Then how can people claim the big bang theory. When people don't know the cause behind it, what cause the big bang. And then what caused that and what caused that and so ect--------
So what I'm asking .for the big bang theory to happen, What was the cause behind it for it to happen and what was cause behind that to happen and what was the cause behind that to happen and so on
OK, we know the Big Bang scenario is essentially correct: the universe is expanding, it is about 13.7 billion years old. It was once much hotter and denser. There is a lot more we know about the details.
What we do NOT know is whether there was a cause for the current expansion. But we don't need to know what the cause is to know that the universe is expanding. We do not need to know a cause to know that the universe was once much hotter and denser.
Furthermore, it is quite possible there *was no cause*. This is the possibility that you are consistently ignoring. It is quite possible the Big Bang doesn't *have* a cause at all.
So your asking for a cause, a 'why did it happen' is making an implicit assumption that may not be actually true: that it must have a cause.