"The Father of Philosophy". A French philosopher, mathematician, and scientist, Descartes is often called the father of modern all Western Philosophy and Science. His famous statement, "Cogito, ergo sum" ("I think, therefore I am"), has become a fundamental element of Western philosophy. His work in mathematics and his method of doubt had a profound impact on the Enlightenment and the development of modern scientific and philosophical thought. His "Discourse on the Method" is the Epistemological foundation of modern science.