In the work I mentioned, Plantinga was doing metaphysics of modality. I don't believe his primary concern was theological, although I could be wrong. He has some confused theological ideas, but his work on the metaphysics of modality is well-respected among professional philosophers.

That said, I don't think the possible world talk is as speculative as it appears. Here's why.

Consider the following definition. As I've used it, a 'possible world' just is a way, given God's omnipotence, He could have created things. (NOTE: There are other uses of 'possible world' talk in the technical literature. These aren't important for our discussion, however.) With that definition in mind, that there are "possible worlds" is not speculative. After all, saying that there are "possible worlds" is equivalent to saying that there are other ways God could have made things, given that He is omnipotent. This seems theologically uncontroversial and nonspeculative.

Second, since it isn't a speculative claim to say that God is eternally omniscient, it isn't speculative to claim that eternally knew every way that He could have made things. Using possible world jargon, this just means that it isn't speculative to claim that God eternally knows all possible worlds.

Third, since it isn't speculative to claim that God's omniscience is logically prior to His act of creation, it isn't speculative to claim that God, in creating, had to select one possible world to create over the others. Or, to eliminate possible world jargon, it isn't speculative to claim that God had to choose to make things one of the ways the He knew He was capable of making them. (By 'logically prior', I simply mean this: God's omniscience comes first in the order of nature. Or, it was necessary for God to be omniscient in order to be the divine Creator.)

As it turns out, it is perfectly plausible to claim that God eternally decreed free human actions, and, in fact, it would be surprising if He didn't. After all, when God created, it seems as though it was necessary for Him to create things only one of the ways that He knew He could make them. Furthermore, since there is moral responsibility in this world, it seems pretty clear that He chose to create a world where Adam sinned freely.

If one were to accept this picture, then one is almost a Calvinist with respect to the doctrine of unconditional election. The only thing left to be convinced of is this: the fall was so devastating that we need God's grace to change our sinful character so that we can freely receive Christ.

(Note: Calvinist confessions of faith say that God "persuades and enables" us to believe the Gospel. He "enables" us by changing our character or 'nature', and he "persuades" us rather than "coerces" us to believe. This persuasion is perfectly efficacious, but really good persuading is compatible with free action. In other words, Calvinists can even say that there is a sense in which we freely chose to believe the Gospel. After all, we weren't coerced, and our faith sprung from our own (newly regenerated) character. So, we can get freedom from top to bottom, but we still have a very strong, anti-Pelagian dependence on God's grace for everything good.)

I hope this post helps you!


"He that hath light thoughts of sin, never had great thoughts of God." ...John Owen