But norms, guidelines, heurisitics, advice, lie on an orthogonal axis to true/false: they are guides to action, not passive reflections. [...]

OK, but [...]

Yes, but that's beside the original point.

You brought it up!

What you call a realistic guideline doesnt work as a guideline at all, and therefore isnt a a charitable interpretation of the PoC.

I continue to think that the version I called realistic is no less workable than your version.

Justifying that PoC as something that works at what it is supposed to do, is a question that can be answered, but it is a separate question.

Again, it's a question you introduced. (And labelled "the question".) But I'm content to put it aside.

noticing and throwing away any initial suspicion I have that a comment's wrong, and then forcing myself to pretend the comment must be correct in some obscure way.

Thats exactly what I mean.

But surely it isn't. Just 8 minutes earlier you wrote that a case where I did the opposite was an "example of PoC".

Cogent doesn't mean right.

See my response to CCC.