I won’t pretend to be able to reproduce it here. You can find the original in English translation in von Neumann’s Mathematical Foundations of Quantum Mechanics. According to Wikipedia,
Von Neumann’s abstract treatment permitted him also to confront the foundational issue of determinism vs. non-determinism and in the book he presented a proof according to which quantum mechanics could not possibly be derived by statistical approximation from a deterministic theory of the type used in classical mechanics. In 1966, a paper by John Bell was published, claiming that this proof contained a conceptual error and was therefore invalid (see the article on John Stewart Bell for more information). However, in 2010, Jeffrey Bub published an argument that Bell misconstrued von Neumann’s proof, and that it is actually not flawed, after all.[25]
So apparently we’re still trying to figure out if this proof is acceptable or not. Note, however, that Bub’s claim is that the proof didn’t actually say what everyone thought it said, not that Bohm was wrong. Thus we have another possible failure mode: a correct proof that doesn’t say what people think it says.
This is not actually as uncommon as it should be, and goes way beyond math. There are many examples of well-known “facts” for which numerous authoritative citations can be produced, but that are in reality false. For example, the lighthouse and aircraft carrier story is in fact false, despite “appearing in a 1987 issue of Proceedings, a publication of the U.S. Naval Institute.”
Of course, as I type this I notice that I haven’t personally verified that the 1987 issue of Proceedings says what Stephen Covey’s The Seven Habits of Highly Effective People, the secondary source that cited it, says it says. This is how bad sources work their way into the literature. Too often authors copy citations from each other without going back to the original. How many of us know about experiments like Robbers Cave or Stanford Prison only from HpMOR? What’s the chance we’ve explained it to others, but gotten crucial details wrong?
I’ve just seen the claim that von Neumann had a fake proof in a couple places, and it always bothers me, since it seems to me like one can construct a hidden variable theory that explains any set of statistical predictions. Just have the hidden variables be the response to every possible measurement! Or various equivalent schemes. One needs a special condition on the type of hidden variable theory, like Bell’s nonlocality.
BTW what was John von Neumann’s “proof”?
I won’t pretend to be able to reproduce it here. You can find the original in English translation in von Neumann’s Mathematical Foundations of Quantum Mechanics. According to Wikipedia,
So apparently we’re still trying to figure out if this proof is acceptable or not. Note, however, that Bub’s claim is that the proof didn’t actually say what everyone thought it said, not that Bohm was wrong. Thus we have another possible failure mode: a correct proof that doesn’t say what people think it says.
This is not actually as uncommon as it should be, and goes way beyond math. There are many examples of well-known “facts” for which numerous authoritative citations can be produced, but that are in reality false. For example, the lighthouse and aircraft carrier story is in fact false, despite “appearing in a 1987 issue of Proceedings, a publication of the U.S. Naval Institute.”
Of course, as I type this I notice that I haven’t personally verified that the 1987 issue of Proceedings says what Stephen Covey’s The Seven Habits of Highly Effective People, the secondary source that cited it, says it says. This is how bad sources work their way into the literature. Too often authors copy citations from each other without going back to the original. How many of us know about experiments like Robbers Cave or Stanford Prison only from HpMOR? What’s the chance we’ve explained it to others, but gotten crucial details wrong?
I’ve just seen the claim that von Neumann had a fake proof in a couple places, and it always bothers me, since it seems to me like one can construct a hidden variable theory that explains any set of statistical predictions. Just have the hidden variables be the response to every possible measurement! Or various equivalent schemes. One needs a special condition on the type of hidden variable theory, like Bell’s nonlocality.