"The medieval addiction to astrology is not merely a sign of "failure of nerve". According to Aristotle, everything that happens in the sub-lunary world is caused and governed by the motions of the heavenly spheres. This tenet served as a rationale for the defenders of astrology, both in antiquity and the Middle Ages. ...In the absence of quantitative laws and causal relations, the Aristotelian... proceeded by deduction from analogies, which were often metaphorical, or allegorical, or purely verbal."