DELMEDIGO, JOSEPH SOLOMON (1591–1655), rabbi, philosopher, mathematician, and astronomer; also known as Joseph Solomon Rofe acronym YashaR) of Candia (Crete). A writer of extensive Jewish and secular learning and of encyclopedic range, he is the author of works whose number is estimated by some authorities at 30, by others at over 60. A member of a distinguished scholarly family, he was the son of Elijah Delmedigo, rabbi in Candia. In accordance with the family tradition, he was given a thorough Jewish and classical education. At the age of 15, he was admitted to the University of Padua, where he studied astronomy and mathematics under Galileo, and also medicine and philosophy, at the same time continuing his Jewish studies. While at Padua, he frequently visited Leone *Modena of the neighboring city of Venice, who, it appears, exercised a lasting influence on him. In 1613, he completed his studies at the University of Padua, and returned to Crete, where he began to practice medicine. From notes which he compiled during this period, he later began to compose his encyclopedic work Ya'ar Levanon ("Forest of Lebanon"), which he never brought to completion. In all likelihood he married in Candia, but there are indications that it was not a happy marriage. He soon found Candia too confining and left his homeland, never to return. Throughout his travels, he encountered misunderstanding and embitterment, since his ideas on the popularization of scientific knowledge aroused opposition and enmity.
His first stop after leaving Candia was Cairo. There he became acquainted with Ali b. Rahmadan, a renowned Arab mathematician, whom he refuted in a public disputation concerning spherical trigonometry. In Egypt, too, he met the physicist, Jacob the Alexandrian, head of the Karaite community there. Delmedigo was attracted to the Karaites by their love for secular learning and it is also possible that the hostility of Orthodox Jews caused him to turn occasionally to the Karaite sectaries for company. He was delighted to find in Egypt several works on Maimonides' Guide, as well as certain writings of Abraham ibn Ezra, whom he greatly admired. From Cairo, Delmedigo went to Constantinople, then a prominent center of learning. Here, again, he befriended several Karaite leaders, including Moses Mezordi, from whom he acquired many Karaite works. Here, too, he came to know some ardent followers of the Kabbalah, in particular Jacob ibn Nehemias. It may, however, be assumed that Delmedigo had already become acquainted with kabbalistic teachings while still at Padua. Yet, he approached its study more seriously during his stay in Poland. He immersed himself in the Kabbalah for two purposes: (1) To find in it solutions which philosophy could not offer, and (2) to criticize it. He wrote Maẓref la-Ḥokhmah, in which he allegedly refuted the attack on the Kabbalah made by his distant relative Elijah *Delmedigo, in his Beḥinat ha-Dat. Since, as Delmedigo himself explains, he was commissioned to write such a refutation, it is unclear whether the work reflects his true convictions. He says in this connection: "Do not presume that you can unravel the author's mind from his book" (ed. Odessa, 1864, p. 85). Leone Modena understood the Maẓref la-Ḥokhmah as a refutation of kabbalistic ideas, using it in his Ari Nohem ("Roaring Lion"), a systematic anti-kabbalistic treatise. Delmedigo next went to Poland, stopping off on the way in Romania, where he became friends with the kabbalist Solomon Arabi. In 1620, he was practicing medicine in Vilna, where he became the private physician of Prince Radziwill, and had many nobles for his patients. During the week, he used to make the circuit of the environs of Vilna to cure the sick, and on the Sabbath he would lecture in the synagogue. His nights were spent in scholastic pursuits. Though a conservative in many of his views, he was also a proponent of many new ideas. His scientific bent of mind having been stimulated by his early contact with Galileo, he was a pioneer in a number of aspects of scientific research. In astronomy, he parted company with the followers of Ptolemy to espouse the Copernician system. He was the first Jewish scholar to use logarithmic tables, which had just been invented. He preferred Platonic philosophy to Aristotelianism which had held almost unchallenged sway during the Middle Ages. In medicine and the natural sciences he emphasized the value of the empiric approach, although at an earlier stage he had criticized scientific empiricism. He spoke against the unsanitary conditions prevailing in the ghettos and the lack of organization and order.
In 1629–31, his Ta'alumot Ḥokhmah, a collection of kabbalistic treatises, was published by his disciple, Samuel Ashkenazi, in Basle, Switzerland. The first section, Maẓref la-Ḥokhmah, appeared in 1629, the second, Novelot Ḥokhmah ("Fallen Fruit of Wisdom"), in 1631. Except for these two books, the only other material that remains of Delmedigo's colossal output is the full text of his letter to Zerah of Troki, which was published together with a German translation in 1840 by Abraham Geiger in his Melo Chofnajim. It is known within the corpus of Delmedigo's published work under the name of Iggeret Aḥuz, after the first word of the letter. This letter is merely a precursory answer to Zerah's inquiries, and was written in 1624 or 1625. Delmedigo refers, in his writings, to a number of other works, which are no longer extant. Among these works are Bosmat bat Shelomo on arithmetic, geometry, astronomy, geography, logic, ethics, and metaphysics; Ir gibborim, divided into two parts: Gevurot Adonai on astronomy, and Nifla'ot Adonai, on chemistry and mechanics; and two medical works, Refu'ot Te'alah, and Mekor Binah which contains the Hebrew translation of the Latin aphorisms of Hippocrates. Toward the end of his life, Delmedigo settled at Frankfurt on the Main, where, as community physician, he again became part of ghetto life. Thereafter, he spent some years in Prague – a period about which little is known. On his tombstone in Prague are written the words: "He practiced what he preached – he was just to everyone – the glorified rabbi, scholar, divine philosopher, and mighty one among physicians."
A. Geiger, Melo Chofnajim (1840), introduction, 1–95 (Ger. pt.) 1–29 (Heb. pt.); idem, Nachgelassene Schriften, 3 (1876), 1–33; G. Alter, Two Renaissance Astronomers (1958; = Československá Akademia Vd, Rozprávy, 68 (1958), 45–74, Eng.); L. Roth, in: Chronicon Spinozanum, 2 (1922), 54–66; C. Roth, Life of Menasseh ben Israel (1934), 132–4; Waxman, Literature, 2 (1960), 326–8; F. Kobler, Treasury of Jewish Letters, 2 (1952), 486–96.