Volume 2, 1999
John F. Wippel
Thomas Aquinas, Siger of Brabant, and Their Use of Avicenna in Clarifying the Subject of Metaphysics
Both Aquinas and Siger were familiar with a fundamental disagreement within the earlier philosophical tradition concerning the subject of metaphysics: Is it being as being, or is it divine being? If Avicenna represented one approach to this issue, and Averroes another, both Thomas and Siger were closer to Avicenna
than to Averroes in their respective solutions. Nonetheless, each resolved the issue in a distinct way. Also contested in the earlier tradition was the question of whether it belongs to physics or to metaphysics to demonstrate the existence of God. Again, Avicenna represents one side on this issue, and Averroes the other. Thomas’s personal position continues to be debated by contemporary scholars, and Siger’s seems to fall between those proposed by Avicenna and Averroes.
Finally, Aquinas is credited with having developed a new and unique way of accounting for the discovery of being as being, through a process known as separatio; though there are antecedents for this in Avicenna.