This talk was delivered on November 9, 2021 at the University of Edinburgh. For information on upcoming events, please visit our website at www.thomisticinstitute.org. About the speaker: John M. Rist was educated in classics at Trinity College, Cambridge. He taught Greek at University College in the University of Toronto from 1959 to 1969 and from 1969 to 1980 was a professor of classics at the University of Toronto. He taught from 1980 to 1983 as Regius Professor of Classics at the University of Aberdeen, and returned to the University of Toronto, where he was professor of classics and philosophy from 1983 to 1996, with a cross-appointment to St. Michael's College from 1983 to 1990. In 1997, Rist became professor emeritus of the University of Toronto in 1997. He has been part-time visiting professor at the Institutum Patristicum Augustinianum in Rome since 1998. In 1976 Rist was elected a Fellow of the Royal Society of Canada, and in 1991 he was elected a life member of Clare Hall, Cambridge. In 1995 he was the Lady Davis Visiting Professor in Philosophy at the Hebrew University in Jerusalem. Professor Rist has written more than 100 scholarly works, including the following books: Man, Soul and Body: Essays in Ancient Thought from Plato to Dionysius (1996), Augustine: Ancient Thought Baptized (1994), The Mind of Aristotle (1989), Platonism and Its Christian Heritage (1985), Human Value: A Study of Ancient Philosophical Ethics (1982), On the Independence of Matthew and Mark (1978), The Stoics (1978), Epicurus: An Introduction (1972), Stoic Philosophy (1969), Plotinus: The Road to Reality (1967), and Eros and Psyche: Studies in Plato, Plotinus and Origen (1964). He is the author of more than 80 articles on ancient Greek philosophy, Hellenistic philosophy, Plotinus and Neoplatonism, Patristics, and medieval philosophy.