Here’s the point. One can not use the big bang as evidence of a beginning of the universe, because the big bang is not evidence of a beginning of the universe in the intuitive sense–i.e., “beginning” has no real meaning when dealing with the beginning of the big bang because time didn’t exist until the big bang. However, this doesn’t mean there was nothingness before that point. Thus, no arguments, theistic or atheistic, can be based on the big bang.
I think the origin of time is the most important question because if there’s an origin of time, science cannot explain the single most important event of reality. Therefore, it is irrelevant with respect to the creation debate, as it totally rests on the causality assumption - that is, any event must have a cause. Explanations like the Big Bang of the multiverse or quantum fluctuations do not work because they presuppose a time origin and a law, that is, there has to be a moment when the law comes into existence from nothing, even if the Big Bang comes later. So, what caused the law? An eternal soup of laws popping out of the non-space? Maybe, but then you need time for the appropriate law to pop out and allow for the Big Bang, etc. Can that soup extend backwards forever? No it can’t because the correct law would have popped somewhere in the past… Where are we now? Is this sound rational reasoning? I don’t think so. A non-caused cause (aka God) is a simpler explanation which has resisted the test of times admirably.
All this is why I always happily say, “I don’t know.”
To make God a non-caused cause doesn’t solve the problem though. It makes as much sense to say the universe (and i mean EVERYTHING, whatever it is, not just our universe) had no cause. We do not know. It may be completely likely that we will never know. In that situation, I do not feel compelled to jump to a God-did-it answer.
As far as “resisted the test of times admirably,” I’d differ with you. Non-natural explanations have been kicked to the curb for 1,000s of years as humans have come to understand the way things work.
Were everyone to just say, “Well, the Big Bang is the origin of it all, which means God did it about 15 billion years ago,” they would have previously said, “Well, the Milky Way is all there is,” and “Well, evil spirits make you sick.” I’m not interested in that way of thinking.
As for the last part of your post, notice that, if the theist claim that a universal truth exists and ours is a God-created universe, it should not be surprising that a number of myths emerged over the centuries with more or less the same ideas. Those would be ideas related to the eternal and universal truths. In fact, if you think about it, under the null assumption of the theist, the really surprising observation would be that there were no common themes across the numerous myths of our past civilizations, and in particular myths related to creation.
On the other hand, if the non-theist claim is correct, it should not be surprising that a number of myths emerged over the centuries with more or less the same ideas. Those would be ideas related to being human–i.e., “eternal” and “universal” truths emerging out of the human condition. In fact, if you think about it, under the null assumption of the non-theist, the really surprising observation would be that there were no common themes across the numerous myths of our past and present civilizations, and in particular myths related to creation.