ARISTOTLE TO AUGUSTINE Alexander standing in Diogenes’ light (Rome, Villa Albani) logician Diodorus Cronos, and was a fellow pupil of Philo, who laid the ground for a development of logic which marked, in some areas, an improvement on Aristotle.13 He himself, however, was more interested in ethics It may seem surprising that a moralist like Zeno should give physics the highest place in the curriculum But for Zeno, and later Stoics, physics is the study of nature and nature is identiWed with God Diogenes Laertius tells us, ‘Zeno says that the whole world and heaven are the substance of 13 On Diodorus and Philo, see Ch below 97