I don't believe in ghosts. I believe there are alternate dimensions, and those dimensions may be occupied by beings. I believe that any mistaken encounters with "ghosts" is probably more along the line of random encounters where the fabric is thin, for whatever reason. Magnetic anomalies, lightning strikes, who knows. Even that is more speculation than I'll normally allow myself.
Mathematical infinity supports this layering of dimensions.
But I don't really care about it, either. Because my reality is here, on this plane which we occupy. Its interesting stuff, but I don't really like listening to the people who speculate on it- because they act like its fact and I find that annoying.
Theres an Asian physicist who routinely speaks on these topics on History, and him I kinda like because he's very informal about it, and just digs the astrophysics.. And he's good at dumbing the concepts down for the layman, such as myself.