Comment by recursive
It seems to be assumed that I've heard of "psi". No definition is given, nor can I even find one on wikipedia. A search yields information about the unit of physical pressure.
One of the examples given of a psi-related phenomenon is extra-sensory perception. As far as I know, ESP has never been rigorously demonstrated to exist, although it's been attempted many times.
What's this about?
It's defined in the second paragraph. Mind reading, extrasensory perception, ghosts, and the like.