The Second Way

The Second Way

Cartwright, Richard L.

Medieval Philosophy and Theology, vol. 5, no. 2 (1996)


My title refers to the second of the arguments for the existence of God commonly called Aquinas’s “Five Ways.” The conclusion is that there exists “some first efficient cause” {aliquant causam efficientem pήmam). Now, anything that is a first efficient cause surely is an efficient cause that has no efficient cause.

So the conclusion of the Second Way must at any rate imply

(1) Ex(EyxCy&~EyyCx),

where C is the relation of efficient causation, that is, the relation x bears to yjust in case x is an efficient cause of y.

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