Descartes, René

René Descartes (1596 – 1650) was a French philosopher and mathematician. Dubbed the father of modern philosophy, Descartes was influential in a new rationalist movement. Descartes set a precedent for examining issues and trying to avoid any presumption. Descartes offered one of the most famous philosophic statements to date:

Cogito ergo sum

— I think, therefore I am

Descartes is sometimes called the Father of ‘Modern’ Philosophy. He created analytical geometry, based on his now immortal Cartesian coordinate system, immortal in the sense that we are all taught it in school, and that it is still perfectly up-to-date in almost all branches of mathematics. Analytical geometry is the study of geometry using algebra and the Cartesian coordinate system. He discovered the laws of refraction and reflection. He also invented the superscript notation still used today to indicate the powers of exponents.

He advocated dualism, which is very basically defined as the power of the mind over the body: strength is derived by ignoring the weaknesses of the human physique and relying on the infinite power of the human mind. Descartes’s most famous statement, now practically the motto of existentialism: “Je pense donc je suis;” “Cogito, ergo sum;” “I think, therefore I am.” This is not meant to prove the existence of one’s body. Quite the opposite, it is meant to prove the existence of one’s mind. He rejected perception as unreliable, and considered deduction the only reliable method for examining, proving and disproving anything.

He also adhered to the Ontological Argument for the Existence of a Christian God, stating that, because God is benevolent, Descartes can have some faith in the account of reality his senses provide him, for God has provided him with a working mind and sensory system and does not desire to deceive him. From this supposition, however, Descartes finally establishes the possibility of acquiring knowledge about the world based on deduction and perception. In terms of the study of knowledge therefore, he can be said to have contributed such ideas as a rigorous conception of foundationalism (basic beliefs) and the possibility that reason is the only reliable method of attaining knowledge.


Descartes’ Big Ideas

  • Discards belief in all things that are not absolutely certain, emphasizing the understanding of that which can be known for sure;
  • Is recognized as the father of analytical geometry;
  • Regarded as one of the leading influences in the Scientific Revolution — a period of intense discovery, revelation, and innovation that rippled through Europe between the Renaissance and Enlightenment eras (roughly speaking, 15th to 18th centuries).

Descartes’ Key Works