René Descartes (1596-1650) was a French philosopher, mathematician, and scientist who is often regarded as the "father of modern philosophy." He is best known for his philosophical statement, "Cogito, ergo sum" ("I think, therefore I am"), which emphasizes the primacy of individual thought and consciousness. Descartes initiated a new era in philosophy by prioritizing rationalism and doubting all beliefs to arrive at certain knowledge. He also made significant contributions to mathematics, laying the groundwork for analytical geometry by developing the Cartesian coordinate system.