I've been recently pondering the same thing...
I
*WANT* to believe in such paranormal things, but having never personally experienced ghosts, demons or evil spirits, I am not apt to
believe.
I always jokingly told people that the reason I've never experienced ghosts, demons and evil spirits is because having studied Ceremonial Magick for
decades that all such things would be terrified of what I might do to them if they ever presented themselves to me.
However, recently I stayed in a haunted house with my daughter and my girl-friend. They both saw and heard the same things throughout the night, but
having been awake I did not see or hear the same things they heard.
It reminded me of the Christian Missionary in the movie
Erik the Viking who never sees the things that the Norse Vikings are seeing, but when
he witnesses a Christian Miracle the Vikings don't see it.
Maybe our senses are limited by the impressionability of our minds. If we want to believe something our senses filter those things exclusively,
ignoring all else. Perhaps our consciousness is only fluid enough to interpret stimuli that it has a predominance to see, or that which it is
expecting to see.
It would certainly explain a lot about Quantum Physics and Atomic Probability and why the predisposition of the observer can change the outcome of the
events observed.