Prof. Gregory Doolan explains how Aquinas uses philosophy to show that angels are real immaterial beings—pure forms with intellect and will—whose place in creation can even be understood in relation to the famous “head of a pin” question.

This lecture was given on February 5th, 2026, at Harvard University.

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About the Speaker:

Gregory T. Doolan is Associate Professor in the School of Philosophy at the Catholic University of America (CUA). His research interest is in the area of Aquinas’s metaphysics, in particular themes concerning Aquinas’s natural theology as well as those concerning the intersection between his semantic theory and his account of metaphysics.

Prof. Doolan received his B.A. in political theory from Georgetown University in 1993 and his Ph.D. in philosophy from CUA in 2003. He taught philosophy at the Dominican House of Studies in Washington, D.C. from 2004–05 and joined the faculty of the School of Philosophy at CUA in 2005. A native of Philadelphia, Prof. Doolan currently lives in Washington, D.C. with his wife, three children, two cats, dog, and a bearded dragon.

Keywords: Aquinas, Angels, Hylomorphism, Immateriality, Intellect, Metaphysics, Separate Substances, Spiritual Beings, Universal Hylomorphism, Virtual Presence