Ghosts do not seem to be objective phenomena
Ghosts, if they are real, do not seem to emit or reflect light in the visual spectrum.
- There’s no good reason to suspect that people who claim to see ghosts are detecting light with their eyes from anything other than the visual spectrum.
- Security cameras and cell phones pick up approximately the same spectrum of light as our eyes (the visible spectrum) and they are roughly as sensitive.
- If ghosts were an objective phenomena emitting or reflecting light from the visible spectrum, then countless cell phone videos would have been made and countless numbers of security camera footage would indicate their objective existence.
- We can conclude that ghosts are not light-emitting/reflecting visual phenomena.
If people are detecting ghosts or spirits but not through the visual spectrum, in what manner are they detecting them? Our understanding of visual perception at this point is essentially exhaustive: we understand exactly the process that rod and cone cells are excited, and we understand exhaustively the photoreceptor cells that make up the light/color detection in our eyes (you can find a cadavar, grab a microscope and verify this yourself), so in what other fashion would genuine visual stimulu operate?
A number of prizes have been offered for any kind of objective demonstration of the existence of paranormal ability or phenomena (including ghosts). None of these prizes have ever been claimed
Ghosts have been repeatedly demonstrated to be subjective phenomena
We know that some people experience visual hallucinations, and we can closely associate visual hallucination with some kinds of medical disorders (e.g. Parkinson’s disease and schizophrenia). Those with Charles Bonnet Syndrome–a genetically inherited condition—experience all kinds of visual hallucinations which we can verify are not objective. source.
We know that our minds fill in the gaps in the dark, particularly as we are going to sleep and waking.
We know that a person’s belief about the existence of spirits strongly modulates their experience “seeing” spirits. A great example of this is Derren Brown’s experiment where he puts various people in a crypt under an old church in the dark for 15 minutes. The people who believe in spirits were freaked out and reported “seeing” various spirits. Those who genuinely didn’t believe in spirits didn’t report any phenomena. In general, it has been demonstrated that we are suggestible to various spiritual phenomena (suggestibility and personality traits can explain spiritual hallucination).
For these reasons, we can have some confidence that ghosts are not an objective phenomenon.