DD4 on time & numbers:

DD: Numbers go on infinitely on both directions, right?
Me: Yes, I think so.
DD: But not days.
Me: You mean time?
DD: Yes, time. It had a beginning.
Me: I guess so.
DD: So it will have an end.
Me: Why?
DD: How can there be a beginning if there were to be no end?
Me: Hmmm. I don't see why that can't be the case.
DD: It makes no sense for it to be infinite only on one direction.
Me: Really?
DD: Really.

Any movie/book recommendations?