Why Something Rather Than Nothing?

[FatAndFaithless]

But even that 'inifnity' is an unsupported presupposition. You can't claim that there could've been an infinite number of possible universes if we only have one universe to possibly examine. We don't know what happened before the big bang or even if there was a 'before' the big bang. You don't get to say that our universe is so unlikely just because it's particular in some constants. It could be that our current universe was the only possibe result of a pre-existing conditions, and there weren't an infinite number of possibilities. Sorry, you don't get to claim knowledge of probability before the beginning of the universe because there's no possible way (right now at least) for anyone to make any affirmative statement about the pre-big bang conditions.

Our universe is one; it's everything that actually exists or existed, including everything really existing "before big bang."

But a possible world is an abstraction defined as a maximally consistent set of propositions which are true in that world. It's an idea in the mind. And there are an infinitude of such ideas.

So, the question is why this all-encompassing actual universe is uniquely this and not any other similarly all-encompassing possible world.

Um..no. You don't get to throw a bunch of somewhat-brainy sounding words together and trot them out as some sort of valid philosophical point. You do not get to say anything about before the big bang, because we now exactly zero about what was before the big bang or if it's even possible to have a 'before' the big bang beacuse our current understanding of temporality begins with the big bang. Also, are you seriously saying that if someone can imagine a consistent world-model, that makes it one of the possible world-models whose form our current universe might've taken? You have absolutely nothing but conjecture, bald assertions, and sloppy appropriation of quasi-scientific language in your posts. Sorry, not even close.