God has some posterior knowledge, such as simple foreknowledge which God knows in virtue of observing the actual world from a timeless perspective. However, does that imply that God, at the moment of creation, learns things? Let us say that God learns things just in case there are some propositions, not previously known by God, which become part of the set of propositions which God knows to be true. For instance, if God is in time, as William Lane Craig and others have proposed, then God must learn a great many propositions as time flows on, since tense is an objective feature of reality and an indissoluble part of propositions about events in time. However, supposing God is outside of time, doesn’t it stand to reason that God did not know to be true, in the non-temporal absence of creation, that which would be true if creation were actual?
In other words, it seems that if any proposition ‘becomes’ true, then God must ‘learn’ it. The confusion here arises because we may imagine that God goes from a state of not knowing, to a state of knowing, and that seems to conflict with his immutability. Of course, if time only exists along with creation, then there is never a time at which God came to know anything true, at least on the classical orthodox view that God is not subject to the flow of time. There is, strictly speaking, no ‘time’ before creation, at which God does not know some truth. Thus, it seems confused to speak about God coming to know anything rather than simply knowing it a posteriori (here being used in an obviously special sense).
What God knows in the absence of creation is a tricky question. Of course, omniscience is typically defined as God knowing all and only truths, and it would seem that if there were no true things then God would be omniscient even if he knew nothing at all. However, it seems that some things about God would be true even in the absence of the world. Let’s define the world as Fr. Coplestone once did: “the real or imagined totality or aggregate of individual objects, none of which contain in themselves alone the reason of their existence.” Candidates for things which would be true in the absence of the world include propositions such as “God exists” or “the world could exist” or “God is a Trinity” or others like these.
Further, we can wonder about the following proposition in the absence of creation: “If creation occurs, x will instantiate” where x will include all the propositions which are true in virtue of correspondence with actual creation. Does God know that in the absence of creation?
Perhaps it is confused to speak this way altogether because propositions are not objects in the world, but rather represent a façon de parler which is only possible given a universe of discourse, which is only possible with the existence of the world as it was previously defined. Thus, strictly speaking, there are no propositions about anything in the absence of the world. Moreover, though the world clearly has a relation to God (such as finding in him its sufficient reason) God does not have any real relations with the world (thus, God does not ‘become’ the creator of the world, nor does God ever truly ‘become’ anything at all).
I might conclude that predication is a function of language, and it is not intelligibly used in the absence of creation. Language is grounded in creation, as is ‘truth’ in the propositional sense. We can speak in one sense of God without creation, so long as we do not confuse this with thinking that God existed while creation did not. However, we cannot intelligibly predicate anything of propositions (such as their being true or false) when propositions in no sense exist, since propositions only exist even now as expressions of that which is actual (or isn’t). In other words, even propositions such as “God is a Trinity” do not ‘exist’ (as expressions), because propositions do not exist (as expressions), in the absence of creation. There are no propositions which are added to the set of propositions God knows to be true, because the entire set itself comes into existence along with the world, thus God does not learn. That seems to mean, though, that God did not know by simple knowledge even what logically possible worlds there were to actualize before he actualized creation.
This is certainly tricky to think through.