*That* is a good question. I doubt there are universal answers, and you've already said that much anyway.

For the case of denying science, I think that people sometimes get carried away. Science gives absolute answers, but only on a highly restricted set of questions. There is a discipline in not answering questions whose answer is unknown, and by extension, not asking questions whose answer is expected to be unobtainable. Many people cannot or won't accept this discipline, and prefer to complete their knowledge on the "big" questions with beliefs rather than leave some questions unanswered.

Which leaves a fascinating ancillary problem: where do the "big" questions come from and why won't they go away? I suspect that kids don't come up with these questions on their own, but rather absorb them and their "importance" from contact with adults, which leads to pressure to resolve them.

--
$E(X_t|F_s) = X_s,\quad t > s$