Astrology in Medieval Judaism

In the Middle Ages, especially in the orbit of Islam, Jews increasingly practiced astrology. A thorough knowledge of this art is evidenced in the Zohar and Sefer Raziel, and astrology is referred to frequently in medieval liturgical poetry, including the works of poets such as Kalir and Ibn Gabirol.

Well known Jewish astrologers of the ninth century were Jacob ibn Turik, whom Ibn Ezra says brought the astrological tables of the Hindus to Baghdad. Of the same period, some astrological works remain extant of Sahl ben Bishr al-Israeli,also known as Rabban al-Tabari (“the rabbi of Tabarisran”).

Biblical Commentaries & Astrology

In this period, the works of Islamic astrologers were translated by Jews into Hebrew. Ibn Ezra himself was an avid follower of astrology, which he referred to as a sublime science. He even translated into Hebrew the astrological work of Mashallah, the court astrologer of Almansur and Marnun, and he authored important works on the constellations and planets.

Referring to astrology in his biblical commentaries, Ibn Ezra understood the heavens to represent the Book of Life in which people’s fate is written. Still, in accordance with the inherited talmudic perspective, he believed that this fate could be overruled by God, to whom humans accordingly have recourse in their quest to reshape their own destiny.

A similar approach appears in the commentary to Maimonides’ Mishneh Torah of Abraham b. David of Posquieries (Rabad). While asserting the influence of the stars upon human destiny, he also avers that faith in God can overcome this influence.

Maimonides,by contrast, alone among the major rabbinic authorities of this period, opposed astrology and declared it explicitly forbidden by Lev. 19:26, “You shall not practice augury or witchcraft.” Maimonides viewed astrology as a dangerous superstition, bordering on idolatry that was “a disease on a science.”

Mazal Tov!

The last important Jewish astrologer was David Gans (in Germany, 1541-1613). Alongside his work on Jewish and general history (Zemah David), he wrote a work on cosmography (Gebulat ha-Erez), an astronomical treatise (Magen David), and a number of mathematical works. His Nehmad ve-Naim, which deals with astronomy and mathematical geography, contains a historical survey of the development of these subjects around the world.

The modern world and the emergence of science has largely brought an end to astronomy and the other magical practices known in talmudic times. One minor throwback to that period is the contemporary use of the Hebrew phrase “Mazal Tov,” literally “A good constellation,” to mean “Good luck!” Similarly, following the approach of the Shulchan Aruch (Yoreh Deah 179, 2), some Jews continue to reject certain days of the week or month for weddings or other ventures.

Reprintedwith permission of The Continuum International Publishing Group from The Encyclopedia of Judaism, edited by Jacob Neusner,
Alan Avery-Peck, and William Scott Green.