The Collaborative International Dictionary of English v.0.48:

Descartes \Descartes\ (d[asl]*k[aum]rt") prop. n.
   Ren['e] Descartes, a French philosopher and mathematician,
   born 1596, died 1650. See biography, below.

   Syn: Rene Descartes.
        [WordNet 1.5] Descartes, Ren['e] (Latinized Renatus
        Cartesius). Born at La Haye, Touraine, France, March 31,
        1596: died at Stockholm, Feb. 11, 1650. A. celebrated
        French philosopher, founder of Cartesianism and of
        modern philosophy in general. He was graduated at
        seventeen from the Jesuit college of La Fl[`e]che, spent
        five years in Paris (1613-18), and then roamed about in
        search of knowledge in Germany, Italy, Holland, and
        Poland. In 1628 he attended the siege of La Rochelle as
        a volunteer. From 1629 to 1649 he led a retired life in
        Holland, spreading and defending his philosophical
        ideas. He finally went to Stockholm on the invitation of
        Queen Christina of Sweden; five months later he died
        there of pneumonia. The work that has made him famous as
        a philosopher is a short treatise entitled "Discours de
        la m['e]thode" (Leyden, 1637). It was published in
        French together with three essays in support of his
        theories, "La dioptrique," "Les m['e]t['e]ores," and "La
        g['e]om['e]trie." In it he revolutionized the science of
        thought. Descartes himself published during his lifetime
        "Meditationes de prima philosophia "(Paris, 1641;
        Amsterdam, 1642; translated into French, 1647),
        "Principia philosophiae" (Amsterdam, 1644), "Trait['e]
        des passions de l'[^a]me" (Amsterdam, 1649), and a
        polemic pamphlet entitled "Epistola Renati Descartes ad
        Gisbertum Vo["e]itum" (Amsterdam, 1643). After his death
        his friends published his "De l'homme" (1664),
        "Trait['e] de la formation du foetus" (1664), "Le monde
        ou trait['e] de la lumi[`e]re de Descartes" (1664),
        "Lettres" (1657-67), and "Opuscula posthuma, physica et
        mathematica" (Amsterdam, 1701). Descartes ranked among
        the foremost mathematicians of his day. A separate
        reprint was made of his geometry, and the work itself
        was translated into Latin in 1649, and re["e]dited in
        1659 with notes and comments. In this form it
        constituted a classic standard throughout Europe, and
        presented an entirely new basis for the study of algebra
        and geometry.
        [Century Dict. 1906]

WordNet (r) 3.0 (2006):

Descartes
    n 1: French philosopher and mathematician; developed dualistic
         theory of mind and matter; introduced the use of
         coordinates to locate a point in two or three dimensions
         (1596-1650) [syn: Descartes, Rene Descartes]