Réne Descartes (1596–1650) was a matehmatician and philosopher famous, amngst other things, for his statement "I think therefore I am". His work on geometry led to what we now call Cartesian coordinates which are used universally in graphics, computer vision and GIS. He believed that there was a sharp divide between {res cogitans}}, the material that forms mind, and res extensa, the physical body -- a form of dualism. This view is near universally rejected by modern philosophers of intelligence and conscousness, who instead espouse physicalism the belief that all thought and human subjectuve experience cam be explained through physical phenomena.
Used on Chap. 1: page 5; Chap. 17: page 397; Chap. 23: page 560
Also known as Descartes