Who said, "Cogito ergo sum (I think, therefore I am)"?
René Descartes (March 31, 1596 – February 11,1650) was a French philosopher, mathematician, and scientist. Much of subsequent Western philosophy is a response to his writings, which are studied closely to this day. He spent about 20 years of his life in the Dutch Republic. His best known philosophical statement is "Cogito ergo sum" (French: Je pense, donc je suis; I think, therefore I am), found in part IV of Discourse on the Method (1637; written in French but with inclusion of "Cogito ergo sum") and §7 of part I of Principles of Philosophy (1644; written in Latin).