Abstract

While the importance of Avicenna as a source of Aquinas’s thought is generally recognized, the details of that dependence are just now being worked out. This article presents Avicenna’s teaching on the “subjects” of the theoretical sciences—physics, mathematics, and metaphysics—as presented in his Introduction to the Book of Healing. Its influence on Aquinas’s commentary on Boethius’s De trinitate, q. 5, art. 1, is then presented. Comparing Avicenna with Thomas in this way shows the profound influence of Avicenna on Thomas’s understanding of the range of the three kinds of theoretical sciences.