Today I had to give a presentation of Luis de Molina’s doctrine of middle knowledge for a philosophy class, and I also received a comment on my blog which invited me to think more deeply about Molinism. The question I want to address in this post is this: how can God prophesy anything without middle knowledge? If God knows that Q* holds in a world ceteris paribus, he cannot know that if he actualizes P* (a prophesy about Q*) that Q* will still obtain, since by actualizing P* God has actualized a different logically possible world to the world he posteriorly observes in which Q*.
Some slightly more elaborate and rougher thoughts can be found in my comments here.
In this post I just wanted to develop my last alternative as food for thought. I said:
Perhaps we can also say that God simply knows that if Q, then P (if Q is actual, then he will actualize P), and also knows that Q and P are simultaneously true. In this way God does not know that Q, and then know that P&Q – but God would simply know [P&Q]&[Q]. God actualizes P if and only if he knows [Q]&[P&Q]. Suppose, then, that there exists some Q*, such that God responds by intending to actualize P*, but with the result that [P*&~Q*] is true, then God knows that in the world where [Q*]&[P*&Q*], he actualizes P*. However, in the actual world, he does not actualize P* just in case ~[P*&Q*]. That seems rather abstruse, perhaps, but I think one can make sense of it. If Q* then God intends P*, but God only actualizes P* in such a world where [Q*&P*] on pain of contradiction.
I realize that answer requires refining, but I think there is something to it.
Let us suppose there are some events Q* which, if they were actual, God would intend to prophesy them (P*). Now let us say that (Q*⊃P*)≡(P*&Q*). In other words God may intend P* in every world with Q*, but only actualize P* if (P*&Q*). Thus, it is only logically possible for God to actualize P* given Q* in worlds where (P*&Q*). In worlds where Q* and ~(P*&Q*), God cannot actualize P*. God’s action (actualizing P*) is only logically possible given the truth of (P*&Q*). God actualizes P* if and only if P*&Q*.
One obvious problem with this is that it seems that, although God intends to actualize P*, God may fail to bring P* about if ~(P*&Q*), which seems to constrain his omnipotence. We could say that his omnipotence only stretches to the logically possible, but it seems odd, in this case, to say that God can intend to bring about P* and Q* where there are possible worlds where Q* and ~P*, and others where Q* and P*, and Q* is actualized freely by an agency other than God, and actualizing P* has no causal relation with Q*. But I seem to be claiming that [(Q*)&(Q*&P*)]⊃P*.
Perhaps we can say that God only wills to actualize P* in the case where Q*&P*.
What I’ve just said may be confused, and is definitely still unrefined, but I have a feeling I’m on to something, because God acts tenselessly in accord with tenseless truth(s). So, perhaps God can only prophesy some libertarian-free event if it is chosen freely even along with the prophesy about it.
[Edit: Therefore, God intended not particular prophesies of events the realities of which depended on Libertarian-Free agencies other than himself, but rather intended that there be some (indefinite-plural), and some Libertarian-Free decisions not only had the effect of bringing about their immediate cause, but also had the effect of determining whether God could prophesy it, since God was giving the Libertarian-Free agent the choice of whether what they did could be prophesied by him. God’s omnipotence, on this view, is no more impeded then he allows it to be because of other instances of Libertarian-Free actions on the part of agencies other them himself. He simply allows Libertarian-Free agents to decide whether he can prophesy this or that activity of theirs, according to what they Libertarian-freely choose to do.]