Galen and Astrology: A Mésalliance?

The author examines the question of Galen\u27s affinity with astrology, in view of Galen\u27s extended astrological discussion in the De diebus decretoriis (Critical Days). The critical passages from Galen are examined, and shown to be superficial in understanding. The author performs a lexical sounding of Galen\u27s corpus, using key terms with astrological valences drawn from the Critical Days, and assesses their absence in Galen\u27s other works. He compares Galen\u27s astrology with the astrology of Ptolemy\u27s Tetrabiblos, and evaluates their respective strategies of scientific reasoning. Three types of inference are introduced and applied to Galen\u27s astrology. Finally, he concludes that the empirical side of Galen\u27s science does not depend upon astrological methods or concepts, but that these were introduced for their rhetorical effect in presenting his new medical methodology. It is suggested that continued attention to Galen\u27s astrology has obscured the truly important empirical scientific method that Galen developed