(5) Our sense of dualism. Our sense of self (and of free-will) creates
the illusion that "soul" or "spirit" exists in a way that is
disconnected from body. I'm not saying that most people on the street
would articulate Cartesian dualism, but I do think that dualism is
implicit in our thinking (even for those of us who explicitly don't
believe in it).
This is related to point (2), but can be listed independently, I agree. You
might as well add factors like illusionary minds, sleep paralysis and so