Rene Descartes

Descartes was a "jack of all trades", making major contributions to the areas of anatomy, cognitive science, optics, mathematics and philosophy. Underlying his methodology is the belief that all science is based on mathematics. This is manifested in his unification of ancient geometry and his new alegbra based on the Cartesian coodinate system.

For Descartes, certainty in philosphy and in mathematics is gained through understanding. We may know that two apples and two apples makes four apples, but Descartes believes that matematics transcends the senses, contributing to an overall mathematical order to the universe that is independent of senses.

Senses were at the center of his Meditations on First Philosphy, a work in which Descartes explores the concepts of self, God and mind. He begins by shaking our belief in the sneses; if they are all an illusion created by a malicious deceiver, what can we trust? His answer is that we can doubt, and that the deceiver cannot cause us to doubt our own existence. Thus, the famous "cogito ergo sum" (I think therefore I am). However, the I is not a physical "i", is is an immaterial mind that is identified by "I".

Thus begins Cartesian Dualism, the theory that there are two fundamental types of entities : mind and matter. The physical bodies exists extended in space, with depth, width and breadth. However, minds are entirely immaterial and nonspatial; they are the "I" he refers to. Since the mind is the only entity that can think (rocks cannot), Descartes uses the cogito arguemnt to prove the existence of a mind.

Rene Descartes

Rene Descartes is one of the most important thinkers of the modern era. A pre-eminent French philosopher, mathematician and scientist, he is known as both the “Founder of Modern Philosophy” and the “Father of Modern Mathematics”. As a mathematician, Descartes invented the Cartesian coordinate system, which unified algebra with Euclidean geometry. In philosophy, Descartes was a major figure in 17th century continental rationalism, later advocated by Spinoza and Leibniz, and opposed by the empiricist school of thought, consisting of Hobbes, Locke, Berkeley, and Hume. Descartes’ most influential work, Meditations on First Philosophy, has inspired numerous contemporary debates in epistemology and philosophy of mind. There, Descartes is best known for employing methodological skepticism in an attempt to arrive at a fundamental set of principles that one can know as true without any doubt. Most famously, he established “I think therefore I am” (cogito ergo sum) as a proposition which he could not doubt.