(October 13, 2014 at 5:40 pm)ChadWooters Wrote: The analogy he uses conveys the idea of contingency. The idea of the cosmological argument is that the existence of whatever is contingent and subject to change is causally dependent on something else whose existence is neither contingent nor subject to change, a first cause.
I think Alvin Plantinga's criticism of Aquinas' third way is worth noting and relevant to Feser's argument, taken from his book God, Freedom and Evil, pp 77-80:
Quote:This and other considerations suggest that perhaps after all Aquinas is not talking about a logically necessary being (one that exists in every world), but about one that has necessity of some other kind. It's not very clear, however, what this kind of necessity might be. And suppose we knew, furthermore, what kind of necessity he had in mind: what leads him to think that if he's proven the existence of a being that is necessary in itself (in whatever sense of necessity he has in mind) he's proved the existence of God? In sections of the Summa Theologica following the passage I quoted he tries to supply some reason for thinking that a being necessary in itself would have to be God. This attempt, however, is by no means wholly successful.
An even more impressive defect in the proof comes to light when we consider (2) and its relation to (3). In the first place
(2) Whatever can fail to exist, at some time does not exist
Why couldn't there be a contingent being that always has existed and always will exist? Is it clear that there could be no such thing? Not very. But even if we concede (2), the proof still seems to be in trouble. For
(3) If all beings are contingent, then at one time nothing existed
doesn't follow. What (2) says is really
(2) For every contingent being B, there is a time t such that B does not exist at t
From this Aquinas appears to infer (3) There is a time t at which no contingent beings exist. This is a fallacious inference it is like arguing from For every person A there is a person B such that Bis the mother of A to There is a person B such that for every person A, B is the mother of A
The first seems reasonable enough, but the second is utterly outrageous; more to the present point, it does not follow from the first. Similarly here: suppose it's true that for each thing there is a time at which it does not exist; we can't properly infer that there is some one time such that everything fails to exist at that time. Aquinas' followers and commentators have tried to mend matters by various ingenious suggestions; none of these, I believe, is successful.
