Fr. Irenaeus Dunlevy introduces Aquinas’ Five Ways, showing how arguments from motion, causality, contingency, gradation, and teleology lead from everyday experience to the rational conclusion that God exists as first mover, first cause, necessary being, supreme perfection, and intelligent governor.

This lecture was given on May 8th, 2025, at North Dakota State University.

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About the Speakers:

Fr. Irenaeus Dunlevy, O.P. is a Coordinator for Campus Outreach at the Thomistic Institute in Washington, DC. He has served as a parochial vicar at St. Pius V Church in Providence, RI, as well as an adjunct professor and assistant chaplain at Providence College. He originates from Columbus, OH, studied architecture in Virginia and Switzerland, and practiced in the DC area before entering the Order of Preachers in 2013. He was ordained a priest in 2020 at the Dominican House of Studies during the quarantine. In his work with the Thomistic Institute, he has given talks on the virtue of penance, loving God with the mind, and the intersection of theology and architecture. He often travels the country visiting Thomistic Institute Campus Chapters, leading seminars that help students grasp Thomistic concepts. Additionally, he coordinates the TI's intellectual retreat programming, which affords students time to pray and integrate into their lives Thomistic theology and philosophy.

Keywords: Act and Potency, Argument from Motion, Contingency and Necessary Being, Degrees of Perfection and Maximum Good, Five Ways to Prove God’s Existence, First Cause and Efficient Causality, Teleology and Intelligent Governor, Thomistic Proofs for God, Unmoved Mover