I have a strong intuitive feeling, based for example on the Bothe-Geiger experiment, that quantum mechanics is nonlocal. But intelligent people who have thought about these things make claims such as that quantum mechanics is nonlocal in the Copenhagen interpretation, but local in the many-worlds interpretation. It seems clear to me that some theories (Newtonian gravity) are definitely nonlocal, and others are definitely local (classical special relativity).
Here are some of the terms used to talk about the EPR paradox:
- counter-factual definiteness
Do some or all of these have definite true/false values for quantum mechanics? For certain interpretations of quantum mechanics? For hidden-variable theories? Do certain boolean combinations of these terms have definite truth values, even if the terms themselves do not?
My current feeling is that these are all fundamentally incoherent notions, and that we should understand them as nothing more than vague philosophical motivations that would lead us to construct actual theories such as hidden variable theories, or to construct tests such as the Bell inequalities. Is my opinion sloppy and overly broad?