René Descartes (1596-1650), also known as Renatus Cartesius, was a French philosopher, scientist, and mathematician, widely considered a seminal figure in the emergence of modern philosophy and science.
Descartes has often been called the father of modern Philosophy, and is largely seen as responsible for the increased attention given to Epistemology in the 17th century. He laid the foundation for continental Rationalism, later advocated by Spinoza and Leibniz, and was later opposed by the empiricist school of thought consisting of Hobbes, Locke, Berkeley, and Hume. The rise of early modern Rationalism – as a highly systematic school of Philosophy in its own right for the first time in history – exerted an immense and profound influence on modern Western thought in general, with the birth of two influential rationalistic philosophical systems of Descartes (Cartesianism) and Spinoza (Spinozism), and opening the doors to the "Age of Reason".
The Meditations on First Philosophy, written in 1641, is still considered today one of the key texts of Western Philosophy. In this essay Descartes rejects all his former beliefs in the quest for new theses, hypotheses and certainties.