What did I have in mind when I said that determinism is an unnatural belief? . Looking at what I was trying to say when I said it, it looks to me as if I wasn't thinking about naive student attitudes toward free will, but simply the fact that in the course of decision-making there are different possibilities that are open to us, one of which we select. Further, it does seem that we consider both choices that we make to be genuine possibilities. But if determinism is true, then the alternative possibility wasn't a real possibility after all. What we did was determined. It's hard to imagine making a difficult decision and asking "Hmmm. What was I predestined to do in this situation?"
I was thinking about the idea we seem to presume that there are possible futures depending on how we act, that become more or less likely depending on what we do. If God has predestined everything, and is determined to do so based on his own nature, then it looks as if there are no possible worlds except alpha.
There does seem to be an at least an illusion of free will when we deliberate and decide. It could be just that, an illusion.