Brief biography of Descartes, the philosopher of “Cogito ergo sum” and inventor of the Cartesian system

Rene Descartes (Descartes), born in 1596 in France, was one of the main philosophers of the modern age, as well as an important scientist and one of the founders of rational thinking. Starting from the concept of doubt, Descartes developed a system of knowledge based on mathematics, which aimed to question all the existing knowledge of his time. Descartes did not push his rationalism to the point of becoming an atheist but, on the contrary, he believed in a Infinite and perfect God, whose existence could be demonstrated with philosophy. As a scientist, he is best known for the conception of Cartesian reference system (or Cartesian axes) which, in reality, had already been developed before him by another scientist. Descartes' theories are known through his treatises, including the famous Discourse on Method.

The life and works of Descartes

René Descartes was born in 1596 in France, in the town of La Haye en Tourraine (today the town is called Descartes in his honor). He is known as Descartes because in his time intellectuals were in the habit of Latinize your own first name, Latin being the language of the learned. Descartes therefore became Cartesius.

Descartes at the desk.

At the time of Descartes, European culture, thanks to the Renaissance and the Scientific Revolution, was undergoing great changes. Descartes was one of the protagonists of evolution, but as a young man he didn't think so much about philosophy and science, but rather about military career. After studying with the Jesuits, he joined the army of the Netherlands and in 1619 reached Germany, where the conflict between Catholics and Protestants known as Thirty Years' War. In the same 1619, however, the young Descartes suffered a sort of intellectual “crisis”. and decided to dedicate his life to science and knowledge. He therefore abandoned the army, returned to France and in 1628, now determined to develop a new system of knowledge, he moved to Holland, the country in which there was greater tolerance for new ideas. In 1637 he published some fundamental works: three scientific treatises – the Dioptrics, the Meteors and the Geometry – introduced by the famous Discourse on the Method. In the following years he was the author of other works and in 1649 he moved to Stockholm at the invitation of Queen Christina of Sweden, a follower of his ideas. In February 1650 he died of pneumonia. In recent years, the unproven hypothesis has been put forward that he had been poisoned.

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Descartes' philosophical thought in brief

Descartes is considered the first modern philosopher, because the problem was posed of building a new system of knowledge, based on rationality. At the center of Descartes' thought is the concept of doubt, which the philosopher believed to be “the origin of wisdom”. In the Discourse on Method, Descartes observed that the reality we perceive with the senses is deceptive and, consequently, all knowledge, as taught in schools, must be questioned (methodical doubt). Even mathematical knowledge can be deceptive, because an “evil genius” could purposely alter it (hyperbolic doubt). Therefore, one must always exercise doubt. Descartes believed that human beings were characterized precisely by the ability to doubt and think. It is no coincidence that cogito, ergo sum (I think, therefore I am) is the philosopher's most famous statement. The complete phrase, which appears in the Discourse on the Method, was Ego cogito, ergo sum, sive existo, that is, I think, therefore I am, that is, I exist.

First edition of the Discourse on the method.

Starting from the concept of doubt, Descartes developed the idea that there were two “substances”: the res cogitanswhich constitutes the immaterial reality and can be perceived through the mind, and the res extensa, constituted by the material reality perceivable through the senses. The theory is known as Cartesian dualism.

Descartes was a rationalist, but he was not an atheist. He believed that God was perfect, infinite, creator and omnipotent and thought that philosophy could provide proof of his existence.

The Cartesian axes

Descartes was also a scientist, author of works on optics and on other sciences. His best-known contribution is that given to geometry with the invention of Cartesian reference system (also known as the “Cartesian axes” system).

The system consists of two axes, that of abscissa (horizontal) and that of order (vertical), which intersect at a named point origin. The system allows you to determine the position of a point in space and to represent a first degree equation on a plane. In this way, geometry and algebra merge into a single discipline, the Analytic geometry.

Cartesian reference system
Cartesian reference system.

The system, in reality, was developed two centuries before Descartes by another French mathematician Nicholas of Oresme; furthermore, in the same period as Descartes it was “invented” independently by another scientist, Pierre de Fermat (who however did not publish his discovery). The system, however, is known as “Cartesian” and, together with the theory of cogito ergo sum, constitutes the French philosopher's most important legacy to science and knowledge.