Ep. #27 – Defending the 3rd Way with Dr. Delfino
Summary
Dr. Delfino ably defends the third way of St. Thomas Aquinas, providing many helpful examples and details along the way. In the first segment, he shows that there must be at least one necessary being. Next, he shows how there must be at least one necessary being that is necessary through itself.
Lastly, he shows that in this reality that is necessary through itself, its essence and existence must be identical. This supports the thesis that there can only be one reality in principle that is necessary through itself. Therefore, there can only be one God.
Guest Bio
Robert A. Delfino received his Ph.D. from the State University of New York at Buffalo, where he specialized in metaphysics and medieval philosophy. His current research interests include metaphysics, ethics, and the relationship between science, philosophy, and religion. He has presented papers at the Comillas Pontifical University in Madrid, Spain, the John Paul II Catholic University of Lublin, in Poland, and the University of Oxford, in the United Kingdom. He is the co-author of a recent book Does God Exist?: A Socratic Dialogue on the Five Ways of St. Thomas Aquinas.
Show Outline
Delfino defends the third way in several steps in detail. In the first segment, Delfino explains why it’s not a weakness to have five ways to God instead of just one. He also defines the key terms of the third way: being, necessary being, and possible being. Along the way, he provides many examples to make the terms of his argument clear.
Delfino argues that there must be at least one necessary being that is necessary through itself. Moreover, he explains that in such a necessary being that is necessary through itself, its existence and essence must be identical.
Delfino deals with objections to the third way related to the fallacy of composition as well as infinite regress. His philosophical arguments conclude with reasoning to the fact that there can only be one necessary reality that is necessary through itself.
Important Quote #1
In efficient causes it is impossible to proceed to infinity “per se”—thus, there cannot be an infinite number of causes that are “per se” required for a certain effect; for instance, that a stone be moved by a stick, the stick by the hand, and so on to infinity.
Summa Theologiae I.46.2, Reply to Objection 7
Important Quote #2
The first [cause] is the cause of the intermediate cause [instrumental cause], and the intermediate is the cause of the ultimate cause [the cause closest to the effect], whether the intermediate cause be several, or only one. Now to take away the cause is to take away the effect.
Summa Theologiae I.2.3
Important Quote #3
An essentially ordered causal series is asymmetric, irreflexive, and wholly derivative. The subsequent members in such series are not only caused by and ontologically dependent on the preceding members, as in a transitive series, they also serve as causes only insofar as they have been caused by and are effects of all the preceding members. Because these intermediate causes possess causal powers only by deriving them from all the preceding causes, they need a first and nonderivative cause…. If there were only intermediate and derivative causes, then there would be no source from which the causal powers of the intermediate causes could be derived, regardless of whether there were a finite or an infinite number of intermediate causes.
Caleb Cohoe, “There Must Be a First: Why Thomas Aquinas Rejects Infinite, Essentially Ordered Causal Series,”British Journal for the History of Philosophy (2013), 839-840.
Resources Mentioned
Every Knee Shall Bow – An AWESOME new Catholic Podcast!
Maps of Meaning by Dr. Jordan Peterson
Does God Exist?: A Socratic Dialogue on the Five Ways of St. Thomas Aquinas by Matt Fradd and Dr. Robert A. Delfino
The Preface to Thomistic Metaphysics: a Contribution to the Neo-Thomist Debate on the Start of Metaphysics by John F. X. Knasas [Note: This book is out of print so I linked to a page where you can search libraries nearby if you want to read it.]
