This is a very good point. Time being, in essence, a knowable dimension.
If there's geometrically no past, there can't be a prior cause.
I understand the conclusion of this statement, but I can't grasp the meaning of a "pior cause." Do you mean outside of time?
Will you please elaborate, thanks.
No. I said that if time doesn't exist before the Big Bang, there can't be a prior cause. "Prior" means "at an earlier time", and "cause" means a specific event at a well-defined place and time. To have a prior cause, there has to be a time at which it occurred.
That's not to say that it's impossible to construct models in which the Big Bang happens in a larger context (i.e., in which the Big Bang can be said to have a cause). Chaotic inflation, for example, has a gigantic number of Big Bangs, each giving rise to many more. Each of those cosmoses can be said to have a cause. My point was that there is no mathematical or philosophical requirement that such an outside context exist, although it may.