“Kepler’s approach to astrology was the same as his approach to his beloved science of harmonic astronomy: he urged that “One must separate the precious stones from the dung, one must glorify the honor of God, by taking for one’s purpose the contemplation of Nature.” Thanks to Max Caspar and the writings of Arthur Koestler, we can determine precisely what Kepler considered the dung and which he thought to be the precious stones. The “dung” he considered:
* acceptance of a qualitative distinction for the twelve signs of the zodiac
* relationship of these signs calculated along the ecliptic to circumstances, ties and fortune
* differentiation between good and bad aspects
* division of lands, human limbs and the four elements among the zodiac signs
The “precious stones” were the planets themselves and the angles or aspects they formed with each other. …
Kepler believed in an “effectus generalis,” a general influence of the planets on nature and man, which had nothing to do with the rules by which the Arabic art of prophecy pledges to predict the individual fates, the “eventus individui.” His description of the degree of control of the planets over human nature firmly establishes a person’s character but has no power to predict individual events; on the one hand determining the fixed nature, but leaving the destiny of the individual as a natural outcome of the behavior of their “type.” The stars do not compel or override free will, nor decide the fate of the individual, but they impress upon the soul a special character…” Planetary Types: the Science of Celestial Influence p.49