Episode III-Early Modern Astrology

Early Modern Astrology
(16th and 17th century)

Kepler's Solid Model

{1} (Keplers solid model of the solar system)

{Men, tell the power of the heavens: the known may be put to our profit;
While in a field unexplored, you can see no gain or profit.
Labor resides in defeat, whereas victory will benefit richly,
Nature's power do reveal, O Mankind, by your wit.}[2]

The previous two episodes, Hellenistic Astrology and Chinese Astrology, explained how astrology was practiced and how the cosmos were believed to effect terrestrial events on Earth. It is important to keep in mind that both Hellenistic and Chinese astrology were in practice before the rise of Christianity. Philosophers from both of these time frames and locations attempted to explain the cosmos the best that they could. For example, Hellenistic astrology based its explanation of the cosmos off of Stoic, Middle Platonic, and Neo-Pythagorean thought. In layman terms, the theories of the universe based on the philosophy of Plato or Aristotle. Early Modern astrology used a model heavily saturated with Aristotelian thought and based off the Ptolemaic system, but there is a twist in the philosophy. Early Modern sciences were based ideally off Christianity. The Bible. The Church played a heavy role in what type of sciences, or theories, were considered to be correct. This is why the Copernican system was reluctant to be widely accepted.

This being said, Early Modern astrology was not practiced in the same context as Hellenistic or Chinese astrology. The underlying theme governing philosophy was Christianity and the Bible. This did not stop influential people from practicing astrology. The great minds of the 17th century were aware of some unknown force that governed the cosmos and not just some divine power, God. Galileo argued the point that the Christianity alone does not govern the heavens. In a letter to the Grand Duchess Christina he argued that the Bible is written in the language of the common person who is not an expert in astronomy. Scripture, he argued, teaches us how to go to heaven, not how the heavens go. [1]

One of the major advocates of astrology in the Early Modern period was the mathematician Johannes Kepler. Keplers best astrological work is On the More Certain Fundamentals of Astrology, which will be heavily cited through this website to illustrate how astrology was practiced in the early modern era. Kepler believed there was a connection between the cosmos and terrestrial events that occur on Earth. One difference in Early Modern astrology and Hellenistic or Chinese astrology is the way Kepler used the cosmos to make predictions, as well as "what" types of things could be accurately predicted. Kepler wrote:

Kepler believed the cosmos held certain mysteries that could be unlocked if man only understood the puzzle before him. In his introduction to this famous work, On the More Certain Fundamentals of Astrology, he said: {But gems must be gathered from the mire; the honor of God must be set off by the proposed contemplation of nature, others much be attracted by example; and we must turn our attention and bend every effort to bring to light from the shadows of ignorance those matters that once served as a distinct advantage to the human race.}[2]

Kepler declared there were two main causes that cosmos employed to effect terrestrial life on Earth. The first of these are the physical causes. The three main sources of physical causes are the sun, the moon, and the planets, in which light is the primary mechanism by which they exert their influence.[2] The physical function of the sun is to heat. Its effectiveness is influenced by three factors; the time of elevation, the nature of the atmosphere, and the angle at which the sun's rays strike the horizon. Further, one must consider the heat capacity of the Earth.[2] The physical function of the moon is to humidify. In addition to monthly moisture cycles, it also influences daily moisture cycles, as witnessed by tides. [2] The physical means by which the planets influence the earth is the light that comes down. Insofar as it is reflected light it humidifies (as with the moon), and insofar as it is radiated light it warms (as with the sun). [2]

An example Kepler uses based on these physical causes has to do with the physical cause of the moon; { I offer this warning to chemists: that the full moon appears unsuitable for the melting of metals because the air is too humid.} Early Modern astrology focus's more on the practical aspects the cosmos play on terrestrial events, such as the sun warming the earth due to it being directly overhead during summer solstice, or by using the full moon example above.

The second cause mentioned by Kepler is the geometrical causes of the cosmos. There are three major sources of geometrical causes: aspects, cycles, and planetary harmonics.[2] In these causes Kepler offers more of a mathematical view as he explains the code the cosmos attempt to relay to humans on earth. Using these two methods to conduct astrological predictions Kepler attempts to predict events that will happen in the year 1602. His book contains predictions on the weather, eclipses, crops, illness, political and military matters, and earthquakes. You can see the transition of astrology go from a mythical or magical art in ancient times to its development into a systematic scientific approach to predict practical occurrences in early modern times.