In the fifth century A.D., Proclus served as head of the Academy in Athens that had been founded 900 years earlier by Plato. Proclus was the last great systematizer of Greek philosophy, and his work exerted a powerful influence in late antiquity, in the Arab world, and in the Renaissance. His treatise On the Eternity of the World formed the basis for virtually all later arguments for the eternity of the world and for the existence of God; consequently, it lies at the heart of neoplatonic philosophy and the controversy between pagans and Christians at the end of antiquity.

Proclus's...