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'I Cannot Tell a Lie': Thomas Aquinas on the Moral Permissibility of Lying – Prof. Christopher Tomaszewski

The Thomistic Institute

Prof. Christopher Tomaszewski argues that Thomas Aquinas teaches lying is intrinsically evil because it uses the faculty of speech against its natural purpose, even in difficult cases often thought to justify deception. This lecture was given on March 19th, 2026, at University of Toronto. For more information on upcoming events, visit us at thomisticinstitute.org/upcoming-events. About the Speakers: Christopher Tomaszewski is an Assistant Professor of Philosophy at Belmont Abbey College, where he teaches philosophy and great books. He holds a PhD in philosophy from Baylor University and a BS in mathematics from Villanova University. His primary research interests include metaphysics, mediæval philosophy, logic, and philosophy of religion (especially Thomistic solutions to contemporary problems in analytic philosophy), and more specifically in philosophical anthropology, classical theism, mereology, and causation. He is the author of several articles in Analysis, International Journal for Philosophy of Religion, Proceedings of the American Catholic Philosophical Association, and other journals. He lives near Charlotte, NC, with his wife Haley and their dog Borromeo. Keywords: Aquinas, Assertion, Candor, Consequentialism, Intrinsic Evil, Lying, Natural Law, Perjury, Truthfulness, White Lies