There is a standard pattern in philosophical conversations. People stumble upon their epistemological limitations and then assume that God’s existence somehow would’ve solved the problem.
For instance, suppose we are talking about Münchhausen trilemma, demonstrating the inability to have completely certain foundation for knowledge. We inspect different horns of the trilemma and then conclude with a sigh:
“Oh well, it seems there is no absolute certainty in our world. Unless, of course, God Himself would tell us that something is true”.
This is deeply related to the idea of curiosity-stoppers. Standard non-answers that make people pretend that the problem is solved and, therefore, cease any further investigation. Naturally, saying “God!” is a very popular one.
But this time the situation is a bit different. The problem was already investigated and discussed. Dare I even say, understood. And yet we are still invoking “God!” as an afterthought. As if we are trying to appeal to His divine vanity and give Him some credit anyway, even if we’ve just explored all the reasons He wouldn’t help at all.
Imagine that it was extremely clear that God existed. Imagine everyone could close their eyes in prayer and in a very literal sense find themselves in a presence of absolute goodness, ready to guide them through the hardships of the life and answer the questions about the nature of the cosmos.
For some question there would be clear answers. For others - just pointers towards the new trains of thought or clever arguments. God wouldn’t spoil all the discovery for you, but could put you back on track were you to be led astray and ask for help.
What things God had revealed were indeed shown to be true by independent validation. And the answers He gave are consistent among people. There was not a single known instance of God lying or being wrong. And so on and so forth.
So imagine all that and then suppose that God told you: “X is true”. Can we now justifiably believe that it’s indeed so with absolute certainty?
At the very least we would have to trust God. And, while doing so in this scenario seems to be quite reasonable, this is the conclusion to which we have arrive the standard way - by analyzing evidence with our own minds. And so the trilemma still stands:
We might have a new and, on a reflection, very trustworthy source of empirical evidence, but it’s still merely empirical evidence, unable to bring us to full certainty. Our reasons to trust such evidence would be of the same kind as reasons to trust our observations and reasoning right now. Addition of God didn’t change anything substantial in the problem.
And it’s not because our imperfect minds are so flawed that even omniscient God can’t help us. The situation is almost the same from the perspective of God himself. Yes, he appears to know everything. But can he trust his own omniscience? Any reason for doing it will be rooted in his own omniscient mind. And what if his mind was created by even more powerful entity in such a way that our poor God was always deluded about the nature of his existence? That he only thought himself to be omniscient while actually being nothing but?
The same goes for other contentious philosophical problems. If we have troubles justifying objective, stance independent morality, God can’t help us with that. His stance on morality will be just another stance, his divine authority - just another authority. God’s eye view is just as subjective as any other.
If we are struggling with the problem of the first cause, existence of God doesn’t resolve it either. We merely get yet another thing to be caused, passing the buck one level further. And if God can be uncaused, well, why not something else?
Some may find this to be a reason for despair. If even omniscient God can not help with our problems, what can we, mere mortals, do? Shouldn’t we just give up and accept that we will never find any solutions?
But I think there is a more optimistic twist on the insight. If the addition of God can’t solve philosophy, then we are not missing much in this regard in a godless world that we seem to be living in. Maybe some questions will have to be refined. Maybe some answers will not be what we’ve initially expected them to be. But whatever answers exist - they are ours to discover.