Dischord: Logged back in for this.
I've covered it before, wasted far too much time on the issue, and if you want to burn a few candles while grinning at Einstein, go ahead; it will answer nothing.
Sorry, but it is late and there is nothing further that I could write that I haven't written before.
Have to sleep, after 5am here.
Cormoran: So you have no actual answe. Talk in circles all you want, that's what it comes down to.
Dude, he may be talking in circles, but you're just repeating yourself hoping for a different outcome. If you really want an answer, science is not yet the correct tool, and neither is anything else. Just like science could not at first prove the neutrino or Higgs boson or quarks. We noticed the effects of all of these things, and we developed theories behind them, but it took time to advance science to the point where they could actually prove stuff.
You're using science in the wrong way. Science uncovers evidence which is then analyzed to determine whether something is proven(?) or disproven. No evidence =/= disproven. Only counterevidence can disprove something.
As for numbers, let's talk science again. According to conservation laws, there should be an equal amount of matter and antimatter, yet there is a vast surplus of regular matter as opposed to antimatter. The explanation? We don't really have one. We have ideas, a few of which are solid, but none that have physical evidence to warrant their becoming a theory.
Likewise, ghosts can have fairly good explanations as to their numbers, lack of evidence, etc. For example, the lack of evidence and of numbers can both be explained as most ghosts being too weak to produce noticeable effects. Cultural differences are also just that. Cultural. The legends/motives are what change from culture to culture, with new features being added and embellished by storytellers and folklorists.
Without evidence or counterevidence, saying one believes in ghosts or not is a statement of belief either way.
Edit: for some weird science, look up Boltzmann Brains. It's a physics joke like Schroedinger's Cat, but it accurately illustrates how scientific extremism with what is only ever a partially correct picture of the universe can be flawed.