John Dillon MRIA, philosopher

Professor Dillon, although by training a Classical scholar rather than a philosopher, focuses his research interests on the philosophy of Plato and the development of the Platonic tradition.

2025 marks twenty years since the RIA and the Higher Education Authority established the Gold Medals to acclaim Ireland’s foremost thinkers in the humanities, social sciences, and across the fields of science. The Gold Medals have become the ultimate accolade in scholarly achievement in Ireland. Since 2005, 34 medals have been awarded. In recognition of this important milestone, past RIA Gold Medals recipients have contributed blogs focusing on their research to our Members’ Research Series.

I have been gradually pursuing the phenomenon of Platonism back to its roots…. meditating on the process by which Plato’s rather open-ended philosophizing solidified, over the centuries, into a fairly rigid scholastic structure.

John Dillon MRIA, Regius Professor of Greek (Emeritus), Trinity College Dublin. He was awarded the RIA Gold Medal in the Humanities in 2005.

I am by training a Classical scholar rather than a philosopher, so that my area of expertise might be reckoned as belonging more to the history of ideas than to philosophy proper. I have also taken an interest in, and down the years written a number of articles on, the role and status of the philosopher in ancient Greco-Roman society, and on other aspects of Classical antiquity.

For my doctorate at the University of California, Berkeley, I turned my attention to an obscure and much-maligned Neoplatonist philosopher, the Syrian Iamblichus of Chalcis, and produced an edition of the fragments of his Platonic commentaries, which was published by Brill in 1973. Over the years, with the co-operation of colleagues, I produced editions of various of his other works: On the Pythagorean way of life, with Jackson Hershbell (SBL, 1991); De anima, with John Finamore (Brill, 2002); De mysteriis, with Emma Clarke and Jackson Hershbell (Brill, 2004); and Iamblichus of Chalcis: the letters, with Wolfgang Polleichner (SBL, 2009).

My chief area of research is in the philosophy of Plato and the development of the Platonic tradition of philosophy, extending from his immediate successors in the so-called ‘Old Academy’, through the period of ‘Middle Platonism’, dating from around 80 bc to ad 240, to the ‘Neoplatonic’ period and beyond, into the Middle Ages and Renaissance. My study titled The heirs of Plato (OUP, 2003) deals with the ‘Old Academy’, and I have also published The Middle Platonists (Duckworth, 1977; 2nd edn 1996).

Over the years, I have also developed a great interest in the Jewish philosopher Philo of Alexandria (c. 25 bc–ad 50), who was much influenced by Platonism, and on whom I have written two books: Two treatises of Philo of Alexandria (with David Winston; Brown University, 1983), and Philo of Alexandria: on the life of Abraham (with Ellen Birnbaum; Brill 2019), as well as in the Christian philosopher Origen of Alexandria (fl. c. ad 220). A selection of my articles has been published in three volumes by Ashgate Publishing (The golden chain, 1990; The great tradition, 1997; and The Platonic heritage, 2012).

It will be noted, from the chronological order of the works listed above, that I have actually moved backwards through the Platonic tradition in my choice of topics, and this reflects the fact that I have been gradually pursuing the phenomenon of Platonism back to its roots, trying to throw light on the more obscure parts of that tradition, and in general meditating on the process by which Plato’s rather open-ended philosophising solidified, over the centuries, into a fairly rigid scholastic structure. Indeed, I have made that question the subject of my most recent book, The roots of Platonism (CUP, 2019). I argued in The heirs of Plato that the development of Platonism as a philosophical system might be most plausibly credited to Xenocrates, the third head of the Academy after Plato, in the late fourth century bc, but was subject to modification in later ages by the assimilation of aspects of both Aristotelian and Stoic philosophy, and I would still stand over that.