Many argue there is no "before" the bang state. Time and space might well have started with the big bang. There would be an absolute zero point in time, and not

Many argue there is no "before" the bang state. Time and space might well have started with the big bang. There would be an absolute zero point in time, and nothing could be before that just like nothing can be colder than 0K. For a while there was also the theory that the universe is cyclical: it eventually collapses and from that compressed state a new big bang is born. That seems very unlikely with what we know right now though. Then there are various forms of the multiverse theory where are kind of spontaneously created in a continuous process. Each universe experiences a big bang in the moment it is created, so talking about "before the big bang" only makes sense outside the universe But I don't think anything rules out a universe laying dormant and then something triggering the big bang either. Changing fundamental constants might well be that something. They don't even have to change continuously or frequently for this to work As you might have guessed, testing any of these is really difficult. Not necessarily impossible, but really really difficult