Throughout all the cultures in the world there is the concept of spirits, angels, fairies, ghost, gnomes, totems etc. A dismissive view is that people who have seen these things are crazy, but a more accepting view is that people have actually seen such things. I myself have had sleep paralysis before and have seen an incubus, and have had the feeling of astral projection while lying in bed. I know these are figments of my imagination, but by seeing them they might as well be real since perception is a major part of reality. My question is do psychologist have an idea of what these things represent, and why they seem to be so universal across all cultures?