How does quantum mechanics explain the big bang? Infinite realities?

[StayFrosty]

I hope I'm not being redundant here. I would like to re-start discussion on how, according to quantum mechanics, the universe can exist. The question could go deeper and ask why, since the universe does in fact exist, did it become so complex, develop life on at least one planet, etc. How did the universe form from nothing and seemingly survive a very long chain of coincidences which lead to such a complex universe? And does quantum mechanics hold the answer to this at all?

I opened a similar discussion on this a few weeks ago over here:
https://www.physicsforums.com/showthread.php?t=636611
I feel that my own 'theory' was too strange, long to read, and not scientific enough, which is why we didn't get too many replies.

But I do still feel that a concept of 'infinite alternate realities' is the best explanation for how our universe exists as it does, and why the big bang happened. In fact, in this event it would be more amazing for our universe not to exist at all than the fact it does exist.

Keep in mind I am not a scientist... I'm just an average joe trying to explain his surroundings. I'm mainly looking for theories here... it doesn't have to be actual scientific fact. Is all I ask is that any theories presented are not contradicted by any science we know to be actual fact. I apologize if I'm not "sciency" enough, but the fact is that helping me out here will help aide my approval of scientific views, and also prevent me from following ideas which I'm sure most of you would strongly reject or laugh it.

 

[cgk]

But I do still feel that a concept of 'infinite alternate realities' is the best explanation for how our universe exists as it does, and why the big bang happened. In fact, in this event it would be more amazing for our universe not to exist at all than the fact it does exist. [...]

If you cannot possibly do experiments to falsify a theory, it's not a theory. It is just speculation.

You can make up all kinds of things about the beginning of the universe or alternate realities. All are exactly as valid as all others.
The truth is: We only know the physical laws now, on earth, and we have no idea what happened a few billion years ago, or what happens even a hundred light years away. Who knows, maybe the physical constants change over time or space and we just can't measure it? Or the laws themselves contain gradient terms we can't see on the tiny time scales we have available...

What you are asking for is not physics and does not belong here.