Discourse on the Method for Reasoning Well
and for Seeking Truth in the Sciences
by René Descartes

Discourse on Method

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.

Part One

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 mistak-en. 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 reason-able 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 able to advance 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.[1]

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 skillful 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.[2] 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 came into my hands dealing with those sciences which are considered the most curious and rare.[3] In 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 heav-en, that philosophy provides a way of speaking plausibly on all matters and making oneself admired by those who are less scholarly, that juris-prudence, 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 le-gitimate 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 ridicu-lous 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.[4]

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 under-stood 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.