Astrology

Abstract

The inclusion of a chapter on astrology in an intellectual history of Byzantium needs some justification. Astrology is widely perceived by intellectuals today, and especially by exact scientists, as a mindless superstition, and plenty of support for dismissing it as unscientific can be found in ancient and medieval literature too. Most Byzantine statements on astrology by non-astrologers are derisive as well as critical, perhaps the most memorable and eloquent being Niketas Choniates’ reports of the consistently wrong astrological predictions in which the emperor Manuel I Komnenos (1143-1180) naively believed, and on which he persistently based his policies. Yet Manuel wrote a treatise in Defense of Astrology, and whatever its intellectual merits, this treatise was at least an intellectual exercise. Astrology had an enduring appeal at all levels of society because it used scientific methods and could be explained according to accepted scientific theories. It was impossible to practice astrology without a basic knowledge of astronomy; apart from the construction and correction of calendars, astrology was the only practical use to which the study of astronomy could be put. The great second-century synthesizer of ancient astronomy, Ptolemy, assumed that the two went together and, in addition to his astronomical works, produced a treatise on astrology, the Tetrabiblos. The calculation of horoscopes depended on the exact mapping of the heavens at a given moment with arithmetical and geometrical precision; astrologers were frequently referred to as “mathematicians” (mathematikoi). The interpretation of a horoscope was a game of skill and judgment, which involved both the application of a rigorous logic and the consideration of many variables. It drew on the entire range of cosmological theories produced by the religious and philosophical systems of antiquity. It originated in Babylonian and, to a lesser extent, Egyptian religion, and its basic doctrine of planetary influences was linked to the identification of the planets with the Olympian gods Hermes (Mercury), Aphrodite (Venus), Artemis (Diana - the Moon), Apollo (the Sun), Ares (Mars), Zeus (Jupiter), and Kronos (Saturn). It was based on the Stoic theory of cosmic sympathy, the idea that all the parts of the universe were interconnected and danced to the same tune. It shared the Pythagorean obsession with number symbolism and adopted Aristotle’s theory of matter.