The Five Ways
JOHN F. WIPPEL
As anyone with even a casual acquaintance with Aquinas's writings is aware, it is in the Summa theologiae (ST) I, q. 2, a. 3 that he presents his best-known formulation of argumentation for God's existence. A number of the arguments from his earlier writings foreshadow most, if not all, of the “five ways” of the Summa theologiae. These points of similarity notwithstanding, Thomas gives a personal and particular touch to each of the five ways themselves. Because of the relatively later date of this treatment (ca. 1266– 1268), because of the apparently wider readership at which the Summa theologiae is aimed, and because of the comprehensive way in which the five ways are fitted together, these arguments for God's existence have received more attention from Thomas's students than any of his other efforts to establish this point. 1
At the same time, it should be remembered that the amount of space accorded to each of the five ways is relatively brief and that in certain instances, at least, familiarity with some of Thomas's most fundamental metaphysical options is presupposed by them. 2 Finally, the question has often been raised concerning whether the five ways are intended by Thomas to form one developing argument for God's existence, or five distinct and more or less independent arguments. To put this in other terms, how are these five proofs intended to fit together? Before making any attempt to answer this question, however, it will first be necessary for us to consider each of them in turn.
Question 2 of the First Part of the Summa theologiae is addressed to this issue: Does God exist? 3 In a. 1 Thomas again rejects any claim that God's existence is self-evident (per se notum) to us, even though he continues to hold that the proposition “God exists” is self-evident in itself. Its predicate is identical with its subject since God's essence is his act of being (esse). Because we do not know of God what he is, that he exists is not known to us per