Ancient and medieval cosmologists used to wonder whether the universe had always existed, or whether it had come into existence at some particular time in the past. (I don’t think it had occurred to them that it might have existed throughout an open temporal interval bounded at the start but with no first point.) One of the arguments in favour of the universe always having existed was based on what philosophers call the Principle of Sufficient Reason. The idea was that if the universe had come into being at some particular time then there should be some reason why it came into being at that time rather than at another. This worry can be beefed up a bit if you think that God created the universe: even if random events can happen for no reason, it seems odd to think God would make a decision for no reason. Of course it’s odd to imagine God paralysed between two bales of hay like Buridan’s ass, but it’s actually kind of hard to explain exactly how arbitrary divine decisions are meant to work.
One option in the face of this problem is to say that the universe has always existed, and if you want to put a theological spin on that then you can say that God constantly acts to keeps the universe going, or that it depends on him in some other way besides being created at a particular time. An alternative is to say that there was no such thing as time independent of the universe being created: God’s act of creating the universe also created time itself. That option goes back a long way, but it’s probably harder to square with a pre-modern understanding of time than with the picture offered by contemporary physics, so people still fretted about it. It’d be nice to have an explanation for why one time to create the universe might have been better than the others, so that’s what I’m going to offer today.
When philosophers of religion aren’t fretting about cosmology, they’re usually fretting about free will and divine foreknowledge. If God knows this morning what I’ll do this afternoon, how can my actions this afternoon be free? Well, one option put forward by Boethius is to say that, just as seeing something happening now isn’t making it happen, seeing/knowing about something happening in the future doesn’t make that happen either. We control what we’ll do, and that determines what God (correctly) believes we’ll do. If that’d be a case of backwards causation, then there’s backwards causation. (Backwards causation? Wouldn't that mean time travel is possible? Well, yes: with God all things are possible.) Now, if you take this line on free will and divine causation, then I can help explain why God created the universe when he did.
The idea is that, at each time while he was waiting to create the universe, God knew which free choices the people would make if he created the universe then. The same initial conditions could lead to different outcomes – that’s what indeterminism is – and at each time God knew which outcomes he’d get if he put his initial conditions in place then. He waited until the time that would lead to the best choices, created the universe then, and here we are.
For someone with the prior commitments I have about time, free will, the existence of God and the principle of sufficient reason, this puzzle is basically moot. But a puzzle being moot never stops philosophers trying to solve it. And if you have different commitments, maybe my idea can help you more substantively. What do you think?