Astrology and Astronomy - Overview

Overview

In pre-modern times, most cultures have not made a clear distinction between the two disciplines, putting them both together as one. In ancient Babylonia, famed for its astrology, there were not separate roles for the astronomer as predictor of celestial phenomena, and the astrologer as their interpreter; both functions were performed by the same person. This overlap does not mean that astrology and astronomy were always regarded as one and the same. In ancient Greece, pre-Socratic thinkers such as Anaximander, Xenophanes, Anaximenes, and Heraclides speculated about the nature and substance of the stars and planets. Astronomers such as Eudoxus (contemporary with Plato) observed planetary motions and cycles, and created a geocentric cosmological model that would be accepted by Aristotle – this model generally lasted until Ptolemy, who added epicycles to explain the retrograde motion of Mars. However, around 250 BC, Aristarchus of Samos postulated a proto-heliocentric theory, which would not be reconsidered for nearly two millennia (Copernicus), as Aristotle's geocentric model was favored. The Platonic school promoted the study of astronomy as a part of philosophy because the motions of the heavens demonstrate an orderly and harmonious cosmos. In the third century BC, Babylonian astrology began to make its presence felt in Greece. Astrology was criticized by Hellenistic philosophers such as the Academic Skeptic Carneades and Middle Stoic Panaetius. However, the notions of the Great Year (when all the planets complete a full cycle and return to their relative positions) and eternal recurrence were Stoic doctrines that made divination and fatalism possible.

In the Hellenistic world, the Greek words 'astrologia' and 'astronomia' were often used interchangeably, but they were conceptually not the same. Plato taught about 'astronomia' and stipulated that planetar phenomena should be described by a geometrical model. The first solution was proposed by Eudoxus. Aristotle favored a physical approach and adopted the word 'astrologia'. Eccentrics and epicycles came to be thought of as useful fictions. For a more general public, the distinguishing principle was not evident and either word was acceptable. For the Babylonian horoscopic practice, the words specifically used were 'apotelesma' and 'katarche', but otherwise it was subsumed under the aristotelian term 'astrologia'.

In his compilatory work Etymologiae, Isidore of Seville noted explicitly the difference between the terms astronomy and astrology (Etymologiae, III, xxvii) and the same distinction appeared later in the texts of Arabian writers. Isidore identified the two strands entangled in the astrological discipline and called them astrologia naturalis and astrologia superstitiosa.

Astrology was widely accepted in medieval Europe as astrological texts from Hellenistic and Arabic astrologers were translated into Latin. In the late Middle Ages, its acceptance or rejection often depended on its reception in the royal courts of Europe. Not until the time of Francis Bacon was astrology rejected as a part of scholastic metaphysics rather than empirical observation. A more definitive split between astrology and astronomy in the West took place gradually in the seventeenth and eighteenth centuries, when astrology was increasingly thought of as an occult science or superstition by the intellectual elite. Because of their lengthy shared history, it sometimes happens that the two are confused with one another even today. Many contemporary astrologers, however, do not claim that astrology is a science, but think of it as a form of divination like the I-Ching, an art, or a part of a spiritual belief structure (influenced by trends such as Neoplatonism, Neopaganism, Theosophy, and Hinduism).