The problems of God foreseeing are well known – if things are known in advance, nothing can be free; if God saw some evil happen, he should have stopped it; if God foresees his own action, even he can’t change his own mind, etc.
I’m not interested in solving the problem, only in pointing out something that is (sometimes? Often?) assumed and implied when we consider the problem, but which no one thinks is true when it is made explicit, namely Foresight is guessing or prognosticating, which is later confirmed or disconfirmed. Presumably, no one thinks that God’s foresight consists in his being the most perfectly talented guesser, or a perfectly well-informed pundit. No one thinks, for example, that my bringing a ham sandwich to work today confirms a previous divine claim that I would do so today.
But what is this foresight if it is not guesswork followed by confirmation? We must mean it is some sort of immediate vision: with God seeing all points in time like we see all the spacial parts in our horizon. God sees things “before they happen”. But we can’t mean that God sees X before X exists; since under such a condition there is no X to see. The best he could see is some image of the event to come, not the event itself. If, for example, I tell you that I saw the September 11 attack before it happened, you’ll assume that I had some sort of vision or dream, but a dream is no more a vision of the event itself before it happens than it is a vision of the event itself after it happens. The vision substitutes for the event whether it is seen before or after, and so the actual event confirms it after happening. But this is exactly the sort of guesswork-confirmation model that no one thinks God is involved with.
Or assume that the vision is not a substitute. Assume that, while sleeping some night in, say, 1996, you really were watching the September 11 attacks happen. But if this is our ontology, we’re saying that in 1996 you watched them happen in 2001. So we can’t simply say that you saw them happen before they happened since you watched them happen in 2001, which is when they happened.
And so if we expose the assumption – believed by no one – that God does not foresee in the sense of guessing or predicting and later being borne out or confirmed, we are left with an ontology that this foresight consists in being able to see a thing happen when it does at the same time as before it does.
And so the answer to a question like “Why did God not stop some sin before it happened” is in a certain sense very simple: i.e. because, like us, he saw the sin when it happened. Indeed, it is necessary for both God and man to see a thing happen when it happens. In the same way, whenever God sees our choices, he also sees them in the exact same vision when they happen. This seeing when the event happens is essential to the vision, whatever else might come with it.
This can be read just as well as a refutation of omniscience: one might just say it’s incoherent to see something when it happens and not when it happens in one and the same vision. But this is what’s God Knowledge comes to, not some infallible prognostication, or God seeing all things that will happen in his head before they do.