This is the last of 17 posts, which are collectively Eternity, etc.
......There is something counter-intuitive about the suggestion of the previous post, of course (even on the modern view of arithmetic). If B is the biggest Beth that has been constructed, then my suggestion denies that 2-to-the-power-of-B exists, where 2-to-the-power-of-B is the cardinality of P(X) when X has cardinality B. Were there no such B, my suggestion would deny that the union of the existing sets has an actual cardinality, on the modern view of the natural numbers (on the older view, it would deny the existence of M + 1, where M is the biggest natural number divinely constructed). Either way, my suggestion is effectively that there are true statements that God did not know but which were bound to be true and which, if we could come to know them, we would most naturally say had always been true. Intuitively, that seems to fall short of divine omniscience.
......Nevertheless, we know from section III that what can seem, with hindsight, to have been timeless truths may not have been. And according to section VII it is logically, not just physiologically, impossible for anyone to say or know all such things. Such statements therefore belong to an indefinitely extensible totality. Would it therefore be more accurate to talk of possible statements here? Maybe not [i], but it’s certainly logically possible that our intuited shortfall is due to our being dependent creatures. For us, even physics is immutable, but God is certainly the ground of metaphysical possibility. And He may well be the ground of all meaning and value. So the counter-intuitiveness of divinely created mathematics may prove, upon reflection, to be no more conclusive than the counter-intuitiveness of Divine Command Metaethics [ii]. After all, my suggestion does not deny that, in the time we took to think of 2-to-the-power-of-B, God had already constructed it [iii].
......So, to recap, God’s omnipotence conflicts with His timelessness, according to section VII, unless we deny arithmetical Realism, or deviate further than Presentism does from standard logic. And under Presentism, even such an omnipotent God could be necessarily omniscient. So what follows from God being necessarily omniscient—and our freedom being libertarian—is primarily disjunctive. Either God has timeless knowledge of the future—if that does cohere with our freedom being libertarian—but Realist arithmetic is paradoxical, or Realist arithmetic is divinely constructed and time is Presentist, or some other option. So even if they regard God as necessarily omniscient, Perfect Being Theists who take a libertarian view of free will—and regard the future as (partially) real—should not reject Open Theism.
......[i] Statements are basically possible assertions (see note ii of Eternity), but a possible statement is not necessarily just a statement. Similarly, one might be unable to say something in French, and yet be able to learn (more) French, so that one would be able to be able to say it. It is of course hard to tell how apposite that analogy is, for the language (so to speak) of God’s thoughts.
......[ii] Lois Malcolm, “Divine Commands,” in Gilbert Meilaender & William Werpehowski (eds.), The Oxford Handbook of Theological Ethics (Oxford Univ. Press, 2005), pp. 112–29.
......[iii] Suppose (see note v of Possible Worlds) that a God who could change had made our 4-dimensional world in an instant. Then some biggest Beth, say B, would be known by Him at all (of our) times. But then we might use “2-to-the-power-of-B” as a definite description of a Beth that He does not know, at any (such) time, which hardly coheres with His being the greatest conceivable being. By contrast, a Presentist God would most plausibly be learning arithmetic too quickly for us to describe any such number.