Such tactics work pretty effectively as reality filtering devices to enforce intellectual taboos. But what happens when a person who rejects the paranormal has his own senses deliver testimony that something paranormal occurred? Often the result seems to be that the person just ignores such testimony of his senses, and keeps on completely rejecting the paranormal.
An example involves the late great scientist Carl Sagan. Referring to his deceased parents, Sagan said this: “Probably a dozen times since their deaths I've heard my mother or father, in an ordinary, conversational tone of voice, call my name.” Did Sagan accept this as evidence of the paranormal? No, he created a ridiculous hypothesis to explain it away, the hypothesis that he was spontaneously re-experiencing a previous sensation. He said, “I still miss them so much that it doesn't seem strange to me that my brain occasionally will retrieve a kind of lucid recollection of their voices.”
Such a hypothesis is quite absurd, because the human mind doesn't act that way. Healthy people may remember clearly a previous statement by another person, but they do not spontaneously and repeatedly “re-hear” something they heard before. Sagan's experiences should have made him very sympathetic to reports of the paranormal. But instead a few years later Sagan wrote a book called The Demon Haunted World in which he attempted a wholesale debunking of the paranormal.
We may have here an example of what Brendan Nyhan and Jason Reifler call the backfire effect: a case of responding to evidence for something by believing even more strongly that such a thing does not exist (or responding to evidence against something by believing even more strongly that such a thing does exist).
A more recent case of the same thing seems to be found in the book “If the Universe Is Teeming with Aliens...Where Is Everybody?“ by physicist Stephen Webb (which is a pretty good book, despite its shortcomings and faulty conclusion). In this interesting book Webb discusses 75 potential solutions to Fermi's Paradox, the riddle of why we have not yet observed extraterrestrial life in a universe that seems to have so many planets.
One of the first potential solutions discussed by Webb is Solution #4: “They Are Watching Us From UFOs.” At the end of his discussion of this potential solution to Fermi's Paradox, Webb reveals his own childhood experience with a UFO. He says the following:
I should state here that I have seen a UFO, and it remains one of my most vivid memories....I looked up and saw a pure white circle about the size of the full moon. Protuberances on either side of the circle made it look rather like Saturn showing its rings edge-on. Whatever it was, it seemed to hover for a few seconds before moving off at tremendous speed. I was with a friend, who also saw it and remembers it still...We definitely saw something in the sky that day and I have absolutely no idea what. But no, it wasn't a flying saucer. It was just a light in the sky.
UFO Speeding Away (in 2015)
We have here an interesting mixture of observation and a refusal to accept the paranormal implications of one's observations. Webb has reported here a sighting that cannot be explained by any natural and earthly hypothesis, since nothing with a round shape manufactured by man when he was a child ever floated around “the size of the full moon” in the sky, while also being capable of “moving off at tremendous speed.” But then he illogically dismisses it as “just a light in the sky” even though his own description (described as “one of my most vivid memories”) completely contradicts such an offhand dismissal.
Anyone experiencing such a sight should be extremely open to the idea that extraterrestrials have visited our planet, and should either believe in such a thing or think such a thing is quite plausible. But instead we seem to see a backfire effect going on in Webb's mind. Not only does he dismiss evidence for UFO's, but at the end of the book he suggests that mankind is alone in the galaxy (“we have a Galaxy to explore and make our own”). He also seems to suggest the idea that man is alone in the entire universe, by saying man is “the only species that can light up the universe with acts of love and humor and compassion,” and making other statements that seem to dismiss the whole possibility of extraterrestrial intelligence.
Again we seem to have:
The senses of a scientist give him dramatic evidence for X. Scientist responds by asserting that no types of things like X exist.
What is the real culprit here? The culprit is the sociological system of conformity constructed by scientific academia, in which acceptance of anything paranormal is a taboo that must be avoided at all costs, even if that means denying large bodies of evidence or the direct testimony of a scientist's senses. This type of herd behavior and groupthink is a weird intellectual straightjacket which many a scientist has tied himself into, a stifling type of thought prison. When you are compelled by your group norms and tribal taboos to reject or ignore the testimony of your senses, something very wrong is going on.