Rene Descartes, French philosopher and mathematician, c 1630.

Etching. Rene Descartes (1596-1650) is regarded as one of the great figures in the history of Western thought, and is widely considered to be the 'father' of modern philosophy. His first major published work was 'Discours de la Methode' (1637), closely followed by 'Meditations on First Philosophy' (1641) and 'Principles of Philosophy' (1644).