There is a major problem with saying that God is not in time with usâŚthe Christian God is also held to be omnipresent. He cannot exist outside of our time and be omnipresent.
But omnipresence, at least on traditional, non-pantheistic understandings, does not mean that God is literally or physically
in the universe. It is more of a presence
to the universe (as cause, sustainer, creator).
This is why proponents of Godâs eternity (Eleonore Stump, for example, whom Peter Plato cited) still formulate a simultaneity relation. Though God is not in time with us, there is a relevant sense in which God exists simultaneously with us. There is analogously a relevant sense in which God is present to us. The former does not imply that he is temporal; the latter does not imply that he is spatial.
I think that the timeless notion is just another attempt to take the sting out of omniscience.
That it does so is less than obvious, I concede. And some philosophers would deny it. (Also, timelessness was formulated, at least as it is generally understood today, first by Boethius, whose solution to the foreknowledge problem in my view did not quite work, or at least requires supplementing,
particularly in terms of a compatible account of omniscience. And that account of omniscience did not come for several hundred years, in Aquinas. So historically, though its relevance to the question of how omniscience works has been noted, itâs not very clear that it was the motivation.)
In any case, I think we have the timeless conception of God because a) it is a clear corollary of traditional proofs concluding that God is pure act in a sense that other conceptions are not and b) it affirms Godâs absolute transcendence.
Another concern is that, prima facie, time and the universe are contingent, but God is not. This does not necessarily rule out the idea that God, by creating, enters into time, but there is generally not a reason given for that position other than the perceived difficulties with timelessness. If timelessness can be made coherent (and I believe it can), then the idea of an essentially timeless God entering into time should be treated as an ontological extravagance. However, that view is also incompatible (at least on the only readings of it that I can imagine) with Godâs lacking all potencies, and for that reason should be discarded anyway.
I also think that for God to be âin timeâ but to be essentially changeless still would require that a timeless account of causation, knowledge, etc. be given anyway. There might be a few ways to avoid that, but again, they strike me as extravagances.