Sometimes when people witness some kind of psychic phenomena, they ask themselves, ‘Am I seeing what I think I'm seeing?’
In a word, yes. Seeing is something that happens in the mind, not in the eyes.
This is particularly an issue when the question of psychic experiences comes up. Biologically, we see something when light waves are reflected off a physical object and stimulate the cells in our retinas that result in impulses to the optic nerves. These nerves take the impulses and transfer them to the visual cortex in our brains and we 'see' the object. Consequently, we can’t see anything that doesn't reflect light, like a pane of glass. We don't 'see' it, but that doesn't mean that it isn't real. We know that it's real when we smash our nose against it.
So, it's possible for us to not see something that’s really there. So is it possible to see something that isn't really there?
People do it all the time.
Our brains are wired to look for things to see. It's a survival mechanism. That shadow that we might notice in our peripheral vision might be just a pattern of sunlight on a nearby rock. Or it could be a hungry tiger. It doesn't really matter much if the shadow is or isn’t 'really' a tiger. If we 'see' the shadow as a tiger, we will run away.
There is a certain amount of expectation involved in what we perceive. If we expect to see a tiger, we will see that tiger and our bodies will react as though that tiger is real. If the shadow wasn't a tiger after all – well, no harm no foul. We will have run away for nothing. But if it was a tiger, then we will have escaped being eaten and thereby survive to perpetuate our species.
So, if we are expecting to see a ghost, we might actually see one in a wisp of smoke, a writhing shadow on the wall, a mysterious beam of light in a dark room. Much of the camera footage shot in haunted houses of 'ghosts' seems to be nothing more than a beam of light diffused by dust that appears as a fuzzy patch of glowing substance that has a vaguely humanoid shape.
So, are we ‘really’ seeing a ghost or just projecting our expectations on a fuzzy patch of light?
Here is where that elusive something called the ‘sixth sense’ comes in. This is, I think, an emotional perception rather than a physical one. We may get emotional impressions from the apparition, such as benevolence, or concern or love. Conversely, we might get anger. hatred or desire for our destruction. Our eyes might be only ‘seeing’ diffused light from an unknown source. But our emotions are perceiving a ghost that might love us or wish us harm.