98 DESCARTES. hy Mersenne, are from various theologians and mathema- ticians. In the second edition there were added, further, the Seventh Objections, by the Jesuit Bourdin, and the Replies of the author thereto. The four books of the Principia PhilosophiiB, published in 1644 and dedicated to Elizabeth, Countess Palatine, give a systematic presentation of the new philosophy. The Discourse on Met/iod a.ppea.red, 1644, in a Latin translation, the Meditations and the Principles in French, in 1647. The Treatise on the Passions was pub- lished in 1650 ; the Letters, 1657-67, in French, 1668, in Latin. The Opera Postuma, 1701, beside the Compendium of Music (written in 161 8) and other portions of his post- humous writings, contain the " Rules for the Direction of the Mind," supposed to have been written in 1629, and the " Search for Truth by the Light of Nature." The complete works have been often published, both in Latin and in French. The eleven volume edition of Cousin appeared in 1824-26.* We begin our discussion with Descartes's noetical and metaphysical principles, and then take up in order his doctrine of nature and of man. I. The Principles. That which passes nowadays for science, and is taught as such in the schools, is nothing but a mass of disconnected, uncertain, and often contradictory opinions. A principle of unity and certainty is entirely lacking. If anything permanent and irrefutable is to be accomplished in science, everything hitherto considered true must be thoroughly demolished and built up anew. For we come into the world as children and we form judgments of things, or re-
- ■ Of the many treatises on the philosophy of Descartes those of C. Shaar-
^ '.vsi.{Descartesund Spinoza, %^d)2in<i]...'L,ov^e., 1855, may be mentioned. Further, M. Heinze has discussed Die Sittenleh-e dts Descartes, 1872 ; Ed. Grimm, Descartes' Lehre von den angeboretten Ideen. 1873 '■> G. Glogau, Dar- le^nng und Kritik des Grundgedaii kens der Cartesianisch. Metaphysik {Zeit- schrift fiir Phihsophie, vol. Ixxiii. p. 2oq se<j.^, 1878 ; Paul Natorp, Descartes* Erkenntnisstheorie, 1882 ; and Kas. Twardowski, Idee und Percepliofi in Des- cartes, 1892. In French, ,Francisque Bouillier {Histoire de la Phihsophie Cart/sienne, 1854) and E. Saisset i^Precurseurs et Disciples de Descartes, 1862)
