This is a post-Aristotelian Greek philosophical text, written at a crucial moment in the defeat of paganism by Christianity, AD 529, when the Emperor Justinian closed the pagan Neoplatonist school in Athens. Philoponus in Alexandria was a brilliant Christian philosopher, steeped in Neoplatanism, who turned the pagans' ideas against them. Here he attacks the most devout of the earlier Athenian pagan philosophers, Proclus, defending the distinctively...