MENDELSSOHN, Moses, was born in 1729 at Dessau, where his father was teacher in a Jewish school. Like all Jewish children he was from his infancy instructed in the Talmud, but the Moreh Nevuchim ("Guide to the Wanderers") of Maimonides was the subject of his most passionate study. To the end of his days, in an impaired constitution and a distorted spine, he carried the marks of his youthful devotion to that book. In 1742 he came to Berlin, following in the footsteps of his instructor David Fränkel, and in the tide of all the aspiring Jewish youth of the day. Here, under Rabbi Israel, who had been expelled from Poland for his liberal studies, he added mathematical knowledge to the circle of his attainments; and under his teachers Emmerich, Keisch, and Solomon Gumpertz, he became acquainted with Latin and modern literature. His own philosophical genius led him to Locke, Leibnitz, and Wolf. At this time he was indebted to his countrymen Itzig, Marcus, and Bernhard for support. The last of these was a wealthy silk manufacturer, who, from being tutor to his children, ultimately raised him to partnership with himself in trade. No sooner did Mendelssohn rise above beggary than he inaugurated the grand mission of his life by aiming a blow at the bleak Talmudism of his nation. Along with Tobias Bock he prepared some short scientific tracts in Hebrew,—a step which called forth the rage and anathemas of the rabbis. In 1754 he became acquainted with Nicolai and Lessing, and began a friendship to which he owed much, and from which the critic, at least, derived profit in being furnished with the prototype of Nathan the Wise. From this time he devoted himself to the study of mental philosophy. His first work was the Briefe über die Empfindungen ("Letters on the Sensations"), and this was followed by a variety of short treatises, distinguished for acuteness more than for originality, but, above all, for the fine ethical tone which ran through them. He was engaged for many years in vindicating Lessing from the charge of Spinozism, which had been brought against him by Jacobi. His best known work, however, in this department of study is the Phaedon, or "Dialogue of Socrates with his friends on the Immortality of the Soul." The characters and descriptive parts are taken from Plato, but the argument is new. Mendelssohn founds his doctrine, not on the simple texture of the soul, which renders it incapable of being resolved into component parts, but on its nature as exempting it from the ordinary laws of change. Kant, however, has shown that this is no argument against the soul's annihilation, and is not even satisfactory against the hypothesis of its gradual enfeeblement and ultimate decadence without any organic change. Of far greater historical importance were Mendelssohn's labours for the elevation of his Jewish countrymen. His translation of the Pentateuch into classic German, printed in Hebrew characters, introduced the literature of Germany into the Jewish schools of Poland, and ultimately extinguished the textbooks which had been conned for ages under the teaching of the Rebbe. Mendelssohn's position in the literary world was all the more startling that it was entirely novel, and whatever influence it gave him was sacredly devoted to the service of those of his own creed. His little book entitled Jerusalem appeared in 1783; and, along with two pamphlets written by the historian Dohm somewhat earlier, paved the way for the civil emancipation of the Jews. In these patriotic efforts he was seconded by many of his country-
men; and the work which he left unfinished was carried out by Hartwig Wesseley, Izaak Eichel, and David Friedländer. In the internal reform of the synagogue, however, he had no share. That was the second harvest of his labours, and one which, in the strictness of his own religious life, he did not anticipate.
Mendelssohn's literary labours were frequently interrupted by attacks of sickness. His constitution, shattered in early youth, received a new shock from every paroxysm of mental activity. Lavater's attempt to win him to Christianity prostrated him in a long and painful illness; and, in his zeal to defend his friend Lessing from the stigma of Spinozism, he so overtasked his energies as to bring on a fever, which terminated his existence in 1786. His works have been collected and published, along with a biography, at Vienna in 1838. A translation of the Phaedon into English appeared in the same year.