there are a couple different places you could categorize it. very broadly it is a form of skepticism, so it could go under 501.8, methods in science, but you could also put it under the parapsychology umbrella in the 133s; 133.7 is for humbugs and quackery, a category that seeks to debunk con artists, but that assumes the person alleging supernatural experience is trying to scam people. if you take them at their word, if they genuinely believe what they're saying, then you could file it under 133.8, psychic phenomena (ESP, clairvoyance, auras, astral projection), the idea here being that the anomalistic psychologist is studying the paranormal with the intention of finding the normalcy underlying it. are these people having psychic visions, or is there a carbon monoxide leak in their house? for specific phenomena, 133.03 contains dictionaries and encyclopedias of the paranormal with potential rational explanations.