The celebrated figure often referred to as the father of modern philosophy is René Descartes. His motto, "Cogito, ergo sum" (I think, therefore I am), exemplifies his approach to philosophical inquiry, emphasizing reason and doubt. Descartes's work, particularly in mathematics and epistemology, laid foundational principles, merging logic with scientific methodology. His influence extends across various disciplines, including mathematics, where he contributed to the development of Cartesian coordinates. Descartes's legacy is crucial in shaping contemporary philosophical thought.