Explanations of the Discourse of the Method – René Descartes

The Discourse of the Method written by the philosopher René Descartes was published in 1637. It was published anonymously in Leiden in 1637, but he was soon recognized as its author.

This text is supposed to be only an explanation of the method used for his scientific works, which are published in a linked way. It is therefore obviously only a reminder of the essential principles for “leading one’s reason well and seeking truth in the sciences” as the full title of this work indicates. But René Descartes knew perfectly well that this essay, whose major ideas and propositions we propose to revisit, would upset the intellectual tradition in a much more profound way.

In addition to a selection of important passages, page after page, you will find explanations to better understand René Descartes’ concepts, approach and reasoning. These explanations are meant to be accessible and simple, ideally matching René Descartes’ exemplary style, clear and devoid of pedantry.

→ René Descartes’ Discourse on Method is the twentieth work featured in our list of 105 books to read before you die.

The first part of the Discourse of Method – René Descartes

Common sense is the most widely shared thing in the world: for each one thinks he is so well provided with it, that even those who are most difficult to please in any other thing, are not wont to desire more of it than they have.

René Descartes, Discourse on Method, Part I

Explanation: René Descartes opens the Discourse on Method with this simple observation: everyone has common sense, that is, everyone is right.

For it is not enough to have a good mind, but the main thing is to apply it well.

René Descartes, Discourse on Method, Part I

Explanation: René Descartes explains himself with an example: someone who would move slowly, but in the right path, would go much further than someone who would move quickly, but away from the path.

I knew that the languages, which one learns there, are necessary for the understanding of the ancient books; that the kindness of the fables awakens the spirit; that the memorable actions of the histories raise it, and that being read with discretion, they help to form the judgment; that the reading of all good books is like a conversation with the most honest people of the past centuries, who were the authors, and even a studied conversation, in which they discover only the best of their thoughts; that eloquence has incomparable strengths and beauties; that poetry has very ravishing delicacies and sweetness; that mathematics has very subtle inventions, and which can hope to satisfy the curious as well as to facilitate all the arts, and to diminish the work of men; that the writing which deals with morals contains several teachings and several exhortations to virtues which are very useful; that theology teaches how to win heaven; that philosophy gives a means of speaking truthfully about all things, and of making oneself admired by the less learned; that jurisprudence, medicine and other sciences bring honors and riches to those who cultivate them; and finally, that it is good to have examined them all, even the most superstitious and the most false, in order to know their just value, and to guard against being deceived by them.

René Descartes, Discourse on Method, Part I

Explanations: This Passage – this sentence! – is famous in René Descartes’ work, which is why we have reproduced it in its entirety. It lists so many areas of knowledge that they have an application in reality, and sees how they can be beneficial. In a way, René Descartes cites all the virtues of the knowledge he has received, before discarding this same knowledge through doubt. In the following paragraph, René Descartes also criticizes some of the uses made of this knowledge. Note that the mention of philosophy “to make oneself admired by the less learned” is an ironic allusion against those who want to appear brilliant rather than seek the truth.

The second part of the Discourse on Method – 

René DescartesExplanations: In this second part, René Descartes describes his own biographical and intellectual journey. In particular, he gives himself four precepts, which he resolves to follow faithfully, and which allow him to be sure of using his reason properly: the result may not be perfect, but thanks to these four precepts he is certain of reasoning in the best possible way.

The first was never to accept anything as true unless I know it to be true.

René Descartes, Discourse on Method, Part 2

Explanation: Put another way, the first precept he gives himself is that of discarding all his prejudices, of taking only what he is certain is true.

The second is to divide each of the difficulties I examine into as many parts as it is possible and necessary to solve them better.

René Descartes, Discourse on Method, Part 2

Explanation: The second precept is to solve one’s problem by breaking it down into small problems.

The third is to lead my thoughts in order, beginning with the simplest and easiest objects to know, and then to ascend little by little, as if by degrees, to the knowledge of the most complex.

René Descartes, Discourse on Method, Part II

Explanations: The third precept is again a matter of logic, and consists simply in starting with what is most obvious, simple, and close to it. Once this is done, it will become possible to understand more and more complex sets.

And the last one, to make everywhere such complete enumerations, and such general reviews, that I would be sure not to omit anything.

René Descartes, Discourse on Method, Part II

Explanation: The fourth precept aims to ensure that he does not miss an element that could call into question everything he has done before. René Descartes therefore resolves to take into account all the dimensions of the problem.

The third part of the Discourse on Method – René Descartes

in order that I might not remain irresolute in my actions, while reason would oblige me to be so in my judgments, and that I might not fail to live from then on as happily as I could, I formed for myself a moral by provision

René Descartes, Discourse on Method, Part 3

Explanation: René Descartes decided to doubt everything, as long as he did not have a certainty. But he is aware that this process takes time. This is why, while waiting to reach a certainty, he decides to keep a “morality by provision”. This morality by provision must allow him to continue to live happily all the time that it will be necessary to him while he puts at work his method of the doubt.

René Descartes defined this morality by provision by three or four maxims.

The first was to obey the laws and customs of my country, constantly holding to the religion in which God gave me the grace to be instructed.

René Descartes, Discourse on Method, Part III

Explanation: To follow this morality by provision is to live like other members of society, like what seems to be normal at the time, and especially what is moderate. Excess is often considered bad; René Descartes therefore chooses to live according to moderate opinions. He thus wanted to follow the opinions of the “better people” in the society in which he lived.

My second maxim was to be as firm and resolute in my actions as I could.

René Descartes, Discourse on Method, Part 3

Explanation: René Descartes takes an example here: it is better, when one is lost in a forest, to walk frankly in one direction, rather than to hesitate and wander. And in this moral by provision, it is better to follow the most probable opinions: “When it is not in our power to discern the truest opinions, we must follow the most probable.”

My third maxim was always to try rather to overcome myself than fortune.

René Descartes, Discourse on Method, Part 3

Explanation: René Descartes chooses to change his own thoughts, his own desires, rather than vainly trying to change the course of the world. He thus joins a long philosophical tradition, and makes of “necessity virtue”. In this provisional morality, and to be content, one should not desire something over which one has no power.

All my purpose tended only to ensure me, and to reject the moving ground and the sand, to find the rock or the clay.

René Descartes, Discourse on Method, Part 3

Explanations: It is with this formula that René Descartes opposes himself to the skeptics, notably of the 16^th century. For him, skeptics “doubt only to doubt”: they are irresolute, have no basis in anything, and get stuck in this shifting earth and sand. René Descartes, on the other hand, thanks to morality by provision and the method of doubt, has no other goal than to finally discover certainties and truths, that is to say, something hard to stand on, just like rock and clay.

The fourth part of the Discourse on Method – René Descartes

[I had] to reject, as absolutely false, everything in which I could imagine the slightest doubt

René Descartes, Discourse on Method, Part 4

Explanation: René Descartes applies his method of doubt. Everything about which he has the slightest doubt must be rejected, in order to rely only on what is certain.

Thus, because our senses sometimes deceive us, I wanted to suppose that there was nothing that was such as they make us imagine it. And because there are men who are mistaken in reasoning (…) I rejected as false all the reasons which I had previously taken as demonstrations. And finally (…) I resolved to pretend that all the things that had ever entered my mind were no more true than the illusions of my dreams.

René Descartes, Discourse on Method, Part 4

Explanation: Doubt applies here to the senses, then to reasoning, and even to the mind. Each time, René Descartes is seized with a doubt about them: he could be only dreaming, or being deceived either by his senses or by his reason. He thus comes to doubt everything.

But, immediately afterwards, I took care that, while I wanted to think thus that all was false, it was necessarily necessary that I, who thought it, was something.

René Descartes, Discourse on Method, Part 4

Explanations: It is precisely this doubt about everything and about himself that makes him realize that to doubt, he must exist. He must be something to be able to doubt.

And noticing that this truth: “I think; therefore I am” was so firm and so sure that all the most extravagant suppositions of the skeptics were not able to shake it, I judged that I could receive it, without scruples, for the first principle of philosophy, which I was looking for.

René Descartes, Discourse on Method, Part 4

Explanation: This is the most important moment of the Discourse of Method, because it is the first truth that René Descartes establishes for sure. It is this first principle that allows him to get out of doubt, to know something for sure, it is the goal he had set for himself. By the very fact that he thinks, he is certain that he exists.

I knew from this that I was a substance whose whole essence or nature is only to think, and which, in order to be, needs no place, nor depends on any material thing.

René Descartes, Discourse on Method, Part 4

Explanations to arrive at this conclusion, René Descartes pretends to have nobody, and even thinks that there is no world. While he cannot pretend that he does not think, he can pretend that he has no body and that there is no world. He is therefore a thinking substance. The whole essence of this substance is only to think.

So that this self, that is, the soul by which I am what I am, is entirely distinct from the body.

René Descartes, Discourse on Method, Part 4

Explanation: In order to exist, the soul does not depend at all on what is material. Indeed, the soul is only a substance whose nature is to think. René Descartes therefore concludes that the soul, i.e. its being, is separate from the body. The soul is distinct from the body.

And having noticed that there is nothing at all in this: I think; therefore I am, which assures me that I am telling the truth, if not that I see very clearly that, in order to think, it is necessary to be: I judged that I could take as a general rule, that the things which we conceive very clearly and very distinctly, are all true.

René Descartes, Discourse on Method, Part 4

Explanation: René Descartes seeks what will henceforth show him the truth of the false. To know what he can consider as true in the future, he studies how he knew that his existence was true. He knew that“I think therefore I am” was true only because he had a clear idea of it. Thus, what is true is that of which one can have a very clear idea.

I saw clearly that it was a greater perfection to know than to doubt, I thought to look for where I had learned to think of something more perfect than I was.

René Descartes, Discourse on Method, Part IV

Explanation: To know is a greater perfection than to doubt. René Descartes holds this idea to be true, because it is clear in him. But René Descartes himself does not know everything. So he wonders, how can he have the idea of something even more perfect than himself? Who put in him the idea that there is something more perfect than him?

It remained that it had been put into me by a nature which was truly more perfect than I was, and even that he had in himself all the perfection of which I could have some idea, that is, to explain myself in a word, that he was God.

René Descartes, Discourse on Method, Part 4

Explanation: This is how René Descartes shows the existence of God. The idea of what is more perfect comes for him necessarily from what is even more perfect. Thus, the idea of perfect necessarily comes from a perfect being. And it is this perfect being that René Descartes calls God.

And let the best minds study this, as long as they please, I do not believe that they can give any reason that it is sufficient to remove this doubt, unless they presuppose the existence of God.

René Descartes, Discourse on Method, Part 4

Explanation: For those who are not yet convinced of the existence of God, René Descartes adds another argument. He who does not believe in God believes he has many things: he believes he has a body, he believes there are stars, that there is a world. But he cannot prove it: he could very well be dreaming, and his senses make him believe that there is a world and stars, when in fact there is not. According to René Descartes, to be certain of all this, they must necessarily admit the existence of God.

[That] The things which we conceive very clearly and distinctly are all truth is only certain because God is or exists, and that he is a perfect being, and that all that is in us comes from him.

René Descartes, Discourse on Method, Part 4

Explanation: The Existence of God is important for René Descartes, because it guarantees the existence of all things. For him, God being a perfect being, everything depends on him. It is God who allows things to exist. Thus the clear ideas that we have are true thanks to God.

reason does not dictate to us that what we see or imagine is true

René Descartes, Discourse on Method, Part 4

Explanation: René Descartes uses an example: when we see the sun, we should not conclude that it is the size we see. And when we imagine a chimera, we should not conclude that there is a chimera in the world.

The fifth part of the Discourse on Method – René Descartes

the action by which he now preserves it [the world], is all the same as that by which he created it

René Descartes, Discourse on Method, Part 5

Explanation: René Descartes holds as certainly an opinion generally accepted by theologians. The world not only had to be created, but also had to be maintained. God is the author of this creation and maintenance. And the maintenance of the world is of the same nature as the creation of the world: God creates ceaselessly to maintain the world.

if there were such machines, which had the organs and the figure of an ape, or of some other animal without reason, we would have no way of recognizing that they would not be in all the same nature as these animals

René Descartes, Discourse on Method, Part 5

Explanation: René Descartes considers that animal functioning is mechanical. (This theory has been contested by many authors)

they could never use words, nor other signs in composing them.

René Descartes, Discourse on Method, Part 5

Explanation: René Descartes explains a fundamental difference that would distinguish between machines made in the likeness of men and real men. A decisive criterion would be language: machines could never have coherent words arranged for this purpose. Indeed, René Descartes acknowledges that sophisticated machines could reproduce the sounds of speech, but they could never adapt and arrange these words in such a way as to produce meaning in all situations.

although they would do many things as well, or perhaps better than any of us, they would infallibly fail in some others

René Descartes, Discourse on Method, Part 5

Explanation: This is the second fundamental difference between real men and machines. Machines could be as good as a human in one area, and even surpass him in performing more precise gestures for example, but machines would not have such performance in all other areas and in all situations of life. It is morally impossible for a machine to act in all of life’s occurrences as well as human reason allows.

By these same two means, we can also know the difference that is between men and beasts.

René Descartes, Discourse on Method, Part 5

Explanation: Similarly, animal functioning is like a machine. The differences between man and machine are therefore the same for René Descartes as between man and animal. So that to distinguish man from the animal, it is possible to apply the two criteria identified the words arranged to give meaning according to the situations, as well as the faculty to adapt to all the situations of the life and to act consequently.

it is a remarkable thing that there are no men so dazed and so stupid, not even the fools, that they are not able to arrange together various words

René Descartes, Discourse on Method, Part 5

Explanation: For René Descartes, all men are capable of speech. Indeed, all men, even the most disadvantaged, handicapped, or insane, are capable of producing words arranged to give meaning. It does not take much reason to be able to speak.

This not only testifies that beasts have less reason than men, but that they have none at all.

René Descartes, Discourse on Method, Part 5

Explanation: This is the proof, for René Descartes, that animals are devoid of reason. It is not that they have only a very weak reason that makes them unable to converse, it is that they have no reason at all. In the same way, René Descartes rejects the hypothesis that animals have their own language that man does not understand, by objecting that if animals really had their own language, they could make themselves understood by men, having similar organs.

It is nature that acts in them.

René Descartes, Discourse on Method, Part 5

Explanation: This formula summarizes René Descartes’ conclusions about animals, whether they are endowed with reason and what makes them live. For René Descartes, animals have no reason. What shows it again is that if animals can be more efficient than humans in a certain type of action, they are not efficient in all situations and for all actions. This is another proof for René Descartes that animals are devoid of reason, and that it is only “nature that acts in them”.

Sixth part of the Discourse on Method – René Descartes

it is possible to arrive at knowledge that is very useful to life

René Descartes, Discourse on Method, Part 6

Explanation: In this part, René Descartes gives an account of the interest he would or would not have in publishing the book of the Discourse of Method. In his considerations, he begins by recalling how knowledge can be useful to man, which can be useful to life. It is a certain idea of progress: progress is possible thanks to knowledge.

We can employ them in the same way for all the uses to which they are appropriate, and thus make ourselves as masters and possessors of nature.

René Descartes, Discourse on Method, Part 6

Explanations: This statement has become famous to justify the progress of technology. However, it is important to understand what René Descartes means by making ourselves masters and possessors of nature. Practical knowledge, for example, knowledge of the force and actions of fire, water, air, and all other bodies, allows man to act on the environment. It is not a question of becoming true masters and possessors of nature. This is the role of God for René Descartes. It is only a question of becoming like masters and possessors of nature, that is to say, of acting on nature in order to live better in it.

This is not only to be desired for the invention of an infinite number of artifices, which would make one enjoy, without any pain, the fruits of the earth and all the conveniences that are found there, but mainly also for the preservation of health, which is undoubtedly the first good and the foundation of all the other goods of this life.

René Descartes, Discourse on the Method, Part 6

Explanation: First, René Descartes considers the benefits that technique, or the application of knowledge, can bring. This would facilitate man’s work, and allow him to benefit more from nature. Then, he poses medicine as the major good. As the mind depends on the health of the body, medicine would allow men to become wiser and more skillful.

For, although it is true that each man is obliged to procure, as far as it is in him, the good of others, and that it is properly worth nothing to be useful to anyone, yet it is also true that our care must extend further than the present time, and that it is good to omit things which would perhaps bring some benefit to those who are living, when it is for the purpose of doing other which bring more to our nephews.

René Descartes, Discourse on Method, Part 6

Explanation: René Descartes then wonders whether or not he should publish the Discourse on Method. To publish the work now would be good for others, because it would be useful and would constitute progress in research. However, René Descartes feared that the controversies that had been provoked, the opposition, would slow down his future work. Yet René Descartes had set himself the goal of continuing his search for knowledge, and responding to opposition would hinder him in this activity. This is why, although publishing his book would bring good to others, he wonders if the good will not be greater if he waits longer before publishing it. The term “nephew” here means descendants.

nor have I ever noticed that, by means of the disputes which are practiced in schools, any truth has been discovered which was previously unknown: for, while each one tries to win, one exercises himself much more in asserting plausibility, than in weighing the reasons of both sides; and those who have been good lawyers for a long time are not for that reason, afterwards, better judges.

René Descartes, Discourse on Method, Part 6

Explanation: René Descartes is still trying to weigh the reasons why he should or should not publish the Discourse on Method. He knows that its publication would lead to controversy, and considers whether such controversy would be profitable. While reminding us that he is not infallible, René Descartes explains why such controversies would not be beneficial. After observing that he was rarely presented with an objection that he had not foreseen, he points out in this passage the sterile character of certain debates. During these debates, René Descartes notes that it is most often a matter of appearing to be right, but not of establishing the truth by considering the reasons of each party. It is a lawyer’s job, not a judge’s, so that the debate has not brought a new truth that was previously unknown. Thus, the controversies to which the publication of the Discourse of the Method would give rise would not bring any new truth, nor would these controversies instruct.

One cannot conceive a thing so well, and make it one’s own, when one learns it from someone else, as when one invents it oneself.

René Descartes, Discourse on Method, Part 6

Explanation: To extend the work of the Discourse on Method, René Descartes considers himself to be in the best position. This is not because others are less intelligent, on the contrary there are undoubtedly more intelligent, but it is because a concept is best known when one has invented it by oneself rather than when one has learned it from someone else. Since René Descartes himself conceived the Discourse of the Method, he is best able to continue his work.

Although I have often explained some of my opinions to people of very good mind (…), they have almost always changed them in such a way that I could no longer admit them as mine.

René Descartes, Discourse on Method, Part 6

Explanation: René Descartes notes a general fact: the words of a philosopher are always transformed. Even if at the time, people seem to have understood very well what a philosopher wanted to say, it turns out that in the end the words are transformed. And they are so transformed that in the end they no longer represent the intentions of this philosopher at all. René Descartes fears that he is a victim of such a process, and asks to avoid it, that the descendants take into account only the words that come directly from the author, in this case only the words of René Descartes himself.

They are like the ivy, which does not tend to climb higher than the trees that support it, and even often comes down again, after it has reached their top.

René Descartes, Discourse on Method, Part 6

Explanation: René Descartes criticizes there by a comparison of the spectators who badly report the words of an author. These spectators (the ivy) believe they understand the author’s words, believe they understand the author’s intention (the tree), and make the mistake of misusing the author’s words.

Not content with knowing everything that is intelligibly explained in their author, they want, in addition to that, to find in it the solution of several difficulties of which he says nothing and of which he has perhaps never thought.

René Descartes, Discourse on Method, Part 6

Explanation: This is an explanation of the comparison with ivy. Thus, those who study an author, i.e. the spectators, the ivy, take the author’s words to answer other questions that the author may never have thought of. These spectators assimilated to the ivy, while they seemed to have reached the ideas of the author, of the tree, finally only come down, because they misuse the author’s words.

if they want to know how to speak about all things and acquire the reputation of being learned, they will achieve this more easily by being satisfied with verisimilitude, which can be found without much difficulty in all sorts of matters, than by seeking the truth

René Descartes, Discourse on Method, Part 6

Explanation: René Descartes again puts forward arguments that would encourage him not to publish the Discourse on Method. The search for truth is only done little by little, it is slow. The search for truth is not interesting for those who want to appear cultured and intelligent: they only have to appear, they only have to look for plausibility. But the Discourse of the Method, which on the contrary is part of a necessarily slow search for truth, would be useless for all those

having always been indifferent between being known or not being known, I could not prevent myself from acquiring some kind of reputation, I thought I had to do my best to exempt myself at least from having it bad.

René Descartes, Discourse on Method, Part 6

Explanation: René Descartes finally gives his reasons for writing and publishing the Discourse of Method. One reason is that he needs the help of others to conduct certain experiments, in order to progress in his research. But the other reason is the fear of being the victim of misunderstandings: some people knew that René Descartes might want to print his writings. It is a matter of saving his reputation, because if he did not publish the Discourse on Method, some people might think that it was for the wrong reasons that he did not publish them.

And if I write in French, which is the language of my country, rather than in Latin, which is the language of my preceptors, it is because I hope that those who use only their natural reason, will judge my opinions better than those who believe only in ancient books.

René Descartes, Discourse on Method, Part 6

Explanations: It is a known peculiarity of the Discourse on Method that the work was published in French and not in Latin as was customary at the time. Latin is indeed the language of scholars, while French could appear vulgar for the most rigorous. René Descartes himself justifies his choice of French, because he only wants to address pure reason, he only wants to address those who use their common sense, and he wants to be accessible to the general public.

→ Corrected Question: Letters to Elizabeth by René Descartes

The book is a quick read and inexpensive, only €3.60 for a work that revolutionized philosophy. We recommend that you get this classic.

(Cover photo: portrait of René Descartes – National Library of Medicine, Bethesda, Maryland)