"a past that we have forgotten about" and "a lot of pasts"

I’d appreciate it if someone would answer my question. Thank you.

A: Everybody has a past and everybody has a future.

B: And the fallacy comes from idealizing a past that we have forgotten about.
(from google)

C: The present moment is made of a lot of pasts. (from google)

I think “a past” in A is a personal past experience, and it’s rightly used.

But how about “a past that we have forgotten about” in B and “a lot of pasts” in C?

I’ve heard such words as “a past that should never have existed” and “a past that has never been present”.

Can you really use “a past” meaning a past time related to the whole universe, not an individual person?