Podcast episode

Episode 127: Dorian Greenbaum on Porphyry and Astrology

Porphyry does some stargazing. Detail of an image from Maître François, Paris, ca. 1475, Augustine, La Cité de Dieu (vol. 1), no. 403, fol. 437v. Thanks to the Nederlandse Koninglijke Bibliotheek.

We are delighted to speak with Dorian Greenbaum, a leading historian of ancient astrology who has devoted special attention to Porphyry’s thought. We begin our interview with your host doing a recap of the various theoretical frameworks underlying practical astrology in our period – including hard fatalism, ‘soft’ or mitigated fatalism, the acausal signs theory , and the naturalistic chain-of-causes theory, following Aristotle; Dr Greenbaum then nuances and corrects this attempt at a general survey, bringing the SHWEP up to date on astrology in the Græco-Roman world (for now).

Having reminded ourselves of where we are in the history of Hellenistic astrology in the third century, we then turn to Porphyry. What kind of an astrologer is Porphyry? We discuss the sources we have for Porphyry’s astrological doctrine, most of which are fragmentary; the one that isn’t, the Introduction to Ptolemy’s Tetrabiblos, is attributed to Porphyry in the manuscript, but seems to be the product of a messy text-history. nevertheless, we can say a few things. We have no solid reason to think that Porphyry was casting horoscopes. That said, for Porphyry, astrology is important. It provides a way of mapping the kosmos through which the soul must descend into the body, and tells us about the various planetary influences that the soul thereby acquires (okay, it’s not the soul, it’s the soul’s pneumatic vehicle that takes on these planetary accretions). It also allows us to find out, whilst embodied, the nature of our guardian daimōn, a crucial bit of information for a Platonist philosopher.

Interview Bio:

Dorian Greenbaum is a historian of later antiquity, of ancient and modern astrology, and of the various interstices between these fields. Her PhD thesis (Warburg Institute) has now become the monograph The Daimon in Hellenistic Astrology: Origins and Influence, published with Brill. She currently teaches on an MA in Cultural Astronomy and Astrology at the University of Wales, Trinity St David. She has published widely on the history of astrology and related matters, some of which can be found in the Recommended Reading section below.

Works Cited in this Episode:


  • Iamblichus on the oikodespotēs: De myst./Response to Porphyry 9.7.11–12.
  • Plato on choosing the personal daimōn before incarnation: R. X 620d8-e1: ἐκείνην δ᾽ ἑκάστῳ ὃν εἵλετο δαίμονα, τοῦτον φύλακα συμπέμπειν τοῦ βίου καὶ ἀποπληρωτὴν τῶν αἱρεθέντων.
  • Porphyry: Most of the texts discussed in this interview are fragmentary, and can be found in Smith 1993 (see below). For the Introduction to the Tetrabiblos, which seems to have at least some Porphyrian content, see Emilie Boer and Stefan Weinstock, editors. Porphyrii philosophii introductio in tetrabiblum Ptolemaei. Number V.4 in Catalogus codicum astrologorum graecorum. Lamertin, Brussels, 1940.
  • Vettius Valens on the two different outcomes which happened to the dancer: Anthology V.6.121–125.


  • Crystal Addey. Divination and Theurgy in Neoplatonism: Oracles of the Gods. Ashgate, Dorchester, 2014.
  • Geoffrey Cornelius. The Moment of Astrology: Origins in Divination. Wessex Astrologer, Bournemouth, 2003.
  • David Pingree. Antiochus and Rhetorius. Classical Philology 72, no. 3, 1977, pp. 203-23.
  • James Wilberding 2011: see below.

Recommended Reading:

  • Luc Brisson, Gwenaëlle Aubry, M-.H. Congourdeau, and F. Hudry, editors. Porphyre: Sur la manière dont l’embryon reçoit l’âme. Histoire des doctrines de l’antiquité classique. Paris, 2012.
  • Dorian Greenbaum. The Daimon in Hellenistic Astrology: Origins and Influence. Brill, Leiden/Boston, MA, 2016, esp. 236-78, 439-45.
  • Ibid. Porphyry of Tyre on the Daimon, Birth and the Stars. In Luc Brisson, Seamus O’Neill, and Andrei Timotin, editors, Neoplatonic Demons and Angels, pages 102–39. Brill, Leiden/Boston, MA, 2018.
  • Aaron P. Johnson. Astrology and the Will in Porphyry of Tyre. In Anna Marmadoro and Brian D. Prince, editors, Causation and Creation in Late Antiquity, page 186–201. Cambridge, 2015.
  • László Levente. Revisiting the Authenticity of Porphyry’s Introduction to Ptolemy’s “APOTELESMATICS”. Classical Philology, 116(3):392–411, 2021.
  • H.D. Saffrey and A.-P. Segonds, editors. Porphyre: Lettre à Anébon l’Égyptien. Les Belles Lettres, Paris, 2012.
  • Andrew Smith, editor. Porphyrius: Fragmenta. Teubner, Leipzig, 1993.
  • Andrei Timotin. La démonologie platonicienne. Histoire de la notion du daimōn de Platon aux derniers néoplatoniciens. Number 128 in Philosophia Antiqua. Brill, Leiden/Boston, MA, 2012.
  • James Wilberding, editor. Porphyry: To Gaurus on How Embryos are Ensouled and On What is In Our Power. Ancient Commentators on Aristotle. Bloomsbury, London/New Delhi/New York, NY/Sydney, 2011.
  • Idem. The Myth of Er and the Problem of Constitutive Luck. In Anne Sheppard, editor, Ancient Approaches to Plato’s Republic, volume 117 of BICS Supplement, pages 87–105. London, 2013.


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