I don't get it...even Guth from MIT who is one of the pioneers of the big bang concept says that "we know that something banged, but why it banged and what caused it to bang is another story" - quoted by memory but the meaning was like that. So...some people think they are too smart to realize that since we don't have time before the big bang - then it makes no sense to measure anything prior to the bang. In a similar fashion if you were the only person in the world before the big bang you cannot ask "where is the big bang" since the word "where" would have no meaning with just you and some infinitely small object. But that's not what bothers me...what really strikes me is the fact that the probability for the big bang to happen is actually....you are right: ZERO. There is no chance if something has existed forever to change its form just like that. However, badly enough this is how modern day physics describes the big bang - as something which exists forever and then out of nowhere decides to explode and change it's shape just like tht. It doesn't matter what probability distribution would you use to describe such behaviour - continous, discrete or whatever - the chance for this is always 0. So something might have caused the big bang. In my opinion the best theory is a white hole. Problem is that I see no way to prove such thing with empirical evidences. Even then it is reasonably to abandon the idea that the big bang is caused randomly. Randomness means that you cannot predict when something is going to happen and not that there is no reason for one thing to happen. Ps: Yes I know it wasn't an "explosion" and it wasn't big. It's just known long ago so I didn't include these tiny details. Other than that: te probability is zero. In layman terms: what is the probability if something has existed forever to die? One in infinity or one divided by infinite amount of numbers - which is 0.0.... or actually zero. So, the big bang problem is a problem of the limit of the human mind - people just desperately desire everything in the world to have a beginning and end - while it has NOT. Just like the universe has no space where it begins and no space where it ends - if you take 2 bodies that have always moved in opposite directions - they WILL be in infinite space distance between each other. So infinity exists and it rejects the big bang all start theory.