But if open theism is true, then God cannot form such beliefs about the future. For open theists agree that God is essentially infallible in his beliefs: it is impossible for God to hold a false belief. But if God were in a habit of forming beliefs about how people will in fact act, then in at least some possible worlds, and probably in this one as well, God would have false beliefs—it may be 99.99% certain that I won't eat a whole unsweetened lemon today, but that just means that there is a 0.01% chance that I will.
So the open theist, in order to hold on to divine infallibility, must say that God keeps from having beliefs on evidence that does not guarantee truth. Why would God keep himself from having such beliefs, given that they seem so reasonable? Presumably to avoid the risk of being wrong about something.
But now notice that open theism has God take really great risks. According to open theism, in creating the world, God took the risk of all sorts of horrendous evils. The open theist God is not at all averse to taking great risks about creation. So why would he be so averse to taking risks with his beliefs?
The open theists who think that there are no facts about the future have an answer here. They will say that my belief that at most a minority of my readers will eat a whole unsweetened lemon today is certainly not true, since the fact alleged does not obtain, and hence that I shouldn't have this belief. Instead, I should have some probabilistic belief, like that present conditions have a strong tendency to result in the nonconsumption of these lemons. My argument here is not addressed to these revisionists.