One day I encountered a phenomenon that is as real and physically dramatic as, say, the electric field of a Van de Graff generator. Being a fan of science I went looking for the math/science/engineering for this phenomenon. Long story short, after a few years of research, I discovered that: 1) this phenomenon has been known since antiquity in a pre-scientific way; 2) several researchers had independently (re-)discovered it multiple times going back about 2.5 centuries; 3) each time it had achieved a certain notoriety but then been debunked and subsequently ignored or forgotten. The first was Mesmer & "animal magnetism", but there are several others including Baron Von Reichenbach & the "Odic force", and Wilhelm Reich & "Orgone". This is repeating today with several kinds of "energy healing" including Reiki (which is distinguished by being Japanese and unabashedly theistic (Rei means Divine)) where practice is widespread, but lacking scientific validation. As I say, I've felt Reiki, so I know it's real, but so far I've personally never been able to interest any scientists in studying it, despite offering to demonstrate it. And the studies that have been done haven't helped. The Wikipedia article for Reiki just straight up calls it pseudoscience.