"...believing in an afterlife (they do not)"
Interesting. "Sister" in catechism class would try to explain infinity or eternity by suggesting we begin counting and never stop. It sort of worked. These days, I read (with  not understanding) of the incredible escalation of awareness of the "un-size" of the universe. The limits and the number of known galaxies expanding inexorably hint at... infinity, eternity.  Then I think of the continued existence of our bits after death and their connectedness with everything of everybody and it seems as true of "before" as after. Of course it's not scientific; of course it's not Sister's catechism, but...it's not such a great big leap to....faith.  Then, it becomes more a matter of what kind...