Many rabbis in the
Geonic era (after the close of the Talmud, early medieval period) discussed the varying
Talmudic and
midrashic views on astrology. One
responsum takes a middle view:
Otzar HaGeonim 113, concludes that astrology has some reality, in that the stars give a person certain inclinations; however each person has the ability to overcome their own inclinations, and thus maintains free will. Astrology was practised by some Jews throughout the
Middle Ages, both as a professional art and as a science. Coming from the East, Jews were sometimes looked upon as heirs and successors of the
Chaldeans. For this reason, Jews sometimes were regarded by the Western world as masters of astrology. Their supposed power over destiny on occasion filled the multitudes with awe and fear.
Abraham ibn Ezra was a follower of astrology, which he calls "a sublime science." Besides translating another
Jewish philosopher
Mashallah's astrological work
Questions and another work of this author on the eclipse of the moon from the
Arabic into
Hebrew, he wrote
Nativity,
Sentences of the Constellations,
Reshit Hokhmah (
Beginning of Wisdom),
Book of the World, a treatise on the
Planets, a treatise on the
Luminaries, and a
horoscope. He often refers to astrology in his
Bible commentaries. To him heaven with its constellations is "the book of life," in which man's destiny is written, and against which there is recourse to God as "the Almighty," who overrules all these influences. A modern scholar summarizes Ibn Ezra's attitude as follows: "The deity has delegated to the stars the governance of the sublunar world. Israel [Jews], however, enjoys a special status, which is manifest most decisively in its possession of the Torah. As long as a Jew is engaged in the study and observance of the Torah, he is linked to a spiritual realm which is itself superior to the stars. In this way a Jew may liberate himself from the decrees of the stars."
Dunash ibn Tamim (850–956, North Africa), who wrote a commentary on the Kabbalistic work
Sefer Yetzirah, wrote a treatise on astronomy which rejected astrology.
Abraham ben David of Posquières asserted the influence of the stars upon destiny, while also contending that by faith in God man may overcome this influence.
Gersonides believed that astrology was real, and developed a naturalistic, non-supernatural explanation of how it works. For Gersonides, astrology was: founded on the metaphysical doctrine of the dependence of all earthly occurrences upon the heavenly world. The general connection imparted to the prophet by the active intellect is the general order of the astrological constellation. The constellation under which a man is born determines his nature and fate, and constellations as well determine the life span of nations....The active intellect knows the astrological order, from the most general form of the constellations to their last specification, which in turn contains all of the conditions of occurrence of a particular event. Thus, when a prophet deals with the destiny of a particular person or human group, he receives from the active intellect a knowledge of the order of the constellations, and with sufficient precision to enable him to predict its fate in full detail..... This astrological determinism has only one limitation. The free will of man could shatter the course of action ordained for him by the stars; prophecy could therefore predict the future on the basis of astrological determination only insofar as the free will of man does not break through the determined course of things. Gersonides believed astrology to be a science that predicts events according to set laws of nature (albeit, a different set than the ones we are used to). He also believed that a person who has perfected his thinking could interact with the laws of nature through the active intellect. Gersonides thus thought of himself as creating a rationalist and non-supernatural theology. In this sense, there is a similarity between Gersonides and Maimonides.
Shlomo ibn Aderet—in a responsum commonly but mistakenly attributed to
Nahmanides—wrote that while one may not ask an astrologer for a prediction, astrology itself is real. He states rules that one must ultimately trust in God, and not in any lesser force, as God can perform miracles to overcome the patterns of nature. As such, he concludes that one is forbidden to ask an astrologer for a prediction, but one may act on the words of an astrologer if advice is freely given.
Nahmanides himself wrote that astrology is a real facet of nature, which astrologers can interpret but not reliably; Jews are forbidden to use astrology and instead required to consult prophets, whose word is always reliable.
Maimonides answered an inquiry concerning astrology, addressed to him from
Marseille. He responded that man should believe only what can be supported either by rational proof, by the evidence of the senses, or by trustworthy authority. He states that he has studied astrology and that it does not deserve to be described as a science. He ridicules the idea that a man's fate could depend on the constellations, arguing that such a theory would rob life of purpose and would make man a slave of destiny.
Isaac ben Joseph ibn Pulgar (14th century, Spain) was a Jewish philosopher who wrote against astrology. The ''
Arba'ah Turim, an early code of Jewish law, brings the views of Maimonides. Joseph Karo in his commentary "Beit Yosef" quotes Nahmanides, whereas in his code the Shulkhan Arukh'', he rules that consulting an astrologer is forbidden, without addressing the question of whether astrology is effective. ==18th century==