Do Hidden Variables include sub-structures?

[PeterDonis]

This is out of bounds for PF discussion. Please do not mention it again or you will receive a warning.

I have edited the post to remove the out of bounds content.

 

[PeterDonis]

In a discussion about hidden variable theories for quantum theory, the context is not that of relativity.

The "context of relativity" here means the basic principle of relativity, that the laws of physics are the same in all frames. It does not mean "relativity" in the sense of the specific theory of SR.

you certainly have to make assumptions about the fundamental character of relativistic symmetry. They are necessarily metaphysical, which means, they cannot be supported by observation alone

But they can be adopted as the simplest assumptions consistent with the experimental facts. If you are going to assume that the principle of relativity is violated, you need to show some evidence that it is. There is no such evidence.

Else, we have the equations for sound waves

Sound waves in a material substance which can be observed, and its properties measured, independently of the propagation of sound. The speed of sound is a property of the substance, not of the laws of physics. The principle of relativity in no way forbids substances from having particular properties.

 

[bhobba]

The "context of relativity" here means the basic principle of relativity, that the laws of physics are the same in all frames. It does not mean "relativity" in the sense of the specific theory of SR.

Of course. But just to further expand on it ordinary QM is based on the Galilean Transformations that strictly speaking allows an infinite speed. Of course its not true, and is just an approximation, but as found in chapter 3 of Ballentine (where he proves Schrodinger equation etc - yes it can be proven if you have never seen it) that is a, perhaps hidden, assumption of normal QM. The reason I say perhaps hidden is my go-to book on QM is Ballentine and it makes it clear - those not exposed to it may not realize it. So those that use locality as an argument in ordinary QM strictly speaking should use QFT. However I can't say it really has caused much if any issues in posts here or books I have read so likely its just being pedantic. Perhaps that's because, like the Galilean transformations themselves, its a limit of QFT, and interpretations etc discussed here usually (but not always) are not affected by it. I will however say in analysing Bell I like to keep in mind the cluster decomposition property of QFT - but that requires a whole new thread that I think may still be going on.

Thanks
Bill

 

[bhobba]

In a discussion about hidden variable theories for quantum theory, the context is not that of relativity.

Not always.

And you certainly have to make assumptions about the fundamental character of relativistic symmetry. They are necessarily metaphysical

No they are experimental. Its not really on topic for this thread but to understand SR you really need to see a modern derivation of it:
http://www2.physics.umd.edu/~yakovenk/teaching/Lorentz.pdf
The constant c that appears in the equations can be, and has been, determined in many ways and all are in agreement. If you want to discuss it further please start a new thread - its not appropriate here.

Just a note, as a moderator, explaining why, by forum rules, we do not discuss LET here, except in a historical context. The modern view of SR is very clear, and illustrative of modern physical ideas of the importance of symmetry. The forum rules are, in part, to stop threads that by their very nature would not really go anywhere.

Thanks
Bill

 

[Elias1960]

No they are experimental. Its not really on topic for this thread but to understand SR you really need to see a modern derivation of it:
http://www2.physics.umd.edu/~yakovenk/teaching/Lorentz.pdf

This "modern derivation" does not present anything at all which would suggest that general assumptions about fundamental symmetries are somehow experimental. They cannot be by their very nature. Experiments give only approximate results, and so they cannot allow, even in principle, to distinguish fundamental symmetries from approximate symmetries. (Ok, except in the case when the approximate character follows already from the experimental data.)

The constant c that appears in the equations can be, and has been, determined in many ways and all are in agreement.

As if somebody has questioned the measurements of the speed of light.

Just a note, as a moderator, explaining why, by forum rules, we do not discuss LET here, except in a historical context. The modern view of SR is very clear, and illustrative of modern physical ideas of the importance of symmetry. The forum rules are, in part, to stop threads that by their very nature would not really go anywhere.

Metaphysical ideas about the importance of symmetries are already quite old now, they were modern 1905 or so. And, in fact, symmetries have always impressed people, in particular, mystics. If you prefer threads going into something wrong given that you forbid certain types of counterarguments (with your "they are experimental" as an example), your choice.

 

[martinbn]

What "tested corollaries" do you have in mind?

Just clarify what I mean by infinite speed of propagation, and what the standard terminology is as far as I understand it. If the electromagnetic field had infinite speed of propagation, then the compas needle over there would move the instant there is current in the wire over here, no matter how far apart they are. So, why do you think that this, for any field, would not be in conflict with relativity and experiment? By the way, why do you put "" around tested corollaries? Are you claiming that there aren't any?

 

[vanhees71]

So those that use locality as an argument in ordinary QM strictly speaking should use QFT.

They should use relativistic QFT. If you want to discuss locality you can never argue with non-relativistic approximations, because there's nothing in Galileo-Newtonian physics which guarantees locality, and already in the Theoretical Physics 1 quite in the beginning we violate it when we write down Newton's Law of gravity. There's nothing wrong with that, but as you rightly say, it's an approximation with some limited range of applicability. It's well applicable within the solar system, but there are also deviations from it known already in the 19th century (perihelion shift of Mercury).

 

[bhobba]

This "modern derivation" does not present anything at all which would suggest that general assumptions about fundamental symmetries are somehow experimental.

What about, for example, the laws of physics is the same in all inertial frames or frames moving at constant velocity to an inertial frame. What is not experimentally verifiable about that?

Experiments give only approximate results, and so they cannot allow, even in principle, to distinguish fundamental symmetries from approximate symmetries. (Ok, except in the case when the approximate character follows already from the experimental data.)

We all know the game of science - we can never prove a conjecture by experiment, only check if the experiment supports it.

As if somebody has questioned the measurements of the speed of light.

The exact speed is not the issue - it's what is said in the paper:
'Knowing about the Maxwell equations and electromagnetic waves, we can identify this parameter with the speed of light.'

In fact it can be detailed further by showing that c can be made part of a derivation of Maxwell's equations:
http://cse.secs.oakland.edu/haskell/Special Relativity and Maxwells Equations.pdf

Metaphysical ideas about the importance of symmetries are already quite old now, they were modern 1905 or so. And, in fact, symmetries have always impressed people, in particular, mystics. If you prefer threads going into something wrong given that you forbid certain types of counterarguments (with your "they are experimental" as an example), your choice.

We forbid very few things here. Yes LET is forbidden - but that's only because it is well and truly superseded so is confined to its historical context. But regarding symmetries being metaphysical and requiring interpretation what about the modern definition of energy as the conserved quantity implied by Noethers Theorem and time invarience?. Is energy just 'metaphysical'? Does the theorem need interpretation - its rather explicit. But please do not post in this thread, start another thread if you want to delve into it further.

Thanks
Bill

 

[Elias1960]

What about, for example, the laws of physics is the same in all inertial frames or frames moving at constant velocity to an inertial frame. What is not experimentally verifiable about that?

Everything. It is a general statement, and general hypotheses cannot be verified by experiments. They can only be falsified.

We all know the game of science - we can never prove a conjecture by experiment, only check if the experiment supports it.

So why you make, then, claims about such conjectures being verifiable?

The exact speed is not the issue - it's what is said in the paper:
'Knowing about the Maxwell equations and electromagnetic waves, we can identify this parameter with the speed of light.'

The point being? It was never a problem to derive the Lorentz symmetry from some general metaphysical hypotheses.

We forbid very few things here. Yes LET is forbidden - but that's only because it is well and truly superseded so is confined to its historical context.

It is certainly not superseded by any experimental fact.

But regarding symmetries being metaphysical and requiring interpretation what about the modern definition of energy as the conserved quantity implied by Noethers Theorem and time invarience? Is energy just 'metaphysical'?

First, mathematics is mathematics, theorems do not need interpretations. But if a given symmetry is fundamental or approximate, and if everything is symmetric or only some part of objective reality, requires interpretation. If time translation invariance is only approximate, then I would expect that energy conservation will be only approximate too. About the metaphysical questions related to energy, I would recommend you to inform yourself in discussions about energy-momentum pseudotensors in GR.

But please do not post in this thread, start another thread if you want to delve into it further.

I answer questions where they appear. I don't want to delve into this further, but once you continue - I don't like to create the impression that I have no answers to such questions.

 

[bhobba]

Everything. It is a general statement, and general hypotheses cannot be verified by experiments.

We all can channel Popper. However physics goes beyond the philosophy of science and actually accepts some things. When a physicist says something general has been experimentally verified what is meant is sufficient experimental proof exists that its generally accepted as correct. That of course does not prove it, but to make progress you have to accept something - even though you know its provisional. I am sure you have read Popper - I suggest also reading Feynman The Character Of Physical Law and The Feynman Lectures.

BTW discussion of Philosophy is not allowed here. The reason is we do not have a mentor suitably qualified in both philosophy and science/engineering to moderate it. We did once but when they left it got out of hand and we had to bar it. A friendly warning from a mentor if that is what you want to discuss this may result in action taken.

First, mathematics is mathematics, theorems do not need interpretations.

That's the point I am making. Both Noether's Theroem and the modern justification of SR are theorems based on assumptions. In a mathematical theorem you state your assumptions and get a result. If the assumptions are true, and for the theorems discussed here they are true in the sense elucidated above, then the the result is also true. I will leave you to nut out what the physical assumption is that goes in Noether's theorem. The point is to doubt SR you have to doubt what went into it and that has very strong support. We do not need any kind of interpretation of SR - it's simply a consequence of things generally accepted as true.

Thanks
Bill

 

[Elias1960]

BTW discussion of Philosophy is not allowed here.

Facepalm. A physics forum where one is not allowed to discuss the scientific method.

The reason is we do not have a mentor suitably qualified in both philosophy and science/engineering to moderate it.

The only question which remains is if this only a particular accidental situation in the moderation team here, or is this simply the general situation in modern physics? In fact, I would tend to the second answer - a complete lack of education about methodology, a strong prejudice against discussions of interpretations in general, and questioning the spacetime interpretation of relativity being anathema seems widely distributed.

But I guess that discussing such general questions will be forbidden here too. Not?

 

[PeterDonis]

A physics forum where one is not allowed to discuss the scientific method.

He didn't say "scientific method". He said "philosophy". They're not the same thing.

I guess that discussing such general questions will be forbidden here too. Not?

We generally do not allow discussions on topics that are simply assertions of opinion, since there is never any resolution to such discussions; people just continue asserting their opinions.

PF's mission is to help people understand mainstream science. To the extent that there is actual mainstream scientific research about how science is done, discussion of it would be allowed here. But bare statements of personal opinion do not qualify.

 

[Elias1960]

He didn't say "scientific method". He said "philosophy". They're not the same thing.

Yes, but the discussion of the scientific method is part of discussing philosophy.

We generally do not allow discussions on topics that are simply assertions of opinion, since there is never any resolution to such discussions; people just continue asserting their opinions. PF's mission is to help people understand mainstream science.

There are a lot of quite precise arguments made, in particular, by Popper, which are beyond the "simply assertions of opinion". And how can one understand mainstream science without understanding at least the basic concepts of Popper's critical rationalism as well as the problems of empiricism/positivism?

 

[PeterDonis]

but the discussion of the scientific method is part of discussing philosophy

That doesn't mean we need to allow other parts of philosophy besides that one.

There are a lot of quite precise arguments made, in particular, by Popper, which are beyond the "simply assertions of opinion".

I wasn't talking about Popper's assertions. I was talking about yours.

how can one understand mainstream science without understanding at least the basic concepts of Popper's critical rationalism as well as the problems of empiricism/positivism?

Many people seem to manage it quite well. Perhaps they don't meet your personal criterion of "understanding", but they can use mainstream science to make accurate predictions.

At the end of the day, the PF rules are what they are, and they are there for reasons, many of which have to do with trying certain kinds of discussions in the past and having them not work. If you want to suggest a change to the PF rules, you should open a thread in the Feedback forum and make your argument. But you should be prepared for the final answer after consideration to be no. For further discussion in this thread, rules are off topic; please stick to the actual thread topic.

 

[bhobba]

Facepalm. A physics forum where one is not allowed to discuss the scientific method.

The scientific method is part of philosophy - sure - it is also part of science with many scientists like Feynman discussing it. Interestingly they often come to different conclusions than actual philosophers. See the following by Wienberg:
https://www.physics.utah.edu/~detar/phys4910/readings/fundamentals/weinberg.html
You can discus the scientific method here. If it strays too much into philosophy some gentle reminders will be posted by mentors to get it back on track.

The only question which remains is if this only a particular accidental situation in the moderation team here, or is this simply the general situation in modern physics? In fact, I would tend to the second answer.

Those of a philosophical bent often say that here, and elsewhere. I once posted a lot on alt.sci.physics.relativty. Actual scientists like John Baez and Steve Carlip also posted. A very high percentage of posts was they thought physics lost its way because it ignored philosophy. We even had a post here that because PhD stands for Doctor of Philosophy scientists were ignoring their training thinking a PhD meant the doctorate was actually in philosophy. Those more influenced by Feynman, Dirac etc disagree. All I will say is it would seem those in the second group have made more progress, but those in the first group still have produced interesting scientific work such as David Wallace who has a PhD in both philosophy and particle physics:
https://www.amazon.com/dp/0198707541/?tag=pfamazon01-20

I have read the above book, but interestingly, for me, it shed more light on Decoherent Histories as advocated by Gell-Mann, and I think Feynman was converted to it towards the end. Still it's a legitimate book to discuss here.

Thanks
Bill

 

[DarMM]

That's interesting, I wasn't much of a fan of Wallace's book. I found it mixed the mathematics and prose in a very odd way. Often assumptions for the theorems appear much earlier in an unassuming form in the prose.

For decoherent histories I found Omnès far better.

Of course this is just taste.