Thomas M. Osborne, Jr., Ph.D., is professor of philosophy at the University of St. Thomas, where he has taught since 2003 and has also served as Chair of the Department of Philosophy and Director of the Center for Thomistic Studies. His areas of specialization include medieval and late scholastic philosophy, ethics, and the history of political philosophy, with particular expertise in Thomas Aquinas, John Duns Scotus, and William of Ockham.

Dr. Osborne is the author of four books, including Thomas Aquinas on Virtue (Cambridge University Press, 2022), Aquinas’s Ethics (Cambridge University Press, 2020), and Human Action in Thomas Aquinas, John Duns Scotus, and William of Ockham (Catholic University of America Press, 2014), which received the 2015 Charles Cardinal Journet Prize. He has published extensively in leading journals and edited volumes on medieval ethics, metaphysics, virtue theory, political philosophy, and Thomism, and he has delivered invited lectures and conference papers internationally in the United States and Europe.

In teaching, Dr. Osborne has taught a wide range of undergraduate and graduate courses in medieval philosophy, metaphysics, ethics, philosophy of law, philosophy of religion, Thomistic ethics, Scotus and Ockham, and theories of action. He is especially known for his work in Thomistic philosophy and for mentoring graduate students in medieval and scholastic thought.

His service to the university and profession has included multiple terms as department chair, leadership roles in the Faculty Senate, membership on numerous university committees, and service to organizations such as the Society for Medieval and Renaissance Philosophy and the American Catholic Philosophical Association. He has also served as a referee and editorial advisor for numerous scholarly journals and academic presses. 

Ph.D. Duke University 

L.M.S. Pontifical Institute of Mediaeval Studies 

M.A. Boston College 

B.A. The Catholic University of America 

Selected Publications:

Osborne, Thomas M. “Practical Truth and Conformity to Appetite: What the Medieval Philosophers Can Teach Us.” In Practical Truth: Historical and Contemporary Perspectives, edited by Christopher Frey and Jennifer A. Frey, 123–139. New York: Oxford University Press, 2025.

Osborne, Thomas M. “The Early Jesuits and Scholastic Theology.” In Ignatius of Loyola and Thomas Aquinas: A Jesuit Ressourcement, edited by Justin Anderson, Matthew Levering, and Aaron Pidel, 1–27. Washington, D.C.: The Catholic University of America Press, 2024.

Osborne, Thomas M. “Francisco De Vitoria on the Nature and Source of Civil Authority.” Review of Politics 85 (2023): 1–22.

Osborne, Thomas M. Thomas Aquinas on Virtue. Cambridge: Cambridge University Press, 2022.

Osborne, Thomas M. Aquinas’s Ethics. Cambridge Elements in Ethics. Cambridge: Cambridge University Press, 2020.

Osborne, Thomas M. “MacIntyre and Thomism.” In Learning from MacIntyre, edited by Ron Beadle and Geoff Moore, 52–76. Eugene, OR: Pickwick, 2020.

Osborne, Thomas M. “Virtue.” In The Cambridge Companion to Medieval Ethics, edited by Thomas Williams, 150–171. Cambridge: Cambridge University Press, 2019.

Osborne, Thomas M. “Which Essence Receives Existence?” The Thomist 81 (2017): 471–505.

Osborne, Thomas M. Human Action in Thomas Aquinas, John Duns Scotus, and William of Ockham. Washington, D.C.: The Catholic University of America Press, 2014.

Osborne, Thomas M. “William of Ockham as a Divine Command Theorist.” Religious Studies 41 (2005): 1–22.

Osborne, Thomas M. Love of Self and Love of God in Thirteenth-Century Ethics. Notre Dame, IN: University of Notre Dame Press, 2005