METAPHYSICS: THE MONADS. 269 above, the New Essays and the Theodicy, we have of philo- sophical works by Leibnitz only a series of private letters, and articles for the scientific journals {tht Journal des Savants in Paris, and the Acta Eruditoriim in Leipsic, etc.), among which may be mentioned as specially important the New System of Nature, and of the Interaction of Substances as well as of the U nion which exists between the Soul and the Body, 1695, which was followed during the next year by three explanations of it, and the paper De Ipsa Natura, 1698. Previous to Erdmann (1840) the following had deserved credit for their editions of Leibnitz : Feller, Kortholt, Gruber, Raspe, Dutens, Feder, Guhrauer (the German works), and since Erdmann, Pertz, Foucher de Careil, Onno Klopp, and especially J. C. Gerhardt. The last named published the mathematical works in seven volumes in 1849-63, and recently, Berlin, 1875-90, the philosophical treatises, also in seven volumes.* In our account of the philosophy of Leibnitz we begin with the fundamental metaphysical con- cepts, pass next to his theory of living beings and of man (theory of knowledge and ethics), and close with his inquiries into the philosophy of religion. I. Metaphysics : the Monads, Representation, the Pre-established Harmony ; the Laws of Thought and of the World. Leibnitz develops his new concept of substance, the monad, f in conjunction with, yet in opposition to, the
- We have a life of Leibnitz by G. E. Guhrauer, jubilee edition, Breslau,
1846 [Mackie's Life, Boston, 1845 is based on Guhrauer]. Among recent works on Leibnitz, we note the little work by Merz, Blackwood's Philosophical Classics, 1884, ^nd Ludwig Stein's Leibniz und Spinoza, Berlin, 1890, in which with the aid of previously unedited material the relations of Leibnitz to Spinoza (whom he visited at The Hague on his return journey from Paris) are "discussed, and the attempt is made to trace the development of the theory of monads, down to T697. The new exposition of the Leibnitzian monadology by Ed. Dillman, which has just appeared, we have not yet been able to examine [The English reader may be referred further to Dewey's Leibniz in Griggs's Philosophical Classics, 1888, and Duncan's Philosophical Works of Leibnitz (selections trans- lated, with notes). New Haven, 1890, as well as to the work of Merz already mentioned. — Tr.] t According to L. Stein's conjecture, Leibnitz took the expression Monad, which he employs after 1696, from the younger (Franc. Mercurius) van Hel- mont.
