René Descartes

1596–1650 · French · Early Modern Europe

Known for: Cogito ergo sum — doubted everything in existence except the fact that he was doubting, then built modern philosophy on that

René Descartes was a French philosopher, mathematician, and scientist who is considered the father of modern Western philosophy. His method of radical doubt — systematically questioning everything until he found something he could not doubt — led to the famous 'cogito ergo sum' (I think, therefore I am). He also invented the Cartesian coordinate system, linking algebra and geometry.

He spent most of his productive life in the Dutch Republic, where intellectual freedom was greater than in Catholic France. His Meditations on First Philosophy proposed a mind-body dualism that shaped Western thought for centuries. He died in Stockholm in 1650 after being invited to tutor Queen Christina of Sweden — the 5 AM lessons in an unheated palace during a Scandinavian winter gave him pneumonia.

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