“Further, why should there always be becoming, and what is the cause of becoming?-this no one tells us.” Aristotle Metaphysics Book 12
It seems to me the ultimate objection to a temporal God is that it reduces God himself to a process – one more species of becoming. But becoming as such is conditioned. The process is a particular process that does this rather than that. As such it demands an explanation for why it goes the way it does. If God’s being is essentially becoming it cannot be such an explanation. Thus the process as a whole – just like Aquinas’ argument for an infinite series of contingent causes – exists inexplicably. Therefore there is no reason why it should exist rather than not. But it does exist. Therefore there must needs be some further back reality that itself is not one more species of becoming, but rather grounds it – an ultimate conditioner that gives rise to all conditioned processes. Thus we come to actus purus, etc.
I suppose one could ask if God’s “relation”to the world, or his conscious states, or his experiences, could themselves be species of becoming which he has determined so to be. Like saying “God is naturally actus purus, but wills to subject himself to a process of becoming.” But this to me is impossible. For what a thing essentially is, it must be, or else it is not itself but something else. Thus if we are led by argument to say that there must be a being who is itself Being and not just a process of becoming, it could not become other than Being, or else it would cease being itself. What one could say I think is that the particular relations in the created things come to be and pass away in a process of becoming. This is what led Aquinas to say things like the change (i.e. becoming) is not in God but only in the creature, and therefore God is “logically” related to the creature rather than “really” related to it as if the two existed in some common medium.
God cannot “become” a process because he is essentially not a process. Were he to undergo such becoming he would cease to be God – in fact he never would have been God, since in order to become anything one must first be able to be moved in some sense. And this implies some lack of being somewhere. It is not that movement or change are necessarily good or bad. This is the error of Process theology, which thinks that Classical theology believes that God is actus purus because it holds that all change must be either for the better or the worse. No. The insight of Classical theology is not that all change must be for the better or worse, but that all change implies a state of incompletion or lack of fullness. A thing takes on some new reality which it did not in the past have. But then the thing must have been in some way incomplete and able to be more and other than it was. It must have had some limitation such that it could not “be” unless it were subject to some process of sequential becoming. But who or what imposed such a metaphysical law? As Aristotle asked, “what is the cause of such becoming?” In short, change implies not necessarily good or bad (though it may). Rather, it implies a limit, which in the change is either now assumed, or now done away with, which the changing thing conforms to and is conditioned by. But then God would have some existing metaphysical limit or law imposed on him from outside himself, and where would that come from? So in either case we come up against some purely unmoved mover, some unconditioned conditioner, itself changeless which gives rise to changing things.
I will end by mentioning briefly in passing the straw man – or rather the misunderstanding – that often attends the idea that God is outside of time and becoming. I mean the idea that if he is so he is “frozen” or “inert.” Such words are merely abstractions from our sensual experience of what a “still” or “motionless” thing is like. But if God is actus purus, then in fact nothing can be further from the truth. Far from being lifeless or stagnant, God is literally pure act, supremely active and dynamic. He literally could not be more intimately involved, more connected, more careful about the world he has made. So let us not be misled by a mere metaphor when we are wondering about if God is outside of time.