Joy Christian wrote:.
Gill's argument above was dismissed by Einstein when Bell was hardly seven years old. The additivity of expectation values simply does not hold for any hidden variable theories.
The Bell-test experiments are verifying Einstein's observation and ruling out the additivity of expectation values. This is the sad end of Bell's theorem. Sadly, it was a nonstarter.
Sorry, Joy, this argument by myself is *not* the argument that was dismissed by Einstein long, long ago. You are doing an "argumentum ad verecundiam" (argument by authority). That's a sign of weakness on your part. Especially since you don't reproduce Einstein's words and reasoning. You have not shown that there is anything wrong with *my* argument.
The Bell-test experiments confirm quantum mechanics and moreover generate results which cannot be explained by local realism. They certainly do not rule out additivity of expectation values. On the contrary, as my argument shows, the fact that they confirm quantum mechanics confirms the additivity of expectation values in quantum mechanics even of non-commuting observables.
Look at Einstein's argument which you yourself kindly reproduced on another thread. "Einstein then said that there is no reason why this premise should hold in a state not acknowledged by quantum mechanics if R, S etc. are not simultaneously measurable". Einstein admits that it does hold under a quantum mechanical state. It holds when we prepare a state in a state rho, one of the states acknowledged by quantum mechanics.
Sorry, Joy, you have to read the small print.