Body-Self Dualism in Contemporary Ethics and Politics, with Robert P. George (New York: Cambridge University, 2008).
Abortion and Unborn Human Life (Washington, D.C.: Catholic University of America, 1996).
“Theology and Thomistic Ethics,” Faith and Reason, 3 (1979): 47–68.
“St. Thomas and Avicenna on the Agent Intellect,” Thomist, 45 (1981): 41–61.
“The Permanence of the Ten Commandments: St. Thomas and His Modern Commentators,” Theological Studies, 42 (1981): 422–43.
“Aquinas and Scotus on Liberty and Natural Law,” Proceedings of the American Catholic Philosophical Association, 56 (1982): 70–78.
“Language about God and the Theory of Analogy,” New Scholasticism, 58 (1984): 40–66.
“The Relation Between Intellect and Will in Free Choice According to Aquinas and Scotus,” Thomist, 49 (1985): 321–42.
“Aquinas on Knowledge of Truth and Existence,” New Scholasticism, 60 (1986): 46–71.
“Existential Propositions in the Thought of St. Thomas Aquinas,” Thomist, 52 (1988): 605–26.
“Reasons and Religious Belief,” Faith and Philosophy, 6 (1989): 19–34.
“Etienne Gilson’s Thomist Realism, A Review Article,” New Scholasticism, 43 (1989): 81–100.
“Principles of Catholic Scholarship,” in Proceedings of the Fellowship of Catholic Scholars, 1988.
“Personhood, the Moral Standing of the Unborn, and Abortion,” Linacre Quarterly, 57 (1990): 80–89.
“Self-Consciousness and the Right to Life,” in Abortion: A New Generation of Catholic Responses, ed. Stephan Heaney (Braintree, Massachusetts: Pope John Center, 1992), 73–84.
“Evidentialism, Plantinga, and the Rationality of Religious Belief,” in Rational Faith: Catholic Responses to Reformed Epistemology, ed. Linda Zagzebski (Notre Dame: University of Notre Dame, 1993) 140–167.
“Existence, Truth and Realism,” in Saints, Sovereigns, and Scholars, ed. R.A. Herrera, James Lehrberger, O.Cist., M.E. Bradford (Peter Lang: New York, 1993), 95–106.
Articles in Encyclopedia of Catholic Doctrine s.v.: Absolute Moral Norms, Capital Sins, Cardinal Virtues, Choice, Conscience, Consequentialism, Cooperation, Deontology, Double Effect, Formation of Conscience, Free Choice, Hedonism, Human Goods, Human Virtues, Legalism, Modes of Responsibility, Natural Law, Passions, Positivism, Practical Reason, Probabilism, Proportionalism, Relativism, Subjectivism, Synderesis, Teleology, Utilitarianism, Vices.
“Human Beings are Animals,” International Philosophical Quarterly, 37 (1997): 291–304.
“Is St. Thomas’s Natural Law Theory Naturalist?” American Catholic Philosophical Quarterly, 61 (1997): 567–88.
“What Sex Can Be: Self-Alienation, Illusion, or One-Flesh Union,” with Robert P. George, American Journal of Jurisprudence, 42 (1997): 135–57.
“The Goodness of Creation, Evil, and Christian Teaching” Thomist, 64 (2000): 239–70.
“Personhood, Dignity, Suicide, and Euthanasia,” National Catholic Bioethics Quarterly, 1 (2001): 329–44.
“Germain Grisez’s Christian Humanism,” American Journal of Jurisprudence, 46 (2002): 137–52.
“Does God Have Emotions,” in God Under Fire: Modern Scholarship Reinvents God, eds. Douglas Huffman and Eric Johnson (Grand Rapids, Mich: Zondervan, 2002), 211–30.
“St. Thomas Aquinas on Human Ensoulment,” with John Haldane, Philosophy, 78 (2003): 255–78.
“The Moral Status of the Human Embryo,” in Nicholas Lund-Molfese and Michael Kelly, eds., Human Dignity and Reproductive Technology (New York: University Press of America, 2003), 71–80.
“Rational Souls and the Beginning of Life,” with John Haldane, Philosophy, 78 (2003): 532–40.
“The Pro-Life Argument from Substantial Identity: A Defense,” Bioethics, 18 (2004), 249–63.
“Are There Exceptionless Moral Norms?” in Nicholas C. Lund–Molfese and Michael Kelly, eds., Bioethics: A Culture War (New York: University Press of America, 2004), 31–41
“The Wrong of Abortion,” with Robert P. George, in Andrew I. Cohen and Christopher�Wellman, eds., Contemporary Debates in Applied Ethics (New York: Blackwell Publishers, 2005), 13–26.
“Abortion and Christian Bioethics: The Continuing Ethical Importance of Abortion,” Christian Bioethics, 10 (2004): 1–31.
“The Human Body and Sexuality in the Teaching of Pope John Paul II,” in C. Tollefsen, ed., John Paul II’s Contribution to Catholic Bioethics (Dordrecht: Springer, 2004), 107–20.
“Soul, Body and Personhood,” American Journal of Jurisprudence, 49 (2004): 87–125.
“Marriage and Acts Reproductive in Kind,” Vera Lex, Journal of the International Natural Law Society, 6 (2005): 163–82.
“Accepting God’s Offer of Personal Communion, in the Words and Deeds of Christ, Handed on in the Body of Christ, His Church,” in Mark J. Cherry, ed., The Death of Metaphysics; the Death of Culture (Dordrecht: Springer, 2006), 330.
“Interrogational Torture,” American Journal of Jurisprudence, 51 (2006): 131–47.
“Embryonic Human Beings,” The Journal of Contemporary Health Law and Policy, 22 (2006): 424–38.
“Substantial Identity and the Right to Life: A Rejoinder to Dean Stretton,” Bioethics, 21 (2007): 93–97.
“Evil as Such is a Privation: A Reply to John Crosby,” American Catholic Philosophical Quarterly, 81 (2007): 469–88
“The Papal Allocution Concerning Care for PVS Patients: A Reply to Fr. O’Rourke,” in Christopher Tollefsen, ed., Artificial Nutrition and Hydration, The New Catholic Debate (The Netherlands: Springer, 2008).
“The Nature and Basis of Human Dignity,” with Robert P. George, in Human Dignity and Bioethics, Essays Commissioned by the President’s Council on Bioethics (Washington, D.C., 2008), 409–34, reprinted in Ratio Juris, 2008.
“Marriage, Procreation, and Same-Sex Unions,” Monist, 91 (2008): 422–45.
“What Male-Female Complementarity Makes Possible: Marriage as a Two-in-One-Flesh Union,” with Robert P. George, Theological Studies, 69 (2008): 641–62.
“Human Nature and Moral Goodness,” in Mark Cherry, ed., The Normativity of the Natural (New York: Springer, 2009), 45–54.
