I am quite certain that some things are provable to the extent of being relatable to the obsarvations we can make about the world. There is great value in being able to admit what you don't know, or that what you know might turn out to be imprecise in the future. But I don't see equal value in insisting that you don't know even if there is some evidence staring you in the face, just for the sake of allowing yourself to equalize the disliked, if more likely answer with the less likely one, albeit preferred, on the grounds of both of them being supposedly beyond the realm of scrutiny.
This brings me back to the question you had asked previously, about the compatibility/incompatibility of science and religion - judging by your personal views on the matter we're just discussing, it would appear that your belief in a creator leads you to discrediting the science related to the realm of creation. You would be very unlikely to find yourself engaged in a scientific effort to explain the origins of the universe, as you appear to already know how it happened, or at least(and forgive me that I'm not sure which it is) that it is impossible, or meaningless to know that. Thus the answers provided by your belief system prevents you from seeking answers in a scientific fashion.
From my point of view, it's just as possible that the big bang occurred without divine intervention and nature took it's course as it is that God created the universe, and a history of that universe that included the big bang.
Do I believe that one is more likely than the other? Yes. Do I know which is the reality? No.
I tend to gravitate towards science based reasoning, but I also never forget that if there is a supernatural being of immense power and knowledge out there, it's quite possibly going to be capable of editing time and energy directly. Such a being could actually create reality, including the history of said reality. One day we might be able to detect the residual effects of godly actions, if there is a god. If/when that occurs, then we'll certainly have many fewer Agnostics in the world.