René Descartes was a French polymath, active across philosophy, including metaphysics, epistemology, ethics, and the philosophy of science; theology; mathematics, in which he connected the previously separate fields of geometry and algebra into analytic geometry; science, including physics, optics, mechanics, cosmology, and meteorology; physiology; and medicine. He has been credited as the father of modern philosophy, particularly due to his transformation of methodology by introducing a systematic, method-based approach to pursuing knowledge.