Astrology: Claudius Ptolemy’s Dubious Legacy

The geocentric Ptolemaic system of the univers...

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Astrology began as a form of divination, originally not so distinct from Astronomy as it is today, and is historically thought to have been invented by the Assyrians and Chaldeans about three millennia ago, culminating in the contributions of the “father of astrology,” Claudius Ptolemy in 150 C.E. in the reference work used by today’s Western astrologers, the Tetrabiblos.

Astrology’s central claim is that the relative positions of celestial bodies in the sky at the time of one’s birth have a real and measurable effect on one’s psychological makeup and destiny, a claim that has not stood up well to evidential scrutiny. Despite the fact that millions of people around the world believe in it, and have for thousands of years, there is no plausible, empirically testable mechanism by which it would work, and most of the evidence to date shows that it has no causative correlation to how we understand ourselves and our role or position in the universe at large.

Physics currently knows of only four fundamental forces: electromagnetism, gravity, and the strong and weak nuclear forces. Of these four, the last two have zero effect outside of an atomic nucleus, and the first two fall off in strength with the square of the distance from the source.

Of these, electromagnetism can be blocked or interfered with by various sorts of matter, which leaves gravity the most often cited as the source of astrological influences.

Let’s look closer at this: the Moon’s gravity causes tides, and humans being about 70% water, astrologers try to argue that these tidal forces also affect the water bound up in human bodies. I’m sure this is true, but the real question is whether it significantly affects humans, and whether this involves any effect on one’s personality from the moment of birth.

First, lunar tidal forces only notably affect fairly large bodies of water, such as really big lakes and up, and taking the law of universal gravitation into account, the obstetrician delivering a newborn has a much greater gravitational effect on the infant than does the moon or any other body in the solar system save the Earth itself.

As well, if gravity is the force of astrological influence as some claim, why don’t black holes, quasars and neutron stars, some of the most massive, gravitationally powerful objects in the universe exert their influence on our personalities and lives as well? Why do astrologers ignore them?

The planet Neptune was discovered by way of predictions made concerning its gravitational effect on Uranus’ orbit, and observations made using those predictions enabled us to find it.

If astrology is a science, why has it never discovered any previously unknown celestial objects by way of their astrological effects alone? What about a new force, unknown to science? It is certainly possible that some currently undiscovered force exists, but until it is actually detected, it’s existence is nothing more than an untested postulate, and is not acceptable as a viable mechanism for astrology.

There are a number of flaws in the original stellar observations and knowledge of those who wrote the manuals used by astrologers, errors which modern astrology has not seen fit to correct: Contrary to the beliefs of Ptolemy’s day, the Earth is not at the center of the Universe, nor are the motions of the planets overlapping circles, nor the sky a crystal dome and the Universe comprised of concentric crystal spheres in which the planets, moon or sun are imbedded.

Further, Ptolemaic astronomers knew of far fewer celestial objects than we know of today. They did not know about the planets Uranus, Neptune and the minor planets Pluto and Eris as well as a grunchload of planetary moons, their influence disregarded by all but the most workaholic astrologers.

It has been claimed that a horoscope must be cast for the year, month, day and time of day, as well as an individual’s geographic location of birth, but the data used in astrological charts for casting horoscopes today are flawed, as accurate methods of telling time have only been developed in the last few centuries, and the data derive from when the original charts were made and such means of telling time did not exist.

Also, since the writing of the Tetrabiblos, the axis of our planet has deviated so that the zodiacal constellations have shifted to the West about thirty degrees from their original locations given in Ptolemy’s book, and modern astrologers have not attempted to compensate for this. The ancient constellations of the zodiac no longer match up to their original locations in the sky, and in the modern zodiac, not officially recognized by astrologers, Ophiuchus, the Serpent-bearer, is the thirteenth sign, from November 30 to December 17, taking up a good chunk of Scorpio’s time, now November 23-29.

Farnsworth (1937) was unable to find any correspondence between artistic talent and either the ascendant sign or the sun in the sign of Libra for the dates of birth of 2,000 famous musicians and painters.

In 1941, Bok and Mayall were unable to find any predominance of any single sign of the zodiac among scientists listed in the American Men of Science directory.

In 1973, Barth and Bennett attempted a statistical study as to whether more men who had chosen a military career had been born under the influence of the planet Mars than those who had chosen non-military careers. No such correlation was found.

McGervey (1977) used a huge number of birth dates of politicians and scientists (6,475 & 16,634 respectively…) born on each day of the year and could find no relationship between their careers and astrological signs.

Further, in 1978, Bastedo did a statistical analysis to find out if those with such characteristics as leadership ability, political leanings, intelligence and 30 other variables often attributed to astrological influence would cluster on certain birth dates under signs that are said to govern those traits, and in a 1,000 person, cross sectional, stratified sample taken from the San Francisco Bay area, the results were completely negative.

The late Carl Sagan once commented, “Nothing will ever put astrologers out of business,” and considering that former president Ronald Reagan consulted an astrologer during his two terms in office, often on matters of state, it appears to me that maybe, just maybe, it’s astrologers, not the stars, who wield the real influence.

(Last Updated: 2011/09/18 – Image Updated/Links Added/Tags Added/No Other Changes)


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