Medieval Philosophy

by Peter S. Adamson

have us turn to Avicenna, whose own more elaborate proof of the necessary existent is lurking in the background. A similar game can be played with the first way. In that case we might seek answers in Aristotle, who is the inspiration for Aquinas’ argument, or elsewhere in Aquinas, by looking to his theory of action to see why absolute self-motion is impossible.10 Of course, we might also use our own ingenuity to improve the argument; plenty of Thomas’ admirers have done so. But a more sensible reaction might be to assume that the student is familiar with these types of argument from studying their Aristotle and Avicenna and is just being reminded of several philosophical approaches to God that can be invoked in the rest of the Summa. To quote another Aquinas scholar, Brian Davies, “the purpose [of the five ways] is to set the ball rolling, not to bring the game to an end.”