Ptolemy's Universe

Book excerpt: Claudius Ptolemy, one of the greatest scientists of all time, probably lived in Alexandria in the second century A.D. His writings dominated astronomy and cosmology in medieval times. The replacement of his Earth-centered cosmology by the Sun-centered cosmology of Copernicus is the most celebrated event in the history of science. Yet, although there has been much scholarly discussion of the mathematical aspects of Ptolemy's astronomy, little attention has been paid to the philosophical, and particularly the ethical, ideas which animate the astronomy. Ptolemy's Universe is the first modern examination of Ptolemy's thought as a whole, and its place in Greek intellectual culture.