Born: March 31, 1596, in La Haye, Tournaine, France

Died: February 11, 1650, in Stockholm, Sweden

René Descartes was a French mathematician, scientist, and philosopher who has earned the reputation as the father of modern philosophy. He coined the famous axiom "I think, therefore I am".

Descartes, the son of a minor noble, displayed brilliance at an early age. He began school at age eight at the Royal College, a Jesuit school, at La Flèche in Anjou. He continued his studies, entering the University of Poitiers at sixteen years old and graduating a lawyer in 1616.

Descartes was influenced for life by the Roman Catholic doctrine of his early teachers. For instance, although he believed in Copernican theory of the universe, he rejected the notion that the planets revolved around the sun when the church declared the idea heretical.

He never practiced law, opting instead for a military career. In 1618, he saw his first action in the service of Prince Maurice of Nassau at Breda, Netherlands. He continued a mercenary's life in the service of the duke of Barvaria in 1619. Then, in November 10 of that year, Descartes said he had a vision that revealed the nature of science more clearly to him.

Disinterested in the machines of war, he focused his attention on the study of philosophy and optics. Having spent time in Italy and France, he returned to the Netherlands in 1628, residing in a number of cities including Amsterdam and Utrecht.

In 1637, he wrote his first major work, Essais Philosophiques. The work contains essays on geometry, optics, meteors and Discourse on the Method, which attempts to explain his philosophy. It establishes four rules: accept nothing as true until recognized as such; solve problems systematically, bit by bit; proceed from the simple to the complex; review everything to make sure nothing is omitted.

Descartes attempted to combine the seemingly unrelated methods of science and mathematics with that of philosophy. This differed from the method of Scholasticism which was based on comparing and contrasting the views of recognized authorities. He held that nothing is true until he could prove that it was true. From the single seed of doubt Descartes logically formulated the certainty, Cogito, ergo sum, or, I think therefore I am.

In 1641, Descartes followed his first work with Meditations on the First Philosophy, which was dedicated to his close friend, Princess Elizabeth Stuart of Bohemia. However, his explanations of many physical phenomena were faulty due to his strict application of scientific techniques. Yet his work is valuable because he substituted a system of concrete mechanical interpretations for the vague spiritual concepts of earlier writers. It is this achievement which earned him the reputation as the founder of modern philosophy.

He is remembered equally for his contributions to science and mathematics. His studies of optics precipitated his discovery of the law of reflection: the angle of incidence is equal to the angle of reflection. His advancements in mathematics include an analytic system of geometry, an attempt to classify curves as equations, and Descartes' rule of signs (a way of determining the number of positive and negative roots for any algebraic equation).

In 1649 Descartes became the philosophical tutor to Queen Christina of Sweden in Stockholm. A year later he caught pneumonia and died.