 The unfinished Disputations is a long and unwelcoming book, made all the more forbidding by its ragged presentation and reliance on so many obscure and technical sources; much of it repeats and reinforces ancient and medieval objections to astrology. Pico extends Ptolemy’s doubts about a few astrological practices, for example, into a broader restriction on celestial influences, which he finds either too diffuse or too slight to be the basis of precise predictions. He exposes the claims made by astrologers who often contradicted themselves and violated the canons of reason and experience that the sciences must rely upon. The logical, methodological and epistemological complaints compiled by Pico had been well known since before the ancient sceptics recorded their objections. Pico’s real breakthrough was to use humanist philology as a new weapon against astrology, which he does not reject categorically.