Fact. I grew up in a house with one, and everyone in the house had some sort of contact with her (although my mother and I were the only ones who ever saw anything).
I think the reason why some people believe in ghosts and some people don’t is because some people are sensitive to whatever it is that ghosts are (energy imprints, souls–whatever), and some people aren’t. I don’t think that ghosts are anything that can be proven. If you feel them, you know, without a doubt, they exist; if you don’t feel them, then they don’t exist.
Just because a color-blind person can’t see colors, however, doesn’t mean colors don’t exist for other people. Reality is not something which is black and white, yes or no; reality is, in large part, what we see through our own unique lens.
(Photo from: http://www.hauntedamericatours.com/toptenhaunted/toptenhauntedbattlefields/) – Ghostly image of a horse in the trees behind the re-enactor on the Chickamauga Battlefield. My husband saw “Old Green Eyes” on this same battlefield.