René Descartes

1596 – 1650

René Descartes publishes the Discourse on Method, founding modern philosophy by doubting everything until arriving at one certainty: "Cogito, ergo sum." He a…

• 1637 CE

  Descartes: "I think, therefore I am"

  René Descartes publishes the Discourse on Method, founding modern philosophy by doubting everything until arriving at one certainty: "Cogito, ergo sum." He also develops analytic geometry, fusing algebra and geometry—and sets the template for Enlightenment rational inquiry.