Astrology

   Pseudoscience that sought to understand the effects of forces thought to emanate from celestial bodies (planets, moon, sun, and stars) on earthly bodies and souls. Its origins go back to the ancient Babylonians, who closely observed the movements of the celestial bodies, thus founding the science of astronomy as well as astrology, two fields that were often closely intermingled. The data observed by astronomers were recorded in tables showing the position of the planets as they appear to revolve around the earth. The whole circle of the visible heavens (the zodiac) is divided into 12 pie-shaped wedges, called "houses," and the basis for all efforts to create a real science out of astrology is that the planets appear to move in a regular and predictable pattern around the circle, spending a specific and equally predictable amount of time in each of the "houses" as they make their annual rotation around the earth. Each of the 12 segments or "signs" (for example, Capricorn, Aquarius, Pisces) of the zodiac is assumed to have certain qualities that produce effects on earthly objects. Likewise, each of the planets has specific characteristics (Mars, for example, is obviously warlike).

   The combination of these forces as a planet moves into, through, and out of one of the signs is what the astrologer attempts to study. The particular planet in ascendancy at the time of a person's birth, joined to the house or sign in which it is located at that moment, places an indelible stamp on the character of the person that affects his or her life. The effects exerted on earthly things by the various houses and the various planets are in fact purely conventional. For example, no astrologer could really offer any explanation why the planet known as Mars should have a warlike effect. Indeed, the use of ancient pagan gods for the names of the planets shows that astrology was closely linked to relics of ancient religious beliefs that no one in the Middle Ages or the Renaissance really understood.

   The most obvious application of this body of learning was in "judicial astrology," that is, the making of general or even very specific predictions about the fate of the individual seeking astrological advice. For an individual whose date and place of birth were known, specific locations of certain planets in the zodiac at the time of birth would indicate that certain dates would be favorable, and other dates unfavorable, for certain types of activity—for starting a new business, setting out on a journey, or getting married, for example.

   Since the medieval church insisted that people's moral responsibility for their own acts was based on their exercise of free will, astrological predictions of future events were inherently contrary to the church's teaching. Although in practice the clergy were just as likely to seek astrological advice as anyone else, any predictions that claimed to determine absolutely events occurring in the future were sinful and unlawful. On the other hand, merely trying to determine favorable and unfavorable days for undertaking a proposed action was theoretically no more objectionable than using meteorological conditions to pick favorable and unfavorable days. Some critics of astrology conceded that the position of celestial bodies did affect events on earth, while arguing that there was no valid way of determining what those effects were and hence no validity in judicial astrology. One of the most famous objectors to astrology, Giovanni Pico della Mirándola, raised an objection that was very difficult for astrology's defenders to refute. The notion that the celestial bodies are "superior" to terrestrial beings and hence are able to "govern" them is based on a verbal equivocation: a planet is "higher" than a human soul only in the spatial sense; in the Platonic hierarchy of being, the human soul, being spiritual, is "higher" and hence more powerful than the planet. Although predicting the future was its most obvious application, astrology was also applied in the practice of medicine. Medieval and Renaissance physicians regularly took the date of the patient's birth— and its supposed astrological consequences—into account when they made diagnoses and prescriptions. In a sense, astrology was conceived as nothing more than applied astronomy. The practice of magic employed astrological influences as one of its principal foundations.