Most ghost experiences are explained by an understanding of how human sensory systems work, specifically hearing and sight. The brain doesn't recieve a faithful photograph of what is in front of us from the eyes. The brain produces a constantly updated model, updated by coded pulses along the optic nerve. The brain essentially simulates what is out there. That is why optical illusions work: the sense data that the brain recieves is compatible with two different versions of reality (for example in those pictures where you can see an old woman or a young womamn in the same image). The same goes for the ears - the sound is not faithfully transported to the brain, but only turned into signals that the brain interprets and simulates.
Understanding this shows how ghost sightings and similar illusions can appear utterly real. I remember as a child being utterly convinced that my dressing gown was gently writhing on hook on the back of the door. But I never thought it was a ghost at the time, just something odd that probably wasn't real. Now I'm older I know the probable reason why that illusion was in front of me. I'd be happy to accept a supernatural explanation for it, if there were any evidence, but I see none and therefore accept the empirical explanation.
Understanding this shows how ghost sightings and similar illusions can appear utterly real. I remember as a child being utterly convinced that my dressing gown was gently writhing on hook on the back of the door. But I never thought it was a ghost at the time, just something odd that probably wasn't real. Now I'm older I know the probable reason why that illusion was in front of me. I'd be happy to accept a supernatural explanation for it, if there were any evidence, but I see none and therefore accept the empirical explanation.