Dorian Greenbaum, historian of astrology and philosophy, discusses astrology in Porphyry and situates it within the history of astrology. They explore the diversity of astrology in the Hellenistic period and the concept of the soul's passage through celestial spheres. The podcast also delves into Porphyry's theory of astrology, including finding the personal daimōn, and the diamond metaphor in Plato's works.