Dirkman wrote:"If there are counterfactual outcomes"
Dirkman wrote:"If there are counterfactual outcomes at various measurement settings, what are they? In other words: if there is objective realism a la EPR, one should be able to identify the hypothetical values that would have been obtained if a different measurement pair had been chosen."
Dirkman wrote:"If there are counterfactual outcomes at various measurement settings, what are they? In other words: if there is objective realism a la EPR, one should be able to identify the hypothetical values that would have been obtained if a different measurement pair had been chosen."
Dirkman wrote:"If there are counterfactual outcomes at various measurement settings, what are they?"
Dirkman wrote:In other words: if there is objective realism a la EPR, one should be able to identify the hypothetical values that would have been obtained if a different measurement pair had been chosen.
I am not the one asserting there are counterfactual cases. Everything I see points to an observer dependent universe, one that lacks local realism. So when someone asks about a particular local realistic theory, one which is excluded by Bell but that the author claims is not, I always ask: Please describe those counterfactual cases.
minkwe wrote:Bell's problem was that he did mathematics by mixing and combining A,B and C in the same expression.
Dirkman wrote:minkwe wrote:Bell's problem was that he did mathematics by mixing and combining A,B and C in the same expression.
"It's not Bell's problem. Bell proved a theorem along the lines of: "All theories of type X have property Y. QM does not have property Y. Therefore, QM is not a theory of type X."
What are you disagreeing about? "
Dirkman wrote:"It's not Bell's problem. Bell proved a theorem along the lines of: "All theories of type X have property Y. QM does not have property Y. Therefore, QM is not a theory of type X."
What are you disagreeing about? "
In discussions of Bell's inequality, "counterfactual" is mentioned in the context of "counterfactual definiteness". CFD says that there is a definite answer to questions such as "What result would Alice have gotten if she had measured X instead of Y?"
Bell in 1964 Paper wrote:Measurements can be made, say by Stern-Gerlach magnets, on selected components of the spins and . If measurement of the component , where is some unit vector, yields the value +1 then, according to quantum mechanics, measurement of must yield the value -1 and vice versa.
minkwe wrote:For example, please describe to me a physical situation for which the relationship P(AB|λ) = P(A|λ)P(B|λ) is true
But the relationship P(AB|λ) = P(A|λ)P(B|Aλ) is false.
Mikko wrote:minkwe wrote:For example, please describe to me a physical situation for which the relationship P(AB|λ) = P(A|λ)P(B|λ) is true
But the relationship P(AB|λ) = P(A|λ)P(B|Aλ) is false.
Both P(AB|λ) = P(A|λ)P(B|λ) and P(AB|λ) = P(A|λ)P(B|Aλ) are true or both are false if P(B|λ) = P(B|Aλ).
Because P(B|λ) = P(A|λ)P(B|Aλ) + (1 - P(A|λ))P(B|Āλ) — where Ā means the logical negation of A — a situation is asked where
(1 - P(A|λ))P(B|Āλ) ≠ 0, i.e., P(A|λ) ≠ 1 and P(B|Āλ) ≠ 0.
" ... the general consensus is that a local hidden variable mechanism which exploits either or both loopholes in a way which would not have shown up in experiments to date would require a theory so perversely conspiratorial as to be almost incredible."
FrediFizzx wrote:Well, when a theory is not experimentally verifiable then perhaps consensus means something for science. There is also the tricky business of "interpretation" that has to be dealt with. I'm not so sure it is so clear cut as Crichton paints it to be. Lot's of grey areas. Especially now-a-days since experimental facts have fallen way behind theory. Even when you have experimental facts, sometimes they are still subject to interpretation.
That is the problem with all the Bell test experiments. They are using the wrong interpretation. Mainly because they don't see the mistake in Bell's reasoning.
thray wrote:FrediFizzx wrote:Well, when a theory is not experimentally verifiable then perhaps consensus means something for science. There is also the tricky business of "interpretation" that has to be dealt with. I'm not so sure it is so clear cut as Crichton paints it to be. Lot's of grey areas. Especially now-a-days since experimental facts have fallen way behind theory. Even when you have experimental facts, sometimes they are still subject to interpretation.
That is the problem with all the Bell test experiments. They are using the wrong interpretation. Mainly because they don't see the mistake in Bell's reasoning.
Fred, even a thought experiment has to be do-able in principle. And if a theory can't support at least a thought experiment, it's not much of a theory.
A theory that is incomplete -- as quantum mechanics surely is -- can't be saved by the right interpretation. There is no way to validate it.
thray wrote:A theory that is incomplete -- as quantum mechanics surely is -- can't be saved by the right interpretation. There is no way to validate it.
minkwe wrote:thray wrote:FrediFizzx wrote:Well, when a theory is not experimentally verifiable then perhaps consensus means something for science. There is also the tricky business of "interpretation" that has to be dealt with. I'm not so sure it is so clear cut as Crichton paints it to be. Lot's of grey areas. Especially now-a-days since experimental facts have fallen way behind theory. Even when you have experimental facts, sometimes they are still subject to interpretation.
That is the problem with all the Bell test experiments. They are using the wrong interpretation. Mainly because they don't see the mistake in Bell's reasoning.
Fred, even a thought experiment has to be do-able in principle. And if a theory can't support at least a thought experiment, it's not much of a theory.
A theory that is incomplete -- as quantum mechanics surely is -- can't be saved by the right interpretation. There is no way to validate it.
Tom, I believe a theory does not have to be complete to be useful.The problem with quantum mechanics is IMHO not quantum mechanics itself. It is a sociological problem, owing largely to how the theory came about. The mathematics did not come out of a core principle or idea that was then formulated into it's current form. Rather, we have a mish-mash of mathematical tricks patched together, that sort of worked by trial and error and nobody knows exactly why it works, so everybody proposes their own wild "interpretation" that fits the mathematics -- some of them are outlandish, mystical and unfortunately given weight by large swaths of the community. Add to that the current political situation in science (http://www.math.columbia.edu/~woit/wordpress/?p=9207), and that explains what we are observing.
If the current QM theory had been derived out of a clear first-principle idea. There would be more progress, even if the mathematical form were essentially the same, and the theory still just as incomplete. There would be less time wasted debating nonsensical "interpretations". Unfortunately, it has now become unfashionable, and career-ending to even suggest that Quantum Mechanics should make sense. The very mechanism that is supposed to get us out of this rot, is being actively stifled in the name of "consensus".
I believe the same problem would exist in any theory if it was arrived at in a similar manner, no matter how successful the theory. Actually, a similar issue existed (and probably still does to some extent) in the field of Probability Theory. There were lots of debates about the interpretation of Probability Theory. At least, there are now very clear derivations of all the rules of probability theory starting from basic first-principle desiderata. This is still lacking in Quantum Mechanics.
FrediFizzx wrote:thray wrote:A theory that is incomplete -- as quantum mechanics surely is -- can't be saved by the right interpretation. There is no way to validate it.
Tom, QM has plenty of validation. That is part of the problem is that it does in fact give us the right answers. It doesn't need saving; it just works. Probably the correct interpretation is that it is a workaround probabilistic method that gets us around our incomplete knowledge of Nature. We are working on that.
Return to Sci.Physics.Foundations
Users browsing this forum: ahrefs [Bot] and 96 guests