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bhobba
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atyy said:Also, the standard 1961 textbook of Messiah does say that hidden variables cannot be ruled out and associates the hidden variable programme with Einstein. Messiah goes on to use Copenhagen (for the practical purpose of doing quantum mechanics) without ruling out hidden variables.
I think after Gleason published his theorem (1956 I think) the assumption was so obvious it could not be ignored. To be specific the assumption made was if A and B are two operators the addition of the expected outcomes is related simply ie if E(O) is the expected outcome of observable O then from a simplistic understanding of expectations you naturally think E(A) + E(B) = E(A+B). This is the assumption Von-Neumann made and is so reasonably obvious when you read the book you don't even bother questioning it. Greta did and saw it didn't necessarily hold up. But such was Von_Neumann's reputation people didn't listen to her - but may have listened to Einstein - he is one of the few that can stand up to Von-Neumann reputation wise. In proving Gleason's theorem you prove that is true - but the assumption is the probability is not basis dependent - called non-contextuality. Once you have seen that Von-Neumann is then quite suspect.
Thanks
Bill