Article abstract: Descartes’s cardinal contribution is the extension of the mathematical method to all fields of knowledge. He is the father of analytic geometry and the author of the most universally appropriate version of mind-body dualism in the history of philosophy.
René Descartes was born to one of the most respected families among the French-speaking nobility in Touraine. His father, Joachim, held the post of counselor to the Parlement de Bordeaux. Descartes’s mother died of tuberculosis only a few days after giving birth to her son, leaving a frail child of chronically poor health to the sole care of his father. René’s physical condition remained delicate until he was in his twenties.
Joachim Descartes was a devoted and admiring father, determined to obtain the best education for “his philosopher.” When Descartes was ten, he was sent to the Collège de La Flèche, newly established by the Jesuits under the auspices of Henry IV.
Descartes was an exemplary student of the humanities and of mathematics. When, at the age of sixteen, he began his study of natural philosophy, he came to the insight that would later give rise to his revolutionary contributions to modern thought. Uncertainty and obscurity, he discovered, were hallmarks of physics and metaphysics. These disciplines seemed to attract a contradictory morass of opinions that yielded nothing uniform or definite. By contrast, Descartes’s studies in mathematics showed him something firm, solid, and lasting. He was astonished to find that while mathematical solutions had been applied to scientific problems, the method of mathematics had never been extended to important practical matters. At La Flèche, Descartes concluded that he would have to break with the traditions of the schools if he were to find knowledge of any worth.
Descartes left his college without regret, and his father subsequently sent him to Paris. Social life there failed to amuse him, and he formed his most intimate friendships with some of France’s leading scholars and teachers. When he was twenty-one, he joined the army but spent little time campaigning. In his spare time, he wrote a compendium of music and displayed his mathematical genius by instantaneously solving puzzles devised for him by soldiers in his company.
Descartes was housed with a German regiment in winter quarters at Ulm, waiting for active campaign, when the whole core of his subsequent thought suddenly took shape. On the night of November 10, 1619, after a day of intense and agitated reflection, Descartes went to bed and had three dreams. He interpreted these dreams as a divine sign that he was destined to found a unified science based on a new method for the correct management of human reason. Descartes’s sudden illumination and resolve on that night to take himself as the judge of all values and the source of all certainty in knowledge was momentous for the world of ideas.
Descartes spent the next ten years formulating his method while continuing scientific researches, and he occupied himself with travel in order to study what he called “the great book of the world.” He had come to the view that systems of human thought, especially those of the sciences and philosophy, were better framed by one thinker than by many, so that systematizing a body of thought from the books of others was not the best method. Descartes wanted to be disabused of all the prejudices he had acquired from the books of others; thus, he sought to begin anew with his own clear and firm foundation. This view was codified in his first substantial work, Rules for the Direction of the Mind. In this work, Descartes set forth the method of rational inquiry he thought requisite for scientific advance, but he advocated its use for the attainment of any sort of knowledge whatever.
Descartes completed a scientific work entitled The World in 1633, the same year that Galileo was condemned by the Inquisition. Upon hearing this news, Descartes immediately had his own book suppressed from publication, for it taught the same Copernican cosmology as did Galileo, and made the claim that indicted Galileo’s orthodoxy: that human beings could have knowledge as perfect as that of God. A few years later, Descartes published a compendium of treatises on mathematics and physical sciences that were written for the educated but nonacademic French community; this work obliquely recommended his unorthodox views to the common people of “good sense” from whom Descartes hoped to receive a fair hearing. This work was prefaced by his Discourse on Method and contained the Geometry, the Dioptric, and the Meteors.
Discourse on Method provided the finest articulation of what has come to be known as Descartes’s method of doubt. This consisted of four logical rules:
1. to admit as true only what was so perfectly clear and distinct that it was indubitable.
2. to divide all difficulties into analyzable elements.
3. to pass synthetically from what is easy to understand to what is difficult.
4. to make such accurate enumerations of the steps of reasoning so as to be certain of having omitted nothing.
The method is fundamentally of mathematical inspiration, and it is deductive and analytical rather than experimental. It is a heuristic device for solving complex problems that yields explicit innovation and discovery. Descartes employed his method to this end in the tract on geometry when he discovered a way to resolve the geometric curves into Cartesian...
(The entire section is 2329 words.)