Begin by doubting.
Descartes resolves to reject as false anything open to the least doubt, in order to discover whether any belief is wholly beyond question.
Understand in about 5 minutes
Discourse on the Method
Descartes sets aside every uncertain belief and rebuilds knowledge from a single certainty discovered by his own reason.
Mind Map
Map of the book's core ideas
Core Message
What the book is really saying
Follow a deliberate method.
He reduces inquiry to a few firm precepts: accept only what is clear and distinct, divide problems, proceed from the simple to the complex, and review completely.
The thinking self cannot be doubted.
Even while supposing all else false, he finds that he who thinks must exist, and takes this as the first certain principle.
Reason belongs to everyone.
Good sense, the power of judging truly, is by nature equal in all; what divides people is how they direct it, not how much they possess.
Summary
The essence in plain English
The Discourse opens with the claim that good sense is shared equally among all people. What separates minds is not the amount of reason they hold but the paths along which they conduct their thoughts, and the prime requisite is to apply reason rightly.
Dissatisfied with the learning he received, Descartes describes resolving to sweep away the opinions he had accepted on trust. Rather than reform others or the state, he undertakes only to rebuild the foundation of his own beliefs.
He compresses his procedure into four precepts: to accept nothing as true that is not clearly and distinctly known, to divide each difficulty into parts, to proceed in order from the simplest objects to the more complex, and to make enumerations so complete that nothing is omitted.
Because suspending all judgment would leave him unable to act, he adopts a provisional code of morals: to obey the laws and customs of his country, to be firm and resolute once a course is chosen, and to master himself rather than fortune, changing his desires rather than the order of the world.
Turning to metaphysics, he rejects everything doubtful and finds that the one thing he cannot doubt is that he who thinks must exist. From this he concludes that the mind, whose essence is thinking, is distinct from the body, and proceeds to argue from his idea of perfection to the existence of God.
Key Concepts
The ideas to keep
Methodical Doubt
Descartes deliberately rejects every belief open to the least doubt to test what remains certain.
Why it matters
It clears away inherited opinion so knowledge can rest on a secure foundation.
The Four Precepts
Inquiry is governed by clarity, division of difficulties, ordered progress, and complete review.
Why it matters
It gives reason a disciplined procedure rather than leaving it to habit and chance.
The Thinking Self
Even while doubting everything, the one who thinks must exist.
Why it matters
It supplies the first certain principle on which the rest is built.
Mental Models
Reusable ways to think
Rebuild the House
Tear down beliefs taken on trust and reconstruct them on a foundation you have examined yourself.
How it helps
It separates what you genuinely know from what you merely inherited.
Clear and Distinct
Affirm only what the mind perceives so clearly and distinctly as to leave no ground for doubt.
How it helps
It gives a working standard for deciding what to accept as true.
Conquer Yourself, Not Fortune
Change your desires rather than the order of the world, since only your own thoughts lie fully in your power.
How it helps
It directs effort toward what can actually be governed.
Selected Quotes
Short passages from the source
Good sense is, of all things among men, the most equally distributed
I see very clearly that in order to think it is necessary to exist
to endeavor always to conquer myself rather than fortune, and change my desires rather than the order of the world
Source
Text used for this page
Source text: Project Gutenberg edition of Discourse on the Method by René Descartes.
HTML text: https://www.gutenberg.org/cache/epub/59/pg59-images.html
Project Gutenberg states that this ebook is for use at no cost with almost no restrictions in the United States and most other parts of the world, subject to local law.
First published 1637; the Project Gutenberg edition uses John Veitch's translation.