René Descartes, also known as Cartesius, was a noted French philosopher, mathematician, and scientist. Dubbed the "Founder of Modern Philosophy" and the "Father of Modern Mathematics," he ranks as one of the most important and influential thinkers of modern times. For good or bad, much of subsequent western philosophy is a reaction to his writings, which have been closely studied from his time down to the present day. Descartes was one of the key thinkers of the Scientific Revolution in the Western World. He is also honoured by having the Cartesian coordinate system used in plane geometry and algebra named after him.