
On the Five Ways of Proving the Existence of God of Saint Thomas Aquinas

The Five Ways of Proving that God Exists — Summa Theologiae Ia, q. 2, a. 3.
(See also Aquinas’ other discussions of God’s existence and his Natural Theology).
Explanations, Analyses and Assessments of the Five Ways
- The Five Ways in Context
- The First Way
- The Second Way
- The Third Way
- The Fourth Way
- The Fifth Way
- (Video Presentations on the Five Ways are available on the Videos Page)
“This Everyone Calls God” – How Aquinas identifies the object of his proofs as the Christian God.
Links to Other Explanations/Analyses of the Five Ways: (arranged in ascending order of detail and sophistication)
- Cosmological Arguments (including Aquinas’) — by Stephen A. Richards
- Revisiting the Argument from Motion (The First Way) by Bp. Robert Barron (Word on Fire Ministries)
- Problems of the First Cause by Fr. William Most, from the electronic library of EWTN.
- Philosophical Proofs on the Existence of God — by S. M. Miranda
- Explanation of the First Way — by Philip A. Pecorino. Also includes other cosmological arguments and objections, especially in the light of Big Bang cosmology.
- To Follow the Second Way of Aquinas — by David McGraw. An explanation of the proof from efficient causality (dynamic punch) and a defense of identifying the First Cause with God. Also includes an impressive list of links to relevant resources on the internet.
- Robert C. Koons, Professor, University of Texas at Austin
- “Does the Universe Have a Cause?” in Contemporary Debates in Philosophy of Religion, 2nd edition, Raymond VanArragon and Michael Peterson (eds.), Wiley-Blackwell, 2019. (Not about Aquinas per se, but helpful.)
- “God’s Existence,” in Neo-Aristotelian Perspectives on Metaphysics, Daniel D. Novotny and Lukas Novak (eds.). (Oxford: Routledge, 2013), pp. 247-68.
- “Ways Two and Three: Thomas Aquinas on the Intelligibility of Being,””Epistemological Foundations for the Cosmological Argument,” in: Oxford Studies in the Philosophy of Religion, Volume 1, edited by Jonathan Kvanvig (Oxford, 2008).
- “St. Thomas Aquinas on Intelligent Design,” with Logan Paul Gage, Proceedings of the American Catholic Philosophical Association 85 (2011):79-97.
Analysis of Thomistic Proofs in General:
- St. Thomas and Big Bang Cosmology — by William Carroll
- Can the Existence of God Be Known by Reason? — by James Arraj
Criticisms of Aquinas or Cosmological Arguments:
- The Resurrection of Thomism, by Doug Erlandson. Claims the principle “nothing comes from nothing” is circular and question begging.
- Reply to Erlandson, by Joseph Magee.
- Internal and External Causal Explanations of the Universe (1995) by Quentin Smith
- Creation Ex Nihilo – without God, by Mark I. Vuletic
- Reply to Vuletic, by Joseph Magee (forthcoming)
See also “Why the Burden of Proof is on the Atheist,” by Ralph McInerny.