René Descartes was an analytical genius. He conceived and articulated ideas about the nature of knowledge that were essential to the Enlightenment and created the philosophical underpinnings for the development of modern science, which included the idea that laws of nature are constant and are sufficient to explain natural phenomena. Descartes felt that truth was clear and accessible to the ordinary human intellect, if the search for truth was directed properly. Two of his writings, Rules for the Direction of the Mind and Discourse on the Method of Rightly Conducting the Reason defined ways of obtaining knowledge. The latter work contained Geometry, that introduced the Cartesian coordinate system and marked the birth of analytic geometry, in which geometric relationships are investigated by means of algebra. Descartes also contributed to areas of music theory, mechanics, physics, optics, anatomy, and physiology.

René du Perron Descartes was born on...