Discourse on Method – René Descartes

"I think, therefore I am."

René Descartes sets out to find a foundation for knowledge that is absolutely certain. By doubting everything that can be doubted, he arrives at the undeniable truth of his own existence as a thinking being. He outlines a method of scientific inquiry based on reason and deduction rather than authority.

This short work marks the beginning of modern philosophy. Descartes's radical skepticism and his separation of mind and matter broke with the medieval tradition, establishing the subject—the individual thinker—as the center of the philosophical universe.