Is the thrust of the thought experiment preserved if we assume that the two versions of water differ on a chemical level, but magically act identically on the macro scale, and in fact are identical except to certain tests that are, conveniently, beyond the technological knowledge of the time period? (Assuming we are allowed to set the thought experiment in the past.)

Surely it's not necessary that the two worlds be completely indistinguishable?

Hm. Personally, I read that as how Harry sees everything that goes wrong - every poor choice that he allows other people to make, every tragedy he didn't adequately anticipate - as expressed, among other places, in his discussions in Diagon Alley with McGonagall about the difficulties growing up smarter than his parents and the potential necessity of a magical first aid kit. But yes, now that you mention it, it certainly could be something to be echoed darkly in the endgame - though I am likewise unaware of the potential edifices of theory surrounding it.

You've responded to several comments just now that were made years ago by people who no longer post here, probably migrated from the earlier form of the website. You may get responses and conversations, but probably will not get direct replies from the commenters you're addressing!

Yeah, it's not really an explanation so much as an expression of where we'd look if we could. Presumably the way to figure it out is to either induce repeat performances (difficult to get funding and review board approval, though) or to study those mechanisms further. I suspect that'd be more likely to help than reading about ghost-emperors, at least.

And what's the point of listing articles like "India Graduates Millions, but Too Few Are Fit to Hire"? Supposedly about "HBD & IQ", actually about education systems and education levels...?

Frankly, it looks like a list the compilation of which was motivated less by a stoic devotion to hard truths and more by an enjoyment of reading about how great white people are.

I'm not sure that that is in fact an admission of being a troll... it reads as fairly ambiguous to me. Do other people have readings on this?

I mentioned Catholicism only because it seems like the "obvious" supernatural answer, given that it's supposed to be a Marian apparition. Though, I do think of Catholicism proper as pretty incoherent, so it'd rank fairly low on my supernatural explanation list, and well below the "scientific explanation" of "maybe some sort of weird mundane light effect, plus human psychology, plus a hundred years". I haven't really investigated the phenomenon myself, but I think, say, "the ghost-emperor played a trick" or "mass hypnosis to cover up UFO experiments by the lizard people" rank fairly well compared to Catholicism.

Cheers! Some find my humor a little dry.

Thanks for the advice! Though I suppose I won't tell you if it turns out to have been helpful?

Are there any good supernatural explanations for that one?! Because "Catholicism" seems like a pretty terrible explanation here.