Rene Descartes, French mathematician and philosopher (31st March 1596 - 11 February 1650). 1835 Steel engraving in \The Gallery of Portraits\" by W. Holl with later colouring after an original by Frans Hals 1649. Descartes created co-ordinate geometry, a bridge between algebra and geometry, now known as Cartesian geometry. He is considered a founding father of modern philosophy, famous for his statement \"Cogito ergo sum\" - \"I think, therefore I am\" (from his 'Discourses on the Method' 1637). He also concluded that as animals are not rational (or can be explained such) they can parsimoniously be considered as machines. As a rationalist philosopher he is regarded as the first to provide a philosophical basis for the Life Sciences by methodological scepticism. He was later opposed by empiricist philosophers, also influential in the life sciences, such as Locke, Rousseau, Hobbes and Hume."