Consciousness
What is required in order for consciousness to exist? How about subconscious? Is there a subconscious? Can "entities" ("demons?") for some sort of consciousness out of something other than a physical brain? Can an inanimate object have a TYPE of consciousness? Or at least be possessed by a consciousness or entity? How do we know if something is conscious?
Edit (4/15/18): http://jonlieffmd.com/blog/microbes/microbes-can-solve-a-problem