That's the essence of the test, over many runs the statistics would be different. The outcome of real tests is consistent with the variables only being determined on detection.

Thank you for response, George

Here's where I find troubling about quantum theory, when it goes from a mathematics of prediction to a theory of nature:

It is conventional to say “a particle exists in multiple states until it is observed”, but I believe I can say with at least as much validity, “how can it be known that a particle exists in multiple states unless and until it can be observed (i.e., known)?”

Regarding “Bell’s Theorem” and its verifications, I maintain that a realistic position on unknowns (i.e., that unknowns are unknown but probably independent of knowingness) is at least as credible as the quantum position (i.e., that unknowns are known to be dependent on knowingness).

Hi

According to the famous John Wheeler's delayed-choice thought experiment, quantum reality does not exists until we measure it.

I've offered an explanation for those experiments which is fully compatible with Relativity (not your typical "crackpottery"), involving a hypothesis that light is at absolute rest, it is mass that is moving in time, and it is our assumption of rest from our 4-D perspective that makes it seem that light is moving. Everything from wave/particle duality to non-locality can be neatly explained in terms of the hypothesis. And I've offered a fairly simple experiment that could confirm it. You'd almost think it would be worth investigating. But somehow the alternative quantum view seems more believable, where it appears that objects only have definite properties when they are observed, and according to Wheeler, photons can anticipate what's ahead in order to choose to manifest as either a wave or particle

Article Title: A hypothesis on the nature of light

Research Proposal Proposal for experimentation regarding an interpretation of ...

In any case, the belief that a photon can do a shape-change if it believes it's about to be observed doesn't actually justify the belief that entangled particles only take a definite property when observed, and at whatever distance. Did the world begin with observers in 4000 BCE?

Well, curious ideas mixing determinism and some kind of theory of "everything". "Could the solution to the dilemma of indeterminism be a universe in which all possible outcomes of an experiment actually occur?

Bryce S. DeWitt"

In 1970 DeWitt wrote an interesting article about quantum reality and measurement. I quote here the abstract.

"Despite its enormous practical success, quantum theory is so contrary to intuition that, even after 45 years, the experts themselves still do not all agree what to make of it. The area of disagreement centers primarily around the problem of describing observations. Formally, the result of a measurement is a superposition of vectors, each representing the quantity being observed as having one of its possible values. The question that has to be answered is how this superposition can be reconciled with the fact that in practice we only observe one value. How is the measuring instrument prodded into making up its mind which value it has observed?

Could the solution to the dilemma of indeterminism be a universe in which all possible outcomes of an experiment actually occur?"

"Could the solution to the dilemma of indeterminism be a universe in which all possible outcomes of an experiment actually occur?"

No.

Well James

I agree with you.

The EPR paradox is trivially resolved (in principle) within the hidden variable theory by Luis de Broglie + David Bohm. Some concreteness (via simple examples) of the resolution of the EPR paradox (in the Bohm modification) was suggested by John Bell, including that described in his famous paper in Physics, vol.1, p.195, Sect. 3.

Indeed, what John Bell has proved in this paper is the impossibility of a

l o c a l hidden variable theory, while the physics community has interpreted his work as a proof of the impossibility of a n y hidden variable theory. Bell himself had a strong belief that quantum mechanics `` cries out" for some hidden variable theory (these are his words), but he

insisted (and demonstrated in many his papers) that such a theory must be non-local.

But again, doesn't the non-local interpretation depend on the assumption that entangled particles were not fixed locally, at their emission? If it is asserted that they are in superposition until observed, that is an assertion of definite knowledge, which is simultaneously being denied. Ironically, it seems to me, quantum physicists are in a superposition of opinion.

Hidden variable theory postulates that the quantum-mechanical description originates from a statistical averaging over hidden variables, while these variables describe quantum-mechanical states deterministically, i.e. as ``dispersion-free" states; this is so called realist

point of view (Einstein, Bohm and others), as distinct to the ``orthodox" view of Bohr and the rest of the physical community (Copenhagen view).

Thus, from the realist point of view, photon spins (or electron and positron spins in the Bohm modification of the EPR experiment) are

definitely fixed at their origin.

Thank you, Vassili

But given the unknowability of that initial, unobserved state, doesn't it render the issue (locality/non-locality?) un-resolvable? Why is it commonly held that non-locality has "won the day"?

It is just the content of Bell's theorem, Physics, vol.1, p.195 (1964)

(described also in many textbooks on Quantum Mechanics), confirmed

experimentally (by A. Aspect et al., and several others).

Here's what always seems vague and mystical: If the state of a particle cannot be known until it is observed, how can it be known that the states of both members of the entangled pair were not already fixed prior to their observation? That would render the claim of non-locality baseless.

Experiment is an ultimate referee. Prior to it only theoretical models exist. If the experiment confirms a model the model is accepted and is used for an interpretation of the observation. If further experiments corroborate the model it becomes a theory. Otherwise it is replaced by another model. It is a standard way how our scientific knowledge progresses.

Once again: before the experiment (before observation) we cannot say

that we k n o w what is the state of a quantum-mechanical system, we can only envisage it. If results of the observation fit our imagination we

are satisfied with it and accept a given theory, at least for the time being. So, I finish with the same paradigm as that at the beginning:

experiment is crucial in contemporary science (as distinct to the science of ancient Greeks who based their understanding of nature mainly on logical, i.e. theoretical, arguments). And experimental studies of EPR effects confirm a non-local interpretation of quantum mechanics, though the question whether a (non-local) hidden variable model can be invoked for the explanation of the results (and for an interpretation of quantum mechanics in general) is answered negatively by a vast majority of theorists.

Ah, but experiment is not so sovereign!

Look! Before this egg is hatched, it is true what I have said, and verified by calculation, that the content has been in a superposition, both a rooster and hen. And now, with the crack of the shell, it is proven what I have said: It is only when we observe the fowl emerge, there is a collapse of the wave function, and only now, it is rooster or hen! Praise be to theory, and experimental confirmation!

I disagree with you. Prior to experiment you are free to envisage a situation as you want, but without experimental tests your ideas will remain abstract, similarly to imaginations of ancient Greek philosophers what the nature is. Sometimes their guesses were correct, but in many cases erroneous.

I see, our discussion gets scholastic (like a dispute what was primary, hen or egg), i.e., as it seems to me, fruitless, I am very sorry.

Yes, there is an unmentioned assumption. That the algebra of complex numbers (amplitudes of probability) can be mapped on positive numbers (probabilities).

Scholastic? Really? You wrote "without experimental tests your ideas will remain abstract." The idea you hold, that a body exists in a superposition of states until it is observed, is no less abstract. Your belief is not subject to experiment. But it is worse. Your belief is no different than a belief that nothing exists unless you open your eyes. Is my belief that the world goes on whether or not I open my eyes subject to experiment? No. But my belief is based on a comprehensive experience of life, where a cat is either alive or dead, and a body that can only be in one or two states is always in one state or the other whether I observe it or not. Your belief is based on a belief that a mathematics of probability is determinate of reality. It is not subject to experimental confirmation and for all the non-mathematicians of the world, it seems crazy.

I am sorry that you are sorry.

Sofia, your example of an unmentioned assumption is entirely mathematical, and as such it is not physically verifiable, and therefore open to question, and so it is a mere assumption.

To assert that a physical belief is valid based on mathematics, and not subject to experimental confirmation (such as "superposition"), that is an assumption, and open to question, such as "are you serious?"

Arnold,

That's elementary mathematics.

You don't verify experimentally that the algebra of complex numbers cannot be mapped on the calculus with positive numbers. You prove it mathematically.

The proof is trivial. The complex numbers form a 'field'. To the difference, the positive numbers don't have the property of inverse under additivity, i.e. the number 0.5 belongs to the positive numbers, but the number -0.5 does not belong.

That's fine. My point is that the physical relevance is subject to physical verification.