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WorkRené Descartes

Discourse on the Method of Rightly Conducting One’s Reason and of Seeking Truth in the Sciences

The book that introduced "I think, therefore I am" — printed in plain French, unsigned, as the preface to three essays on optics and geometry.

by René Descartes111 passages held

  • English, a translation held here, and your language
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First published
(aged 41)
Original language
French

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Overview

In 1633 Descartes learned that the Roman Inquisition had condemned Galileo, and he shelved The World, the physics he had nearly finished, rather than risk the same. Four years later he found a quieter way to put his ideas before the public. Discourse on the Method appeared at Leiden in 1637, in French rather than the Latin of the schools and without his name on it — a preface of barely eighty pages fronting three scientific essays, the Dioptrics, the Meteorology and the Geometry, which it was written to introduce. The essays were the samples; the method was the pitch. Descartes offers four rules for conducting reason, a narrative of how he came to doubt everything he had been taught, and the sentence that would outlast all of it: je pense, donc je suis — I think, therefore I am — here making its first appearance, four years before the Meditations rebuilt the argument in Latin. Writing in French put the case to anyone who could read, not to the universities alone, and readers wrote back with queries about his rejection of the scholastic "substantial forms" and his split between mind and body, several of which he answered in later letters. It founded modern philosophy's habit of beginning from the self that cannot doubt its own doubting.

Key concepts

What are Descartes's four rules of method?

Accept nothing as true that is not clearly and distinctly evident; divide each difficulty into as many parts as it needs; conduct thoughts in order, from the simplest objects upward to the complex; and review the whole so completely that nothing is left out. Descartes offers them as a replacement for the tangled rules of scholastic logic, four maxims a mind can actually carry and use.

What are the three essays the Discourse introduces?

The Discourse was published as a preface to three scientific samples that showed the method at work: the Dioptrics, on optics and lenses; the Meteorology, on weather and the rainbow; and the Geometry, which founded analytic geometry. The essays were the demonstration, the method the pitch. Reading the preface alone, later generations largely forgot it was ever meant to introduce anything.

Why did Descartes publish it in French and unsigned?

Latin was the language of the universities; French put the case to any literate reader rather than to the authorities alone. Descartes also withheld his name. Four years earlier he had shelved his physics, The World, on learning the Inquisition had condemned Galileo, and the anonymous French preface was the quieter way he found to put his ideas before the public without inviting the same fate.

What are the scholastic 'substantial forms' he rejects?

In the Aristotelian teaching of the schools, each kind of thing had a substantial form, an inner nature that explained why it behaved as it did. Descartes discards them. In his physics a body's behaviour follows from matter, size, shape and motion alone, with no hidden forms or qualities, and readers wrote to him puzzled by a nature explained entirely by mechanism.

How does the Discourse relate to the later Meditations?

The Discourse sketches in a few French pages the metaphysics the Meditations would expand in Latin four years later, in 1641. Here the doubt and the je pense, donc je suis appear briefly, as the story of how Descartes came to think; there they are rebuilt as a rigorous six-day argument, circulated first to objectors. The Discourse announces the method the Meditations then deepens into radical doubt.

Themes of the book

What this book returns to, gathered into themes and ordered by how much of the text each one occupies.

A method for conducting reason

Good sense, Descartes claims, is shared by everyone; only the way it is used sets minds apart. Four rules are offered to steer reason toward truth without a master.

Reason is distributed equally, Descartes insists, and what divides people is method. Against the crowded syllogisms of the schools he sets four spare rules: accept nothing not clearly evident, divide each difficulty, order thoughts from the simple upward, and review until nothing is left out. He reached them, he says, by setting aside the opinions custom and his teachers had lodged in him and rebuilding on what he alone could see. Writing in plain French rather than school Latin was the same gesture, putting the case to anyone who reasons rather than to the authorities who certify.

  • methodology
  • reason
  • logic
  • judgment
  • education
  • epistemology
  • custom
  • authority
  • truth
  • ethics

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The one thing doubt cannot touch

If everything the senses and custom taught might be false, is anything left standing? Descartes finds a single point doubt cannot reach and refounds knowledge on it.

Resolving to treat as false whatever he could doubt in the least, Descartes lets go of the senses, the world, even mathematics, and notices that while he doubts, he who doubts must exist. Je pense, donc je suis makes its first appearance here, four years before the Meditations rebuilt the argument in Latin. The self that cannot doubt its own doubting becomes the fixed point on which the rest is refounded. This is the habit he handed modern philosophy: to begin not from the world or from authority but from the thinking self that survives every attempt to deny it.

  • skepticism
  • certainty
  • truth
  • metaphysics
  • epistemology
  • method
  • self-knowledge

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The living body as a machine

Can a beating heart, a moving limb, an animal's whole behaviour be explained the way a clock is, by parts and motion alone? Descartes says nearly all of it can.

Turning from mind to body, Descartes describes the human frame as a machine, working the circulation of the blood and the motions of the limbs from mechanical causes with no soul steering each act. Animals he treats as automata entirely; only reason and speech, he argues, mark the human off. The move belongs to the physics he had shelved after Galileo's condemnation, a universe in which bodies too run on matter in motion. It set the mind sharply apart precisely by handing everything else over to mechanics, and readers wrote back pressing him on the split.

  • physiology
  • anatomy
  • science
  • blood circulation
  • causation
  • intellectual humility
  • mathematics

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Within this work

passages held
111
distinct concepts
199
by passages held, corpus-wide
#176

What this book thinks together

Every arc around the wheel is one concept in this book. A ribbon joins two the text reaches for together, and its width is how many of its passages hold both. Strongest: epistemology with methodology.
Concept co-occurrence, strongest first 8 concepts, joined by 9 pairings. 43 shared passages in all. 41 weaker pairings reach beyond these concepts and are not drawn.
ConceptPaired conceptShared passages
epistemologymethodology9
biologyphysiology6
mechanicsphysiology6
biologymechanics5
epistemologytruth5
epistemologyreason4
certaintyepistemology3
reasontruth3
certaintytruth2

Works held

The author's work in order, this book marked in place. Your-language title first, the original beneath it where the two differ; side chips show which full texts are held.

  1. 1637 Discourse on the Method of Rightly Conducting One’s Reason and of Seeking Truth in the Sciences you are here FREN
  2. 1641 Meditations on the First Philosophy: In Which the Existence of God and the Immortality of the Soul Are Demonstrated (Meditationes de prima philosophia)

    Cast as six days of solitary meditation and issued in Latin with six sets of Objections and Replies, this is Descartes's central metaphysical work; it deepens into radical doubt the method the Discourse had only announced.

     FREN
  3. 1644 Selections from the Principles of Philosophy

    Where the Meditations argues, the Principles teaches: Part I condenses that metaphysics, and Parts II–IV build it out into a mechanical physics of the heavens and the earth — Descartes's bid to become the standard university text.

     FREN
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