(Also known as Levi ben Gerson, Gershuni, and Ralbag) Provençal philosopher.
An Aristotelian philosopher, mathematician, astronomer, and inventor, Gersonides is best known as the author of Sefer Milhamot Ha-Shem (1329; The Wars of the Lord), which attempts to resolve a number of philosophical problems through a synthesis of Aristotelianism and Judaism. The most prolific of Medieval Jewish authors, Gersonides wrote on a wide range of scientific and philosophical subjects, including astronomy, prophecy, zoology, divine knowledge, mathematics, and creation. His exegetical works on the Torah are widely respected even to this day. Although many of his beliefs were radical and contentious, his influence in both scientific and religious circles has been considerable.
Very little is known of Gersonides besides what he reveals in his writings, in which he discusses his philosophy rather than his life. Levi ben Gerson was born in Provence, probably in the town of Bagnols, a district of Orange, in 1288; his father is thought to have been Gershom ben Salomon de Beziers. It is not known where he received his education. He spoke Provençal, wrote in Hebrew, and perhaps had a working knowledge of Latin and Arabic. Except for occasional trips to Avignon, he seldom left Orange, where he was a moneylender and possibly a part-time physician. Gersonides was greatly influenced by the works of Aristotle, which he learned through the commentaries of Averroes, a twelfth-century Spanish Muslim philosopher, and through the works of Moses Maimonides, a notable Jewish philosopher.
All of Gersonides's works are written in Hebrew. His first significant work is Sefer Ha-heqesh Ha-yashar (1319; On Valid Syllogisms), which deals with aspects of Aristotle's modal reasoning. Sefer Ma'aseh Hoshev (1321; The Work of a Counter) is a mathematical treatise that treats proofs for various Euclidean axioms and their practical applications as well as discussion of fractions, permutations, and mathematical induction. The Wars of the Lord is undisputedly Gersonides's masterwork. It is a massive and complicated work, some twelve years in the making, organized along six separate philosophical problems dealing with the immortality of the soul, prophecy, God's knowledge of particulars, providence, the nature of the heavens, and the beginning of the universe. The Wars of the Lord includes 136 chapters devoted to astronomy; the finest study of trigonometry available in Western Europe at the time it was written; and a vast range of philosophical and theological content including large sections on creation and divine cognition. Many of Gersonides's other philosophical works are commentaries on Averroes's commentaries on Aristotle. Gersonides's biblical commentaries are often organized into three sections: in the first part he explains what particular words mean, in the second he interprets the meaning of the entire book in question, and lastly he presents lessons that can be drawn from the book. The most popular of his commentaries is Perush ‘al Sefer Iyob (1325; Commentary on Job), which is considered a classic. Additionally, he wrote commentaries on the biblical Canticles, Ecclesiastes, Ruth, Esther, Genesis, Exodus, Leviticus, Numbers, Deuteronomy, Samuel, Proverbs, Daniel, Ezra, Nehemia, and Chronicles. Gersonides held that Ezra, Nehemia, and Chronicles were all the work of the same author.
Considered by many contemporaries to be a radical, even a heretic, Gersonides was vilified for his philosophical works from the start. His original solutions to the problems of creation and divine knowledge angered conservatives into vicious and sometimes unfair attacks. Seymour Feldman, among others, has pointed out that there was also another side to Gersonides, “expressed in his willingness to defend traditional theological doctrines against current philosophical dogmas if he thought that the latter were philosophically unpersuasive.” Modern critics praise his courage in arguing for his beliefs, even when they ran counter to those of Aristotle, Maimonides, or Averroes. Gersonides's biblical commentaries were always well received, however, and accepted into the corpus of Jewish theology. Much current Gersonides scholarship is centered on explaining his philosophy, arguments, and their implications. His thoughts on creation are examined by Jacob J. Staub, T. M. Rudavsky, and by Seymour Feldman, who also analyzes the influence of Plato on Gersonides. J. David Bleich studies the influence of Maimonides, as does Menachem Marc Kellner. Critics almost uniformly assess Gersonides's writing style as unexciting, although Amos Funkenstein attempts to justify his analytical style by explaining that it reflects Gersonides's aversion to mystery and obscurity.