ADCMS - good post. Sagan makes good points that I hadn't really considered before.
Also, perhaps evolution using the scientific method, explains spirituality. I am ignorant of this but would love to study religion/spirituality from an evolutionary perspective.
I read a book on human evolution that contained details of fossilised camp sites used by H. sapiens, H. ergaster, H. erectus and other species (I think).
Maybe there exist fossilised shrines too?
Cofty, oubliette, S&R, anyone?