Awesome thread. It sounds like the gist of it all is people have seen or heard things that they can?t explain so they wonder if maybe it?s ghosts. Other people are sceptical, but until the believers get an explanation for what they saw or heard they are going to stick with their belief. Which is all fair enough.
It does pay to keep in mind though that the human brain is an absolutely hopeless and untrustworthy device for observation.
Most people if they are distracted by counting passes in a basketball game won't notice a man in a gorilla costume walk on court, beat his chest, and walk off...
Most people speaking to a receptionist over the counter won't notice anything if the receptionists ducks down to pick up something from below the counter and a different person reappears instead of the original receptionist.
Whole parts of pictures can change before your eyes and you won't notice anything. And that's just Change Blindness. Throw in a few hundred other cognitive distortions that happen and you'll start to get an idea of how bad the human brain is at doing its job.
People watching a film of a car crash will judge the cars as going faster and will recall broken glass at the crash site depending on whether or not they are asked "How fast were the cars going when they smashed into each other?" and "How fast were the cars going when the collided into each other?".
The brain is great at filling in the blanks too. Say you dreamt of a car crash but initially you don't remember what color the cars were. Then you see a car crash the next day with a white car. Your brain then fills in the blank and tells you your dream was of a white car. And you're left thinking wow that's amazing, when really your brain is just being a dodgy worker and lazily just going "oh yeah that information will do, I'm going to chuck that into the memory from the dream now because I forgot what was really there to start with".
Throw in examples of how poorly people perform with picking people out of line ups... look it up, we are all ridiculously hopeless at it.
And light bulb memories like september 11 where you can recall so much detail of the day you saw it all happen... sorry to tell you but 99% of that detail is your brain just making **** up. Yet it convinces you that those details are 100% correct...
Then throw in the fact that your brain just makes stuff up and tells you that's what you're seeing, like where the optic nerve crosses the retina and the brain just goes "hey I see the stuff around that spot, I'm just going to fill in the blank with whatever is around that blind spot" and that's a constant thing. Your brain is constantly deliberately deluding you into seeing things that aren't there. Throw in other things the brain does like Mach lines which is the brain just making up arbitrary distinctions between different shades of colors, etc... etc... etc... etc... and all the other delusions/optic illusions.
And lets not even get started with what the brain can just make up with the right chemical environment, hallucinations both visual and auditory, etc...
Heck even chimpanzees vastly outperform humans when it comes to some number recognition tasks.
The point is that the reason why people have experiences of ghosts but no documented proof is because those experiences rely on the brain which is unreliable, and proof relies on something tangible and falsifiable.
The reason we have the scientific method is because it regulates this lazy unreliable thing called our brain, and tests its observations through controlled falsifiable ways.
For now let's all look for the most parsimonious explanations before we invent another dimensional realm full of ghosts and spirits crossing over into our dimension for reasons unknown in order to explain away what really in most instances boils down to brain farts and group think.
Sorry for the lecture, a 4 year psychology degree has left me with a whole heap of boring information that people really aren?t interested in hearing
