I do not believe that scientists will eventually learn everything about the universe or reality. In fact, I’m all but certain that such a goal will
never be realized, since we are fallible human beings with limited intelligence.
However, that’s all beside the point. This conversation is not about the direction of science, but rather the epistemic question of whether or not there
must be, in principle, an explanation for every fact. I see no reason to believe this is true, and plenty of reason to suspect it isn’t (cf.
my discussion with J. D. Sinclair on W. L. Craig’s forum). In the case of the universe’s existence, we have a prime candidate.
No! By saying that the universe “appeared one day,” you’re implicitly referencing some larger context which is entirely unknown to us, and using it to provide an explanation (albeit a strange one) for the existence of the universe. But if the universe’s existence is a brute fact, then it has no explanation at all: there is no larger context in which it can be said to have “appeared.” (if we exist, there MUST have been a beginning. you simply choose to be ignorant of that which you can’t explain).
With brute facts, we stop cold. We can’t explain them at all, by definition.
So, in light of this, there is no reason to accept your dichotomy of a godless “actual infinity” versus God. What other explanation would you render for the existence of the universe? You’re “humans are too dumb” doesn’t count. What other organism’s brain would you like to borrow? How about an alien? Nah, you’d have to filter the info through your own human brain to understand it. What if the alien said to you “You humans are just not intelligent enough to understand actual infinity, but there is an answer. Just trust me.” Would you believe the alien on blind faith??? Now who is religious? Don’t feel bad. Aliens might be smarter than us, but they wouldn’t know either. Actual infinity is unknowable by definition. I have other objections to such dichotomies, as well, but the brute fact objection will suffice for now.