Descartes, René
Pronunciation: /ˈdeɪkɑːt, dekaʀt/
Aiming to reach totally secure foundations for knowledge, Descartes concluded that everything was open to doubt except his own conscious experience, and his existence as a necessary condition of this: ‘Cogito, ergo sum’ (I think, therefore I am). From this certainty he developed a dualistic theory regarding mind and matter as separate though interacting. In mathematics Descartes developed the use of coordinates to locate a point in two or three dimensions