Science and Magic Part I: Astrology

One of the earliest attempts by man to understand the universe and man’s place in it was the study of astrology.

Early History

Astrology is basically the study of the effects of the movements of the planets and the stars on human activities. The study of astrology dates back to the days of the Babylonians. Its principles were further developed by the Greeks and Romans and later in the middle ages by the Arabs. The Egyptians, Indians, Persians, and the Chinese all observed the planets and the stars in order to predict the course of present and future events whether they were personal, political, military or environmental (prediction of natural disasters).

One famous astrologer/ astronomer was Ptolemy (Claudius Ptolemaeus) who lived in the second century in Alexandria, Egypt. He codified the astrological tradition of the Babylonians and was responsible for coining such terms as “planets ascendant in a solar or lunar house” or the “Age of Aquarius.” He set out his astrological principles in his book “Tetrabiblos.” He thought that you could predict a person’s appearance and temperament by knowing the positions of the planets and the stars at the time of an individual’s birth. 

In Ptolemy’s time, there was no clear distinction between astrology and astronomy so that he also wrote about the motion of planets, the precession of the equinoxes, and atmospheric friction.  He named the stars, listed their brightness, argued that the Earth was a sphere, and set down rules for predicting eclipses. Ptolemy tried to understand why planets at times exhibit a strange wandering motion known as retrograde motion, which is the perception by an observer on Earth that a passing planet is moving backwards. This effect occurs when one planet “on the inner lane” or smaller orbit passes a slower moving planet with a larger orbit resulting in each planet “seeing” the other one as apparently moving backwards. Ptolemy’s idea of an Earth centered universe with all planets including the sun moving around it had been known for thousands of years before his time. He imagined that the planets orbiting the Earth were attached to transparent spheres via little wheels.  He built a mechanical device that demonstrated planetary motion (in fact Archimedes is reported to have built a similar device 400 years earlier). Ptolemy’s model was supported by the church for centuries and probably prevented the advance of astronomy for 1000 years.

Importance of Astrology in the 16^th century

During the 16^th century in Europe people felt powerless in a world full of famine, disease, and constant religious conflict. It is therefore of little wonder that many people sought explanations for what was happening around them in the certainty of the stars in the sky. Astrologers took advantage of people’s fears by preparing nativities (horoscopes), which predicted their future and told them what they should do.

Early “scientists” during the 16^th century postulated that the universe was comprised of 7 stars or planets that included the Sun, the Moon, Saturn, Jupiter, Mars, Venus and Mercury. These bodies constantly shifted their position in relation to the Earth against a backdrop of the stars forming the 12 signs of the zodiac. A horoscope was a map of the positions of these bodies in the heavens at some future point in time in order to predict what influence the heavens would have on any given occasion.

As strange as it may seem to us today, the doctrines of astrology at the beginning of the 16^th century in Europe was an essential part of the intellectual framework accepted by most educated people at the time. These doctrines taught that there were 4 elements earth, air, water, and fire that these were constantly combining and recombining dependent on the movements of the planets and the stars. It was believed that all physical change was comprised of the interaction of the physiological qualities of heat and cold, dryness and moisture. It was considered necessary to understand astrology in order to understand the physiology of medicine. The stars were also thought to affect plants and minerals (botany and metallurgy) as well as psychology and ethnography. Astrology pervaded all aspects of scientific thought.

Astrologers were very influential in medieval times and physicians also consulted horoscopes to know how best to treatment patients.

Paracelsus’s ideas were based on believing that god provided a remedy for every disease and that the stars influenced human behavior and destinies (astrology and alchemy were considered scientific pursuits in those days).

Types of Astrological Practice

In the 16^th and 17^th centuries, astrology or judicial astrology (since the term astrology was considered synonymous with astronomy in those days) was divided into 4 fields those of the general predictions, nativities, elections, and horary questions. General predictions took into account the movements of the heavens (including eclipses of the sun and moon) in order to forecast the weather, the state of crops, questions of mortality, epidemics, and those of politics and war. The nativities were maps of the sky at the time of a person’s birth that were created in order to predict a person’s prospects for the future. Elections were all about giving advice about choosing the right moment for the right actions by comparing a person’s horoscope with what was known about the future movements of the heavens, Horary questions,  the most controversial of the services offered by the astrologer, were based on the state of the heavens at the time of the “birth of the mind.” For instance if a person had a medical question he would provide the astrologer with a sample of urine and the astrologer’s answer would be his interpretation of the sky at the moment the urine was voided. However, every personal question could be answered as a horary question. (see Religion and the Decline of Magic by Keith Thomas. Penguin Books, London, 1971. pp 337-347)

Famous Practitioners of Astrology

Astrologers (those practicing astrology and preparing horoscopes) at first only consulted kings. Astrologers  were very influential in medieval times e.g. monarchs such as Elizabeth I had her own astrologer, John Dee. Other famous scientists were also astrologers including Tycho Brahe, Johannes Kepler and even Galileo Galilee.  Physicians also consulted horoscopes to know how best to treatment patients (e.g. William Harvey the discoverer of blood circulation). Other 17th century scientists who believed or practiced astrology included Edmund Gunter the mathematician, and Henry Oldenburg (a president of the Royal Society). Isaac Newton also had an interest in astrology as a young man and it might have been his interest in astrology that led him to astronomy

Up to the 18^th century the heavens and the universe were viewed as the perfect creation of god. However it became increasingly difficult to defend this idea due, for instance, to the discoveries of sunspots and that the surface of the moon was not smooth but riddled with craters by Galileo, and the observation by Tycho Brahe that comets traveled higher than the moon when passing over the Earth. This indicated that the universe was corrupt and changeable. Edmond Halley showed that the appearance of comets in 1531, 1607, and 1682 were all the same one and he correctly predicted that the next appearance would be in 1758.

Modern Attitudes and a Criticism of Astrology

Even today according to a Gallup poll held in 2005 based on telephone calls to around 1000 people, approximately 25% of Americans  believe that the position of the stars and planets can affect people’s lives. There are according to Carl Sagan, 10,000 astrologers in the US and approximately 3000 astronomers and in France more astrologers than Roman Catholic clergy (see the Demon Haunted World by Carl Sagan, Ballantine Books, NY 1996 pp 302-304). These numbers fly in the face of the fact there is no evidence that astrology works. Other facts call astrology into question e.g. the constellations of stars identified to be important in determining horoscopes have changed their positions over time (over 30 degrees). For instance, the original position of the constellation Aries in ancient Greece was pinpointed at its position at the spring equinox. However over the millennia since that time, the sign of Aries is no longer where it originally was. Astrologers however continue to calculate horoscopes based on the old position rather than allowing the position of Aries to move with the equinoxes.

In addition, the only planets that are considered by astrologers are those that can be seen with the naked eye. They do not take into account any newly discovered astronomical objects (e.g. near earth asteroids). Astronomers are inconsistent with the information they require to calculate the position of stars and planets at the time of a subjects birth e.g. the time at birth is taken into consideration but not the latitude and longitude of where a person was born (since this would also affect the observed position of the planets). It has been shown that different astrologers make different predictions when given the same data to start,that there is a lack of correlation of predictions for identical twins, and no correlation has been shown between horoscopes and psychological tests such as the Minnesota
Multiphasic Personality Inventory.

The popularity of astrology may have something to do with the selective bias of people who have horoscopes done i.e. that they tend to remember predictions that confirm what they want to believe and conveniently forget those predictions that are false. Perhaps one can consider belief in astrology as somewhere between religion and psychotherapy.

References:

• Science in Medieval Islam by Howard R. Turner. University of Texas Press, Austin1997. pp 108-111
• Cosmos by Carl Sagan. Random House, New York 1980. pp 48-51
• Religion and the Decline of Magic by Keith Thomas. Penguin Books, London, 1971. pp 337-347