Ascend – The Great Books Podcast

Episode: Platonic Thought in St. Thomas Aquinas

Guest: Dr. Donald Prudlo

Date: January 27, 2026
Hosts: Deacon Harrison Garlick & Adam Minihan

Overview

This episode explores the influence of Platonic thought—both direct and indirect—on St. Thomas Aquinas. Host Deacon Harrison Garlick and Adam Minihan welcome Dr. Donald Prudlo, a historian and Thomist, to unravel misunderstandings of Aquinas as a “pure Aristotelian,” delve into the nuances of medieval philosophical synthesis, and trace Platonic elements in Aquinas’ thought, touching on key philosophical, metaphysical, and theological themes.

Key Discussion Points & Insights

Debunking the “Pure Aristotelian” Caricature of Aquinas

[07:30–10:38]

• The widespread portrayal of Aquinas as merely a Christian Aristotelian or as someone who “baptized” Aristotle is deemed inaccurate, both historically and philosophically.
  • Dr. Prudlo: “Scholars over the last 50 or so years have been very patiently making the story much more complex, much more rich, to show the great variety of sources that Thomas used and gladly used.” [07:55]
• The danger of reducing Thomism to an intellectual rupture from the first 1200 years of church tradition is highlighted. Instead, Aquinas is better seen as deepening and synthesizing the Christian intellectual heritage, not replacing it.

The Intellectual Environment: What Platonic Thought Did Aquinas Receive?

[17:01–24:24]

• Aquinas had only partial access to Plato: chiefly the Timaeus (if at all). His real exposure to Platonic thought was mediated through:
  • The Church Fathers (primarily Augustine, also Origen and the Cappadocians)
  • Neoplatonic sources (Pseudo-Dionysius, Proclus), often indirectly or via works attributed incorrectly to Aristotle (e.g., the Liber de Causis)
  • Latin thinkers like Boethius and Anselm
  • Translations and commentaries from Muslim philosophers (e.g., Avicenna, Al-Farabi), who synthesized Platonic and Aristotelian traditions
• The overall effect is that Aquinas inherited a Platonic tradition “veiled” by centuries of interpretation and harmonization.

Medieval Thought as Harmonization, Not Conflict

[25:12–27:07]

• Aquinas, like Boethius, operates in an intellectual world striving to harmonize Plato and Aristotle, seeking both commonalities and respectful recognition of their differences:
  • Dr. Prudlo: “Thomas is a part of that great age of medieval harmonization. He knows they disagree on some points, but he sees the two as complementary, essentially, as approaching things from different angles and reaching so many of the same conclusions.” [25:44]

Platonic Structures in Aquinas’ Theology

1. Exitus-Reditus: The Arc of Creation and Return

[29:23–31:01]

• Aquinas’ Summa Theologiae follows a Neoplatonic-Plotinian pattern: all things come forth from God (exitus) and return to Him (reditus), but this cycle is completed through the person of Christ and the drama of salvation, not via necessary emanation.

2. The Doctrine of Evil as Privation

[31:59–32:44]

• Aquinas’ teaching that evil is “privation of the good” comes from Plotinus and Augustine, not Aristotle.
  • Dr. Prudlo: “He wholesale incorporates the Augustinian Neoplatonic framework for his analysis of evil…not really the way that Aristotle would have put it.” [32:09]

3. The Forms and Universals

[34:21–40:56]

• St. Augustine had already “relocated” Plato’s forms to the Divine Mind. Aquinas accepts this, stating universals exist ultimately in God, but he sides with Aristotle’s moderate realism for earthly particulars: universals are real, but found only in particulars, not as “floating” forms.

Creation, Participation, and the One & Many

[41:49–62:19]

• Aquinas’ breakthrough is the esse–essentia (existence–essence) distinction:
  • Only in God are existence and essence identical
  • All else participates in Being; God is Ipsum Esse Subsistens (Being Itself)
  • This creates a metaphysical hierarchy reminiscent of the Platonic ladder, but with the new Christian inflection that creation is a free gift of love, not a necessary emanation.
  • Dr. Prudlo: “For Thomas, unlike every philosopher before him, the really interesting thing was that [anything] exists at all.” [57:41]

Aquinas’ Use and Correction of Both Traditions

[47:36–49:01]

• Aquinas corrects both Platonism and Aristotelianism:
  • For Platonists: insists on the goodness of the body (due to the Incarnation), balancing Platonic dualism with Aristotelian hylomorphism.
  • For Aristotelians: asserts the individuality and immortality of the soul, which Aristotle (and especially his medieval Muslim commentators) failed to defend.

Beauty and the Ladder of Love

[64:53–78:48]

• While Aquinas does not foreground “beauty” in the same way as Plato, beauty remains crucial as “that which pleases when seen,” integrating proportion, clarity, and order.
  • Aquinas’ contributions to liturgical poetry (e.g., Pange Lingua) reveal his own sense of beauty.
  • Dr. Prudlo: “God is beautiful because he’s the cause of all beauty. For Thomas, beauty is integrity, proportion, clarity. It is that which pleases when seen.” [70:28]
• The Platonic ascent—“ladder of love”—lives on in Aquinas’ ethics of virtue and participation in grace; ascent toward God is realized through living a virtuous life, ever increasing in being and perfection.
  • “Nature, grace builds upon nature, and grace does not destroy nature… these are all steps on that ladder.” [78:22]

Aquinas’ Intellectual Maturation

[82:08–85:22]

• A clear trajectory: early focus on Aristotelianism, later increasingly integrating Neoplatonic/Augustinian influences.
  • For a strong Platonic imprint in his works, look to later disputed questions (On Spiritual Creatures, On Separated Substances) and his biblical commentaries.

Notable Quotes

• “Thomas is astonishing in that he finds truth in nearly every previous thinker that there’s some aspect that he can use, that he can incorporate.” – Dr. Prudlo [10:15]
• “We need to read Aristotle, we need to read Plato, but there’s also this cloud of witnesses…” – Dr. Prudlo [15:18]
• “The more I look into St. Thomas Aquinas, the more I’m coming to believe that a lot of people who talk about Thomas don’t actually know Thomas.” – Deacon Harrison [08:49]
• “Every other philosopher before [Thomas] had been interested in the question what is it. For him, the really interesting thing was that it is, that it exists at all.” – Dr. Prudlo [57:45]
• “The dichotomy is not between God and Satan, it’s between God and nothing.” – Dr. Prudlo [63:57]

Timestamps for Major Segments

• 07:30 – Disputing the “Christian Aristotelian” label
• 14:48 – Pitfalls of reading Aquinas without reading Plato/Aristotle
• 18:42 – What Platonic writings did Aquinas actually know?
• 25:12 – Medieval project of harmonization
• 29:23 – Exitus-reditus structure in Summa and its Platonic origin
• 31:59 – Doctrine of evil as privation
• 34:21 – The problem of ideas/forms and Aquinas’ synthesis
• 41:49 – Essay–essentia: Aquinas’ unique metaphysical move
• 47:36 – Correction of both Platonic and Aristotelian extremes
• 64:53 – Participation, virtue, and moral ascent as the “ladder of being”
• 70:28 – Aquinas on beauty
• 78:22 – Virtues, grace, and the ascent toward God
• 82:08 – Development of Platonic influences within Aquinas’ work
• 87:38 – Where to study further: recommended resources

Further Reading & Resources

• Robert Henle, St. Thomas and Platonism
• Aquinas the Augustinian (Dauphine, Levering, Barry)
• David Burrell, “Analogy, Creation and Theological Language in the Theology of Thomas Aquinas”
• Wayne Hanke, “Aquinas, Plato and Neoplatonism” in the Oxford Handbook of Thomas Aquinas
• Edward Feser, Scholastic Metaphysics

Memorable Moments

• Dr. Prudlo relating the Platonic “exitus-reditus” to the very structure of the Summa
• Discussion of how medieval Christian, Jewish, and Muslim thinkers all sought harmonization between Plato and Aristotle
• The playful anecdote on how Aristotle’s lost dialogues might have changed perceptions, and how his existing texts come across as “lecture notes or even notes taken by a student” [67:45]

Tone & Language

• The conversation is erudite but accessible, candid, and generous—often displaying the hosts’ and guest’s affection for both Plato and Aquinas as thinkers who “bear witness to wisdom.”
• Dr. Prudlo engages history, philosophy, and theology seamlessly, frequently reiterating the importance of patience, deep reading, and gratitude for tradition. The episode encourages listeners to see the Great Books as a living dialogue.

Summary Conclusion

This episode provides a robust, nuanced introduction to the Platonic inheritance in Aquinas’s thought, disabusing listeners of simplistic narratives and offering a roadmap for exploring the “great conversation” among Christian, pagan, Jewish, and Muslim thinkers. Aquinas emerges not as a mere Christian Aristotelian, but as a masterful synthesizer who drew from, transformed, and elevated the Platonic tradition to serve the radiance of revealed truth.

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