What exactly is the whole Guernica thing about and how is it relevant to whether there exist any supernatural beings that aren't invented human concepts?
Reality -> Art -> Perception and interpretation
Supernatural -> myth -> interpretation.
Remember the Hindu Hypothesis? RAZD, I believe, is trying to say that religious myths are to supernatural beings what Guernica is to the horrors of war. An intermediary through which we have to do some interpretation. He seems to be talking about information being transmitted in non-scientific ways, presumably religious notions are proposed to contain non-literal information like various art does.