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Faculty Research

Philosophy is a quest for wisdom.

Research and teaching are integral aspects of appropriating, renewing and promulgating this ennobling activity.

The department's research spans the history of Western philosophy, with particular coverage in medieval and contemporary thought and their interconnection. Inspired by the Catholic intellectual tradition, the department's topical research is concentrated particularly in metaphysics and philosophical anthropology, but it also has strengths in aesthetics, ethics, philosophy of liberal learning, philosophy of mind and language, philosophy of religion, philosophy of science, and political and social philosophy.

Historical Research Areas:

Post- Kantian


Professors Engelland, Frank, Parens, Sanford, Sepper, Associate Professors Nielsen,  Simmons


The department has developed interests in post-Kantian philosophy and its relation to ancient and medieval thought, with special focus on metaphysics, phenomenology, hermeneutics, and personalism. Research foci include Buber, Gadamer, Hegel, Heidegger, von Hildebrand, Husserl, Kripke, Marcel, Merleau-Ponty, Nietzsche, Scheler, Strauss, and Wittgenstein.

Representative Publications:

Engelland, Chad. Heidegger’s Shadow: Kant, Husserl, and the Transcendental Turn. New York: Routledge, 2017.

Engelland, Chad. Phenomenology. Cambridge, MA: The MIT Press, 2020.

Frank, William. “The Personalist Dimensions of Property.” In Das Eigentum als eine Bedingung der Freiheit / Property as a Condition of Freedom, edited by Anton Raushcer, 37-57. Berlin: Duncker & Humblot, 2013.

Nielsen, Cynthia. Foucault, Douglass, Fanon, and Scotus in Dialogue: On Social Construction and Freedom. New York: Palgrave Macmillan, 2013.

Nielsen, Cynthia. “Gadamer and Scholz on Solidarity: Disclosing, Avowing, and Performing Solidaristic Ties with Human and Natural Others.” Journal of the British Society for Phenomenology 48 (2017): 1–16.

Parens, Joshua. Leo Strauss and the Recovery of Medieval Political Philosophy. Rochester: University of Rochester, 2016.

Sanford, Jonathan J. ”Scheler vs. Scheler: The Case for a Better Ontology of the Person.” American Catholic Philosophical Quarterly 79 (2005): 145-161.




Professors Parens, Sepper


The department has developed interests in the rise of modern thought and science, with particular emphasis on the figures of Descartes and Spinoza.

Representative Publications:

 Parens, Joshua. Maimonides and Spinoza: Their Conflicting Views of Human Nature. Chicago: University of Chicago Press, 2012.

 Sepper, Dennis. Descartes’s Imagination: Proportion, Images, and the Activity of Thinking. Berkeley and Los Angeles: University of California Press, 1996.



Professors FrankParens, Sanford; Associate Professors Knobel,  Lehrberger, Walz


The department has developed interests in metaphysics and the relation of faith and reason. Research foci include Augustine, Boethius, Anselm, Thomas Aquinas, Bonaventure, Duns Scotus, and Islamic and Jewish thinkers.

Representative Publications:

Frank, William. Duns Scotus, Metaphysician. Co-authored with Allan B. Wolter. Purdue University Press Series in the History of Philosophy. West Lafayette, IN: Purdue University Press, 1995.

Knobel, Angela. Aquinas and the Infused Moral Virtues. South Bend: University of Notre Dame Press, 2021.

Lehrberger, O.Cist., Fr. James. “Aquinas’ Philosophical Critique of Philosophy.” Verbum: Analecta Neolatina 7 (2004): 39-49.

Parens, Joshua. Metaphysics as Rhetoric: Alfarabi’s “Summary of Plato’s Laws.” Albany, N.Y.: State University of New York Press, 1995.

Parens, Joshua. “Maimonidean Ethics Revisited: Development and Asceticism in Maimonides?” Journal of Jewish Thought and Philosophy 12:3 (2003): 33–62.

Parens, Joshua. “Theory and Practice in Medieval Aristotelianism.” Polity 26 (1993): 317–330.

Walz, Matthew, translator. Anselm of Canterbury, Proslogion (including Gaunilo’s objections and Anselm’s replies). Introduction and Notes. South Bend: St. Augustine’s Press, 2013.

Walz, Matthew. “Stoicism as Anesthesia: Philosophy’s ‘Gentler Remedies’ in Boethius’s Consolation,” International Philosophical Quarterly 51 (2011): 501-19.

Walz, Matthew. “Theological and Philosophical Dependencies in St. Bonaventure’s Argument Against an Eternal World and a Brief Thomistic Reply.” American Catholic Philosophical Quarterly 97 (1998): 75-98.



Professors ParensSanford, and Vorwerk; Associate Professors Mirus, Walz


 The department has developed interests in the metaphysics and ethics of Aristotle and Plato.

Representative Publications:

Mirus, Christopher. “The Homogeneous Bodies in Meteorology IV.12.” Ancient Philosophy 26 (2006): 45–64.

Mirus, Christopher. Being Is Better than Nonbeing: The Metaphysics of Goodness and Beauty in Aristotle. Washington, DC: Catholic University of America Press, 2021.

Parens, Joshua. “Socrates: Sisyphean or Overflowing?” In Socrates in the Cave: On the Philosopher’s Motive in Plato, ed. Paul J. Diduch & Michael P. Harding, 185-203. Springer Verlag, 2019.

Sanford, Jonathan J. “Aristotle on Evil as Privation.” International Philosophical Quarterly 57 (2017): 195-209.

Vorwerk, Matthias. Plotins Schrift ‘Über den Geist, die Ideen und das Seiende (Enneade V 9 [5]). Text, translation, commentary. Beiträge zur Altertumskunde 145. Munich – Leipzig: Saur, 2001.

Vorwerk, Matthias. “Maker or Father? The Demiurge from Plutarch to Plotinus.” In One Book, The Whole Universe: Plato’s “Timaeus” Today, ed. R. Mohr, 79-100. Las Vegas, Zurich, and Athens: Parmenides Publishing, 2010.

Walz, Matthew. “The Opening of On Interpretation: Toward a More Literal Reading.” Phronesis 51 (2006): 230-51.

Topical Research Areas:



Professor Engelland; Associate Professor Nielsen


The department has developed interests in the ontology of the work of art, the history of aesthetics, the philosophy of music, and the intersection of art and the phenomenology of perception and nature.

Select Publications:

Engelland, Chad. “The Play of Life in Art.” Journal of Aesthetics and Phenomenology 2 (2015): 127-142.

Nielsen, Cynthia. “Gadamer on Play and the Play of Art.” In The Gadamerian Mind, ed. Theodore George and Gert-Jan van der Heiden. New York: Routledge, 2021.

Nielsen, Cynthia. “Harsh Poetry and Art’s Address: Romare Bearden and Hans-Georg Gadamer in Conversation.” The Polish Journal of Aesthetics 43 (2016): 103–123.

Nielsen, Cynthia. Interstitial Soundings. Philosophical Reflections on Improvisation, Practice, and Self-Making. Eugene, OR: Cascade Books, 2015.



Professors Sanford; Associate Professors KnobelLehrberger and Simmons


The department has developed interests in virtue theory, applied ethics, and natural law.

Representative Publications:

Knobel, Angela. “An Instinct for the Divine: Faith and the Formation of Infused Virtue.” In Faith and Virtue Formation, ed. Adam Pelser and Scott Cleveland. Oxford: Oxford University Press, 2021.

Knobel, Angela. “The Reception of Aquinas's Ethics.” In The Oxford Handbook of the Reception of Aquinas, ed. Matthew Levering Marcus Plested, 554-564. Oxford: Oxford University Press 2021.

Knobel, Angela. “Rethinking Unplugging.” The Journal of Medicine and Philosophy: A Forum for Bioethics and Philosophy of Medicine, Volume 44, Issue 6, (2019): 698–711.

Lehrberger, O.Cist., Fr. James. “Crime without Punishment: Thomistic Natural Law and the Problem of Sanctions.” In Law and Philosophy: The Practice of Theory, ed. John A. Murley et al, 237-57. Athens, OH: Ohio University Press, 1992.

Lehrberger, O.Cist., Fr. James. “Deontology, Teleology, and Aquinas; Virtue Ethic.” Saints, Sovereigns, and Scholars: Studies in Honor of Frederick D. Wilhelmsen, ed. James Lehrberger et al, 107-22. New York: Peter Lang, 1993.

Sanford, Jonathan J. Before Virtue: Assessing Contemporary Virtue Ethics. The Catholic University of America Press, 2015.

Sanford, Jonathan J. “Justice is Beautiful: Aristotle, Aquinas, and Justice as a Virtue.” In Beauty and the Good: Recovering the Classical Tradition from Plato to Duns Scotus, ed. Alice Ramos, 115-135. Washington, DC: The Catholic University of America Press, 2020.

Simmons, Lance. “Pretense, Corruption, and Character in ‘Modern Moral Philosophy.’” American Catholic Philosophical Quarterly 86 (2012): 271-91.

Simmons, Lance. “Kant’s Highest Good: Albatross, Keystone, Achilles Heel.” History of Philosophy Quarterly 10 (1993): 355-68.

Simmons, Lance. “Three Kinds of Incommensurability Thesis.” American Philosophical Quarterly 31 (1994): 110-31.



Professors Engelland, Parens, Sanford; Associate Professors Lehrberger, Mirus


The department has developed interests in ancient, medieval, and contemporary approaches to metaphysics.

Representative Publications:

Engelland, Chad. "'Rational Animal' in Heidegger and Aquinas." The Review of Metaphysics 71 (2018): 723-53.

Lehrberger, O.Cist. Fr. James. “The Anthropology of Aquinas’ De Ente et Essentia.” The Review of Metaphysics 51 (1998): 829–47.

Lehrberger, O.Cist., Fr. James. “Dialectic and Demonstration in Aristotle’s Argument for an Eternal Cosmos." Il cannonicchiale: revista di studi filosofici 1:2 (1996): 67-81.

Mirus, Christopher. Being Is Better than Nonbeing: The Metaphysics of Goodness and Beauty in Aristotle. Washington, DC: Catholic University of America Press, 2021.

Sanford, Jonathan J. Categories: Historical and Systematic Essays, co-edited with Michael Gorman. Washington, D.C.: The Catholic University of America Press, 2004.

Philosophical Anthropology


Professors EngellandFrank, Nielsen, and Vorkwerk; Associate Professors Walz


The department has developed interests in the philosophy of education, the metaphysics of personhood, embodiment, and race.

Representative Publications:

Engelland, Chad. “Heidegger and the Human Difference.” Journal of the American Philosophical Association 1 (2015): 175-193.

Engelland, Chad. “On the Personal Significance of Sexual Reproduction.” The Thomist 79 (2015): 615-639.

Frank, William, translator. The Anti-Emile: Reflections on the Theory and Practice of Education against the Principles of Rousseau by Hyacinth Sigismond Gerdil. With Introduction and Notes. Preface by Rocco Buttiglione. South Bend, Ind.: St Augustine Press, 2011.

Frank, William. “Personal Being and the Principle of Subsidiarity.” In Besinnung auf das Subsidiaritätsprinzip / Reflections on the Principle of Subsidiarity, ed. Anton Rauscher, 19-34. Berlin: Duncker & Humblot, 2015.

Nielsen, Cynthia. “Rehumanizing the Inmate: Wacquant on Race-making, Sequestered Spaces, and the Quest for a We Narrative.” In Philosophy Imprisoned. The Love of Wisdom in the Age of Mass Incarceration, ed. Sarah Tyson and Joshua M. Hall, 255-272. New York: Lexington/Rowman & Littlefield, 2014.

Nielsen, Cynthia. “Unearthing Consonances in Foucault’s Account of Greco-Roman Self-Writing and Christian Technologies of the Self.” Heythrop Journal 55 (2014): 188–202.”

Vorwerk, Matthias. “Citizenship of the Heavenly Fatherland: A Platonist Alternative to the Stoic Concept of Cosmopolitanism.” In Polis and Cosmopolis: Problems of a Global Era, vol. 2, ed. K. Boudouris, 230-40. Athens: Ionia Publications, 2003.

Walz, Matthew. “What is a Power of the Soul? Aquinas’ Answer.” Sapientia 60 (2006): 319-48.

Philosophy of Liberal Learning


Professors Frank, Sanford; Associate Professors Lehrberger, Simmons, Walz

Aims: The department has developed interests in the nature of liberal learning and the place of philosophy within it.

Representative Publications:

Frank, William. “An Essay in American Liberal Education: University of Dallas’s ‘Core Curriculum.’” In The College Curriculum: A Reader, ed. by Joseph Devitis, 125-39. New York: Land, 2013.

Frank, William. “A Reading of Augustine’s Confessions and Its Implications for Education.” Arts of Liberty Journal 1 (2013): 26-50.

Sanford, Jonathan J. “Newman and the Virtue of Philosophy.” Expositions 9 (2015): 41-55.

Simmons, Lance. “The Core Curriculum and Free Inquiry at the University of Dallas.” Fellowship of Catholic Scholars Newsletter 16 (1993): 810.

Walz, Matthew. “Augustine’s Modification of Liberal Education: Reflections on De doctrina Christiana.” Arts of Liberty 1 (2013): 51-97.

Philosophy of Mind and Language


Professor EngellandSepper


The faculty has developed interests in language acquisition, embodiment, linguistics, and phenomenology.

Representative Publications:

Engelland, Chad. Ostension: Word Learning and the Embodied Mind. MIT Press, 2014.

Engelland, Chad, editor. Language and Phenomenology. New York: Routledge, 2020.

Sepper, Dennis. “Phenomenology” and “Mind-Body Problems.” In The Oxford Companion to the History of Modern Science, ed. John L. Heilbron. Oxford: Oxford University Press, 2003.

Philosophy of Religion


Professor Parens; Associate Professors Lehrberger, Walz

Aims: The department has developed interests in the Catholic intellectual tradition, including the harmony of faith and reason, and in Islamic and Jewish approaches to the relation of faith and reason.

Representative Publications:

Lehrberger, O.Cist., Fr. James. “‘The Blessed in the kingdom of Heaven will see the Punishments of the Damned so that their Bliss may be more Delightful to them’: Nietzsche and Aquinas.” The Thomist 80 (2016): 425-62.

Lehrberger, O.Cist., Fr. James. “Intelligo ut Credam: St. Augustine’s Confessions.” Thomist: A Speculative Quarterly Review 52 (1988): 23-39.

Parens, Joshua. An Islamic Philosophy of Virtuous Religions: Introducing Alfarabi. Albany, N.Y.: State University of New York Press, 2006.

Walz, Matthew. “Synthesizing Aquinas and Newman on Religion.” International Journal of Religion, 86 (2019): 173-198. 

Philosophy of Science


Professor Sepper; Associate Professors Mirus, Simmons


The department has developed interests in the origins of ancient and modern science.

Representative Publications:

Mirus, Christopher. “Aristotle on Beauty and Goodness in Nature.” International Philosophical Quarterly 52 (2012): 79–97.

Mirus, Christopher. “Homonymy and the Matter of a Living Body.” Ancient Philosophy 21 (2001): 357–73.

Mirus, Christopher. “The Metaphysical Roots of Aristotle’s Teleology.” The Review of Metaphysics 57 (2004): 699–724.

Sepper, Dennis. Goethe contra Newton: Polemics and the Project for a New Science of Color. New York: Cambridge University Press, 1988.

Sepper, Dennis. Newton’s Optical Writings: A Guided Study. Masterworks of Discovery. New Brunswick, N.J.: Rutgers University Press, 1994.

Sepper, Dennis. Understanding Imagination: The Reason of Images. Studies in History and Philosophy of Science, 33. Dordrecht: Springer Verlag, 2013.

Political and Social Philosophy


Professors Frank, Parens; Associate Professor Nielsen


The department has developed interests in both classical political thought and Catholic social thought, and it applies these traditions to contemporary questions.

Representative Publications:

Frank, William. “Tolerance and the Autonomous Individual in Modern Democratic Liberalism.” in Toleranz und Menschenwürde / Tolerance and Human Dignity, ed. by Anton Rauscher (Berlin: Duncker & Humblot, 2011) pp 341-56.

Frank, William. “Authority and the Common Good in Democratic Governance.” Review of Metaphysics 60 (June 2007): 813–32.

Nielsen, Cynthia. “Inmates, Education, and the Public Good: Deploying Catholic Social Thought to Deconstruct the Us-Versus-Them Dichotomy.” Co-authored with Dr. Peter S. Dillard. Heythrop Journal 56 (2015): 769-777.

Nielsen, Cynthia. “Resistance is Not Futile: Frederick Douglass on Panoptic Plantations and the Un-Making of Docile Bodies and Enslaved Souls.” Philosophy and Literature 35.2 (2011): 251–68.

Parens, Joshua. (Edited in collaboration with Joseph C. Macfarland:) Medieval Political Philosophy: A Sourcebook. 2nd edition. Ithaca: Cornell University Press, 2011.

Parens, Joshua. “Multiculturalism and the Problem of Particularism.” American Political Science Review 88:1 (1994): 169–181.