Then I would ask why. What is the criteria for a ghost to be created. It can't be a violent death or places like Omaha beach would be swimming with them. It also can't be unfinished business because nearly everyone has some unfinished business.
That is a good point indeed.. By the way I love your Baldur's Gate inspired avatar!.. So, to the point. Maybe it doesn't depend on a violent death. Maybe there are different forces at play in different world(s) that we may not understand or even guess about. .. If you know Planescape: Torment, the city of Sigil has many doors to different planes that are triggered sometimes by a gesture, a song, a spell or complete randomness. Maybe there are places not unlike those where the seal between different worlds is not as strong and some things manage to slip through, perhaps, without an intention. But that's just my speculation
I dont believe in sentient "spirits". I do believe in the possibility of bleed through from other dimensions \ times. I also believe its possible that certain events may get "recorded" in ...areas.
Science is starting to show data that strongly suggests we are part of a simulated universe. Kind of like a huge computer program. If so, its not hard to extrapolate sectors of "run over" data that were never fully "erased" or where if a trillion simulated universes are being processed at the same time, "fight" for processor time happens and as a result data becomes merged at some level for a finite amount of time.
all the people who see in ghosts are people who WANT to believe in ghosts