McKenna was probably an alien

"...and then as I broadened my interest as a pre-adolescent child I got into science fiction and as I look back on it now I see it was simply that it broke down barriers, conceptual barriers about what was possible, and that it was setting me up for this position vis-à-vis the input of the world which was that I would entertain any idea but believe in nothing. And this is I think a very – you know if we are trying to actually talk about a psychedelic cannon – this is a very central part of the psychedelic attitude toward the world: to entertain all possibilities but to never commit to belief. Belief always being seen as a kind of trap, because if you ever believe something you are ever precluded from believing its opposite. So you had run a line down the center of the cognitive universe and divided things into the believable and the unbelievable. Well you know how a child lives in fantasy and how fantasy then gives way, and gave way in my case to science fiction. This is a kind of pre-psychedelic mind-set that many many people of my generation were experiencing as they came up through the Eisenhower years…"

Okay maybe he wasn't a card carrying alien, but he certainly had an entity.