Guth wrote that the Big Bang may not have been an isolated event, that Big Bangs happen all the time. First there is a universe and then a Big Bang happens inside it and cuts itself off from that universe. You can start with a universe, right? Big Bangs happen all over the place, and Big Bangs happen inside previous Big Bangs and so on forever. Kind of a fractal thing.
Doesn't matter, all roads lead to the first Bang.