" Thus only the pattern is cosmically determined, not any particular event; within that pattern, man is free. In his later years, this Gestalt concept of cosmic destiny became more abstract and purified from dross. The individual soul, which bears the potential imprint of the entire sky, reacts to the light coming from the planets according to the angles they form with each other, and the geometrical harmonies or disharmonies that result - just as the ear reacts to the mathematical harmonies of music, and the eye to the harmonies of colour. This capacity of the soul to act as a cosmic resonator has a mystic and a causal aspect: on the one hand it affirms the soul's affinity with the anima mundi, on the other, it makes it subject to strictly mathematical laws. At this point, Kepler's particular brand of astrology merges into his all-embracing and unifying Pythagorean vision of the Harmony of the Spheres. "

― Arthur Koestler , The Sleepwalkers: A History of Man's Changing Vision of the Universe