Hugh LaFollette considers Plantinga’s arguments and finds them lacking. The argument being responded to is this:
Consider, [Plantinga] says, some human, Maurice, who will, at some time t in the near future, be free with respect to some insignificant action — like having oatmeal for breakfast. That is, at time t, he will be free to take oatmeal, but also free to take something else, say, shredded wheat. “Next suppose we consider S’ a state of affairs that is included in the actual world and includes Maurice’s being free at time t to take oatmeal and free to reject it.” This S’, Plantinga tell us, includes neither Maurice’s taking nor rejecting the oatmeal. … God knows that one of the following conditionals is true:
(8) If S’ were to obtain, Maurice will freely take the oatmeal.
(9) If S’ were to obtain, Maurice will freely reject the oatmeal. (99)
Suppose that S’ obtains and (God knows that) (8) is true there. Then the world W’ in which Maurice will freely reject the oatmeal, though possible, is “unfeasible” for God. For if God leaves things be, then Maurice will freely take the oatmeal and W’ will not be actualized; if God forces Maurice to reject the oatmeal, then our hero’s decision will no longer be free, and once again W’ will not be actualized.
LaFollette argues that to say that S’ obtains, (8) is true, and Maurice freely rejects the oatmeal is to utter a logical contradiction. And contradictions indicate impossible not merely unfeasible worlds. The issue here turns on how best to reconcile God’s foreknowledge and contingent events. If we say that God knowledge depends on or is determined by creaturely actions, then LaFollette’s complaint cannot be sustained: it could have happened that W’ occurred and then God would have known something different, namely that Maurice would freely not take the oatmeal.
In other words, (8) is true because W’ does not occur; but if it were to occur, then (8) would be false and God would have known that. It is certainly true that the conjunction of S’, (8) and W’ is impossible, but that is irrelevant, because (8) and W’ will never occur together; the truth value v of (8) is a variable that is counterfactually dependent on the occurrence or non-occurrence of W’. By knowing v first through simple intelligence and ultimately by vision, God foreknows what Maurice will as a matter of fact do. But if that is so, then it is not within God’s power to cause Maurice to freely choose not to have oatmeal, yet the world in which this happens is clearly a possible one.
However, I agree with LaFollette that Plantinga’s defense is inadequate. Plantinga’s argument is that
∀(x)(x has committed even a single moral evil ⊃ ◊(x has transworld depravity)) or, equivalently,
∀(x)(x has committed even a single moral evil ⊃ ◊□(x is depraved)) or, from the S5 system of modal logic,
∀(x)(x has committed even a single moral evil ⊃ □(x is depraved)) or, simply,
(a) ∀(x)(x is depraved ⊃ □(x is depraved)).
There is really no evidence either for (a) or against (a), but (a) is conceivable, and that, Plantinga seems to argue, is sufficient to demonstrate the compatibility of
(1) God is omnipotent, omniscient, and perfectly good; and
(5) The actual world contains moral evil.
In other words, we can say that based on our current knowledge of things, it is not appropriate to confidently affirm that (1) and (5) contradict each other.
We can even strengthen (a) to
(b) □∀(x)(x is depraved ≡ □(x is depraved)).
The problem is that it remains a possibility that there may be a world populated entirely by perfect saints, i.e., a world in which no one is depraved. This eventuality may be denied with a still stronger statement:
(c) □∀(x)(◊(x is depraved) ≡ □(x is depraved)),
but at the cost of making it false. For (c) has two unhappy implications. Now every possible human being is “possibly depraved”; that’s the essence of the human condition, free will, etc. First, if it follows from this that such a creature is depraved necessarily, then it means that sin is necessary and absolutely unavoidable. The Catholic Encyclopedia argues rather that “while of our own strength we cannot avoid sin, with God’s grace we can.” Perhaps in a world whose nature is less viciously corrupt than ours, a life of unwavering natural righteousness is occasionally possible even without grace. Plantinga bothers with no such distinctions. Second, it implies that no actual human being has ever lived a sinless life. But there is a counterexample: Mary the Mother of God. Hence, (c) is false and this particular counter to the problem of evil stands undermined.