THE NEW SCHAFF-HERZOG
Animals he regards as soulless, mechanical automata \v hicli are moved by vital springs after the analofjy of a watch. He denies tliat death is due to the departure of the soul from the body, holdinj;, on the contrary, that the soul de])arts because the machine that we call the body has run down. In conformity to this mechanical view of animal life, Descartes and his followers practised vivisection freely, interpreting the cries of their victims as the creakings of breaking machinery. For Descartes the whole sensible world was a mechanism whose essential qualities were ext cnsion and mobility. Given these, he was ready to reconstruct a priori, and with mathematical exactness, the whole universe. The idea of necessity was so strong in him that in an unguarded moment he even identified God with the order of nature. He did not attempt a systematic treatment of ethics; but when he touches the subject, in his letters to Queen Christina and Princess Elizabeth and in Les Passions de I'dine (Paris, 1649), he follows Greek rather than Christian ideals. He counsels humility from practical considerations, and usually interprets moral obligation in a eudemonistic sense.
Descartes is properly called the father of modern philosophy, for it was through him that the sway of scholasticism was finally broken 7. Estimate and a new method and content given of His to philosophy. He stands at the head Work. of the modern rationalistic development, both in philosophy and theology; and in his insistence on the importance of experiment he rivals Bacon as one of the founders of English empiricism. The rationalistic school that he established was practically dominant till the time of Kant; and, indeed, most speculation since Descartes has been an attempt to overcome the intellectual difficulties of his extreme dualism. If mind and matter are absolutely opposed to each other, how can they react on each other ? This was the problem of Descartes' successors. Geulincx and Malebranche solved it with the theory of occasional causes (occasionalism), Leibnitz with his preestablished harmony, Spinoza with his unica substantia, or pantheism, others with materialism. Kant showed that the spatial, as well as the temporal, aspect of our experience is only a form of sense-perception. His German successors then took the further step to absolute idealism.
In the history of mathematics Descartes is famous as the founder of analytic geometry. He also systematized the use of exponents, and gave new significance to negative quantities. He was the first to hit upon the undulatory theory of light, afterward developed by his pupil Christian Huyghens; and in his view that the world was evolved from a chaotic state by vortical motions he anticipated the nebular hypothesis of Kant and Laplace. The most important Latin and French editions of Descartes's works are. Opera omnia (8 vols., Amsterdam, 167(1-83; 9 vols., 16!)2-1701 ); (Eufrr.s vols., Paris, 1721-2(t; ed. Victor Cousin, 11 vols., 182)-20}. The best English translations of the philosophical works are; The Method, Mcilitations, and Selections jrom the lYineiples of I)escaHes, by J. Veitch (London and Edinburgh, 1850-
1853; new ed., New York, 1899); The Philosophy of Deseartes in E.rtidels from his Writings, by H. A. P Torrey (New York, 1S(»_'). A monumental edition of his works is now in preparation under the auspices of the French Academy (10 vols., Paris, 1897 sqq. ). See Materialism, § 5; and Elizabeth, Albertine. Hubert Evans.
Bibliography: On the life consult: A. Baillet, La Vie de M. Des Cartes, 2 vols., Paris, 1691; A. Provost, CEuvres . . . de Descartes, precedees d'une notice sur sa vie, ib. 1855; J. Millet, Descartes, 2 vols., ib. 1867-70; W. Ernst, Descartes, Leipa, 1869; C. J. Jeannel, Descartes et la princesse Palatine, Paris, 1869; J. P. Mahaffy, Descartes, Edinburgh, 1881; K. Fischer, Geschichte der neueren Philosophie, vol. 1, Heidelberg, 1897, Eng. transl., New York, 1887; Ehzabeth S. Haldane, Descartes, London, 1905. On his philosophy consult: V. Cousin, in the CEuvres of Descartes, i. 1-80, Paris, 1824; J. B. Bordas-Demoulin, Le Cartcsianisme, 2 vols., ib. 1843; F. X. Schmid, Rene Descartes und seine Beform der Philosophie, Nordlingen, 1859; F. Bouillier, Hist, de la philosophie cartesienne, Paris, 1868; C. Waddington, Descartes et le spiritualisme, ib. 1868; W. Cunningham, The Influence of Descartes on Metaphysical Speculation in England, London, 1876; F. Bowen, Modern Philosophy, pp. 22-37, New York, 1877; R. A. Meincke, Descartes' Beweise vom Dasein Gottes, Heidelberg, 1883; A. Barthel, Descartes' Leben und Metaphysik, Erlangen, 1885; G. Monehamp, Hist, du cartcsianisme en Belgique, 'Brussels, [1887; E. Caird, Essays on Literature and Philosophy, Glasgow, 1892; G. F. Hertling Descartes' Beziehung zur Scholastik, Munich, 1899; J. Iverach, Descartes, Spinoza, the New Philosophy, Edinburgh, 1904.