René Descartes was a French philosopher, scientist, logician, and mathematician, widely considered a seminal figure in the emergence of modern philosophy and science during Renaissance era. Mathematics was paramount to his method of inquiry, and he connected the previously separate fields of geometry and algebra into analytic geometry.
Refusing to accept the authority of previous philosophers, Descartes frequently set his views apart from the philosophers who preceded him. In the opening section of the Passions of the Soul, an early modern treatise on emotions, Descartes goes so far as to assert that he will write on this topic "as if no one had written on these matters before." His best known philosophical statement is "cogito, ergo sum" ("I think, therefore I am," French: "Je pense, donc je suis").
Descartes has often been called the father of modern philosophy, and he is largely seen as responsible for the increased attention given to epistemology in the 17th century. He was one of the key figures in the Scientific Revolution, and his Meditations on First Philosophy and other philosophical works continue to be studied.