Photo of D. Gregory MacIsaac

D. Gregory MacIsaac

Associate Professor; Bachelor of Humanities

Degrees:B.A. (University of King's College/Dalhousie), M.A., Ph.D. (Notre Dame)
Phone:613-520-2600 x 1803
Office:2A40 Paterson Hall.
Office Hours:
Mondays, 10AM-11AM
Tuesdays, 11:30 AM - 12:30 PM
Website:Humanities Commons Profile


D. Gregory MacIsaac is Associate Professor of Humanities at Carleton University. He has taught in the B.Hum program since 1998. He grew up in Antigonish County, Nova Scotia, entering the Foundation Year Programme at the University of King’s College – Dalhousie (Halifax) in 1988. He took his B.A. degree in 1992 from the Dalhousie Department of Classics, in Ancient Languages and Ancient and Medieval Philosophy, and his M.A. (1994) and Ph.D. (2001) at the Department of Philosophy, University of Notre Dame (Indiana), with a thesis on the soul in Proclus, under the direction of Stephen Gersh.

He spent the academic year 1994-95 visiting the Hoger Instituut voor Wijsbegeerte (Higher Institute of Philosophy) at the Katholieke Universiteit Leuven, Belgium, studying Neoplatonism and Contemporary Continental Philosophy. In 2005-06 he was a Chercheur Étranger at the École Pratique des Hautes Études and C.N.R.S., Paris. In 2011-12 he was a visiting research at the Plato Centre, Trinity College Dublin, and at the Institute of Classical Studies, University of London. In 2019-20 he was Chercheur Associé, at the Laboratoire ‘Logiques de l’Agir’, Université de Franch-Comté, Besançon, France.

Professor MacIsaac spent twenty years working on aspects of the soul’s knowledge in the Neoplatonist Proclus. More recently, he has begun working on Plato, with a major research project on the dialogues TheaetetusParmenides, and Sophist.

In the Bachelor of Humanities, Professor MacIsaac’s main duty is HUMS 2000, the second-year Core-Humanities Seminar, Reason and Revelation. This is an intensive course on Ancient and Medieval Philosophy, covering authors from Plato to Dante. Professor MacIsaac also teaches HUMS 3500, Ancient and Medieval Intellectual History, whose topic is often the dialogues of Plato. He has also taught a number of fourth-year Research Seminars on topics such as Plato, Aristotle, Plotinus, Eriugena, Hegel, and Heidegger. Prof. MacIsaac currently teaches HUMS 1200, Humanities and Classical Civilization, the required first-year Humanities writing course.

Prof. MacIsaac is an award-winning teacher. At Carleton he has won:

  • Excellence in Blended and Online Teaching Award
  • Provost’s Teaching Fellowship
  • Teaching With Technology Award
  • Faculty of Arts and Social Sciences Teaching Award
  • Teaching Achievement Award

Research Interests

  • Neoplatonism, especially Proclus and Neoplatonic epistemology
  • Plato and the history of Platonism
  • Dante, philosophical literature

2023-2024 Courses

HUMS 2000 Reason and Revelation (F/W)

HUMS 1200A Humanities and Classical Civilization (F)

HUMS 4901B/CLCV 4800B/RELI  Plato and the Sophists (W)


“Plato’s Account of Eleaticism: A New Interpretation of Parmenides,” forthcoming in the Proceedings of the Symposium Platonicum XII, on Plato’s Parmenides (Paris, 2019).

“The Role of the Digression on the Man of the Law Courts and the Philosopher (172b-177c) in the Argument of Theaetetus,” Dionysius 38 (2020) pp.8-21

“Geometrical First Principles in Proclus’ Commentary on the First Book of Euclid’s Elements,” Phronesis 59 (2014) pp.44-98.

“Non enim ab hiis que sensus est iudicare sensum. Sensation and Thought in Theaetetus, Plotinus and Proclus,” International Journal of the Platonic Tradition 8 (2014) pp.192-230.

“Philosophy as the Exegesis of ‘Sacred’ Texts,” in Philosophy and the Abrahamic Religions: Scriptural Hermeneutics and Epistemology, ed. T. Kirby, R. Acar and B. Bas (Cambridge Scholars Publishing, 2013) pp.95-134.

“The Nous of the Partial Soul in Proclus’ Commentary on the First Alcibiades of Plato,” Dionysius 29 (2011) pp.29-60.

“Νόησις, Dialectique et Mathématiques dans le Commentaire aux Éléments d’Euclide de Proclus,” in Études sur le Commentaire de Proclus au premier livre des Éléments d’Euclide, ed. A. Lernould (Presses Universitaires du Septentrion, 2010) pp.125-138.

“Platonic Deconstruction:  A Review-article of Neoplatonism after Derrida.  Parallelograms.  By Stephen Gersh,” Dionysius, 27 (2009) pp.199-232.

“The Soul and the Virtues in Proclus’ Commentary on the Republic of Plato,” Philosophie Antique, 9 (2009) pp.115-143.

“The origin of determination in the Neoplatonism of Proclus,” in  Divine Creation in Ancient, Medieval, and Early Modern Thought.  Essays presented to the Rev’d Doctor Robert D. Crouse , ed. Willemien Otten, Walter Hannam, Michael Treschow (Leiden: E.J. Brill, 2007) pp.141-172.

“Neoplatonism and the Hegelianism of James Doull,” Animus, 10 (2005) pp. 30-43.  Online philosophy journal, Memorial University of Newfoundland.

“Projection and Time in Proclus,” in Medieval Philosophy and the Classical Tradition in Islam , Judaism, and Christianity, ed. John Inglis (London: Curzon Press, 2002) pp.83-105.

Phantasia between Soul and Body in Proclus,” Dionysius , 19 (2001) pp.125-136.

“The Final Section of Proclus’ Commentary on the Parmenides: A Greek retroversion of the Latin translation, by Carlos STEEL and Friedrich RUMBACH, with an English translation by D.Gregory MACISAAC,” Documenti e studi sulla tradizione filosofica medievale (Brepols, 1997) pp.211-267.

Work in Progress:

Book: Plato, Sophistry, and the Mixing of Forms: Theaetetus, Parmenides, and Sophist. This is an extended commentary on three dialogues of Plato.

Book: The Humanities Writing Guide. This is a textbook that teaches first-year students how to write an exegetical Humanities essay.

Article: “Plato’s Account of Sophistry in Sophist

Article: “Plato’s Account of Presocratic Materialism in Theaetetus

Article: “Plato’s Account of Eleaticism in Parmenides