Moses Mendelssohn (6 September 1729 – 4 January 1786) was a German-Jewish philosopher and theologian. His writings and ideas on Jews and the Jewish religion and identity were a central element in the development of the Haskalah, or 'Jewish Enlightenment' of the eighteenth and nineteenth centuries.
Born to a poor Jewish family in Dessau, Principality of Anhalt, and originally destined for a rabbinical career, Mendelssohn educated himself in German thought and literature. Through his writings on philosophy and religion he came to be regarded as a leading cultural figure of his time by both Christian and Jewish inhabitants of German-speaking Europe and beyond. His involvement in the Berlin textile industry formed the foundation of his family's wealth.
His descendants include the composers Fanny and Felix Mendelssohn; Felix's son, chemist Paul Mendelssohn Bartholdy; Fanny's grandsons, Paul and Kurt Hensel; and the founders of the Mendelssohn & Co. banking house.
Moses Mendelssohn was born in Dessau to Mendel Heymann and Bela Rachel Wahl. His father's name was Mendel, but Moses and his brother Saul were the first to adopt the surname Mendelssohn ("Mendel's son"). Moses's son Abraham Mendelssohn wrote in 1829 (to Felix), "My father felt that the name Moses Ben Mendel Dessau would handicap him in gaining the needed access to those who had the better education at their disposal. Without any fear that his own father would take offense, my father assumed the name Mendelssohn. The change, though a small one, was decisive."
Mendel was an impoverished scribe—a writer of Torah scrolls—and his son Moses in his boyhood developed curvature of the spine. Moses' early education was provided by his father and by the local rabbi, David Fränkel, who, besides teaching him the Torah and Talmud, introduced to him the philosophy of Maimonides. In 1743 Fränkel received a call to Berlin, and a few months later Moses followed him. Moses, age 14, "entered Berlin at the Rosenthaler Tor, the only gate in the city wall through which Jews (and cattle) were allowed to pass." "Mendelssohn enrolled in Frankel's exacting seminary, where the program consisted of unending rote repetitions of early medieval texts, interpretations thereof, elaborations of Talmudic law, and copious commentary accumulated over the centuries."
A refugee Polish Jew, Israel Zamosz, taught him mathematics, and a young Jewish physician taught him Latin. He was, however, mainly self-taught. He learned to spell and to philosophize at the same time (according to the historian Graetz). With his scanty earnings he bought a Latin copy of John Locke's An Essay Concerning Human Understanding, and mastered it with the aid of a Latin dictionary. He then made the acquaintance of Aaron Solomon Gumperz, who taught him basic French and English. In 1750, a wealthy Jewish silk-merchant, Isaac Bernhard, appointed him to teach his children. Mendelssohn soon won the confidence of Bernhard, who made the young student successively his bookkeeper and his partner.
It was possibly Gumperz who introduced Mendelssohn to Gotthold Ephraim Lessing in 1754, who became one of his greatest friends. It is said that the first time Mendelssohn met Lessing, they played chess. In Lessing's play Nathan the Wise Nathan and the character Saladin first meet during a game of chess. Lessing had recently produced the drama Die Juden, whose moral was that a Jew can possess nobility of character. This notion was, in the contemporary Berlin of Frederick the Great, generally ridiculed as untrue. Lessing found in Mendelssohn the realization of his dream. Within a few months, the two became closely intellectually allied. Lessing also brought Mendelssohn to public attention for the first time: Mendelssohn had written an essay attacking Germans' neglect of their native philosophers (principally Gottfried Leibniz), and lent the manuscript to Lessing. Without consulting the author, Lessing published Mendelssohn's Philosophical Conversations (Philosophische Gespräche) anonymously in 1755. In the same year there appeared in Danzig (now Gdańsk, Poland) an anonymous satire, Pope a Metaphysician (Pope ein Metaphysiker), which turned out to be the joint work of Lessing and Mendelssohn.
Early prominence as philosopher and critic
Mendelssohn became the leading spirit of Friedrich Nicolai's important literary undertakings, the Bibliothek and the Literaturbriefe, and ran some risk by criticizing the poems of Frederick II, King of Prussia; Frederick’s good nature kept him out of trouble. In 1762 he married Fromet Guggenheim, who survived him by twenty-six years. In the year following his marriage Mendelssohn won the prize offered by the Berlin Academy for an essay on the application of mathematical proofs to metaphysics, On Evidence in the Metaphysical Sciences; among the competitors were Thomas Abbt and Immanuel Kant, who came second. In October 1763 the king granted Mendelssohn, but not his wife or children, the privilege of Protected Jew (Schutzjude), which assured his right to undisturbed residence in Berlin.
As a result of his correspondence with Abbt, Mendelssohn resolved to write on the immortality of the soul. At the time, materialist ideas were widespread, and belief in immortality had declined. At this favourable juncture appeared Phädon oder über die Unsterblichkeit der Seele (Phaedo or On the Immortality of Souls; 1767). Modelled on Plato's dialogue of the same name, Mendelssohn's work possessed some of the charm of its Greek exemplar and impressed the German world with its beauty and lucidity of style. Phaedo was an immediate success, and besides being one of the most widely read books of its time in German was speedily translated into several European languages, including English. The author was hailed as the "German Plato", or the "German Socrates"; royal and other aristocratic friends showered attentions on him, and it was said that "no stranger who came to Berlin failed to pay his personal respects to the German Socrates."
So far, Mendelssohn had devoted his talents to philosophy and criticism; now, however, an incident turned the current of his life in the direction of the cause of Judaism. In April 1763, Johann Kaspar Lavater, then a young theology-student from Zurich, made a trip to Berlin, where he visited the already famous Jewish philosopher with some companions. They insisted on Mendelssohn telling them his views on Jesus and managed to get from him the statement, that, provided the historical Jesus had kept himself and his theology strictly within limits of orthodox Judaism, Mendelssohn "respected the morality of Jesus' character." Six years later, in October 1769, Lavater sent Mendelssohn his German translation of Charles Bonnet's Inquiries concerning Christianity, with a preface where he publicly challenged Mendelssohn to refute Bonnet or if he could not then to "do what wisdom, the love of truth and honesty must bid him, what a Socrates would have done if he had read the book and found it unanswerable." Mendelssohn answered in an open letter in December 1769: "Suppose there were living among my contemporaries a Confucius or a Solon, I could, according to the principles of my faith, love and admire the great man without falling into the ridiculous idea that I must convert a Solon or a Confucius." The ongoing public controversy cost Mendelssohn much time, energy and strength.
Lavater later described Mendelssohn in his book on physiognomy, Physiognomische Fragmente zur Beförderung der Menschenkenntnis und Menschenliebe (1775–1778), as "a companionable, brilliant soul, with piercing eyes, the body of an Aesop [who was traditionally considered ugly]—a man of keen insight, exquisite taste and wide erudition [...] frank and open-hearted"—ending his public praise with the wish of Mendelssohn recognizing, "together with Plato and Moses... the crucified glory of Christ." When, in 1775 the Swiss-German Jews, faced with the threat of expulsion, turned to Mendelssohn and asked him to intervene on their behalf with "his friend" Lavater, Lavater, after receiving Mendelssohn's letter, promptly and effectively secured their stay.