The Real Estate theorem of ghost disproval
What happens if you bulldoze a "real haunted house" and build a 24-hour Walgreens on the site? Would you now have a haunted 24-hour Walgreens, or would the resident ghost have to relocate to a spooky Victorian mansion in your town's historic district? That story doesn't sound very scary: "Sometimes I see the ghost of a weeping little girl sitting on the edge of my bed. She used to haunt the Old Johnson Place on Elm Street, but she had to move after they built the new Walgreens. That's probably why she's always weeping." I'm going to call this the "Real Estate theorem of ghost disproval."
How come the majority of ghosts tend to be a few hundred years old or less, regardless of the era? You hardly ever see, or hear a good story about a 3,000 year old ghost. Is it because ghosts are usually able to complete their "unfinished business" in a few century time frame? Is it because ancient ghosts either predate the religious tradition that gives them a philosophical foundation, or because extremely old ghosts can't speak English (or whatever the local modern language is)? Is it because, as was hinted by the Real Estate theorem of ghost disproval, ghosts are intimately tied to the structures they inhabit and there are very few usable structures which have survived for more than 3,000 years? It might also be a ghost demographics phenomenon, in that many more people have died more recently than 3,000 years ago than died longer than 3,000 years ago. Therefore ancient ghosts are simply numerically less common than more modern ghosts. Someone on those Ghost Hunters International TV shows should take a spectral census to get to the bottom of this.
The ambient music theorem of ghost disproval
Ghost stories and haunted houses require a certain ambience in order to get the full effect. Typically this is low lighting inside a 19th century house or an abandoned building, low firelight around a campsite, and either silence, or old-timey music such as Big Band, Ragtime, Jazz, or some lonesome piano music. This ambience is maintained because people want to be scared because it's fun...that's the whole point for them. But are there certain types of ambient music and lighting environments in which ghosts simply cannot exist? For example if you had a multicolor laser light show, inside a bright white room with all white walls and white floor with no furniture, and blared Miley Cyrus Party in the USA, is it impossible to be scared by a ghost?
The absurd juxtaposition ghost disproval theorem
Is it possible to be involuntarily haunted by a ghost if you take steps to be absurd or silly to counteract the scariness of the ghost? For example, you could enter a "real haunted house" with everyone in your group dressed in realistic looking dolphin costumes. The absurdity of a group of humans waddling into the old haunted house dressed as a pod of dolphins might be too much for the ghost to handle. It will throw the ghost off her haunting game and will cause her to be too embarrassed to come out and haunt you.
As I think of more silly theorems of ghost disproval I will continue to add them to this list. If you can think of any along the same lines, let me know! I hope to one day collect the definitive internet list of silly ghost disproval theorems.