From the fixity of the past to the fixity of the independent—Andrew Law, Phil Stud (2021) 178:1301–1314
Here’s a nice discussion of the question of the fixity of the past, which has relevance beyond a theological context.
In general, I have no dog in this fight, and not just because I don’t believe in God. God’s foreknowledge is a problem for Libertarian views of free will. Suppose freedom requires that there be no fact of the matter about what we will do before we do it. But if God knows what we will do before we do it, then there is a fact of the matter, and therefore our actions aren’t free. (And if he doesn’t, the argument goes, he’s not omniscient.)
To a compatibilist about free will, like me, this is no problem. If freedom is compatible with our actions being causally determined by the past, then it doesn’t matter if some Laplacian demon, or God, is able to exploit that to predict them.
The argument from the fixity of the past backs this problem up in a way that resembles Van Inwagen’s consequence argument. If God knew what I would do before I did it, the argument goes, then my doing something else would require me to change a fact about the past, namely what God thought beforehand. And I can’t change the past!
This also widens the reach of the agument slightly. Consider an indeterminist block universe, where there is a fact of the matter about what I will do in the future, but it isn’t determined by the past. If your view of freedom requires only the absence of determinism, then you might not be troubled by God knowing the future; but you could still be troubled by the impossiblity of changing God’s past knowledge. (Just as some compatibilists are worried by Van Inwagen.)
Replacing the fixity of the past with the fixity of the independent offers a way out of this. The idea is that what is fixed is not the past as such, but things that don’t depend on your actions. If God’s knowledge is the result of your actions, then it depends on them, and so shouldn’t be regarded as fixed.
Law gives several reasons for preferring FI to FP, which are I think persuasive on (non-theological) metaphysical grounds. The fixity of the past depends on various apparently contingent assumptions; in a possible world where backward causation is rife, the past is no more fixed than the future. (Specifying “the past” also raises problems with Relativity.) The better view, I’m persuaded, is that past is fixed, if it is, because it’s independent of our actions. Not the other way around.
What he doesn’t say, unless I missed it, is why we should think God’s knowledge of our actions is dependent on our actions. (Perhaps that’s assumed in this literature, I’m very much not a specialist here.) The best reason I can think of is that God is not a Laplacian demon. He’s not taking a snapshot of the world and running a full-scale physics simulation to predict the future. He’s eternal! He can simply observe the future directly, as easily as he can the present. No need for all that modelling work. So his knowledge of my actions depends on them in the same way ordinary after-the-fact knowledge does. And he can know about them whether or not my actions are causally determined or otherwise fixed by the past.