Which classes of paranormal phenomena, if any, have a grounding in scientific fact, i.e., are legitimate?
None of the ones you mention have any reliable evidence behind them. Even the full-moon phenomena (where there is more violence or crime in certain phases of the moon) have been discredited. Further, there isn’t even a reasonable scientific basis for most of them. There are a few exceptions: chiropractic has been shown to be useful for back problems, but that is it, so far. It is possible that creatures like the Snowman or Nessie exist, and that aliens have visited this planet. But nobody has any good evidence for any of them. But the other things would require new theories of physics for how they could even possibly work, that makes them really, really unlikely. So scientists, not having unlimited time or funding, tend not to pay attention to them. Like explorers striking out for new territory, they start with what is known and go from there. It is so funny that people think about the Abominable Snowman and other legends, when there are just as interesting real animals being discovere
