_______________________________
Custom Search
Rene Descartes
Discourse on the Method for Reasoning
Well and for Seeking Truth in the Sciences
Translated by
Ian Johnston
Vancouver Island University
Nanaimo, BC
Canada
[Revised May 2010]
[For details about use of this text,
please see Copyright]
HISTORICAL
NOTE
René Descartes (1596-1650) published Discourse
on Method in 1637 as part of a work containing sections on optics,
geometry, and meteorology. The fourth section, the Discourse,
outlined the basis for a new method of investigating knowledge. He later (in
1641) published a more detailed exploration of the philosophical basis for this
new approach to knowledge in Meditations on First Philosophy.
TABLE OF
CONTENTS
[Preface]—Part
One—Part
Two—Part
Three—Part
Four—Part
Five—Part
Six
RENÉ DESCARTES
DISCOURSE ON METHOD
[PREFACE]1
If this discourse seems too long to be
read in a single sitting, it can be divided up into six parts. In the first
will be found various considerations concerning the sciences; in the second,
the principal rules of the method which the author has discovered; in the
third, some rules of morality which he has derived by this method; in the
fourth, the reasons which enable him to establish the existence of God and of
the human soul, which are the foundations of his metaphysics; in the fifth
part, the order of questions in physics which he has looked into, and
particularly the explanation for the movements of the heart and for some other
difficulties which are part of medicine, including the difference which exists
between our souls and those of animals; in the last part, some matters he
believes necessary for further advances in research into nature, beyond where
he has been, along with some reasons which have induced him to write.
The most widely shared thing in the
world is good sense, for everyone thinks he is so well provided with it that
even those who are the most difficult to satisfy in everything else do not
usually desire to have more good sense than they have. In this matter it is not
likely that everyone is mistaken. But this is rather a testimony to the fact
that the power of judging well and distinguishing what is true from what is
false, which is really what we call good sense or reason, is naturally equal in
all men, and thus the diversity of our opinions does not arise because some people
are more reasonable than others, but only because we conduct our thoughts by different
routes and do not consider the same things. For it is not enough to have a good
mind. The main thing is to apply it well. The greatest minds are capable of the
greatest vices as well as the greatest virtues, and those who proceed only very
slowly, if they always stay on the right road, are capable of advancing a great
deal further than those who rush along and wander away from it.
As for myself, I have never presumed
that my mind was anything more perfect than the ordinary mind. I have often
even wished that I could have thoughts as quick, an imagination as clear and
distinct, or a memory as ample or as actively involved as some other people.
And I know of no qualities other than these which serve to perfect the mind. As
far as reason, or sense, is concerned, given that it is the only thing which
makes us human and distinguishes us from the animals, I like to believe that it
is entirely complete in each person, following in this the common opinion of
philosophers, who say that differences of more and less should occur only
between accidental characteristics and not at all between
the forms or natures of individuals of the
same species.
But I will not hesitate to state that I
think I have been very fortunate to have found myself since my early years on
certain roads which have led me to considerations and maxims out of which I
have created a method by which, it seems to me, I have a way of gradually increasing
my knowledge, raising it little by little to the highest point which the
mediocrity of my mind and the short length of my life can allow it to attain.
For I have already harvested such fruit from this method that, even though, in
judging myself, I always try to lean towards the side of distrust rather than
to that of presumption and although, when I look with a philosopher's eye on
the various actions and enterprises of all men, there are hardly any which do
not seem to me vain and useless, I cannot help deriving extreme satisfaction
from the progress which I think I have already made in my research into the
truth and conceiving such hopes for the future that, if among the occupations
of men, simply as men, there is one which is surely good and important, I
venture to think it is the one I have chosen.
However, it could be the case that I am
wrong and that perhaps what I have taken for gold and diamonds is only a little
copper and glass. I know how much we are subject to making mistakes in what
touches ourselves and also how much we should beware of the judgments of our
friends when they are in our favour. But I will be only too happy to make known
in this discourse what roads I have followed and to reveal my life in it, as if
in a picture, so that each person can judge it. Learning from current reports
the opinions people have of this discourse may be a new way of educating myself, something I will add to those which I habitually
use.
Thus, my design here is not to teach
the method which everyone should follow in order to reason well, but merely to
reveal the way in which I have tried to conduct my own reasoning. Those who
take it upon themselves to give precepts must consider themselves more skilful
than those to whom they give them, and if they are missing the slightest thing,
then they are culpable. But since I intend this text only as a history, or, if
you prefer, a fable, in which, among some examples which you can imitate, you
will, in addition, perhaps find several others which you will have reason not
to follow, I hope that it will be useful to some people, without harming
anyone, and that everyone will find my frankness agreeable.
I was nourished on literature from the
time of my childhood. Because people persuaded me that through literature one
could acquire a clear and assured understanding of everything useful in life, I
had an intense desire to take it up. But as soon as I had completed that entire
course of study at the end of which one was usually accepted into the rank of scholars,
I changed my opinion completely. For I found myself burdened by so many doubts
and errors that it seemed to me I had gained nothing by trying to instruct
myself, other than the fact that I had increasingly discovered my own
ignorance. Yet I had been in one of the most famous schools in Europe, a place
where I thought there must be erudite men, if there were such people anywhere
on earth. I had learned everything which the others learned there, but still,
not being happy with the sciences which we were being taught, I had gone
through all the books which I could lay my hands on dealing with those sciences
which are considered the most curious and rare.2In addition, I knew how other people were judging me, and I saw
that they did not consider me inferior to my fellow students, although among
them there were already some destined to fill the places of our teachers. And finally our age seemed to me as flourishing and as fertile in
good minds as any preceding age. Hence, I took the liberty of judging
all the others by myself and of thinking that there was no doctrine in the
world of the kind I had previously been led to hope for.
However, I did not cease valuing the
exercises which kept people busy in the schools. I knew that the languages one
learns there are necessary for an understanding of ancient books, that the
gracefulness of fables awakens the intellect, that the memorable actions of
history raise the mind, and if one reads with discretion, help to form one's
judgment, that reading all the good books is like a conversation with the most
honourable people of past centuries, who were their authors, even a carefully
prepared dialogue in which they reveal to us only the best of their thoughts,
that eloquence has incomparable power and beauty, that poetry has a most
ravishing delicacy and softness, that mathematics has very skillful inventions
which can go a long way toward satisfying the curious as well as facilitating
all the arts and lessening the work of men, that the writings which deal with
morals contain several lessons and a number of exhortations to virtue which are
extremely useful, that theology teaches one how to reach heaven, that
philosophy provides a way of speaking plausibly on all matters and making
oneself admired by those who are less scholarly, that jurisprudence, medicine,
and the other sciences bring honour and riches to those who cultivate them, and
finally that it is good to have examined all of them, even the most superstitious
and false, in order to know their legitimate value and to guard against being
wrong. But I believed I had already given enough time to languages and even to
reading ancient books as well, and to their histories and stories. For talking
with those from other ages is almost the same as travelling. It is good to know
something about the customs of various people, so that we can judge our own
more sensibly and do not think everything different from our own ways
ridiculous and irrational, as those who have seen nothing are accustomed to do.
But when one spends too much time travelling, one finally becomes a stranger in
one's own country, and when one is too curious about things which went on in
past ages, one usually lives in considerable ignorance
about what goes on in this one. In addition, fables make us imagine several
totally impossible events as possible, and even the most faithful histories, if
they neither change nor increase the importance of things to make them more
worth reading, at the very least almost always omit the most menial and less
admirable circumstances, with the result that what is left in does not depict
the truth. Hence, those who regulate their habits by the examples which they
derive from these histories are prone to fall into the extravagances of the
knights of our romances and to dream up projects which exceed their powers.
I placed a great value on eloquence,
and I was in love with poetry, but I thought that both of them were gifts given
to the mind rather than fruits of study. Those who have the most powerful
reasoning and who direct their thoughts best in order to make them clear and intelligible
can always convince us best of what they are proposing, even if they speak only
the language of Lower Brittany and have never learned rhetoric. And those who
possess the most pleasant creative talents and who know how to express them
with the most adornment and smoothness cannot help being the best poets, even
though the art of poetry is unknown to them.
I found mathematics especially delightful
because of the certainty and clarity of its reasoning. But I did not yet notice
its true use. Thinking that it was practical only in the mechanical arts, I was
astonished that on its foundations, so strong and solid, nothing more imposing
had been built up. By contrast, I compared the writings of the ancient pagans
which deal with morality to really superb and magnificent palaces built on
nothing but sand and mud. They raise the virtues to a very great height and
make them appear valuable, above everything in the world, but they do not teach
us to know them well enough, and often what they call by such a beautiful name
is only apathy or pride or despair or parricide.3
I revered our theology and aspired as
much as anyone to reach heaven, but having learned, as something very certain,
that the road there is no less open to the most ignorant as to the most learned
and that the revealed truths which lead there are beyond our intelligence, I
did not dare to submit them to the frailty of my reasoning, and I thought that
undertaking to examine them successfully would require me to have some extraordinary
heavenly assistance and to be more than a man.
I will say nothing of philosophy other
than this: once I saw that it had been cultivated for several centuries by the
most excellent minds which had ever lived, and that, nonetheless, there was
still nothing in it which was not disputed and which was thus not still in
doubt, I did not have sufficient presumption to hope to fare better there than
the others. Considering how many different opinions, maintained by learned
people, philosophy could have about the same matter, without there ever being
more than one which could be true, I reckoned as virtually false all those
which were merely probable.
Then, as for the other sciences, since
they borrow their principles from philosophy, I judged that nothing solid could
have been built on such insubstantial foundations, and neither the honour nor
the profit which they promise were sufficient to convince me to learn them,
for, thank God, I did not feel myself in a condition which obliged me to make a
profession of science in order improve my fortune, and, although I did not, in
some cynical way, undertake to proclaim my disdain for glory, nonetheless I
placed very little value on the fame I could hope to acquire only through false
titles. And finally, as for bad doctrines, I thought I already understood
sufficiently what they were worth in order not be taken in either by the
promises of an alchemist, by the predictions of an astrologer, by the impostures
of a magician, or by the artifice or the bragging of any of those who made a
profession of knowing more than they know.
That is why, as soon as my age permitted
me to leave the supervision of my professors, I completely stopped the study of
letters, and, resolving not to look any more in any other science except one
which could be found inside myself or in the great book of the world, I spent
the rest of my youth travelling, looking into courts and armies, associating
with people of various humours and conditions, collecting various experiences,
testing myself in the encounters which fortune offered me, and everywhere
reflecting on the things I came across in such a way that I could draw some
profit from them. For it seemed to me that I could arrive at considerably more
truth in the reasoning that each man makes concerning the matters which are
important to him and in which events could punish him soon afterwards if he
judged badly, than in the reasoning made by a man of letters in his study concerning
speculations which produce no effect and which are of no consequence to him, except
perhaps that from them he can augment his vanity—and all the more so, the
further his speculations are from common sense, because he would have had to
use that much more wit and artifice in the attempt to make them probable. And I
always had an extreme desire to learn to distinguish the true from the false,
in order to see clearly in my actions and to proceed with confidence in this
life.
It is true that while I did nothing but
examine the customs of other men, I found hardly anything there to reassure me,
and I noticed as much diversity among men as I had earlier among the opinions
of philosophers. Consequently, the greatest profit which I derived from this
was that, by seeing several things which, although they seem really extravagant
and ridiculous to us, were commonly accepted and approved by other great
people, I learned not to believe too firmly in anything which I had been
persuaded to believe merely by example and by custom. Thus, I gradually freed
myself of plenty of errors which can obfuscate our natural light and make us
less capable of listening to reason. But after I had spent a few years studying
in this way in the book of the world, attempting to acquire some experience,
one day I resolved to study myself as well and to use all the powers of my mind
to select paths which I should follow, a task which brought me considerably
more success, it seems to me, than if I had never gone away from my own country
and my books.
I was then in Germany, summoned by the
wars which have not yet concluded there.4 As I was returning to the army from the coronation of the emperor,
the onset of winter stopped me in a place where, not finding any conversation
to divert me and in addition, by good fortune, not having any cares or passions
to trouble me, I spent the entire day closed up alone in a room heated by a
stove, where I had complete leisure to talk to myself about my thoughts. Among
these, one of the first was that I noticed myself thinking about how often
there is not so much perfection in works created from several pieces and made
by the hands of various masters as there is in those which one person has
worked on alone. Thus, we see that the buildings which a single architect has undertaken
and completed are usually more beautiful and better ordered than those which
several people have tried to refurbish by making use of old walls built for
other purposes. That is why those ancient cities which were only small villages
at the start and became large towns over time are ordinarily so badly laid out,
compared to the regular places which an engineer has designed freely on level
ground. Even though, considering the buildings in each of them separately, we
often find as much beauty in the former town as in the latter, or more,
nonetheless, looking at them as they are arranged—here a large one, there a
small one—and the way they make the streets crooked and unequal, we would say
that chance rather than the will of some men using their reason designed them
this way. And if one considers that nonetheless there have always been certain
officials charged with seeing that private buildings serve as a public
ornament, one will readily see that it is difficult to achieve really fine
things by working only with other people's pieces. Thus, I imagined to myself
that people who were semi-savages in earlier times and who became civilized
only little by little and created their laws only as they were compelled to by
the extent to which crimes and quarrels bothered them would not be so well regulated
as those who, from the moment they first assembled, followed the constitution
of some prudent legislator. It is indeed certain that the state of the true
religion, whose laws God alone created, must be incomparably better ordered
than all the others. And, to speak of human affairs, I believe that if Sparta
was in earlier times very prosperous, that was not on account of the goodness
of each of its laws in particular, seeing that several were very strange and even
contrary to good morals, but on account of the fact that they were devised by
only a single man and thus they contributed towards the same end. Similarly I
thought that the sciences contained in books, at least those whose reasons are
only probable and without any proofs, since they were put together and crudely
fashioned little by little out of the opinions of several different people,
therefore did not approach the truth as much as the simple reasoning which a
man of good sense can make quite naturally concerning matters of his own
experience. In the same way I thought that because we were all children before
we were men and because it was necessary for us to be governed for a long time
by our appetites and our supervisors, who were often at odds with each other,
with neither of them perhaps advising us always for the best, it is almost
impossible that our judgments are as pure and solid as they would have been if
we had had the total use of our reason from the moment of our birth and had
never been led by anything but our reason.
It is true that we see little point in
demolishing all the houses of a city for the sole purpose of rebuilding them in
another way and thus making the streets more beautiful. But we do see several
people demolish their houses in order to rebuild them, and, indeed, sometimes
they are compelled to do so, when the houses are in danger of collapsing on
their own and when their foundations are not steady. This example persuaded me
that there would probably be little point for a particular man to draw up a
design for reforming a state, changing all of it from the foundations,
overturning it in order to put it up again, or even for reforming the body of
sciences or the order established in the schools for teaching the sciences. But
so far as all the opinions which I had received up to that point and which I
believed credible were concerned, I convinced myself that the best possible
thing for me to do was to undertake to remove them once and for all, so that
afterwards I could replace them either by other better ones or perhaps by the
same ones, once I had adjusted them to a reasonable standard. And I firmly
believed that by this means I would be successful in conducting my life much
better than if I built only on the old foundations and relied only on principles
which I had been persuaded to accept in my youth, without ever having examined
whether they were true. For, although I recognized various problems with this approach,
these were not without remedy and could not compare to those which occur in the
reform of the least matters concerning the public. It is too difficult to
re-erect those large bodies if they are thrown down or even to keep them once
they are weakened, and their collapses cannot be anything but very drastic.
Then, as far as the imperfections of large public bodies are concerned, if they
have any (and the variety among such bodies alone is sufficient to assure us
that there are several imperfections), habit has no doubt considerably softened
these and has even managed to avoid some problems or corrected a number of them
insensibly, which people's caution could not have managed so well, and finally
the imperfections are almost always easier to bear than changing them would be,
in the same way that the major roads which wind among the mountains gradually become
so smooth and convenient from being used, that it is much better to follow them
than to set out to go more directly by climbing up over the rocks and going
down right to the bottom of the precipices.
That is why I cannot approve at all of
those muddled and worried temperaments who, without being summoned by their
birth or fortune to the management of public business, never stop proposing
some idea for a new reform in it. If I thought that there was the slightest
thing in this text which would enable someone to suspect me of this
foolishness, I would be very reluctant to allow it to be published. My
intention has never been to do more than try to reform my own thoughts and to
build on a foundation which is entirely my own. And if my work has pleased me
sufficiently to make me show you the model of it here, that is not because I
wish to advise anyone to imitate it. Those to whom God has given more of his
grace will perhaps have loftier intentions, but I fear that this work may already
be too bold for several people. The single resolution to strip away all the
opinions which one has previously absorbed into one's beliefs is not an example
which everyone should follow. Most of the world is made up of two sorts of
minds for whom such a resolution is not suitable. First, there are those who, believing
themselves more clever than they are, cannot stop making hasty judgments,
without having enough patience to conduct their thoughts in an orderly way,
with the result that, once they have taken the liberty of doubting the
principles they have received and of leaving the common road, they will never
be able to hold to the track which they need to take in order to proceed more
directly and will remain lost all their lives. Then, there are the ones who,
having sufficient reason or modesty to judge that they are less capable of
differentiating truth and falsehood than several others from whom they can be instructed,
must content themselves with following the opinions of these others rather than
searching for better opinions on their own.
As for me, I would have undoubtedly
been among the number of this latter group if I had only had a single master or
if I had known nothing at all about the differences which have always existed
among the opinions of the most highly educated men. But I learned from my
college days on that one cannot imagine anything so strange and so incredible
that it has not been said by some philosopher and, later, in my travelling, I
found out that all those who have views very different from our own are not
therefore barbarians or savages, but that several use as much reason as we do,
or more. I also considered how much the same man, with the same mind, raised
from his infancy on among the French or the Germans, would become different
from what he would have been if he had always lived among the Chinese or the cannibals,
and how, even in our style of dress the same thing which pleased us ten years
ago and which will perhaps please us again ten years from today, now seems to us
extravagant and ridiculous. This being the case, we are clearly persuaded more
by custom and example than by any certain knowledge. Nonetheless, a plurality
of voices is not a proof worth anything for truths which are a little difficult
to discover, because it is far more probable that one man by himself would have
found them than an entire people. Since I could not select anyone whose
opinions it seemed to me one should prefer to those of other people, I found
myself, so to speak, compelled to guide myself on my own.
But like a man who proceeds alone and
in the shadows, I resolved to go so slowly and to use so much circumspection in
all matters, that if I only advanced a very short
distance, at least I would take good care not to fall. I did not even wish to
begin by rejecting completely any of the opinions which could have slipped into
my beliefs previously without being introduced by reason, before I had taken up
enough time drawing up a plan for the work I was undertaking and seeking out
the true method for arriving at an understanding of everything my mind was
capable of knowing.
When I was younger, among the branches
of philosophy, I had studied a little logic and, among the subjects of
mathematics, geometrical analysis and algebra, three arts or sciences which
looked as if they ought to contribute something to my project. But in looking
at them, I took care, because, so far as logic is concerned, its syllogisms and
most of its other instructions serve to explain to others what one already
knows or even, as in the art of Lully, to speak without judgment of things
about which one is ignorant, rather than to learn what they are.5 Although philosophy does, in fact, contain many really true and
excellent precepts, mixed in with them there are always so many injurious or
superfluous ones that it is almost as difficult to separate them as to draw a
Diana or a Minerva out of a block of marble which has not yet been carved.
Then, so far as the analysis of the ancients and the algebra of the moderns are
concerned, other than the fact that they deal only with really abstract
matters, which have no apparent use, the former is always so concentrated on
considering numbers that it cannot exercise the understanding without considerably
tiring the imagination, and in the latter is so subject to certain rules and
symbols that it has been turned into a confused and obscure art which clutters
up the mind rather than a science which cultivates it. Those were the reasons
why I thought I had to look for some other method which included the advantages
of these three subjects but was free of their defects. And since a multitude of
laws often provides excuses for vices, so that a state is much better ruled
when it has only a very few laws which are very strictly observed, I thought
that, instead of that large number of rules which make up logic, I would have
enough with the four following rules, provided that I maintained a strong and
constant resolution that I would never fail to observe them, not even once.
The first rule was that I would not accept
anything as true which I did not clearly know to be true. That is to say, I
would carefully avoid being over hasty or prejudiced, and I would understand nothing
by my judgments beyond what presented itself so clearly and distinctly to my
mind that I had no occasion to doubt it.6
The second was to divide each difficulty
which I examined into as many parts as possible and as might be necessary to
resolve it better.
The third was to conduct my thoughts in
an orderly way, beginning with the simplest objects, the ones easiest to know,
so that little by little I could gradually climb right up to the knowledge of
the most complex, by assuming the same order, even among those things which do
not naturally come one after the other.
And the last was to make my calculations
throughout so complete and my review so general that I would be confident of
not omitting anything.
Those long chains of reasons, all simple
and easy, which geometers have habitually used to reach their most difficult
proofs gave me occasion to imagine to myself that everything which could fall
under human knowledge would follow in the same way and that, provided only that
one refused to accept anything as true which was not and that one always kept
to the order necessary to deduce one thing from another, there could not be
anything so far distant that one could not finally reach it, nor so hidden that
one could not discover it. And I did not have much trouble finding out the
issues which I had to deal with first. For I already knew that it had to be
with the simplest things, the ones easiest to know. When I thought about how,
among all those who had so far searched for truth in the sciences, it was only
the mathematicians who had been able to find some proofs, that is to say, some
certain and evident reasons, I had no doubt at all that I should start with the
same things which they had examined, although I did not hope for any practical
results, other than that they would accustom my mind to revelling in the truth
and not remaining happy with false reasons. But for all that I did not plan
trying to learn all the particular sciences which people commonly call
mathematical. Since I saw that, even though their objects were different, they
were alike in that they all agreed they should consider nothing except the
various relationships or proportions among the objects of study found there, I
thought that it would be more valuable if I examined only these proportions in
general, without assuming that they were present in the objects, except for
those which would help to provide me knowledge of them most readily, but
without in this way restricting them at all to those objects, so that they
could be all the better applied later to every other object for which they
might be suitable. Then, because I observed that, in order to understand these
things, I would sometimes need to consider each one in particular and sometimes
only to remember them or to understand several of them together, I thought that
to consider them better separately, I ought to assume that they were like
lines, because I know of nothing simpler, nothing which I could more distinctly
represent to my imagination and my senses. But in order to remember them or to
understand several of them together, I had to explain them by some formulas as
short as possible and, by this means, I would borrow all the best elements of
analytic geometry and algebra and would correct all the defects of one by the
other.7
As a matter of fact, I venture to say that
the precise observation of these few precepts which I had selected gave me such
a facility at disentangling all the questions which these two sciences cover,
that in the two or three months that I used them to examine these questions,
starting with the simplest and the most general and letting each truth I found
serve as a rule which I could use afterwards to find others, not only did I
resolve several problems which I had previously judged very difficult, but it
also seemed to me towards the end that I could determine, even with those
questions where I was ignorant, the way to resolve them and the extent to which
such resolution was possible. In saying this, perhaps I will not appear too
vain if you consider that, since there is only one truth for each thing,
whoever finds it knows as much as one can know about it and that, for example,
a child instructed in arithmetic, having made an addition following the rules,
can be confident of having found, so far as the sum he is examining is
concerned, everything that the human mind can find out. For the method which
teaches one to follow the true order and to count exactly all the relevant
details in what one is looking for contains everything which gives certainty to
the rules of arithmetic.
But what pleased me the most with this
method was that with it I was confident of using all my reason, if not
perfectly, at least as well as was in my power. In addition, I felt, as I
applied it, that my mind was accustoming itself gradually to think more clearly
and distinctly about its objects, and because I had not restricted this method
to one matter in particular, I was hopeful that I could apply it just as
usefully to difficulties in the other sciences as I had applied it to those in
algebra. But for all that, I did not venture to try immediately examining all
those scientific problems which presented themselves. For
that would have been contrary to the order which my method prescribed.
But I noticed that the principles of science all had to be borrowed from philosophy,
a subject in which I no longer found anything certain. So I thought that,
before anything else, I should attempt to establish such principles there and
that, since this was the most important matter in the world, where one had to
be most fearful of overhasty and biased judgments, I would not try to get
through it until I had reached an age considerably more mature than I was then
at twenty-three and until I had used a lot more time preparing myself, weeding
out of my mind all the bad opinions which I had accepted before that time, as
well as collecting several experiences so that later they could be the subject
matter of my reasoning, always practising the method which I had set for myself
in order to keep on improving myself in these matters.
Finally, before one starts to rebuild
the lodgings where one lives, it is not sufficient to knock them down and
provide for materials and architects or to work on the architecture oneself,
having, in addition to that, carefully drawn up a design. One must also provide
oneself with some other place where one can lodge comfortably during the time
one works on the building. Thus, in order not to be irresolute in my actions
while my reason obliged me to be so in my judgments and in order not to prevent
myself living from then on as happily as I could, I drew up for myself a provisional
morality, consisting of only three or four maxims, which I wish to share with
you.
The first was to obey the laws and the
customs of my country, constantly holding to the religion which God gave me the
grace to be instructed in since my childhood and governing myself in all other
things in accordance with the most moderate opinions, the ones furthest removed
from excess, which were commonly accepted and practised by the most sensible of
those people among whom I would be living. Since, from that point on, I began
to estimate my own views as worthless, because I wished to subject them all to
examination, I was confident that I could not do better than to follow those of
the most sensible people. And even though there might perhaps be people just as
sensible among the Persians or the Chinese as among us, it seemed to me that
the most practical thing would be for me to guide myself by those among whom I
had to live and that, in order to understand their real opinions, it would be
better for me to pay attention to what they practised rather than to what they
said, not only because, given the corruption of our morals, there are few
people who are willing to state everything they believe, but also because
several are themselves ignorant of what they believe. For the act of thinking
by which one believes in something is different from the act of thinking by
which one understands that one believes it, and one of these separate acts
frequently appears without the other. Moreover, among several opinions equally
well received, I chose only the most moderate ones, as much because such opinions
are always the most convenient to practice and probably the best, for all
excess is usually bad, as because they would also not take me as far from the
true road, if I made a mistake, as if I had chosen one of the extremes when it
was the other one which I should have followed. And I especially included among
what was excessive all promises by which one reduces one's liberty. Not that I
disapprove of laws which, in an attempt to remedy the fickleness of feeble
minds, permit people with a good plan or even an indifferent arrangement for
security in business to make vows or contracts obliging them to maintain their
provisions. But because I did not see anything in the world which remained
always in the same condition and, in my particular case, because I promised
myself that I would increasingly perfect my judgments and not make them worse,
I would have thought I was committing a great error in good sense if, because I
then approved of something, I obliged myself to continue to take it as
something good later on, when it had perhaps ceased to be so or when I had
ceased to value it as something good.
My second maxim was to be as constant
and as resolute in my actions as I could, and to follow the most doubtful
opinions, once I had settled on them for myself, with no less constancy than if
they had been very sure, imitating in this matter travelers who, finding themselves
lost in some forest, should not wander around, shifting direction this way and
that; even less should they stop in one place; they should move on always as
straight as they can in the same direction and not change it for inadequate
reasons, even though at the beginning it was perhaps only chance which led to
their choice of direction. For in this way, if they do not come out exactly
where they want to, they will at least end up arriving somewhere where they
will probably be better off than in the middle of a forest. And because the
actions of life often brook no delay, it is certainly very true that, when it
is not in our power to determine the truest opinions, we ought to follow the
most probable ones, and even when we see no difference in probability among
this group of truths or that one, nevertheless, we have to decide on some for
ourselves and then to consider them, not as something doubtful with regard to
the practical matter at hand, but as manifestly true and very certain, because
the reason which made us choose them has these qualities. This method was able
from then on to relieve me of all the regrets and remorse which usually upset
the consciences of those weak and wavering minds which permit themselves to
work inconsistently with things which they accept as good but which they later
judge to be bad.
My third maxim was to try always to
overcome myself rather than fortune and to change my desires rather than the
order of the world, and generally to get in the habit of believing that there
is nothing which is entirely within our power except our thoughts, so that
after we have done our best concerning those things which lie outside of us,
everything which our attempt fails to deal with is, so far as we are concerned,
absolutely impossible. That alone seemed to me to be sufficient to prevent me
from desiring anything in future which I might not achieve and thus to make me
happy. For since our will has a natural tendency to desire only things which
our understanding represents as in some way possible, it is certain that if we
think about all the good things which are outside of us as equally distant from
our power, we would no more regret missing those whose loss appears due to our
birth, when we are deprived by no fault of our own, than we would regret not
possessing the kingdoms of China or Mexico. By making, as the saying goes, a
virtue of necessity, we would not desire health when we are sick or freedom
when we are in prison, any more than we now desire to have either a body made
of some material as incorruptible as diamonds or wings to fly, like the birds.
But I admit that there is a need for a long discipline and frequently repeated
meditation in order to accustom oneself to looking at
everything from this point of view. And I believe that this is the principal
secret of those philosophers who have been able in earlier times to escape from
the demands of empire and fortune and who, despite pains and poverty, could
rival their gods in happiness. For, constantly busy thinking about the limits
prescribed for them by nature, they persuaded themselves so perfectly that
nothing was in their power except their thoughts, that that alone would be
enough to prevent them from having any affection for other things, and they
acquired such an absolute control over their thoughts that they found in that
process reason to think themselves more rich and more powerful and more free
and more content than any other men, who, because they did not possess this
philosophy, never had the same control over everything they desired, no matter
how favoured they might be by nature and fortune.
Finally, to conclude these moral precepts,
I advised myself to draw up a review of the various occupations which men have
in this life, in an attempt to make a choice about the best and, without
wanting to say anything about the others, I thought that I could not do better
than to continue in the very occupation I was engaged in, that is, using all my
life to cultivate my reason and to progress as far as I could in a knowledge of
the truth, following the method which I had prescribed for myself. I
experienced such extreme contentment once I started using this method that I
did not think that one could find anything more sweet and innocent in this
life. Since every day I discovered through this method some truths which seemed
to me sufficiently important and commonly unknown to other men, the satisfaction
I got from it so filled my mind that nothing else affected me. Moreover, the
three maxims mentioned above were founded only for the plan I had to continue
my self-instruction. For since God has given each one of us some light to
distinguish truth from falsehood, I would not have thought I could remain
content with other people's opinions for one moment, if I had not set out to
use my own judgment to examine them when the time was right, and I would not
have known how to free myself from scruples in following these opinions, if I
had not hoped that I would not, in the process, lose any opportunity to find
better ones, in cases where these existed. Finally I would not have known how
to limit my desires nor how to rest content, if I had
not followed a road by which I believed I could be confident of acquiring all
the knowledge I was capable of. I thought by the same means I could acquire all
the true benefits I was capable of obtaining, all the more so since our will
tends to follow or to fly away from only those things which our understanding
has represented to it as good or bad. So in order to act well it is sufficient
to judge well, and to judge as well as one can is sufficient to enable one to
do one's best, that is, to acquire all the virtues, along with all the other
benefits which one can get, and when one is certain that that is the case one
could not fail to be content.
After assuring myself of these maxims
in this manner and storing them away, along with the truths of the faith, which
have always been first in my beliefs, I judged that, so far as all the rest of
my opinions were concerned, I could freely set about dispensing with them.
Since I hoped to be able to arrive at my goal more easily by talking with men
rather than staying any longer closed up in the room with the stove where I had
had all these thoughts, before that winter was over and done with, I set about
my travels again. And in all the nine years following I did nothing else but
roll around here and there in the world, trying to be a spectator rather than
an actor in all the comedies playing themselves out there. By reflecting on
each matter, in particular on what there was which could render it suspect and
give us an opportunity to make mistakes, I rooted out
from my mind all the errors which could have slid into it in the previous
years. Not that in the process I copied the skeptics, who doubt only for the
sake of doubting, and pretend that they are always irresolute. For my entire plan, by contrast, tended only to make me confident
about throwing away the shifting ground and the sand, in order to find the rock
or the sedimentary clay. This gave me considerable success, it seems to
me, inasmuch as in my attempts to discover the falsity or the uncertainty of
the propositions I examined, not by weak conjectures, but by clear and confident
reasoning, I came across nothing so doubtful that I did not always draw some
fairly certain conclusion from it, even if that conclusion was that it
contained nothing certain. Just as when we tear down an old lodging, we usually
keep the scrap to use in building a new structure, so, as I destroyed all those
opinions of mine which I judged poorly grounded, I made various observations
and acquired several experiences which were of use to me later in establishing
more certain ones. In addition, I continued to practice the method which I had
set for myself. For apart from the fact that I took care, in general, to
conduct all my thinking according to the rules, from time to time I set aside a
few hours which I used to apply the method to mathematical difficulties in
particular, or even to some other difficulties as well, ones which I could
frame in a manner somewhat similar to those in mathematics, stripping from them
all the principles of the other sciences which I did not find sufficiently
strong, as you will see I have done in several which are explained in this
volume.8 Thus, without living in a way apparently different from those who
have nothing else to do but spend a sweet and innocent life studying how to
separate pleasures from vices and enjoying their leisure by making use of all
honourable entertainments without getting bored, I did not fail to follow my
plans and to benefit from the knowledge of the truth, perhaps more so than if I
had only read books or associated with men of letters.
However, these nine years passed by
before I had yet taken any stand concerning the difficulties which are usually
matters of dispute among the scholars. Nor had I started to seek the
foundations of any philosophy more reliable than common philosophy. The example
of several excellent minds who had earlier had the same idea but who, it seemed
to me, had not succeeded, made me imagine such great difficulties that I would
perhaps not have ventured to undertake it so quickly, if I had not seen that
some people had already spread the rumour that I had concluded my work. I don't
know what to say about the basis for this rumour. And if I contributed
something to it by my conversations, that could have been by confessing where I
was ignorant more ingenuously than those who have studied little are accustomed
to do and perhaps also by making known the reasons I had to doubt many things
which other people considered certain, rather than by boasting about any
doctrine. But having a heart sufficiently good not to wish people to take me
for someone other than the man I am, I thought it necessary to attempt by every
means to make myself worthy of the reputation which people ascribed to me. For
exactly eight years this desire made me resolve to distance myself from all
those places where there might be people I know and to retire here, in a
country where the long duration of the war has established such order that the
armies which maintain it appear to serve only to enable the people to enjoy the
fruits of peace with even more security and where, among the crowd of a great
and very active people, who are more careful about their own affairs than
curious about those of other people, with no lack of any commodities present in
the most frequently visited towns, I was able to live retired in solitude, just
as if I were in the most isolated deserts.9
I don't know if I should share with you
the first meditations which I made there, for they are so metaphysical and so out
of the ordinary that they will perhaps not be to everyone's taste. However, in
order that people may be able to judge if the foundations which I set are sufficiently
strong, I find myself in some way compelled to speak of them. For a long time
previously I had noticed that where morals are concerned it is necessary
sometimes to follow opinions which one knows are extremely uncertain as if they
are indubitable, as mentioned above. But since at that time I wanted only to
carry out research into the truth, I thought I must do the opposite and reject
as absolutely false everything about which I could imagine the least doubt, in
order to see if there would be anything totally indisputable remaining after
that in my belief. Thus, because our senses deceive us sometimes, I was willing
to assume that there was nothing which existed the way our senses present it to
us. And because there are men who make mistakes in reasoning, even concerning
the most simple matters of geometry, and who create paralogisms,
and because I judged that I was subject to error just as much as anyone else, I
rejected as false all the reasons which I had taken earlier as proofs. Finally,
considering that all the same thoughts which we have when awake can also come
to us when we are asleep, without there being truth in any of them at the time,
I determined to pretend that everything which had ever entered my mind was no
more true than the illusions of my dreams. But immediately afterwards I noticed
that, while I wished in this way to think everything was false, it was
necessary that I—who was doing the thinking—had to be something. Noticing that
this truth—I think; therefore, I am—was so firm and so sure that all the
most extravagant assumptions of the skeptics would not be able to weaken it, I
judged that I could accept it without scruple as the first principle of the
philosophy I was looking for.10
Then I examined with attention what I
was, and I saw that I could pretend that I had no body and that the world and
the place where I was did not exist, but that, in spite of this, I could not
pretend that I did not exist. By contrast, in the very act of thinking about
doubting the truth of other things, it very clearly and certainly followed that
I existed; whereas, if I had only stopped thinking, even though all the other
things which I had ever imagined were real, I would have no reason to believe
that I existed. From that I recognized that I was a substance whose essence or
nature is only thinking, a substance which has no need of any location and does
not depend on any material thing, so that this “I,” that is to say, the soul,
by which I am what I am, is entirely distinct from the body and is even easier
to know than the body, and that, even if the body were no longer there, the
soul could not help being everything it is.
After that, I considered in general
what is necessary for a proposition to be true and certain, for since I had
just found one idea which I knew to be true and certain, I thought that I ought
also to understand what this certitude consisted of. And having noticed that in
the sentence "I think; therefore, I am" there is nothing at all to
assure me that I am speaking the truth, other than that I see very clearly that
in order to think it is necessary to exist, I judged that I could take as a
general rule the point that the things which we conceive very clearly and very
distinctly are all true. But that left the single difficulty of properly
noticing which things are the ones we conceive distinctly.
After that, I reflected on the fact
that I had doubts and that, as a result, my being was not completely perfect,
for I saw clearly that it was a greater perfection to know than to doubt. I realized
that I should seek out where I had learned to think of something more perfect
than I was. And I concluded that obviously this must be something with a nature
which was, in effect, more perfect. As for the thoughts which I had of several
other things outside of me, like the sky, the earth, light, heat, and a
thousand others, I was not worried about knowing where they came from, because
I did not notice anything in them which seemed to me to make them superior to
myself. Thus, I was able to think that, if they were true, that was because of
their dependence on my nature, in so far as it had some perfection and, if they
were not true, I held them from nothing, that is to say, that they were in me
because I had some defect. But that could not be the same with the idea of a
being more perfect than mine. For to hold that idea from
nothing would be manifestly impossible. And because it is no less
unacceptable that something more perfect should be a consequence of and
dependent on something less perfect than that something should come from
nothing, I could not derive this idea from myself. Thus, I concluded that the
idea had been put in me by a nature which was truly more perfect than I was,
even one which contained in itself all the perfections about which I could have
some idea, that is to say, to explain myself in a single phrase, a nature which
was God. To this I added the fact that, since I know about some perfections
which I do not have, I was not the only being which existed (here I will freely
use, if you will permit me, the language of the schools), but it must of
necessity be the case that there was some other more perfect being, on whom I depended
and from whom I had acquired all that I had. For if I had been alone and
independent of everything else, so that I derived from myself all perfection,
no matter how small, of the perfect being, I would have been able to have from
myself, for the same reason, all the additional perfections which I knew I
lacked, and thus be myself infinite, eternal, immutable, all knowing, all
powerful, and finally have all the perfections which I could observe as present
in God. For, following the reasoning which I have just made, to know the nature
of God, to the extent that my reasoning is able to do that, I only had to think
about of all the things of which I found some idea within me and consider
whether it was a sign of perfection to possess them or not. And I was confident
that none of those ideas which indicated some imperfection were in God, but
that all the others were there, since I perceived that doubt, inconstancy, sadness,
and similar things could not be in God, in view of the fact that I myself would
have been very pleased to be free of them. Then, in addition, I had ideas about
several sensible and corporeal things. For although I supposed that I was
asleep and that everything which I saw or imagined was false, nonetheless I
could not deny that the ideas had truly been in my thoughts. But because I had
already recognized in myself very clearly that intelligent nature is distinct
from corporeal nature, when I considered that all composite natures indicate
dependency and that dependency is manifestly a defect, I judged from this that
God's perfection could not consist of being composed of these two natures, and
that thus He was not, but that if there were some bodies in the world or even
some intelligences or other natures which were not completely perfect, their
being had to depend on God's power, in such a way as they could not subsist for
a single moment without Him.
After that I wanted to look for other
truths, and I proposed to myself the subject matter of geometricians, which I
understood as a continuous body or a space extended indefinitely in length,
width, and height or depth, divisible into various parts, which could have various
figures and sizes and be moved or transposed in all sorts of ways, for the
geometricians assume all that in their subject matter. I glanced through some
of their simplest proofs, and having observed that this grand certainty which
all the world attributes to them is founded only on the fact that they plan
these proofs clearly, following the rule which I have so often stated, I notice
also that there is nothing at all in their proofs which assures me of the existence
of their objects. So, for example, I do see that, if we assume a triangle, it
must be the case that its three angles are equal to two right angles, but, in
spite of that, I do not see anything which assures me that there is a triangle
in the world. But, by contrast, once I returned to an examination of the idea
which I had of a perfect being, I found that that being contains the idea of
existence in the same way as the fact the three angles of a triangle are equal
to two right angles is contained in the idea of a triangle, or that in a sphere
all the parts are equidistant from the centre, or it is even more evident, and
that, as a result, it is as just as certain that God, this perfect being, is or
exists as any geometric proof can be.
But the reason there are several people
who persuade themselves that there are difficulties in understanding this and
even knowing what their soul is, as well, is that they never raise their minds
above matters of sense experience and that they are so accustomed not to consider
anything except by imagining it, which is a way of thinking in particular of
material things, so that everything which is not imaginable seems to them unintelligible.
This point is obvious enough in the fact that even the philosophers in the
schools maintain the axiom that there is nothing in the understanding which has
not first of all been in the senses. But it is certain that the ideas of God
and the soul have never been present in sense experience. It seemed to me that
those who want to use their imagination to understand these things are acting
just as if they want to use their eyes to hear sounds or smell odours, except
that there is still this difference, that the sense of sight provides us no
less assurance of the truth of what it sees than do the sense of smell or
hearing; whereas, neither our imagination nor our senses can assure us of
anything unless our understanding intercedes.
Finally, if there are still some people
who are insufficiently persuaded of the existence of God and their soul by the
reasons I have provided, I would like them to know that everything else which
they perhaps are more confident about in their thinking, like having a body and
knowing that there are stars and an earth, and things like that, are less
certain than God's existence. For although one has a moral assurance about
these things, something which makes doubting them appear at least extravagant,
nonetheless, unless one is an unreasonable being, when a question of metaphysical
certainty is involved, one cannot deny that there is insufficient material here
to make one completely confident, for we notice that one can imagine in the
same way while sleeping that one has another body and that one sees other stars
and another earth, without such things existing. For what is the source of our
knowledge that the thoughts which come while dreaming are false, rather than
the others, seeing that often they are no less lively and distinct? And if the
best minds study this matter as much as they please, I do not think that they
will be able to give any reason which will be sufficient to remove this doubt
unless they presuppose the existence of God. First of all, the very principle
which I have so often taken as a rule—only to recognize as true all those
things which we conceive very clearly and very distinctly—is guaranteed only
because of the fact that God is or exists, that He is a perfect being, and that
everything which is in us comes from Him. From that it follows that our ideas
or notions, being real things which come from God, to the extent that they are
clear and distinct, in that respect cannot be anything but true. Consequently,
if we often enough have some ideas or notions which contain something false,
that can only be those which contain some confusion and obscurity, because in
this they participate in nothing, that is to say, they are so confused in us
only because we are not completely perfect. And it is evident that it is no
less repugnant that falsity or imperfection, in itself, should come from God
than that truth or perfection should come from nothingness. But if we did not
know that everything real and true within us comes from a perfect and infinite
being, then no matter how clear and distinct our ideas were, we would not have
a single reason to assure us that they had the perfection of being true.
Now, after the knowledge of God and the
soul in this way has made us certain of this rule, it is really easy to see
that the dreams which we imagine while asleep should not, in any way, make us
doubt the truth of the thoughts we have while awake. For if it happened, even
while we were sleeping, that we had some really distinct idea, as, for example,
in the case of a geometer inventing some new proof, the fact that he is asleep
does not prevent it from being true, and as for error, it doesn't matter that
the most common dreams we have, which consist of representing to us various
objects in the same way as our external senses do, can give us occasion to
challenge the truth of such ideas, because these ideas can also mislead us
often enough without our being asleep, as, for example, when those people suffering
from jaundice see all objects as yellow, or when the stars or other bodies at a
great distant appear to us much smaller than they are. For, finally, whether we
are awake or asleep, we should never allow ourselves to be persuaded except by
the evidence of our reason. And people should note that I say of our reason and
not of our imagination or of our senses, since even though we see the sun very
clearly, we should not for that reason judge that it is only the size which we
see it, and we can easily imagine distinctly the head of a lion mounted on the
body of goat, without having to conclude, because of that, there is a chimera
in the world: for reason does not dictate to us that what we see or imagine in
this way is true, but it does dictate to us that all our ideas or notions must
have some foundation in truth, for it would not be possible that God, who is
completely perfect and totally truthful, put them in us without that.11 Because our reasoning is never so evident or complete during
sleeping as while we are awake, although then sometimes our imaginations are as
vital or explicit, or more so, reason also dictates to us that our ideas cannot
all be true, because we are not completely perfect—those which contain the
truth must without exception come in those we experience while awake rather
than in those we have while asleep.
I would be very pleased to continue and
make you see here all the chain of other truths which I deduced from these
first ones. But because that would require that I talked of several questions
which are controversial among scholars, things I do not want to get mixed up
with, I think it would be better to refrain from that and speak only in general
about what these matters are, so that I leave it to wiser heads to judge if it
would be useful for the public to be informed about more particular details. I
have always lived firm in the resolution that I had taken not to assume any
other principle than the one which I have just used to demonstrate the existence
of God and the soul, and to accept nothing as true which did not seem to me
more clear and more certain than the proofs of geometers had seemed to me
previously. Nonetheless, I venture to say that, not only did I find a way of
satisfying myself in a short time concerning all the difficult principles which
people are accustomed to deal with in philosophy, but also I noticed certain
laws which God has established in nature in such a way and of which he has
impressed such notions in our souls, that after we have reflected on them sufficiently,
we cannot doubt that they are precisely observed in everything which exists or
which acts in the world. Then, as I considered the consequence of these laws,
it seemed to me that I had discovered several truths more useful and more important
than everything which I had previously learned or even hoped to learn.
But since I attempted to explain the
principles in a treatise which certain considerations prevented me from
publishing, I do not know how better to make them known than stating here in
summary form what that treatise contains. Before writing that text, I had the intention
of including in it all that I thought I knew concerning the nature of material
things. But just as painters cannot portray equally well in a flat picture all
the various surfaces of a solid body and choose one of the main surfaces, which
they set by itself facing the light and, by placing the others in shadows, do
not allow anything to appear more than one can see by looking at them, in the
same way, fearing that I could not put in my discourse everything I had in my
thoughts, I tried only to reveal there fairly fully
what I understood about light, and then at the appropriate time, to add
something about the sun and the fixed stars, because almost all light comes
from them, about the heavens, because they transmit light; about the planets,
comets, and the earth, because they reflect light, and in particular about all
the bodies on earth, because they are coloured, or transparent, or luminous,
and finally about man, because he is the one who looks at these things. Even
so, in order to shade in all these things a little and to be able to speak more
freely of what I was judging, without being obliged to follow or to refute
received opinions among the scholars, I resolved to leave everyone here to
their disputes and to speak only of what would happen in a new world, if God
now created somewhere in imaginary space enough material to compose it, and if
He set in motion, in a varied and disorderly way, the various parts of this material,
so that it created a chaos as confused as poets could make it, and then
afterwards He did nothing other than lend His ordinary help to nature and allow
it to act according to the laws which He established.12So first of all I described this material and tried to picture it
in such a way that there is nothing in the world, it seems to me, clearer and
more intelligible, except what has been said from time to time about God and
the soul. For I even explicitly assumed that in the world there were none of
those forms or qualities which people argue about in the schools, nor, in
general, anything the knowledge of which was not so natural to our souls that
we could not even pretend to remain ignorant of it. In addition, I made known
the laws of nature, and without basing my reasoning on any principle other than
the infinite perfections of God, I tried to demonstrate all of these laws about
which one could entertain any doubts, to show that they are such that, although
God could have created several worlds, there would not be one where these
failed to be observed. After that, I showed how the greatest part of material
in chaos would have to, as a result of these laws, organize and arrange itself
in a certain way which made it similar to our heavens, how, in so doing, some
of its parts must have made up an earth and some parts planets and comets, and
some other parts a sun and fixed stars. And at this point, dwelling on the
subject of light, I explained at some length the nature of light which must be
found in the sun and the stars, how from there it crossed in an instant the
immense distances of heavenly space, and how it is reflected from the planets
and comets towards the earth. To this I added several things concerning the
material, the arrangement, the movements, and all the various qualities of these
heavens and these stars. Consequently, I thought I had said enough about these
matters to make known the fact that one observes nothing in these features of
this world which must not, or at least could not, appear entirely similar to
those of the world which I described. From there I went on to speak in particular
about the earth, about how, although I had expressly assumed that God had
placed no heaviness in the material of which it is composed, all its parts
could not help tending precisely to its centre, how, having water and air on
its surface, the arrangement of the heavens and the stars, and particularly of
the moon, had to create on earth an ebb and flow similar in all its features to
the ones we see in our oceans, and, beyond that, a certain flow in the water as
well as in the air, from east to west, like the one we also observe between the
tropics, how the mountains, seas, fountains, and rivers can naturally form out
of that, how earth's metals come into the mines, and how the plants on earth
grow in the fields, and, in general, how all the things we call mixed or
composite could be produced on earth. And, among other things, because I know
of nothing, other than the stars, which produces light except fire, I studied
to understand really clearly everything associated with the nature of fire, how
it arises, how it is nourished, how sometimes it has heat without light and
sometimes light without heat, how it can introduce various colours in different
bodies, as well as various other qualities, how it melts some things and makes
others harder, how it can consume almost everything or convert it into ash and
smoke, and finally how, out of these cinders, simply by the violence of its
actions, it makes glass. For this transformation of cinders
into glass seemed to be as wonderful as anything else which happens in nature,
and I took particular pleasure in describing it.
However, I did not want to conclude
from all these things that this world was created in the fashion which I was
proposing. For it is much more probable that God made the world from the
beginning just what it had to be. But it is certain, and this is an opinion commonly
accepted among theologians, that the actions by which God now preserves the
world are exactly the same as the method by which He created it, in such a way
that even if He did not give it at the start any form other than a chaos,
providing that He had first established the laws of nature and had given His
assistance, so that it would act as it usually does, we can believe, without
denying the miracle of creation, that because of these facts alone all purely
material things would have been able, over time, to become the way we now
observe them, and their nature is much easier to conceive when one sees them
born gradually in this way than if one thinks of them only as made all at once
in a finished state.13
From the description of the inanimate
bodies and of plants, I moved onto the bodies of animals and especially the
body of man. But because I did not yet have sufficient knowledge to speak of
that in the same way as of other things, that is to say, to speak of effects in
terms of causes, by revealing the seeds and the methods by which nature had to
produce them, I contented myself with assuming that God formed the human body
completely like one of our own, both in the external shape of its limbs and in
the arrangement of its inner organs, without making them of any material other
than the one which I had described and without, at the start, placing in that
body any reasonable soul or any other thing to serve the body as a vegetative
or sensitive soul, except that He kindled in its heart one of those fires
without light which I had already explained and which I conceived as in no way
different in its nature from the fire which heats hay when it is stored before
it is dry or which makes new wines bubble when they are allowed to ferment on
the crushed grapes. For, by examining the functions which, as a result of this
assumption, could be present in this body, I found precisely all those which
could be in us without our being able to think, and thus those functions to
which our soul, that is to say, that distinct part of the body whose nature is
solely to think (as I have said above) does not contribute, functions which are
exactly the same as those in which we can say the animals without reason are
similar to us. But in doing this, I could not find any of those which, because
they are dependent on thought, are the only ones which pertain to us, to the extent
that we are men; whereas, I found all of them afterwards, once I assumed the
God had created a reasonable soul and joined it to this body in the particular
way which I described.
But so that you can see how I dealt
with this material in that treatise, I want to put in here the explanation for
the movement of the heart and the arteries, the first and the most universal
thing which one observes in animals. From that one will easily assess what one
should think of all the others. And so that people have less difficulty
understanding what I am going to say, I would like those who are not versed in
anatomy to take the trouble, before reading this, to have the heart of some
large animal with lungs dissected in front of them. For it is in all respects
sufficiently similar to the heart in man. And I would like them to have
demonstrated to them the two chambers or cavities which are in that heart.
First, there is one chamber on its right side, to which two very large tubes
correspond, that is, the vena cava, which is the principal
receptacle of blood and, as it were, the trunk of the tree of which all the
other veins of the body are the branches, and the vena arteriosa, which has, with that label, been poorly
named, because it is, in fact, an artery, the one which, originating at the
heart, divides up, after leaving the heart, into several branches, which go out
to distribute themselves throughout the lungs.14 Then there is the chamber on the left side of the heart, to
which, in the same way, two tubes correspond, which are as large or larger than
the ones just mentioned: that is, the venous artery, which is also misnamed,
because it is nothing but a vein which comes from the lungs, where it is
divided into several branches interwoven with those from the arterial vein and
with those associated with the tube called the windpipe, through which air enters
for respiration; and the large artery which, leaving the heart, sends its
branches throughout the body. I would also like someone to point out carefully
to them the eleven small strips of skin which, just like so many small doors,
open and close the four openings in these two chambers, that is, three at the
entry of the vena cava, where they are so arranged that they cannot in any way
prevent the blood contained in the vena cava from flowing into the right
chamber of the heart and, at the same time, effectively prevent its ability to
flow out; three gates at the entry of arterial vein, which, being arranged in
precisely the opposite way, easily allow the blood in this chamber to move
toward the lungs but do not allow the blood in the lungs to return to that
chamber of the heart. Then, in the same way, there are two other strips of
membrane at the opening to the venous artery which allow the blood from the
lungs to flow towards the left chamber of the heart, but prevent its return,
and there are three at the entry of the great artery which allow blood to leave
the heart but prevent it from returning there. There is no need to seek for any
reason for the number of these membranes, beyond the fact that since the
opening of the venous artery is an oval, because of its location, it can be
readily closed with two; whereas, since the others are round, they can be more
easily closed with three. In addition, I would like people to notice that the
large artery and the arterial vein have a composition much harder and firmer
than the venous artery and the vena cava, that these last two get bigger before
entering the heart and there make a structure similar to two small sacks,
called the auricles of the heart, which are composed of flesh like that of the
heart, that there is always more heat in the heart than in any other place in
the body; and finally that, if any drop of blood enters its cavities, this heat
in the heart is capable of making the drop quickly swell and expand, just as
all liquors generally do when one lets them fall drop by drop into some really
hot container.
After all that, I have no need to say
anything else to explain the movement of the heart, other than the following:
when its cavities are not full of blood, then necessarily blood flows from the
vena cava into the right chamber and from the venous artery into the left,
because these two blood vessels are always full and their openings, which are
oriented towards the heart, cannot then be blocked. But as soon as two drops of
blood have entered the heart in this way, one in each of its chambers, these
drops, which could only be of a considerable size because the openings through
which they enter are very large and the vessels they come from are really full
of blood, become thinner and expand, on account of the heat they encounter
there, as a result of which they make the entire heart expand, and then they
push against and close the five small gates which stand at the openings of the
two vessels from which these drops of blood have come, thus preventing any more
blood from moving down into the heart. And, continuing to become increasingly
thinner, the drops of blood push against and open the six other small gates
which stand at the opening of the two other vessels, through which they flow
out, in this way causing all the branches of the arterial vein and great artery
to expand, almost at the same instant as the heart, which immediately
afterwards contracts, as do these arteries as well, because the blood which has
entered them gets colder again there, and their six small gates close once
more. Then the five valves on the vena cava and the venous artery re-open, and
allow passage of two more drops of blood, which, once more, make the heart and
the arteries expand, just as in the preceding steps. And because the blood
which enters the heart in this manner passes through these two small sacks
called auricles, this motion causes the movement of the auricles to be the
opposite of the heart's movement—they contract when the heart expands. As for
the rest, so that those who do not understand the force of mathematical proofs
and who are not accustomed to distinguishing true reasons from probable reasons
do not venture to deny this matter without examining it, I wish to advise them
that this movement which I have just explained is as necessarily a result of
the mere arrangement of the organs which one can see in the heart with one's
own eyes and of the heat which one can feel there with one's fingers and of the
nature of blood which one can recognize from experience, as the movement of a
clock is necessarily a result of the force, the placement, and the shape of its
counter-weights and wheels.
But if someone asks how the blood in
the veins does not exhaust itself as it flows continually into the heart in this
way and how the arteries are not overfilled because all the blood which passes
through the heart goes into them, there's no need for me to say anything in
reply other than what has already been written by an English doctor, to whom we
must give the honour of having broken the ice in this area and of being the
first to teach that there are several small passages at the extremities of the
arteries through which the blood which they receive from the heart enters into
the small branches of the veins, from where it proceeds to move once again
towards the heart, so that its passage is nothing other than a constant
circulation.15He proves this really well by the common experience of surgeons
who, having bound up an arm moderately tightly above a place where they have
opened a vein, cause the blood to flow out more abundantly than if they had not
tied the arm. And the opposite happens if they place the binding below the cut,
between the hand and the opening, or if they make the binding above the opening
very tight. For it is clear that the binding, when moderately tight, can only
prevent the blood which is already in the arm from returning towards the heart
by the veins, but in doing that the binding does not stop the blood from
continuing to flow to the place from the arteries, because the arteries are
situated below the veins and because the skin of the arteries, being harder, is
less easy to press down. Thus, the blood which comes from the heart tends to
move with more force through the arteries towards the hand than it does in returning
from the hand towards the heart through the veins. And because this blood
leaves the arm by the opening in one of the veins, it must necessarily be the
case that there are some passages below this binding, that is to say, towards
the extremities of the arm, through which it can come there from the arteries.
He [Harvey] also demonstrates really well what he says about the flow of blood
through certain small membranes which are so arranged in various places along
the veins that they do not allow blood to move in the veins from the middle of
the body towards the extremities, but only to return from the extremities
towards the heart. Moreover, he demonstrates this by an experiment which shows
that all the blood which is in the body can leave it in a very little time by a
single artery, if it is cut, even if it has been tightly bound really close to
the heart and cut between the heart and the binding, so that one simply could
not imagine any explanation other than that the blood flowing out is coming
from the heart.
But there are several other things
which attest to the fact that the true cause of this movement of blood is as I
have described it. For, firstly, the difference which one notices between the
blood which comes from the veins and the blood which flows out of the arteries
could come about only if the blood is rarefied and, as it were, distilled in
passing through the heart. It is more subtle, more lively,
and warmer immediately after leaving the heart, that is to say, in the
arteries, than it is shortly before entering the heart, that is to say, when it
is in the veins. And if one pays attention, one will find that this difference
is only readily apparent close to the heart and not so evident in places which
are more distant from it. Then, the hardness of the skins making up the
arterial vein and the large artery shows sufficiently well that the blood beats
against them with greater force than it does against the veins. And why would
the left chamber of the heart and the great artery be more ample and larger
than the right chamber and the arterial vein, if it were not for the fact that
the blood of the venous artery, which has only been in the lungs since passing
through the heart, is more subtle and more strongly and more easily rarefied
than the blood which comes immediately from the vena cava? And what could
doctors diagnose by testing the pulse, if they did not know, in keeping with
the fact that blood changes its nature, that it can be rarefied by the heat of
the heart more or less strongly and more or less quickly than before? And if
one examines how this heat is transferred to the other limbs, is it not
necessary to admit that it is by means of the blood, which, passing through the
heart, is re-heated in it and from there spreads throughout the entire body?
That's the reason why, if one takes blood from some part of the body, in that
very process one takes the heat, and even if the heart were as hot as a burning
fire, it would not be sufficient to re-heat the feet and the hands as much as
it does, if it did not continually send new blood there. From this we also
understand that the true purpose of respiration is to bring sufficient fresh
air into the lungs to ensure that the blood which comes from the right chamber
of the heart, where it has been rarefied and, as it were, changed into vapour,
thickens and changes back again into blood, before falling back into the left
chamber, without which it would not be fit to serve as nourishment for the fire
there. What confirms this is that we observe that the animals which have no
lungs also have only one cavity in the heart and that children, who cannot use
their lungs while they are closed up in their mother's womb, have an opening
through which blood flows from the vena cava into the left cavity of the heart
and a passage by which the blood comes from the arterial vein into the large
artery without passing through the lungs. Next, how would digestion take place
in the stomach, if the heart did not send heat there through the arteries and
with that some of the more easily flowing parts of the blood which help to
dissolve the food which has been sent there? And the action which converts the
juice of this food into blood—surely that is easy to understand, if one
considers that it is distilled, as it passes and re-passes through the heart,
perhaps more than one or two hundred times each day? What else do we need to
explain nutrition and the production of the various humours in the body, other
than to say that the force with which the blood, as it gets rarefied, passes
from the heart towards the extremities of the arteries, brings it about that
some portions of it stop among those parts of the limbs where they are, and
there take the place of some other parts which the blood pushes away, and that,
depending on the situation or the shape or the smallness of the pores which
these parts of blood encounter, some of them go off to certain places rather
than to others, in the same way that anyone can see with various screens,
which, being pierced in different ways, serve to separate various grains from
one another? Finally, what is most remarkable in all this is the generation of
animal spirits which resemble a very slight wind or rather a very pure and very
lively flame which, by climbing continually in great quantities from the heart
into the brain, goes from there through the nerves into the muscles and gives
movement to all the limbs, without it being necessary to imagine any other
cause which has the effect of making the most agitated and most penetrating
parts of blood, those most appropriate for making up these animal spirits, move
towards the brain rather than elsewhere, other than that the arteries which
carry these parts of the blood are those which come from the heart toward the
brain by the most direct route and that, following the laws of mechanics, which
are the same as nature's laws, when several things collectively tend to move
towards the same place where there is insufficient room for all of them, as the
parts of blood which leave the left cavity of the heart tend towards the brain,
the most feeble and less agitated parts must be turned away from the brain by
the strongest parts. In this way, only the latter parts reach the brain.
I explained in particular detail all
these things in the treatise which I had planned to publish previously. And
then I demonstrated what the nerves and muscles in the human body must be made
of, so that the animal spirits, once inside the nerves, would have the power to
move its limbs, as one sees that heads, for a little while after being cut off,
continue to move and bite the earth, in spite of the fact that they are no
longer animated. I also showed what changes must take places in the brain to
cause the waking state, sleep, and dreams, how light, sounds, smells, tastes,
heat, and all the other qualities of external objects could imprint various
ideas on the brain through the mediation of the senses, just as hunger, thirst,
and the other inner passions can also send their ideas to the brain; what must
be understood by common sense where these ideas are taken in, by memory which
preserves them, and by fantasy which can change them in various ways and
compose new ones, and, in the same way, distribute animal spirits to the
muscles and make the limbs of the body move in all the different ways—in
relation to the objects which present themselves to the senses and in relation
to the interior physical passions—just as our bodies can move themselves
without being led by the will. None of this will seem strange to those who know
how many varieties of automata, or moving machines, human industry
can make, by using only very few pieces in comparison with the huge number of
bones, muscles, nerves, arteries, veins, and all the other parts in the body of
each animal. They will look on this body as a machine, which, having been made
by the hand of God, is incomparably better ordered and more inherently
admirable in its movements than any of those which human beings could have
invented. And here, in particular, I stopped to reveal that if there were
machines which had the organs and the external shape of a monkey or of some
other animal without reason, we would have no way of recognizing that they were
not exactly the same nature as the animals; whereas, if there was a machine
shaped like our bodies which imitated our actions as much as is morally
possible, we would always have two very certain ways of recognizing that they
were not, for all their resemblance, true human beings. The first of these is
that they would never be able to use words or other signs to make words as we
do to declare our thoughts to others. For one can easily imagine a
machine made in such a way that it expresses words, even that it expresses some
words relevant to some physical actions which bring about some change in its
organs (for example, if one touches it in some spot, the machine asks what it
is that one wants to say to it; if in another spot, it cries that one has hurt
it, and things like that), but one cannot imagine a machine that arranges words
in various ways to reply to the sense of everything said in its presence, as
the most stupid human beings are capable of doing. The second test is that,
although these machines might do several things as well or perhaps better than
we do, they are inevitably lacking in some others, through which we would
discover that they act, not by knowledge, but only by the arrangement of their
organs. For, whereas reason is a universal instrument which can serve in all
sorts of encounters, these organs need some particular arrangement for each
particular action. As a result of that, it is morally impossible that there is
in a machine's organs sufficient variety to act in all the events of life in
the same way that our reason empowers us to act. Now, by these two same means,
one can also recognize the difference between human beings and beasts. For it
is really remarkable that there are no men so dull and stupid, including even
idiots, who are not capable of putting together different words and of creating
out of them a conversation through which they make their thoughts known; by
contrast, there is no other animal, no matter how perfect and how successful it
might be, which can do anything like that. And this inability does not come
about from a lack of organs For we see that magpies and parrots can emit words,
as we can, but nonetheless cannot talk the way we can, that is to say, giving
evidence that they are thinking about what they are uttering; whereas, men who
are born deaf and dumb are deprived of organs which other people use to
speak—just as much as or more than the animals—but they have a habit of
inventing on their own some signs by which they can make themselves understood
to those who, being usually with them, have the spare time to learn their language.
And this point attests not merely to the fact that animals have less reason
than men, but to the fact that they have none at all. For we see that it takes
very little for someone to learn how to speak, and since we observe inequality
among the animals of the same species just as much as among human beings, and
see that some are easier to train than others, it would be incredible that a
monkey or a parrot which was the most perfect of his species was not equivalent
in speaking to the most stupid child or at least a child with a troubled brain,
unless their soul had a nature totally different from our own. And one should
not confuse words with natural movements which attest to the passions and can
be imitated by machines as well as by animals, nor should one think, like some
ancients, that animals talk, although we do not understand their language. For
if that were true, because they have several organs related to our own, they
could just as easily make themselves understood to us as to the animals like
them. Another truly remarkable thing is that, although there are several
animals which display more industry in some of their actions than we do, we
nonetheless see that they do not display that at all in many other actions.
Thus, the fact that they do better than we do does not prove that they have a
mind, for, if that were the case, they would have more of it than any of us and
would do better in all other things; it rather shows that they have no reason
at all, and that it is nature which has activated them according to the
arrangement of their organs—just as one sees that a clock, which is composed
only of wheels and springs, can keep track of the hours and measure time more accurately
than we can, for all our care.
After that, I described the reasonable
soul and revealed that it cannot be inferred in any way from the power of
matter, like the other things I have spoken about, but that it must be expressly
created, and I described how it is not sufficient that it is lodged in the
human body like a pilot in his ship, except perhaps to move its limbs, but that
it is necessary that the soul is joined and united more closely with the body,
so that it has, in addition, feelings and appetites similar to ours and thus
makes up a true human being.16 As for the rest, here I went on at some length on the
subject of the soul, because it is among the most important. For, apart from
the error of those who deny God, which I believe I have adequately refuted
above, there is nothing which distances feeble minds from the right road of virtue
more readily than to imagine that the soul of animals is the same nature as our
own and that thus we have nothing either to fear or to hope for after this
life, any more than flies and ants do; whereas, once one knows how different
they are, one understands much better the reasons which prove that the nature of
our souls is totally independent of the body, and thus it is not at all subject
to dying along with the body. Then, to the extent that one cannot see other
causes which destroy the soul, one is naturally led to judge from that that the
soul is immortal.
It is now three years since I reached
the end of the treatise which contains all these things and since I started to
revise it in order to put it into the hands of a printer. Then I learned that
people to whom I defer and whose authority over my actions could hardly be less
than my own reason over my thoughts had expressed disapproval of an opinion
about physics published a little earlier by someone else.17 I do not wish to say that I subscribed to that opinion, but,
although I had observed in it nothing before their censure which I could
imagine prejudicial to religion or the state, and thus nothing which would have
prevented me from writing it if reason had persuaded me, this I made me afraid
that there might nonetheless be something among my opinions where I had gone
astray, notwithstanding the great care I always took not to accept new ideas
into my beliefs for which I did not have very certain proofs and not to write
anything which would work to anyone's disadvantage. This was sufficient to
oblige me to alter my resolution to publish my opinions. For although the
reasons I had adopted earlier had been very strong, my inclination, which has
always led me to hate the profession of producing books, made me immediately
find enough other reasons to excuse myself in this matter. And, given the
nature of these reasons, on one side or the other, not only am I quite
interested in stating them here, but the public may perhaps also be interested
in knowing them.
I have never made a great deal of the
things which come from my own mind, so while I gathered no other fruits from
the method I was using, other than that I satisfied myself concerning some
difficulties in the speculative sciences or else that I tried to regulate my
morals by reasons which my method taught me, I did not think myself obliged to
write anything. For where morals are concerned, every person is so full of his
own good sense that it would be possible to find as many reformers as heads, if
it was permitted to people other than those God has established as sovereigns
over his people or those to whom he has given sufficient grace and zeal to be
prophets to try changing anything in our morality. Although my speculations
pleased me a great deal, I thought that other people also had their own
speculations which pleased them perhaps even more. But immediately after I had
acquired some general notions concerning physics and, by starting to test them
on various particular difficulties, had noticed just where they could lead and
how much they differed from principles which people have used up to the present
time, I thought that I could not keep them hidden without sinning greatly
against the law which obliges us to promote as much as we can the general good
of all men. For my notions had made me see that it is possible to reach
understandings which are extremely useful for life, and that instead of the
speculative philosophy which is taught in the schools, we can find a practical
philosophy by which, through understanding the force and actions of fire,
water, air, stars, heavens, and all the other bodies which surround us as
distinctly as we understand the various crafts of our artisans, we could use
them in the same way for all applications for which they are appropriate and
thus make ourselves, as it were, the masters and possessors of nature.18 But it was not only a desire for to invent an infinite
number of devices which might enable us to enjoy without effort the fruits of
the earth and all the commodities found in it, but mainly also my desire for
the preservation of our health, which is, without doubt, the principal benefit
and the foundation of all the other benefits in this life. For even the mind
depends so much on the temperament and the condition of the organs of the body
that, if it is possible to find some means to make human beings generally wiser
and more skilful than they have been up to this point, I believe we must seek
that in medicine. It is true that the medicine now practiced contains few
things which are remarkably useful. But without having any design to denigrate
it, I am confident that there is no one, not even those who make a living from
medicine, who would not claim that everything we know in medicine is almost
nothing in comparison to what remains to be known about it and that we could liberate
ourselves from an infinity of illnesses, both of the body and the mind, and
also perhaps even of the infirmities of ageing, if we had sufficient knowledge
of their causes and of all the remedies which nature has provided for us. Now,
intending to spend all my life in research into such a necessary science and
having encountered a road which seemed to me such that one should infallibly
find this science by following it, unless one was prevented either by the brevity
of one's life or by the lack of experiments, I judged that there was no better
remedy against these two obstacles than to communicate faithfully to the public
the little I had found and to invite good minds to try to move on further, by
contributing, each according to his own inclination and power, to the
experiments which need to be conducted and also by communicating to the public
everything they learn, so that the most recent people begin where the previous
ones have finished. If we thus joined the lives and labours of many people,
collectively we might go much further than each particular person could.
Besides, I noticed that, where experiments
are concerned, they are increasingly necessary as one's knowledge advances, for
at the beginning it is better to conduct only those which present themselves to
our sense and which we cannot ignore, provided that we engage in a little
reflection, rather than to seek out more rare and recondite experiments,
because these rarer ones are often misleading, when we do not yet know the
causes of the more common phenomena, and the circumstances on which they depend
are almost always so particular and so precise, that it is very difficult to
observe them. But in this work I kept to the following order: first, I tried to
find the general principles or the first causes of everything which exists or
could exist in the world, without considering anything germane to my purpose
other than the fact that God alone created the world, not deducing anything
additional, other than certain grains of truth which are naturally in our
souls. After that, I examined what were the first and most common effects we
could deduce from these causes. By doing that, it seems to me, I found the
heavens, the stars, and earth, and even on the earth water, air, fire,
minerals, and some other things, the sort which are the most common of all and
the simplest, and thus the easiest to know. Then, when I wanted to move down to
more particular matters, so many varied ones presented themselves to me that I
did not think it would be possible for the human mind to distinguish the forms
or species of bodies on the earth from an infinity of others which could exist
there if the will of God had put them there and, thus, that one could not adapt
them to our use, unless one proceeded to the causes through the effects and
made use of several particular experiments. After that, I turned my mind onto
all the objects which had ever presented themselves to my senses. I venture to
say that I didn't notice in them anything which I could not explain easily
enough by the principles which I had found. But I must also confess that the
power of nature is so ample and vast and its principles are so simple and so general
that I observed hardly any particular effect which I did not immediately
understand as being capable of being deduced in several different ways, so that
my greatest difficulty is usually to find on which of these ways the effect
depends. In dealing with this matter, I did not know any expedient other than,
once again, to look for some experiments which would be such that their outcomes
would not be the same if one of these ways had to explain it rather than some
other way. As for the rest, I am now at a point where I perceive well enough,
it seems to me, the method one has to use to make most of those experiments
which can serve for this purpose. But I also see that they are of such a kind
and that there are so many of them that neither my hands nor my income, even if
I had a thousand times more of both than I do, could suffice for all of them,
so that from now on my progress in understanding nature will be proportional to
the means I have for conducting more or fewer experiments. This was what I
promised myself I would make known in the treatise which I had written, as well
as showing in it the practical value which the public could gain from these
experiments so clearly that I would oblige all those who wished to promote the
general well being of man, that is to say, all those who are truly virtuous and
who are not false by pretending to virtue or merely virtuous by public opinion,
to communicate to me all the experiments which they have already made, as well
as to help me in researching those which remain to be done.
But since that time I have had other
reasons which made me change my mind and think that I really must continue to
write down all matters which I judged to have some importance, to the extent
that I discovered truth in them, and to bring to my writing the same care that
I would if I wanted it published, so that I would have more time to examine
such things well, since there is no doubt one always looks more closely at what
one thinks many people must see than at what one does only for oneself, and
often matters which seemed to me true when I began to think of them appeared
false to me when I wished to put them on paper. By writing things down, I would
not lose any opportunity to benefit the public, if I could, and, if my writings
are worth anything, those who have them after my death could use them wherever
they were most relevant. But I thought I must not, on any account, agree that
they be published during my life, so as to prevent the hostility and
controversies which they could perhaps arouse and the sort of reputation which
I could acquire from giving me any occasion to waste the time which I planned
to use to instruct myself. For although it is true that each man is obliged to
provide as much as is in him for the good of others and that there is no value
whatsoever in anything which has no benefit for anyone, nevertheless it is also
true that we should care about things more distant than the present and that it
is good to forget about things which might bring some benefit to those now living
when one's intention is to create other things which will bring more benefits
to our descendants. In fact, I really wanted people to understand that the
little I had learned up to this point is almost nothing in comparison with what
I am ignorant of and what I do not despair of being able to learn. For it is
almost the same with those who discover truth little by little in the sciences
as it is with those who, once they start to become rich, have less trouble in
making large acquisitions than they did previously, when they were poorer, in
making much smaller ones. Or, again, one can compare them to leaders of armies
whose forces usually grow in proportion to their victories and who, in order to
capture towns and provinces, need more leadership to maintain their forces
after the loss of a battle than they do after winning one. For it is truly a
matter of giving battle when one tries to overcome all the difficulties and
mistakes which prevent us from reaching an understanding of the truth. And it
is a battle loss when one accepts some false opinion concerning any matter at
all general and important. Afterwards one requires a great deal more skill to
put oneself in the same condition one was in previously than one has to have to
make great progress when one already has confirmed principles. In my case, if I
have previously found some truths in the sciences (and I hope that the matters
contained in this volume will make people conclude that I have found some), I
can say that those are only the consequences of and dependent upon five or six
major difficulties which I overcame and that I count these as so many battles
in which victory was on my side. Still, I will not hesitate to state that I
think I need to win only two or three others like those in order to reach the
final goal of my project and that I am not so advanced in years that, given the
ordinary course of nature, I still can have enough leisure to bring my project
to its conclusion. But I think that I am all the more obliged to manage the
time remaining to me, now that I have more hope of being able to use it well,
and I would, no doubt, have many chances to lose that time, if I published the foundations
of my physics. For although these foundations are almost all so evident that
one need only hear them to believe them and there are none of them which, in my
view, I cannot demonstrably prove, nevertheless, because it is impossible that
they will agree with all the various opinions of other men, I anticipate being
often distracted by the hostility they would give rise to.
One could say that this opposition
would be useful, to the extent it makes me understand my mistakes, and that, if
I have anything good, others will by this means have a more complete
understanding. Since several people can see more than one man by himself, if
people begin from now on making use of my principles, they will also help me
with their inventions. But even though I recognize that I am extremely prone to
error and that I almost never have faith in the first thoughts which come to
me, nevertheless the experience which I have of objections which people could
make about me prevents me from hoping for any benefit from such objections. For
I have already undergone the criticism of so many of those whom I held as
friends and of some others who I thought considered me indifferently and even
of some in whom I knew malignity and envy would try hard enough to uncover what
affection concealed from my friends. But it rarely happened that someone made
an objection which I had not in some way anticipated, unless it was really
distant from my subject, so that I have almost never met any critic of my opinions
who did not appear to me to be less rigorous or less fair than myself.
Moreover, I have never observed that anyone has discovered any truth of which
people were previously ignorant by means of the disputes practised in the
schools. For when each person tries to emerge victorious, people strive much
harder to establish probability than to weigh the reasons on one side or the
other, and those who have been good pleaders for a long time are not, on that account,
better judges afterwards.
As for the practical use which other
people derive from the communication of my thoughts, it could not be all that
great, since I have not taken them so far that there is no need to add a great
many things before they can be practically applied. And I think I can say
without vanity that if there is anyone who can do that, this person should be
me rather than anyone else, not because several minds incomparably better than
mine could not be found in this world, but because one cannot conceive of something
so well and make it one's own when one learns it from someone else as when one
comes up with it oneself. What is really true about this material is that,
although I have often explained some of my opinions to people with very good
minds, who, while I was talking to them, seemed to understand my opinions very clearly,
nonetheless, when they have repeated them, I have noticed that almost always
they have changed them in such a way that I could no longer admit them as mine.
Incidentally, I am more than happy to take the opportunity here to beg our
descendants never to believe anything that people will tell them comes from me,
when I never divulged them myself, and I am not astonished at the extravagant
things which people attribute to those ancient philosophers whose writing we do
not possess. I do not judge that their thoughts were really irrational on that
account, seeing that they were the best minds of their times, but merely assume
that their thoughts have been misrepresented to us. For we see also that it
almost never happens that any of their disciples surpasses them, and I am
confident that the most passionate of those people who follow Aristotle
nowadays would consider themselves fortunate if they could have as much
knowledge of nature as he had, even on condition that they would never know any
more. They are like ivy which tends not to climb higher than the trees which support it and which often even comes down again
when it has reached the tree tops. For it seems to me that those people also
come back down, that is, make themselves in some way less knowledgeable than if
they were to abandon their studying, when, not content with knowing everything
intelligibly explained by their author, they wish to find, beyond that, the
solution to several difficulties about which he has said nothing and has
perhaps never even thought. However, their way of practising philosophy is extremely
comfortable for those who have nothing but really mediocre minds, for the
obscurity of the distinctions and the principles they use enables them to speak
of everything as boldly as if they understood what they were talking about and
to defend everything that they state against the most subtle and skillful
minds, without anyone having the means to argue against them. In this it
strikes me they are similar to a blind man who, in order to fight on equal
terms against someone who can see, makes him come into the bottom of some
really obscure cave. And I can state that such people have an interest in my
abstaining from publishing the principles of philosophy I use, because, given
that they are very simple and very evident, if I published them, I would be
doing roughly the equivalent of opening some windows and bringing the light of
day into this cave where they have gone down to fight each other. But even the
best minds have no occasion to want to know these principles. For if they want
to know how to speak about everything and to acquire the reputation of being
scholarly, they will get there more easily in contenting themselves with
probability which can be found in all sorts of matters without great trouble,
rather than by seeking out the truth, which is not discovered except little by
little in some matters and which, when it is a question of speaking of other
matters, requires us to confess frankly that we are ignorant of them. If they
would rather have the undoubtedly preferable condition of knowing a few truths
over the vanity of appearing to be ignorant about nothing, and if they wish to
follow a plan similar to my own, for that they do not need me to say anything
more to them than I have already said in this discourse. For if they are
capable of moving on further than I have done, they will also, with all the
more reason, find for themselves everything I think I have found. Since I have
never looked at anything except in due order, it is certain that what remains
for me to discover is inherently more difficult and more hidden than what I
have been able to find up to this point, and they would have much less pleasure
in learning that from me than from themselves. Beyond that, the habit they will
acquire by searching first for easy things and then moving on gradually by
degrees to other more difficult things will serve them better than all my instructions
will be able to. As for me, I am convinced that if I had been taught from my
youth all the truths which I have found since my demonstrations and if I had
had no trouble in learning them, I would perhaps have never known any others.
At the very least I would never have acquired the habit and the skill which I
think I have in constantly finding new truths to the extent that I apply myself
in looking for them. In a word, if there is in the world some work which cannot
be properly completed by anyone other than the same person who started it, it’s
the work I do.
It is true that so far the experiments
which can help in that work are concerned, one man by himself is not sufficient
to undertake them all. But he cannot put to practical use hands other than his
own, except those of craftsmen or such people as he can pay, who with the hope
of profit, which is a very effective means, will carry out everything exactly
as he instructs them. As for volunteers who from curiosity or a desire to learn
perhaps offer to help him, apart from the fact that ordinarily they promise
more than they deliver and that they come up with nothing but fine propositions,
none of which ever succeeds, they inevitably want to paid with the explanation
of some difficulties or at least with compliments and useless discussions which
would cost him more time than he could afford. As for the experiments which
other people have already carried out, even though they should be willing
enough to tell him about them, those who call such experiments secrets will
never do that. Such experiments for the most part contain so many superfluous
circumstances or ingredients that it would be very difficult for him to
decipher the truth of them. Beyond that, he would find almost all of them badly
explained or even false, because those who have carried them out have forced
themselves to make the experiment appear to conform to their principles, so
that if there were some experiments he could use, once again it would not be
worth the time he would have to take up to pick them out. In the same way, if
there were in the world someone in whom people had great confidence that he was
capable of finding the greatest things and the most useful for the public as
possible, and if for this reason other men tried hard to help him in every way
to carry out his project with success, I don't see that they could do anything
for him other than to furnish the costs of the experiments he needed to carry
out, and, as to the rest, they could prevent his leisure from being taken away
by anyone's importunity. But beyond the fact that I do not presume so much of myself
as to wish to promise anything extraordinary and that I do not indulge in
thoughts so vain as to imagine to myself that the pubic ought to show a great
deal of interest in my plans, I do not have a soul so base that I would be
willing to accept from anyone a favour which people might think I did not
deserve.
All these considerations combined were
the reason, three years ago, that I did not wish to publish the treatise which
I had in my hands. I even made a resolution that during my life I would not
make public any other treatise which was so general and from which one could
learn the foundations of my physics. But, once again, there have been two other
reasons since then which have obliged me to set down here some particular
essays and to give the public some account of my actions and my plans. The
first is that if I failed to do this, several people who knew of the intention
I had previously of having some of my writing published could imagine that the
reasons why I held back from doing so were more disadvantageous to me than they
were. For although I do not like glory excessively, or, if I dare say it,
although I dislike it to the extent that I see it as contrary to peace and
quiet, which I value above everything, nonetheless I have also never tried to
hide my actions as if they were crimes, nor have I taken many precautions to
remain unknown, as much because I would have thought myself wrong if I did so,
as because that would have given me a sort of unease which would, once again,
have been contrary to the perfect peace of mind which I am looking
for. Also, being always indifferently poised between care to get
known or not to get known, since I could not prevent myself from acquiring some
kind of reputation, I thought that I ought to do my best at least to avoid
having a bad one. The other reason which obliged me to write this is that I
realized more and more every day how the plan I had to teach myself was
suffering a delay, because of an infinite number of experiments I needed and
because it is impossible that I carry them out without the help of others. Although
I do not flatter myself so much as to hope that the public pays great attention
to my interests, nonetheless by the same token I do not want to let myself down
so much so that I give an excuse for those who will come after me to reproach
me some day by saying that I could have left many things much better than I
did, if I had not so neglected making them understand the ways in which they
could contribute to my project.
And I thought that it would be easy for
me to chose some matters which, without being subject to a great deal of
controversy and without requiring me to state more of my principles than I
wanted to, would permit me to reveal with sufficient clarity what I could or
could not do in the sciences. In these matters I cannot say if I have been
successful, and I have no desire to ward off anyone's criticism, as I talk in
person about my own writings. But I will be very pleased if people examine
them. In order for people to have more chances to do this, I request that all
those who could have some objections take the trouble to send them to my
publisher. If he tells me about them, I will try to attach my response to their
objection and publish them at the same time. In this way, the readers, seeing
the objections and my replies together, will judge the truth all the more
easily. For I promise never to make long replies to such objections but only to
confess my errors very candidly, if I recognize them, or else, if I cannot see
them, to state simply what I believe is required for the defence of the things
I have written, without adding there an explanation of any new material, so
that I do not get endlessly involved with one matter after another. If some of
those things which I have talked about at the beginning of On Dioptrics and On Meteors are
shocking at first, because I call them suppositions and I do not seem to have
any desire to prove them, I urge people to have the patience to read the whole
text with attention, and I hope that they will be satisfied with it. For it
seems to me that the reasons follow there in sequence in such a way that the
last ones are established by the first ones, which are their causes, and the
first ones are reciprocally established by the last ones which are their effects.
And people should not imagine that, in doing this, I am committing the error
which logicians call arguing in a circle. For since experimentation makes most
of these effects very certain, the causes which I have deduced do not serve so
much to prove these effects as to explain them, so the case is precisely
reversed: it is the causes which are proved by the effects. And I used the name
suppositions for these causes so that people might know that I think I can
deduce them from these first truths which I have explained above but that I expressly
wanted to avoid doing so, in order to prevent certain minds who imagine that
they understand in a single day everything that another man has thought out in
twenty years, as soon as he has said only two or three words about these
matters to them, and who are all the more subject to error and less capable of
truth, the more penetrating and bright they are, from taking the opportunity to
construct some extravagant philosophy on what they believe are my principles,
and in order to prevent people from attributing the fault for that to me. As
for the opinions which are entirely mine, I do not seek to excuse them as new.
To the extent that people think carefully about the reasons for them, I am
confident that they will find my opinions so simple and so consistent with
common sense that they will seem less extraordinary and less strange than some
others which people might have on the same subjects. And, in addition, I do not
boast that I am the first inventor of any of them, although I have never
accepted them merely because they were said by others or because they have not
been said by others, but simply because reason persuaded me to accept them.
If craftsmen cannot immediately carry
out the inventions explained in the Dioptrics,
I do not think that people can, for that reason, say that the text is a poor
one. For to the extent that dexterity and skill are required to make and to
adjust the machines which I have described, without missing the slightest
detail, I would be no less amazed if they were successful on the first attempt
than if someone could learn in a single day to play the lute extremely well,
simply because someone had given him a good musical score. And if I write in
French, the language of my country, rather than in Latin, the language of my
teachers, the reason is that I hope those who use only their natural reason,
pure and simple, will judge my opinions better that those who believe nothing
but ancient books. And as for those who combine good sense with study, who are the
only ones I hope to have as my judges, I am confident that they will not be so
partial to Latin that they will refuse to listen to my reasons because I
explain them in the common language.
As for the rest, I do not wish to talk
here in particular detail about the future progress which I hope to make in the
sciences, nor to commit myself to promising the public what I am not confident
of achieving. But I will only say that I have resolved not to use the time
remaining to me for anything other than trying to acquire some knowledge of
nature of such a kind that people can derive from it rules for medicine more
reliable that those which they have at present, that my inclination keeps me so
far away from all kinds of other projects, mainly those which can be practically
useful to some people only by harming others, and that if some circumstance
forced me to use my time in this way, I do not think I would be capable of
succeeding in it.
In saying this, I am making a declaration
here which I well understand cannot make me important in the world, but also I
have no desire to be important. I will always hold myself more obliged to those
by whose favour I enjoy my leisure unencumbered than to those who might offer
me the most prestigious positions on earth.
NOTES
1This heading does not appear in Descartes’
text. [Back to
Text]
2The word “science” in Descartes’ vocabulary means
any formally organized theoretical knowledge. It does not refer merely to the
natural sciences.[Back to
Text]
3The word “parricide” may seem odd here, but it
refers to acts committed against one’s own family in the name of justice (i.e.,
a love of justice so strong that one is willing to kill members of one’s own
family who have done wrong). In certain pagan moralists, such acts were
considered particularly virtuous. [Back to
Text]
4In 1618 Descartes, who was Catholic, voluntarily
joined the Protestant army of Maurice of Nassau, who was active in organizing
the forces of the Dutch Republic in its fight with Spain. [Back to
Text]
5Ramon Llull was a
thirteenth-century philosopher who wrote a rational defence of Christianity. [Back to
Text]
6The translation of the crucial and much-discussed words
clairment
and distinctement
as clearly and distinctly is extremely common. Descartes’ Principia Philosophiae, 1:45-6, discusses (in Latin) his use of
these terms: “I call an idea clear (claram)
when it is present and manifest to a mind focusing on it, just as we say we
perceive something clearly when it is present to the observing eye, and stimulates
it sufficiently strongly and fully. I call an idea distinct (distinctam) which, while it is clear, is separated
and marked off from everything else in such a way that it consists of absolutely
nothing which is not clear.” It may be that Descartes has in mind the clarity
and distinctiveness of geometrical propositions. [Back to
Text]
7Descartes here is referring to his discoveries in
analytic geometry, in which algebraic equations are represented
geometrically. [Back to
Text]
8In the same book as this Discourse,
Descartes included sections on optics, geometry, and meteorology. [Back to
Text]
9That is, in Holland. The “nine years” Descartes
refers to earlier are 1619-1628. [Back to
Text]
10In a later work this statement “I think; therefore,
I am” (je pense, donc je
suis) becomes the famous
Latin sentence Cogito ergo sum. As the subsequent lines in the
discussion above indicate, this claim might be more properly translated “I am
thinking; therefore, I am,” since the certainty remains only during the process
of thinking. [Back to
Text]
11A chimera is a mythological Greek
monster, made up of different animals. [Back to
Text]
12Descartes is here describing a thought experiment
in which he imagines how the world might have developed historically from material
distributed randomly in the universe. The idea is potentially dangerous because
it goes against the description given in Genesis. Hence, later on Descartes
explicitly denies that he is claiming the process he is summarizing actually
took place. [Back to
Text]
13Here Descartes is again coming close to potentially
dangerous speculations. To propose that God’s actions in developing the world
are subject to natural laws, even if God is the origin of those laws, is to
suggest that there are some restrictions on God’s later actions (i.e., His
interventions and actions in the world must conform to those laws). However,
the value of thinking about the development of the world as a historical
process guided by laws (rather than as the product of the divine miracle of Creation)
is that it enables human beings to come to a rational understanding of nature
and thus makes the modern scientific study of nature possible, even if only in
a thought experiment. [Back to
Text]
14vena arteriosa: arterial vein, now called the pulmonary
artery. [Back to
Text]
15The English doctor is William Harvey who published
his pioneering work on the heart and circulation of the blood in 1628. [Back to
Text]
16Descartes here announces the most challenging issue
arising from his views. If the body is mechanical and the soul is not and if
they must interact in some way, then how does that interaction takes place? How
can one explain consciousness in mechanistic terms? This is still the thorniest
problem in modern biology. [Back to
Text]
17someone else:
a reference to Galileo, whose publication in defence of Copernicus’ sun centered
model of the solar system (in 1632) got him into
serious difficulties with the church. [Back to
Text]
18In this famous statement Descartes makes clear one
of the major purposes of the new natural philosophy (science): to gain power
over nature.[Back to
Text]
[Back to johnstonia Home Page]
Page loads on johnstonia web files
18,400,998
View Stats