he broad scope of literature is illustrated by its inclusion of the writings of René Descartes (Latinized, Renatus Cartesius). Deliberately turning away from books, and making naught alike of learned precedent and literary form, he yet could not but avail himself unconsciously of the heritage which he had discarded.
This notable figure in seventeenth-century philosophy was born of ancient family at La Haye, in Touraine, France, March 31st, 1596; and died at Stockholm, Sweden, February 11th, 1650. From a pleasant student life of eight years in the Jesuit college at La Flèche, he went forth in his seventeenth year with unusual acquirements in mathematics and languages, but in deep dissatisfaction with the long dominant scholastic philosophy and the whole method prescribed for arriving at truth. In a strong youthful revolt, his first step was a decision to discharge his mind of all the prejudices into which his education had trained his thinking. As a beginning in this work he went to Paris, for observation of facts and of men. There, having drifted through a twelvemonth of moderate dissipation, he secluded himself for nearly two years of mathematical study, as though purposing to reduce his universe to an equation in order to solve it. The laws of number he could trust, since their lines configured the eternal harmony.
At the age of twenty-one he entered on a military service of two years in the army of the Netherlands, and then of about two years in the Bavarian army. From 1621, for about four years, he was roaming as an observer of men and nature in Germany, Belgium, and Italy, afterward sojourning in Paris about three and a half years. In 1629 he began twenty years of study and authorship in practical seclusion in Holland. His little work, 'Discours de la Méthode' (Leyden, 1637), is often declared to have been the basis for a reconstitution of the science of thought. It would now perhaps be viewed by the majority of critics rather as a necessary clearing of antiquated rubbish from the ground on which the new construction was to rise. Next to it among his works are usually ranked 'Meditationes de Prima Philosophia,' and 'Principia Philosophiæ.'
The long sojourn in Holland was ended in September 1649, in response to an urgent invitation from the studious young Queen Christina of Sweden, who wanted the now famous philosopher as an ornament to her court. After some hesitancy he sailed for Stockholm, where only five months afterward he died.
It has been said of Descartes that he was a spectator rather than an active worker in affairs. He was no hero, no patriot, no adherent of any party. He entered armies, but not from love of a cause; the army was a sphere in which he could closely observe the aspects of human life. He was never married, and probably had little concern with love. His attachment to a few friends seems to have been sincere. For literature as such he cared little. Erudition, scholarship, historic love, literary elegance, were nothing to him. Art and æsthetics did not appeal to him. Probably he was not a great reader, even of philosophic writers. He delighted in observing facts with a view to finding, stating, and systematizing their relations in one all-comprehending scheme. He never allowed himself to attack the Church in either its doctrine or its discipline. As a writer, though making no attempt at elegance in style, he is deemed remarkably clear and direct when the abstruseness of his usual themes is considered.
Descartes's method in philosophy gives signs of formation on the model of a process in mathematics. In all investigations he would ascertain first what must exist by necessity; thus establishing axioms evidenced in all experience, because independent of all experience. The study of mathematics for use in other departments drew him into investigations whose results made it a new science. He reformed its clumsy nomenclature, also the algebraic use of letters for quantities; he introduced system into the use of exponents to denote the powers of a quantity, thus opening the way for the binomial theorem; he was the first to throw clear light on the negative roots of equations; his is the theorem by use of which the maximum number of positive or negative roots of an equation can be ascertained. Analytical geometry originated with his investigation of the nature and origin of curves.
His mathematical improvements opened the way for the reform of physical science and for its immense modern advance. In his optical investigations he established the law of refraction of light. His ingenious theory of the vortices—tracing gravity, magnetism, light, and heat, to the whirling or revolving movements of the molecules of matter with which the universe is filled—was accepted as science for about a quarter of a century.
In mental science Descartes's primary instrument for search of truth was Doubt: everything was to be doubted until it had been proved. This was provisional skepticism, merely to provide against foregone conclusions. It was not to preclude belief, but to summon and assure belief as distinct from the inane submission to authority, to prejudice, or to impulse. In this process of doubting everything, the philosopher comes at last to one fact which he cannot doubt—the fact that he exists; for if he did not exist he could not be thinking his doubt. Cogito, ergo sum is one point of absolute knowledge; it is a clear and ultimate perception.
The first principle of his philosophy is, that our consciousness is truthful in its proper sphere, also that our thought is truthful and trustworthy under these two conditions—when the thought is clear and vivid, and when it is held to a theme utterly distinct from every other theme; since it is impossible for us to believe that either man who thinks, or the universe concerning which he thinks, is organized on the basis of a lie. There are "necessary truths," and they are discoverable.