Aristotelian Thomism

8 Theses of Aristotelian Thomism

From "The River Forest School and the Philosophy of Nature Today" by Benedict Ashley, O.P.
  1. "[T]he philosophy of Aquinas, as distinct from his theology, is best gathered not from the Summa Theologiae (supplemented by the Commentary on the Sentences and the Summa Contra Gentiles, etc.), as Gilson for example chose to do, but from the commentaries on Aristotle, in which the philosophical disciplines are treated according to their own principles and methods via inventionis."
  2. "Aquinas ought to be interpreted as a convinced Aristotelian who vigorously opposes every tendency to Platonize in epistemology, and admits Platonic elements into this thought from the Church Fathers only in so far as he can validate them in accordance with Aristotelian epistemology."
  3. "[A] correct interpretation of Aquinas' philosophy depends on a careful observance of his theory of the order of the sciences."
  4. "[T]he many attempts (originating it would seem with Wolff and as a consequence of the Scotistic tradition just mentioned [which 'held that the proper object of the human intellect is metaphysical, not physical Being {ens mobile}, and therefore that the order of learning begins with the study of Being in its widest sense and the application of its principles to the special sciences.']) to distinguish the natural sciences as empirical from philosophy as 'rational' cannot be admitted in authentic Thomism."
  5. "[T]he key to reading Aristotle and Aquinas on natural science is a good understanding of the Organon and especially the Posterior Analytics (which by the way deals with the kind of questions which today are commonly called 'philosophy of science')."
  6. "[T]he strikingly apparent differences between natural science as it developed after Galileo and as Aquinas conceived it are not due to any formal difference in the kind of knowledge which modern science achieves, but are due to the confused self-understanding of modern science which resulted from its ideological history after Galileo." [This is the so-called "continuity thesis." See: Synthese 83:2-3.]
  7. "[T]he natural science of Aristotle and Aquinas, no matter how obsolete in its details, still can provide modern science with the foundational analysis which can resolve the many paradoxes in which it now is bound up in intellectual incoherence and which have led to disastrous cultural and ethical results."
  8. "[T]his task of revising modern science on the basis of its original foundations cannot be evaded by a flight to metaphysics or theology."

From Edward Feser's "The Thomistic Tradition (part 1)" (vide also part 2):

This approach emphasizes the Aristotelian foundations of Aquinas’s philosophy, and in particular the idea that the construction of a sound metaphysics must be preceded by a sound understanding of natural science, as interpreted in light of an Aristotelian philosophy of nature. Accordingly, it is keen to show that modern physical science can and should be given such an interpretation. Charles De Koninck (1906-1965), James A. Weisheipl (1923-1984), William A. Wallace, and Benedict Ashley are among its representatives. It is sometimes called “Laval Thomism” after the University of Laval in Quebec [which produced this brilliant thesis: Thomism and Mathematical Physics], where De Koninck was a professor. The alternative label “River Forest Thomism” derives from a suburb of Chicago, the location of the Albertus Magnus Lyceum for Natural Science, whose members are associated with this approach. It is also sometimes called “Aristotelian Thomism” (to highlight its contrast with Gilson’s brand of existential Thomism) though since Neo-Scholastic Thomism also emphasizes Aquinas’s continuity with Aristotle, this label seems a bit too proprietary. (There are writers, like the contemporary Thomist Ralph McInerny, who exhibit both Neo-Scholastic and Laval/River Forest influences, and the approaches are not necessarily incompatible.)

See also: E.g., Heisenberg recognized in his Physics and Philosophy that the probability wave concept in quantum mechanics "was a quantitative version of the concept of 'potentia' in Aristotelian philosophy" (p. 41) and that the "concept of the soul for instance in the philosophy of Thomas Aquinas was more natural and less forced than the Cartesian concept of 'res cogitans,' even if we are convinced that the laws of physics and chemistry are strictly valid in living organisms." (p. 80).

Physics and Quantum in The Thomist

These are some of the physics- and quantum-related articles from The Thomist, roughly sorted in terms of decreasing relevance with the most relevant first:
  1. From Schrödinger's Cat to Thomistic Ontology by Wolfgang Smith
  2. Natural Motion in Inanimate Bodies by Thomas Larson
  3. The Natural Motion of Matter in Newtonian and Post-Newtonian Physics John W. Keck
  4. Aristotle's Aether and Contemporary Science by Christopher A. Decaen
    1. Cf. Steven Baldner's "Thomas Aquinas on Celestial Matter;" this and Decaen's article are crucial for understanding the Galileo affair,
    2. Decaen's lecture "Galileo Galilei, Scriptural Exegete, and the Church of Rome, Advocate of Science," and
    3. John S. Daly's The Theological Status of Heliocentrism.
    4. The Principle and Journey to the Center of the Universe documentaries on the Copernican principle
    5. Hanson, Norwood Russell. “The Mathematical Power of Epicyclical Astronomy.” Isis 51, no. 2 (June 1960): 150–58.
  5. Quantum Mechanics: A Dialectical Approach to Reality by Wojciech P. Grygiel, F.S.S.P.
  6. Elemental Virtual Presence in St. Thomas by Christopher Decaen
    1. The Principles of Nature by St. Thomas Aquinas
  7. St. Thomas, Physics, and the Principle of Metaphysics by Lawrence Dewan, O.P.
    1. Reply of Benedict Ashley, O.P.
    2. For a definitive reply to Dewan, see Benedict Ashley, O.P.'s excellent overview of Aristotelian Thomism and how the natural sciences are epistemologically first: The Way toward Wisdom (p. 146-163) or "The River Forest School and the Philosophy of Nature Today"
    3. Cf. also "Physics & Metaphysics" by Pierre Duhem
  8. Act, Potency, and Energy by Thomas McLaughlin
    1. Cf. Rankine's "Outlines of the Science of Energetics," which inspired Duhem's energetics program.
  9. Part and Whole in Aristotle's Concept of Infinity by David A. White
  10. Thomism and the Quantum Enigma by William A. Wallace, O.P.
    1. William Wallace, O.P., refers to this in his excellent book The Modeling of Nature
  11. Modern Physics and Thomist Philosophy by E. F. Caldin
  12. Space-Time and the Community of Beings: Some Cosmological Speculations by George A. Kendall
  13. The Metaphysics of Chaos: A Thomistic View of Entropy and Evolution by Wojciech P. Grygiel, F.S.S.P.
  14. Reconciling Science with Natural Philosophy by Michael Augros
    1. Vide also his "A 'Bigger' Physics."
  15. The Law of Inertia and the Principle Quidquid Movetur ab Alio Movetur by Antonio Moreno, O.P.
    1. The Aristotelian definition of motion and the principle of inertia, a thesis by McLaughlin, Thomas J., University of St. Thomas (Houston), author of "Nature and Inertia" in The Review of Metaphysics, Vol. 62, No. 2 (Dec., 2008), pp. 251-284
  16. Time and Relativity: Some Philosophical Considerations by Antonio Moreno, O.P.
  17. Thomas and the Universe by Stanley L. Jaki
  18. Cantor's Transfinite Numbers and Traditional Objections to Actual Infinity by Jean W. Rioux
  19. Thomism and Modern Science: Relationships Past, Present, and Future by William A. Wallace, O.P.
  20. Some Causes of the Elimination of Causality in Contemporary Science by Gerald F. Kreyche
  21. Substantial Form and the Recovery of an Aristotelian Natural Science by John Goyette
  22. Beyond Aristotle and Beyond Newton: Thomas Aquinas on an Infinite Creation by Thomas P. Bukowski
  23. Scientific Reporting, Imagination, and Neo-Aristotelian Realism by Michael W. Tkacz
  24. What is Intelligible Matter? by Paul O'Reilly
  25. Experience and Experimentation: The Meaning of experimentum in Aquinas by Mark J. Barber
  26. Nature and the Process of Mathematical Abstraction by Yves R. Simon
  27. The Notion of Equivocal Causality in St. Thomas by Christopher A Decaen

Scholasticism in Empiriological Sciences

From footnote †7 on pg. 24 of St. Thomas Aquinas's Division and methods of the sciences, a commentary on Boethius's De Trinitate questions V and VI, translator Armand Maurer mentions these articles relating Scholasticism to empiriological sciences like modern physics.

The growth in modern times of empiriological science, as distinct from philosophy in its formal object and method, renders impossible a physical theory that would be applicable in a univocal way to both. Such a theory, which denies the distinction between philosophical and empiriological analysis, has been proposed by R. Nogar, "Toward a Physical Theory," The New Scholasticism 25 (1951), 397-438.

J. Weisheipl proposes a return to St. Thomas and St. Albert for "a unifying physical theory" that would include both the philosophy of nature and the empirical or experimental sciences. For Weisheipl these constitute one specific discipline, both materially and formally. However, he regards the sciences employing mathematical principles as really distinct from natural philosophy. See J. Weisheipl, The Development of Physical Theory in the Middle Ages; "The Relationship of Medieval Natural Philosophy to Modern Science: The Contribution of Thomas Aquinas to Its Understanding," in Science. Medicine and the Universities 1200-1550. Essays in Honor of Pearl Kibre (= Manuscripta 20 [1976]), pp. 181-196; idem, Introduction to The Dignity of Science. Studies in the Philosophy of Science Presented to William Humbert Kane OP (= The Thomist 24 [1961]).

In the same spirit, see C. De Koninck, "The Unity and Diversity of Natural Science," in The Philosophy of Physics, ed. V. E. Smith, pp. 5-24; W. A. Wallace, "St. Thomas's Conception of Natural Philosophy and its Method," in Studi Tomistici. La philosophie de la nature de saint Thomas d'Aquin, ed. L. Elders, pp. 7-27; idem, Causality and Scientific Explanation [cf. idem, Review of Metaphysics 27:3 (March 1974)].

For further discussions of this topic, see E. McMullin, "Philosophies of Nature," The New Scholasticism 43 (1969), 29-74; J. Compton, "Reinventing the Philosophy of Nature," The Review of Metaphysics 33 (1979), 3-28; E. McMullin, "Compton on the Philosophy of Nature," ibid., pp. 29-58; idem, "Is There a Philosophy of Nature?" Proceedings of the International Congress of Philosophy, Vienna, 1968, 4: 295-305.

This is what the Society of Scholastics and the Institute for Advanced Physics seek to promote. See also the Society of Scholastic's Constitution, Thomas Aquinas College's founding document, the 24 Thomistic Theses with P. Lumbreras, O.P.'s commentary, and especially the works on which I have commented here.


St. Thomas Aquinas in English (bibliography) and in Latin: Opera Omnia, Leonine edition (1882):
tomes 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 22, 23, 26, 28, 40, 41, 42, 43, 45, 47
Natural philosophy books:
  1. Universe Without Space and Time by Victor Philip Warkulwiz
  2. Essence & Topicality of Thomism by Reginald Garrigou-Lagrange, O.P.
  3. Modern Thomistic Philosophy by Richard Percival Phillips
  4. The Physical System of St. Thomas by Giovanni Maria Cornoldi
  5. Physics and Philosophy: A study of Saint Thomas' commentary on the eight books of Aristotle's Physics by J. A. McWilliams
  6. Philosophical Physics by Vincent Edward Smith
  7. Thomism and Mathematical Physics, a thesis by Bernard I. Mullahy
  8. The Principles of Nature, Commentary on Aristotle's Posterior Analytics, and Commentary on Aristotle's Physics by St. Thomas Aquinas
  1. Pope Leo XIII's encyclical Æterni Patris (in Latin here) on the restoration of Thomism
  2. A Scholastic List of Definitions for Philosophical Terms and of Philosophical Axioms
  3. Question 1 of the Summa Theologica by St. Thomas Aquinas
  4. The natural sciences are epistemologically first according to Aristotelian Thomism.
  5. "The Philosophy of Nature" by Joseph Kenny, O.P.
  6. Four Ages of Understanding by John Deely, an excellent history of philosophy (vide this review and the chapters "Charles Sanders Peirce and the Recovery of the Signum" and "The Impact of Semiotics on Philosophy")

Contra Scientism

  1. The Plague of Scientistic Belief by Wolfgang Smith
  2. "Physics & Metaphysics," "Physics of a Believer," excerpt from To Save the Phenomena, and excerpt from The Aim & Structure of Physical Theory by Pierre Duhem (vide also his biography, physicist biography, philosopher biography, and these papers on his physics)
  3. The Problem of Mechanism by David L. Schindler
  4. The structure of the encyclical "Humani Generis" by Reginald Garrigou-Lagrange, O.P.

Faith & Reason

On the differences and similarities between faith—"a kind of knowledge, inasmuch as the intellect is determined by faith to some knowable object" (Summa Theologiæ, Iª q. 12 a. 13 ad 3)—and reason, read:
  1. Philosophy & Catholic Theology: A Primer by Philip A. Egan, Chapter 1
  2. Reason and Faith from TruthInspire
  3. "Faith and Reason" from Étienne Gilson's The Philosophy of St. Thomas Aquinas (criticism)
  4. "The Dream of Natural Philosophy" by Brian Mullady, O.P.
  5. Fives Ways to Prove God's Existence by St. Thomas Aquinas
  6. On Faith and Reason from Vatican I's Dei Filius
  7. How Science Enriches Theology by Benedict Ashley, O.P. & John Deely
  8. Note on the Validity of the Principles of Inertia and Conservation of Energy by Garrigou-Lagrange & Duhem


Biographies mostly of perhaps lesser-known yet still very innovative scientists, from the Dictionary of Scientific Biography. Experiment with St. Hildegard von Bingen's cryptography.

WorldCat Lists

Visit my WorldCat list on Aristotelian Thomism. It includes many more books and articles pertaining to the relationship between Aristotelian-Thomistic scholastic philosophy and the empiriological sciences like modern physics. Also, see my "History of Science", "History of Philosophy", "Catholic", and "Thomism" WorldCat lists. See also the St. Isidore e-book library.