This article is born out of ignorance, not mine but the one I had to withstand at my most recent stay in the hospital: Where religious people from assorted Hogwarts Schools attempted to convert me into their clubs...
When 1000 prayers are totally unable to find a rock the size of a marble in my gallbladder... While a skilled doctor touching my abdomen with a single finger was able to (to later corroborate the assumption with a nice echography).
Believing in ghosts, spirits, and other "spooky" things is something that is traditional in our species since ancestral times. Entire religions were forged with the anvil and hammer ignorance shapes. "Spirits" attempting to explain the purpose of death after life of an individual, in an attempt to grant us some sort of immortality; exploiting that desire for everlasting existence in exchange of a present, tangible financial benefit to the organization.
This sort of belief still endures today, yet, how much truth hides behind that nonsense? Even with thousands of paranormal researchers attempting to find hints of supernatural beings everywhere (some even got TV shows at "reputable scientific TV channels"!!!) for decades: science is still waiting for a single, convincing and verifiable proof.
All the supposed "evidences" found until today are nothing but hoaxes, falsifications, instrumental errors or too ambiguous to be even consider them any of the previously mentioned ones. Literal: Worthless shit.
Paranormal activity? Yeah, because that is what rational people call rat infestations, termites in old houses and materials dilatation by temperature change.
A nice example of these "bad practices" in this "paranormal club" are the so called orbs, these white spots that show up in pictures from time to time. Modern ghostbusters adore when they find these in pictures located at graveyards or old mansions, while, as any photographer knows they are nothing else but dust specks, humidity or insects that pass by as the flash lights up. Close, and out of focus: you get that result.
Knowing this does not stop some people from believing it is some sort of paranormal manifestation. Ignoring hard, reproducible facts for the sake of having a "find" that feeds the always hungry ignorant pleb that follows them.
Ah, pictures... About hem we've nothing to do, even videos with enough effort are doubtful evidence. Today, anyone with a decent computer can produce hundreds of "visual evidences" of whatever they like! Of course, paranormal believers require more faith than logic to believe...
What really convinces people about spirits is other people's testimony about what they "saw". The complicated evidence to be found is, an explanation to the thousands of testimonies all around the globe that would group them all in a single, solid, explanation. A theory!
In this article I wanted to review some of the natural causes that induce people into believing that they witnessed "paranormal activity", because (even when many "believers" say otherwise) science (and common sense), CAN explain many of those experiences (and the ones left with no explanation, are yet to come; otherwise Zeus would still exist as reason for thunder striking... but we don't like making up answers). So, here's a beautiful example.
Visions, noises and "entities"
In 1998 employees in a lag claimed that they could see ghostly figures in their peripheral vision that vanished as they attempted to look directly into them.
As two researchers decided to look for the reasons behind this phenomenon, instead of declaring the lab "cursed" they found out that a lab was making the air vibrate at 18.98 hertz. -Oh, the irony!- Our eyeballs are at the same frequency! This means that, that slight air pulsation leads into our eyes deforming, making light behave like it shouldn't in there. You don't believe me? Try it out yourself!
Of course, as they turned off the fan, the visions were gone... Some claim that it was the fan that was cursed, others state that it's the frequency that summons entities from the underworld, ready to feast on the vision of the unaware mortal souls...
I prefer, sticking with Science.