The Discourse on the Method (1637) is a philosophical and autobiographical essay by René Descartes, published in French in Leiden. In it he describes how he decided to doubt everything, and sets out four rules of method and the principle that thinking proves one's existence.
An autobiography of the mind
Descartes tells how, after a classical education, he found that nothing he had learned was certain, and resolved to seek truth in himself and in 'the great book of the world'.
He describes his travels, his winter of meditation in 1619 and his decision to rebuild knowledge from the ground up.
The method
He gives four rules: accept nothing as true that is not clearly and distinctly known, divide problems into parts, proceed from the simple to the complex, and make complete reviews.
In the fourth part, doubting everything that can be doubted, he finds that the thought 'I think, therefore I am' cannot be doubted, and makes it the first principle of his philosophy.
Publication
The Discourse was published anonymously in Leiden in 1637 as a preface to three essays on optics, meteorology and geometry. Writing in French rather than Latin, Descartes wanted to reach any reader of good sense.
It was translated into Latin in 1644 and into English in 1649; John Veitch's English translation of 1850 became a standard version.
Anecdotes
Good sense
The Discourse opens with the ironic remark that good sense is the most fairly shared thing in the world, since everyone thinks he has enough of it.
A geometry appendix
The Geometry published with the Discourse introduced the method of describing curves with equations, the basis of analytic geometry.
Frequently asked questions
What is the Discourse on the Method about?
Descartes's search for certain knowledge, his rules of method and the discovery that thinking proves his existence.
Why did Descartes write in French?
To be read by anyone with good sense, including those who did not know Latin.
What essays accompanied the Discourse?
La Dioptrique, Les Météores and La Géométrie.