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A Brief History of Astrology
Chaldeans -> Greeks -> Ptolemy

Justifying Astrology to the Educated

You might wonder what an erudite man/they of science, history and self-cultivation is doing playing around with the seemingly disreputable Astrology. What is my justification for this strange relationship?

In this time of antagonistic polarities, I firmly believe that it is necessary to bridge the gap — reach across the aisle — in order to heal the greater organism, which is our world. With healing in mind, it is important to understand and respect the beliefs of our self-identified opponents. One antagonism is between the so-called New Agers and those with a supposedly scientific mentality. It doesn’t need to be. The hostility is unnecessary.

Fundamentalists, both spiritual and scientific, block any real discussion. Due their dogmatic biases, they look down upon the other as misguided sinner who is going to hell or as a superstitious, ignorant fool. This series of essays on astrology is not for either of these judgmental groups. Rather it is aimed at those open-minded and tolerant human beings who would like to get along with their neighbors. Getting along entails becoming acquainted with the beliefs that motivate and provide comfort for our fellow humans in these difficult times.

Astrology is one of those bizarre dividing lines that frequently divides the educated from the rank and file. Many create rigid unbridgeable Platonic categories to identify Us and Them: either for or against, either superstitious or logical. The educated, although secretly fascinated, are bound by group dogma to deny their curiosity to avoid being looked down upon by their Tribe.

Lest you think this topic trivial: Astrology is based in a rich historical cultural tradition and is an enduring feature of Western civilization. Indeed, many scholars feel that Plato’s support for astrology was instrumental in its acceptance by the Greek population. Further, Ptolemy’s accurate mathematical models of planetary motion ultimately led to modern science. Some even believe that the mechanistic nature of his astrology-inspired models contributed to the rise of monotheism, predestination and the scientific determinism that is so prevalent today. So if the foundations of Western Civilization fascinate you, read on.

An Introduction to Astrology: her History & Philosophy

A prevalent mindset, especially among the educated, holds is that we live in an impersonal, material Universe. This perspective is based upon the limited insights of the physical sciences.

An alternate viewpoint holds that there is some kind of divine order. While there is no scientific evidence in this regard, Science has been unable to invalidate this perspective either. Ultimately, it is a matter of personal preference which viewpoint we adopt.

The divine order finds its practical manifestation in astrology, the study of the heavenly bodies and their symbolic application to human personality and destiny. Many believe that the divine order is reflected through the celestial bodies that surround us. Scientists observe and experiment to discover the hidden order of the heavens. Astrologers observe the stars to see how this regularity relates to the order of our lives.

Rather than debate the pros and cons of star-based divination, the object of this trio of essays is to introduce you the Reader to Astrology — first, its background history (this article), second, its underlying philosophy according to Greeks (the subsequent article) and third, a comparison of modern and ancient astrological practises (the final article of the series). Let’s start with the history.

The Crucial Importance of Ptolemy’s Tetrabiblos

Claudius Ptolemy’s work, the Tetrabiblos, (2nd century CE) represents both an end and a beginning for astrology. The book presents a comprehensive system of divination that synthesizes the ancient attitudes towards the heavens as a divine symbol. We employ the exact same astrological system nearly two millennia later. In this way, Ptolemy’s system is the end of historical development and the beginning of modern astrology.

“The first modern astrological textbook, the Tetrabiblos, is attributed to the great astronomer, mathematician, and geographer Claudius Ptolemy, who was born in Alexandria. Ptolemy, one of the leading intellectuals of his day, worked between AD 150–180 establishing principles of cosmic influences that lie at the heart of modern astrological practices. “ (Parker, p16)

Because this book has supplied many of the foundations of astrology, it will serve as the center around which this paper will revolve.

Ptolemy in Alexandria recorded the astrological synthesis that occurred at this time of the Chaldean, Greek, and Egyptian star systems. Not only did he record the techniques by which this new simplified method could be achieved, but he also argued the case for astrology in an extremely clear and systematic way. This multi-cultural synthesis by Ptolemy has proved so vital that his landmark book was considered an astrological bible until the 15th century (Ptolemy, X, introduction by Robbins).

The Tetrabiblos, although its emphases are different and certain astronomical details were as yet unknown and hence misunderstood at that time, remains perfectly relevant to the foundation of modern astrology. It included all the tools of the contemporary astrologer, i.e., the horoscope, the zodiac, the planets, the houses, and the angles or aspects. Ptolemy’s Tetrabiblos acts as a switch in time, reflecting an ancient order and supplying a modern foundation.

The Confused State of Astrology before Ptolemy

To appreciate the importance of Ptolemy’s Tetrabiblos, we must witness its transit in history, i.e. what led to its becoming and what has become of the system he formulated. First what was astrology before Ptolemy? Ptolemy says:

“We shall decline to present the ancient method of prediction, which brings into combination all or most of the stars, because it is manifold and well-nigh infinite, if one wished to recount it with accuracy.… Besides, it depends much more upon the particular attempts of those who make their inquires directly from nature than of those who can theorize on the basis of the tradition; and furthermore we shall omit it on account of the difficulty in using it and following it.” (Ptolemy, p 227)

He seems to consider his system a simplification of older systems. He justifies his simplification on the grounds that it is easier to follow and based upon a more consistent foundation. In support of his claim, Ptolemy makes the further point that the older systems are based upon natural observation and the diviner’s talent. His system of astrology supposedly avoids this problem because it is built upon recorded planetary positions combined with a plausible theory. Maybe these dual aspects of simplification and consistency are the reasons why Ptolemy’s system has survived while the other systems have become extinct.

Note that his system requires less natural observation than the older systems. We shall come back to this point when we talk about modern astrology, which uses no naturalistic observation.

Chaldean Divination lays Basis of Horoscope-based Astrology

The ancients all had their methods of divination but it is thought that the Chaldeans of Babylon with their two systems, i.e. liver divination and star-gazing, laid the true foundations of Ptolemy’s horoscope based astrology. (Lindsay, p.9) The practice of liver divination was motivated by specific questions, whose answer was revealed by the nature of the liver at the moment of sacrifice.

“The Babylonian diviner somehow felt that the blow of the sacrificial knife linked the victim with the whole universe in a sort of lightening stroke.” (Lindsay, p.26)

This sense of the importance of the moment is carried over into astrology where the moment of birth has ultimate significance. As evidence of the connection, Ptolemy devotes a section of his introduction to the justification of this notion of a starting point, katarche. He also stresses the importance of the exact moment of birth, necessary to “the fraction of the hour of the birth.” (Ptolemy, p.228) The significance of the sacrificial moment becomes linked to the moment of birth.

Chaldean liver divination had a personal characteristic that was determined by the individual destiny of those performing the sacrifice or posing the questions. Their second system of divination, through the stars, had a more general nature. It dealt with the heavenly bodies in relation to the national destiny; this concerned itself primarily with the undertakings of the ruler.

The phenomena of primary interest were those most readily observable, i.e. eclipses, the relation of the sun and moon, and the appearance of the sky in general. Because the eclipse was the most dramatic of the celestial phenomena it came to have special significance. Its appearance portended danger. (Lindsay , Page 3)

With this interest in the sky as an omen came the need for detailed recording and observation of the positions of the heavenly bodies

“Archaeological excavation confirms that early in the first millennium BC accurate knowledge existed of the Sun’s annual course, of the phases of the Moon and of the periodicities of certain planets.” (Encyclopedia Britannica p. 640)

The ability to predict planetary position based on calculations was the primary step that allowed astrology to become a universal tool for divination. Prior to this, the astrologer was dependent on a clear sky for his forecasts. Prediction was the first step away from naturalist observation towards an increasingly heavy reliance on ephemerides, tables of planetary positions.

The ability to predict planetary position was based on a deeper understanding of the mechanics of the celestial bodies. Let it be stressed that in the study of the sky as a divine symbol that interpretation of the symbol can only go as far as the knowledge of the symbol itself. For this reason, the technology of astronomy and the art of astrology have proceeded hand-in-hand. We see time and again changes in astronomical theory preceding an astrological innovation. This relationship is manifested most clearly in the case of Ptolemy who was the foremost authority of his day (and for over a millennium) in both astronomy and astrology.

Ptolemy’s Debt to Chaldean Astronomy

Ptolemy’ system reflects the Chaldean emphases. For instance he stresses the primary importance of the national destiny in considering the total effect of the stars.

“Prognostication by astronomical means is divided into two great and principal parts. … that which relates to whole races, countries, and cities, which is called general, and the second and more specific is that which relates to individual men. … And since weaker natures always yield to the stronger, and the particular always falls under the general, it would by all means be necessary for those who purpose an inquiry about a single individual long before to have comprehended the more general considerations.” (Ptolemy, p. 119)

In Ptolemy’s astrology, just as for the Chaldean diviners, the heavens come to stand first for general matters, such as the nation, and only second for individual matters. Further, the individual must be considered in relation to the general.

In Ptolemy’s astrological system, eclipses still have an important role. And they are still considered to be dangerous, just as in the Chaldean system.

“The positions most dangerous and hardest to avoid are those in which either of the luminaries is possession of the place of the eclipse, or the degree opposite.” (Ptolemy, p.191)

Additionally, the eclipse even comes to have significance as the starting point or horoscopal birth point for a nation or world, just as the time of birth would for an individual. The eclipse becomes the sacrificial moment for the earth.

Astrology from Chaldea to Alexandria

The Chaldeans didn’t practice individual astrology until late in their astrologic history. In fact, it is likely that the astrological establishment actually looked down on this new development.

“Some sections of astrologers remained contemptuous of the petty applications. Strabon, late first century: ‘A settlement is put apart for the local philosophers called Chaldeans, who are chiefly devoted to the study of astronomia. Some, not approved by the rest, profess to understand genethliology or the casting of nativities.”

Be this as it may, the first horoscopes are Babylonian, from the fifth century BCE. The earliest Greek horoscopes arise four centuries later, from the first century BCE (Neugebauer & Van Hoesen, p. vii). It is suggested, by at least Lindsay, that when the court astrologers of the Chaldeans were deposed from power by the Persian invaders that they turned their attention from the royal astrology of the state to the individual astrology of horoscopes. (Lindsay, p.75)

While it took a foreign invasion to turn the Chaldeans to individual astrology, it took Alexander’s world conquest to spread astrology to the rest of the world, i.e. Greece, Rome, Egypt and India. Although astrology was known in the Greek city-states before Alexander (probably through the efforts of a few wandering astrologer-mathematicians), it is thought that the cultural mixture resulting from Alexander’s conquests is what really brought astrology to the Hellenistic masses. Instead of rejecting the Chaldean priesthood, as had the Persians, Alexander actually favored them and honored their institutions. (Lindsay, p. 59)

After Alexander’s conquest, the seaport of Alexandria on the Nile delta came to have great cultural significance. In talking about the development of astrology, Lindsay says,

“The main impetus came from the Babylonians, and was developed by Greek mathematical astronomers, but the Egyptians made certain contributions, especially in the matter of time-division and on the iatro-mathematical side. Clearly there was a welter of influences in the third century BC; and since Alexandria was the great cultural center of the Hellenistic age, much of the development must have gone on there.” (Lindsay, p214)

The cultural mixture of Alexandria transformed Chaldean astrology into a new type of divination — a tri-cultural synthesis. Ptolemy both developed and recorded the culminating form of this mixture early in the Common Era.

In reviewing the historical forces behind Ptolemy’s astrological system, we have seen that the Chaldean tradition supplied the mainstream of the astrologic-astronomical system. However, its emphasis was somewhat different than Ptolemaic astrology. Chaldean astronomia was 1) more general, involved with nations and kings, and 2) based on a less sophisticated cosmic system.

The astrological transition probably began in the 3rd century BC in Alexandria, where as a result of Alexander’s conquest, a cultural synthesis occurred between Chaldean, Greek, and Egyptian astronomical systems. Ptolemy wrote the textbook of the most advanced form of this Alexandrian astrology, basing it on a mathematically based cosmic model. We continue to employ Ptolemy’s enduring astrological system two millennia later in the 21st century.

Why has astrology persisted for so long, despite lacking a scientific basis? Could astrology just be the reflection of our human predilection for projecting order on random events? Or could it be that the planetary configurations really do reflect and communicate some kind of divine correspondences? Does it really matter?

Regardless of true or false, astrology can be fun — a harmless way of forming a relationship with our planetary neighbors — a different kind of language for understanding reality. It can also be motivational as when it identifies time of action.

The next articles in the series:

II. Astrological Philosophy of the Greeks: Plato, Ptolemy & Plotinus

III. Ancient vs. Modern Astrological Practices

Astrology Articles


Muse-driven: Quieting the Mind, Listening to my Little Voice & Following her Directive.

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