René Descartes

Born in 1596 in La Haye in Touraine, France, René Descartes became one of the central thinkers of the Scientific Revolution. He studied at the Jesuit college of La Flèche, served briefly in the military, and spent much of his working life in the Dutch Republic, where he wrote many of his most influential books.

Descartes is remembered for pushing doubt as a method: instead of accepting inherited ideas, he asked what could be known with certainty. That search led to his best-known insight, usually given in Latin as Cogito, ergo sum — "I think, therefore I am." His major works include Discourse on the Method, Meditations on First Philosophy, and Principles of Philosophy, and his ideas about mind, body, knowledge, and science shaped philosophy for centuries.

He was also an important mathematician. By linking algebra with geometry, Descartes helped lay the groundwork for the coordinate system still associated with his name. He died in Stockholm in 1650, but his writing continues to be read by anyone interested in reason, self-knowledge, and the beginnings of modern philosophy.