in my belief that was wholly indubitable.  Accordingly,
seeing that our senses sometimes deceive us, I was willing to suppose that
there existed nothing really such as they presented to us; and because
some men err in reasoning, and fall into paralogisms, even on the simplest
matters of geometry, I, convinced that I was as open to error as any
other, rejected as false all the reasonings I had hitherto taken for
demonstrations; and finally, when I considered that the very same thoughts
(presentations) which we experience when awake may also be experienced
when we are asleep, while there is at that time not one of them true, I
supposed that all the objects (presentations) that had ever entered into
my mind when awake, had in them no more truth than the illusions of my
dreams.  But immediately upon this I observed that, whilst I thus wished to
think that all was false, it was absolutely necessary that I, who thus
thought, should be somewhat; and as I observed that this truth, I think,
therefore I am (COGITO ERGO SUM), was so certain and of such evidence that
no ground of doubt, however extravagant, could be alleged by the sceptics
capable of shaking it, I concluded that I might, without scruple, accept
it as the first principle of the philosophy of which I was in search

In the next place, I attentively examined what I was and as I observed
that I could suppose that I had no body, and that there was no world nor
any place in which I might be; but that I could not therefore suppose that
I was not; and that, on the contrary, from the very circumstance that I
thought to doubt of the truth of other things, it most clearly and
certainly followed that I was; while, on the other hand, if I had only
ceased to think, although all the other objects which I had ever imagined
had been in reality existent, I would have had no reason to believe that I
existed; I thence concluded that I was a substance whose whole essence or
nature consists only in thinking, and which, that it may exist, has need
of no place, nor is dependent on any material thing; so that " I," that is
to say, the mind by which I am what I am, is wholly distinct from the
body, and is  even more easily known than the latter, and is such, that
although the latter were not, it would still continue to be all that it is.

After this I inquired in general into what is essential I to the truth and
certainty of a proposition; for since I had discovered one which I knew to
be true, I thought that I must likewise be able to discover the ground of
this certitude.  And as I observed that in the words I think, therefore I
am, there is nothing at all which gives me assurance of their truth beyond
this, that I see very clearly that in order to think it is necessary to
exist, I concluded that I might take, as a general rule, the principle,
that all the things which we very clearly and distinctly conceive are
true, only observing, however, that there is some difficulty in rightly
determining the objects which we distinctly conceive.

In the next place, from reflecting on the circumstance that I doubted, and
that consequently my being was not wholly perfect (for I clearly saw that
it was a greater perfection to know than to doubt), I was led to inquire
whence I had learned to think of something more perfect than myself; and I
clearly recognized that I must hold this notion from some nature which in
reality was more perfect.  As for the thoughts of many other objects
external to me, as of the sky, the earth, light, heat, and a thousand
more, I was less at a loss to know whence these came; for since I remarked
in them nothing which seemed to render them superior to myself, I could
believe that, if these were true, they were dependencies on my own nature,
in so far as it possessed a certain perfection, and, if they were false,
that I held them from nothing, that is to say, that they were in me
because of a certain imperfection of my nature.  But this could not be the
case with-the idea of a nature more perfect than myself; for to receive it
from nothing was a thing manifestly impossible; and, because it is not
less repugnant that the more perfect should be an effect of, and
dependence on the less perfect, than that something should proceed from
nothing, it was equally impossible that I could hold it from myself:
accordingly, it but remained that it had been placed in me by a nature
which was in reality more perfect than mine, and which even possessed
within itself all the perfections of which I could form any idea; that is
to say, in a single word, which was God.  And to this I added that, since I
knew some perfections which I did not possess, I was not the only being in
existence (I will here, with your permission, freely use the terms of the
schools); but, on the contrary, that there was of necessity some other
more perfect Being upon whom I was dependent, and from whom I had received
all that I possessed; for if I had existed alone, and independently of
every other being, so as to have had from myself all the perfection,
however little, which I actually possessed, I should have been able, for
the same reason, to have had from myself the whole remainder of
perfection, of the want of which I was conscious, and thus could of myself
have become infinite, eternal, immutable, omniscient, all-powerful, and,
in fine, have possessed all the perfections which I could recognize in
God.  For in order to know the nature of God (whose existence has been
established by the preceding reasonings), as far as my own nature
permitted, I had only to consider in reference to all the properties of
which I found in my  mind some idea, whether their possession was a mark
of perfection; and I was assured that no one which indicated any
imperfection was in him, and that none of the rest was awanting.  Thus I
perceived that doubt, inconstancy,  sadness, and such like, could not be
found in God, since I myself would have been happy to be free from them.
Besides, I had ideas of many sensible and corporeal things; for although I
might suppose that I was dreaming, and that all which I saw or imagined
was false, I could not, nevertheless, deny that the ideas were in reality
in my thoughts.  But, because I had already very clearly recognized in
myself that the intelligent nature is distinct from the corporeal, and as
I observed that all composition is an evidence of dependency, and that a
state of dependency is manifestly a state of imperfection, I therefore
determined that it could not be a perfection in God to be compounded of
these two natures and that consequently he was not so compounded; but that
if there were any bodies in the world, or even any intelligences, or other
natures that were not wholly perfect, their existence depended on his power
in such a way that they could not subsist without him for a single moment.

I was disposed straightway to search for other truths and when I had
represented to myself the object of the geometers, which I conceived to be
a continuous body or a space indefinitely extended in length, breadth, and
height or depth, divisible into divers parts which admit of different
figures and sizes, and of being moved or transposed in all manner of ways
(for all this the geometers suppose to be in the object they contemplate),
I went over some of their simplest demonstrations.  And, in the first
place, I observed, that the great certitude which by common consent is
accorded to these demonstrations, is founded solely upon this, that they
are clearly conceived in accordance with the rules I have already laid
down In the next place, I perceived that there was nothing at all in these
demonstrations which could assure me of the existence of their object:
thus, for example, supposing a triangle to be given, I distinctly
perceived that its three angles were necessarily equal to two right
angles, but I did not on that account perceive anything which could assure
me that any triangle existed:  while, on the contrary, recurring to the
examination of the idea of a Perfect Being, I found that the existence of
the Being was comprised in the idea in the same way that the equality of
its three angles to two right angles is comprised in the idea of a
triangle, or as in the idea of a sphere, the equidistance of all points on
its surface from the center, or even still more clearly; and that
consequently it is at least as certain that God, who is this Perfect
Being, is, or exists, as any demonstration of geometry can be.

But the reason which leads many to persuade them selves that there is a
difficulty in knowing this truth, and even also in knowing what their mind
really is, is that they never raise their thoughts above sensible objects,
and are so accustomed to consider nothing except by way of imagination,
which is a mode of thinking limited to material objects, that all that is
not imaginable seems to them not intelligible.  The truth of this is
sufficiently manifest from the single circumstance, that the philosophers
of the schools accept as a maxim that there is nothing in the
understanding which was not previously in the senses, in which however it
is certain that the ideas of God and of the soul have never been; and it
appears to me that they who make use of their imagination to comprehend
these ideas do exactly the some thing as if, in order to hear sounds or
smell odors, they strove to avail themselves of their eyes; unless indeed
that there is this difference, that the sense of sight does not afford us
an inferior assurance to those of smell or hearing; in place of which,
neither our imagination nor our senses can give us assurance of anything
unless our understanding intervene.

Finally, if there be still persons who are not sufficiently persuaded of
the existence of God and of the soul, by the reasons I have adduced, I am
desirous that they should know that all the other propositions, of the
truth of which they deem themselves perhaps more assured, as that we have
a body, and that there exist stars and an earth, and such like, are less
certain; for, although we have a moral assurance of these things, which is
so strong that there is an appearance of extravagance in doubting of their
existence, yet at the same time no one, unless his intellect is impaired,
can deny, when the question relates to a metaphysical certitude, that
there is sufficient reason to exclude entire assurance, in the observation
that when asleep we can in the same way imagine ourselves possessed of
another body and that we see other stars and another earth, when there is
nothing of the kind.  For how do we know that the thoughts which occur in
dreaming are false rather than those other which we experience when awake,
since the former are often not less vivid and distinct than the latter?
And though men of the highest genius study this question as long as they
please, I do not believe that they will be able to give any reason which
can be sufficient to remove this doubt, unless they presuppose the
existence of God.  For, in the first place even the principle which I have
already taken as a rule, viz., that all the things which we clearly and
distinctly conceive are true, is certain only because God is or exists and
because he is a Perfect Being, and because all that we possess is derived
from him:  whence it follows that our ideas or notions, which to the extent
of their clearness and distinctness are real, and proceed from God, must
to that extent be true.  Accordingly, whereas we not infrequently have ideas
or notions in which some falsity is contained, this can only be the case with
such as are to some extent confused and obscure, and in this proceed from
nothing (participate of negation), that is, exist in us thus confused because
we are not wholly perfect.  And it is evident that it is not less repugnant
that falsity or imperfection, in so far as it is imperfection, should proceed
from God, than that truth or perfection should proceed from nothing.  But if
we did not know that all which we possess of real and true proceeds from a
Perfect and Infinite Being, however clear and distinct our ideas might be,
we should have no ground on that account for the assurance that they possessed
the perfection of being true.

But after the knowledge of God and of the soul has rendered us certain of
this rule, we can easily understand that the truth of the thoughts we
experience when awake, ought not in the slightest degree to be called in
question on account of the illusions of our dreams.  For if it happened
that an individual, even when asleep, had some very distinct idea, as, for
example, if a geometer should discover some new demonstration, the
circumstance of his being asleep would not militate against its truth; and
as for the most ordinary error of our dreams, which consists in their
representing to us various objects in the same way as our external senses,
this is not prejudicial, since it leads us very properly to suspect the
truth of the ideas of sense; for we are not infrequently deceived in the
same manner when awake; as when persons in the jaundice see all objects
yellow, or when the stars or bodies at a great distance appear to us much
smaller than they are.  For, in fine, whether awake or asleep, we ought
never to allow ourselves to be persuaded of the truth of anything unless
on the evidence of our reason.  And it must be noted that I say of our
reason, and not of our imagination or of our senses:  thus, for example,
although we very clearly see the sun, we ought not therefore to determine
that it is only of the size which our sense of sight presents; and we may
very distinctly imagine the head of a lion joined to the body of a goat,
without being therefore shut up to the conclusion that a c