René Descartes

Born in France in 1596, René Descartes became one of the most influential thinkers of the seventeenth century. He studied at the Jesuit college of La Flèche, trained in law, and spent many years traveling and living in the Dutch Republic, where he did much of his major writing.

Descartes is best known for asking what can be known with certainty. That search led to his famous idea usually summed up as “I think, therefore I am,” and to major works including Discourse on the Method, Meditations on First Philosophy, and Principles of Philosophy. His writing shaped debates about reason, science, the self, and the relationship between mind and body.

He was important in mathematics as well as philosophy. Descartes is widely credited with helping create analytic geometry, a development that linked algebra and geometry and influenced later science and mathematics. He died in Stockholm in 1650, but his books still feel lively because they begin with questions many readers still ask: What can I trust, and how do I know what is true?