Please justify invoking logical positivism to causal patches and black hole interiors in quantum gravity! [closed]

Logical positivism is often invoked to explain why external observers can't talk about black hole interiors, or why we can't talk about what happens outside our causal patch in inflationary models. But just exactly how justified is this questionable philosophy of logical positivism? According to another philosophical tradition, scientific realism, it is meaningful to ask about what happens inside a black hole, or beyond our causal patch.

Just because we can't measure something in principle doesn't mean it doesn't exist!

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closed as off-topic by ACuriousMind, Kyle Kanos, CuriousOne, Martin, GertApr 9 at 0:57

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Positivism isn't questionable, it is obvious. The arguments against is are very weak. – Ron Maimon Aug 12 '11 at 14:22
Logical positivism is obviously false, as anyone who's spent more than 30 seconds thinking about it could tell you. If you can't see why, read this article. Either way, this isn't a physics question. – Kyle Kanos Apr 6 at 1:48
I'm voting to close this question as off-topic because it's about philosophy and not physics. – Kyle Kanos Apr 6 at 1:49

So it is appropriate to view your question as a scientific one. Then there may actually be a pretty good reason, besides the philosophical stance you mention, why exterior observers shouldn't talk about the detailed microscopic events in the black black hole interior. If the black hole complementarity is right, then $$[\phi(x,t)_{\rm out},\phi(x',t')_{\rm in}] \neq 0.$$ If you take two points $x,t$ and $x',t'$ outside and inside a black hole that are space-like separated, according to classical geometry, the corresponding fields in effective field theory should commute with each other. But it's very likely that in the exact quantum gravity, they don't. The non-vanishing of the commutator seems to be necessary to get rid of the strict locality and strict causality. The strict locality and strict causality are bad because they are the key assumptions that allow one to prove the demonstrably wrong proposition that the information is being lost during black hole evaporation.
Much like in the uncertainty principle you can't talk about the exact values of $x,p$ at the same moment because they don't commute with each other, you can't talk about physical observations inside and outside at the same moment because they don't commute with each other. So the question "what actually happened inside the black hole" may really be ill-defined for the observers outside. Not only they have no way to find out; but even in principle, the answer may fail to exist. The infalling observers do see some outcomes; but their perspective may be fundamentally incompatible with the observers who stay outside.