A Bohr's solution to the EPR paradox

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Bohr's resolution to the EPR paradox emphasizes that the state of a particle is not an independent property but is influenced by the experimental conditions. He argues that predictions about a particle's behavior depend on the measurements made, asserting that unmeasured properties do not necessarily have defined values. John Bell expresses confusion over Bohr's terminology and the implications of counter-factual definiteness (CFD), questioning whether it can be applied to quantum measurements. The discussion highlights the distinction between the outcomes of measurements and the assumptions made about unmeasured states, reinforcing that quantum mechanics does not support the idea of independent states outside of experimental contexts. Ultimately, the conversation seeks to clarify the nature of quantum states and the validity of counter-factual reasoning in quantum experiments.
  • #91
Zafa Pi said:
Thus all states follow from the state of the big bang, right?
Maybe... right ? .. :oldtongue: . :oldtongue:
 
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  • #92
stevendaryl said:
Well, that's a mistake. It's an application of a generalization.
In spite of that not being the prevailing view, and not treated in the vast majority of texts, I see your point.
 
  • #93
OCR said:
Maybe... right ? .. :oldtongue: . :oldtongue:
The big bang knew you would say that.
 
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  • #94
Zafa Pi said:
The big bang knew you would say that.
I know..... :oldwink:
 
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  • #95
Zafa Pi said:
Thus all states follow from the state of the big bang, right?

Yes, that is a direct implication (of course under the assumption that classical physics, say EM + GR are a fundamental, correct description of nature). Classical physics is also reversible so you could calculate the state at the big bang from the present one, if the required data would be available.
 
  • #96
Your answer to
Zafa Pi said:
Thus all states follow from the state of the big bang, right?
was
ueit said:
Yes, that is a direct implication (of course under the assumption that classical physics, say EM + GR are a fundamental, correct description of nature). Classical physics is also reversible so you could calculate the state at the big bang from the present one, if the required data would be available.
but earlier when I said
Zafa Pi said:
I think your position in this post is referred to as superdeterminism. That is not the prevailing view of CT, rather it is local determinism.
you said
ueit said:
This is false. Classical determinism implies that any state follows uniquely from a past state. Classical EM is like that. This is not a controversial position at all.
Now I refer you to https://www.physicsforums.com/threa...minism-and-bells-theorem.914439/#post-5761059
Then why all the controversy?
 
  • #97
BTW... you are welcome !
Zafa Pi said:
Thanks for the question mark?
 
  • #98
Zafa Pi said:
Your answer to
was
but earlier when I said
you said

Now I refer you to https://www.physicsforums.com/threa...minism-and-bells-theorem.914439/#post-5761059
Then why all the controversy?

Look, do you deny that determinism implies that the present state follows uniquely from the past state? If so, please define what you mean by determinism, and state clearly if you think that in classical EM the state at a certain time is or it is not determined by the past state of the system.

As long as I didn't make use of any assumption other than the properties of classical EM I feel no need to go into the subject of superdeterminism. We can if you want, but at this point is not necessary.
 
  • #99
ueit said:
Look, do you deny that determinism implies that the present state follows uniquely from the past state?
Look, all I was doing was pointing out there was controversy that you were denying. I'm merely a simple mathematician that believes in the axiom of choice. IMO determinism is an idea about reality (yuck) that's not even wrong.
 
  • #100
Zafa Pi said:
Look, all I was doing was pointing out there was controversy that you were denying. I'm merely a simple mathematician that believes in the axiom of choice. IMO determinism is an idea about reality (yuck) that's not even wrong.

This is what determinism is, according to Laplace:

https://en.wikipedia.org/wiki/Laplace's_demon

"We may regard the present state of the universe as the effect of its past and the cause of its future. An intellect which at a certain moment would know all forces that set nature in motion, and all positions of all items of which nature is composed, if this intellect were also vast enough to submit these data to analysis, it would embrace in a single formula the movements of the greatest bodies of the universe and those of the tiniest atom; for such an intellect nothing would be uncertain and the future just like the past would be present before its eyes."

Classical electrodynamics is such a theory. Both the concept of determinism and the formulation of classical electrodynamics predate Bell's theorem and his invented word "superdeterminism" so your attempt to change the subject in that direction makes little sense.

"Free choice" is not an axiom of classical electromagnetism so I find it irrelevant to this discussion. In fact I doubt there is any place for this concept in any physical theory, quantum mechanics included.

The fact that you believe that determinism is wrong is again irrelevant. I'm not arguing here that it is true (although I do believe so). What I am trying to argue is that in classical electromagnetism you cannot have isolated systems in the way you want. So, can you please make a clear statement about your opinion on this? Can you provide an example of physical system that is described by classical electrodynamics and yet can be shown to consist of two subsystems that are isolated in the way you envision?
 
  • #101
Thread closed for moderation.

Edit by @DrClaude: this thread was going nowhere and will stay closed.
 
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