René Descartes

René Descartes is often called the father of modern philosophy. His method of systematic doubt — attempting to find truths that could not be questioned — led to his famous cogito and established a new foundation for knowledge in the self-evident certainty of the thinking subject.

Descartes also made fundamental contributions to mathematics, inventing the Cartesian coordinate system and contributing to the development of calculus. His mind-body dualism — the claim that mind and matter are distinct substances — shaped debates in philosophy of mind for centuries.