I Is there a bad intuition or bad explanation in quantum entanglement?

[syed]

TL;DR Summary

Title

I keep reading throughout this forum from many members that the general motivation for finding a deeper explanation within QM, specifically with regards to quantum entanglement, is due to an inability to grasp reality based off of classical intuitions. On the other hand, if QM was truly incomplete, and there was a deeper explanation that we haven't grasped yet that would explain why particles tend to be correlated to each other seemingly instantly despite vast separated distances, then that would mean our current theory simply failed to explain all of reality.

In other words, a failure of an explanation seems to suspiciously look the same as a failure of an intuition. So my question is for the people who propose that there is nothing more to reality when it comes to quantum entanglement, or that reality is fundamentally stochastic: how do you differentiate between quantum entanglement simply not obeying your intuitions vs. physicists just not having a complete theory of quantum entanglement yet?

 

[javisot]

TL;DR Summary: Title

if QM was truly incomplete, and there was a deeper explanation that we haven't grasped yet that would explain why particles tend to be correlated to each other seemingly instantly despite vast separated distances, then that would mean our current theory simply failed to explain all of reality.

The question is whether the textbook and the more complete interpretations are truly complete, in the sense of being able to describe all the results of all possible experiments involving quantum effects. It seems a legitimate question, since we don't know in advance "all the results of all possible experiments involving quantum effects" to truly know if QM is complete in its domain.

Whether QM is complete or incomplete is a separate issue from seeking a classical explanation for entanglement (which contradicts Bell's theorem).

 

[syed]

The question is whether the textbook and the more complete interpretations are truly complete, in the sense of being able to describe all the results of all possible experiments involving quantum effects. It seems a legitimate question, since we don't know in advance "all the results of all possible experiments involving quantum effects" to truly know if QM is complete in its domain.

Whether QM is complete or incomplete is a separate issue from seeking a classical explanation for entanglement (which contradicts Bell's theorem).

Well even regarding the second point, what's the difference between a "non classical" explanation and an incomplete explanation?

 

[pines-demon]

Here is a usual scheme for entanglement

• There are two entangled particles.
• Alice receives one of the particles, Bob receives the other one. Alice and Bob are far away from each other.
• Alice measures the spin z of her particle, it collapses the result of spin z of Bob's particle.

The bad analogy of quantum entanglement that is repeated in most popular physics content:

• There is a pair of shoes (it can also be gloves). The pairs are put randomly in two boxes.
• Alice receives one of the boxes. Bob receives the second box.
• When Alice opens her box, she knows instantaneously the chirality (left/right) of Bob's shoe before Bob opens his Bob. It is like if Alice collapsed Bob's shoe.

Why is it a very bad analogy:

• You are basically explaining the entangled particles with a hidden variable model and there is no issue with that here.
• You kind of want to imply that the particles, contrary to the shoes, were not defined before measurement, but where is that required here? Somebody that challenges quantum mechanics is not going to be convinced with this analogy.
• There is only one observable (spin-z, shoe chirality). Any Bell-like inequality or even the orginal EPR paper have at least another incompatible observable (spin at different angles/position-momentum). This is key.

A better analogy: GHZ experiment as explained by Mermin device.

 

[Peter Morgan]

The idea that QM is incomplete whereas, presumably, CM is complete, has colored the foundations of physics for too long. I suggest that QM is complete in the sense that it has enough resources to model any collection of data from multiple experimental sources: that is, QM is empirically complete.
OK, so what about CM? I suggest taking the no-go theorems as an indication that CM is incomplete, which I suppose leads quickly to asking how CM could be completed to be as-complete-as QM? I presented such a completion well enough for it to be published in Annals of Physics in 2020, where I call that Completed Classical Mechanics 'CM+'.
The starting point for that construction as I had it there was Koopman's Hilbert space formalism for CM, which makes it possible to compare QM with CM in the shared mathematical context of Hilbert spaces. There are two key aspects, which can be characterized as

• QM allows arbitrary unitary transformations whereas CM allows only the much more restricted canonical transformations; fixing this difference is straightforward and allows us to model incompatible experimental contexts in a classically natural way, as contextuality, within CM+. This change can be thought of as introducing the tools of Generalized Probability Theory into CM.
• If we think in a more classical way, one clear question is "What the difference is between quantum fluctuations/noise and thermal fluctuations/noise?" An unequivocal answer to this comes from Quantum Field Theory: quantum noise is Lorentz invariant whereas thermal noise is not invariant under boost transformations. This difference can be used in a classical formalism, but it requires us to work in a Minkowski space formalism, which, together with a desire to match the physics of QFT pushes us into using a classical random field theory formalism.

That out of the way, let us consider the idea of entanglement. I think, crucially, that there is such an idea only if we have an idea of a Hilbert space as a way to model systems and their properties and an idea of a tensor product of multiple Hilbert spaces as a tool for modeling a compound system and its properties. In QFT there is no such idea in the Wightman axioms and it is only by rather hand-waving arguments that we can introduce tensor products (and partial traces, which are natural enough once we have introduced a tensor product). Everything we think we know about entanglement for non-relativistic QM models is tendentious for QFT models, so that my suggestion is that we will be better to come back to entanglement when we better understand the relationship between QFT and CM+.
The ideas in that article in Annals of Physics 2020, in another article in Physica Scripta 2019, and in another in Journal of Physics A 2022 (those are arXiv links, the DOIs for the published versions can be found there) are developed further in various academic talks. As far as I can tell, everybody in physics who comes across these ideas is waiting for someone else to tell them that it's OK or not OK: being published in a reputable old-school physics journal is only a very small step towards ideas becoming widely known (unless an idea makes it into Nature or PhysRevLett or into one a few other very select places). For three of those recent talks, with the most recent, for NSU Dhaka, being the most accessible, I'm told:

• “A Dataset & Signal Analysis Interpretation of Quantum Mechanics” (Announcement, YouTube, PDF) Colloquium, School of Engineering and Physical Science, North South University, Dhaka, May 18th, 2025.
• “A Dataset & Signal Analysis Unification of Classical and Quantum Physics” (Announcement, YouTube, PDF) Special Physics Seminar, Physics Department, Yale University, May 1st, 2025.
• “A Dataset & Signal Analysis Interpretation of Quantum Field Theory” (YouTube, PDF) Philosophy of Physics Seminar, Oxford University, October 24th, 2024.

I emphasize that these do not present a complete story. It will take more than just my blundering about in a complex world to repair a century of misdirection. I don't even claim that I'm getting anything 'right'. This is my best attempt at valley-crossing, which I hope might give someone else the right push for them to do something much better.

 

[javisot]

The idea that QM is incomplete whereas, presumably, CM is complete, has colored the foundations of physics for too long. I suggest that QM is complete in the sense that it has enough resources to model any collection of data from multiple experimental sources: that is, QM is empirically complete.
OK, so what about CM? I suggest taking the no-go theorems as an indication that CM is incomplete, which I suppose leads quickly to asking how CM could be completed to be as-complete-as QM? I presented such a completion well enough for it to be published in Annals of Physics in 2020, where I call that Completed Classical Mechanics 'CM+'.
The starting point for that construction as I had it there was Koopman's Hilbert space formalism for CM, which makes it possible to compare QM with CM in the shared mathematical context of Hilbert spaces. There are two key aspects, which can be characterized as

• QM allows arbitrary unitary transformations whereas CM allows only the much more restricted canonical transformations; fixing this difference is straightforward and allows us to model incompatible experimental contexts in a classically natural way, as contextuality, within CM+. This change can be thought of as introducing the tools of Generalized Probability Theory into CM.
• If we think in a more classical way, one clear question is "What the difference is between quantum fluctuations/noise and thermal fluctuations/noise?" An unequivocal answer to this comes from Quantum Field Theory: quantum noise is Lorentz invariant whereas thermal noise is not invariant under boost transformations. This difference can be used in a classical formalism, but it requires us to work in a Minkowski space formalism, which, together with a desire to match the physics of QFT pushes us into using a classical random field theory formalism.

That out of the way, let us consider the idea of entanglement. I think, crucially, that there is such an idea only if we have an idea of a Hilbert space as a way to model systems and their properties and an idea of a tensor product of multiple Hilbert spaces as a tool for modeling a compound system and its properties. In QFT there is no such idea in the Wightman axioms and it is only by rather hand-waving arguments that we can introduce tensor products (and partial traces, which are natural enough once we have introduced a tensor product). Everything we think we know about entanglement for non-relativistic QM models is tendentious for QFT models, so that my suggestion is that we will be better to come back to entanglement when we better understand the relationship between QFT and CM+.
The ideas in that article in Annals of Physics 2020, in another article in Physica Scripta 2019, and in another in Journal of Physics A 2022 (those are arXiv links, the DOIs for the published versions can be found there) are developed further in various academic talks. As far as I can tell, everybody in physics who comes across these ideas is waiting for someone else to tell them that it's OK or not OK: being published in a reputable old-school physics journal is only a very small step towards ideas becoming widely known (unless an idea makes it into Nature or PhysRevLett or into one a few other very select places). For three of those recent talks, with the most recent, for NSU Dhaka, being the most accessible, I'm told:

• “A Dataset & Signal Analysis Interpretation of Quantum Mechanics” (Announcement, YouTube, PDF) Colloquium, School of Engineering and Physical Science, North South University, Dhaka, May 18th, 2025.
• “A Dataset & Signal Analysis Unification of Classical and Quantum Physics” (Announcement, YouTube, PDF) Special Physics Seminar, Physics Department, Yale University, May 1st, 2025.
• “A Dataset & Signal Analysis Interpretation of Quantum Field Theory” (YouTube, PDF) Philosophy of Physics Seminar, Oxford University, October 24th, 2024.

I emphasize that these do not present a complete story. It will take more than just my blundering about in a complex world to repair a century of misdirection. I don't even claim that I'm getting anything 'right'. This is my best attempt at valley-crossing, which I hope might give someone else the right push for them to do something much better.

Very interesting. One question: Are there differences between CM and CM+, or does CM+ simply represent the idea that CM is complete? Is CM+ a hidden-variable theory, or is it something even deeper?

 

[phinds]

TL;DR Summary: Title

if QM was truly incomplete

Whether QM is complete or incomplete is a separate issue from seeking a classical explanation for entanglement (which contradicts Bell's theorem).

I suggest that QM is complete in the sense that it has enough resources to model any collection of data from multiple experimental sources: that is, QM is empirically complete.

QM is KNOWN to be incomplete, although not regarding entanglement (I make no argument either way on that) but rather because it cannot handle gravity. QM is incomplete because it cannot handle the actions of subatomic particles.

We need a merge of the two into a Quantum Gravity Theory to make both complete. It's possible that that will never happen.

Both are "complete" within their own spheres of influence.

 

[Peter Morgan]

Very interesting. One question: Are there differences between CM and CM+, or does CM+ simply represent the idea that CM is complete? Is CM+ a hidden-variable theory, or is it something even deeper?

CM+ includes contextuality/measurement incompatibility, which allows multiple experiments to be modeled in a single algebraic structure, exactly as one finds in QM. This, I claim, is classically natural.

CM+ can be thought of as a hidden-measurement theory: though it begins as ordinary CM, it's more a version of thermodynamics by the end of my talks. Another way to think about how CM+ is different is that it's more like Signal Analysis than it's like CM: in the first instance there is no idea of a particle in signal analysis as an explanation for features of a noisy signal, which is different from CM, which begins with there are particles.

The idea that particles can be added later, if they can be justified, is closer to how QFT is than to how QM is. IMO, our interpretations ought to be addressing QFT in a natively QFT way instead of saying "for QFT everything is just the same as for QM".

If you watch some of that NSU Dhaka talk, which some people have liked and some have even liked a lot, let me know how you feel about it. You can have a look at the slides before committing to watching.

 

[RUTA]

In other words, a failure of an explanation seems to suspiciously look the same as a failure of an intuition. So my question is for the people who propose that there is nothing more to reality when it comes to quantum entanglement, or that reality is fundamentally stochastic: how do you differentiate between quantum entanglement simply not obeying your intuitions vs. physicists just not having a complete theory of quantum entanglement yet?

Allori has a nice overview of different types of explanation used in quantum foundations here:

https://www.mdpi.com/2624-960X/5/1/7

The two types we contrast in our papers and new book are constructive vs principle. If you want a constructive account of QM, you're looking for an explanation of entanglement via dynamical laws governing the behavior of microphysical objects (aka causal or mechanistic explanation). For example, in the kinetic theory of gases the temperature of a gas is understood constructively via the mean kinetic energy of the gas molecules. According to constructive approaches to QM, such as Bohmian mechanics, standard QM is definitely incomplete.

In contrast, quantum information theorists have developed a principle account of QM whereby its stochasticity is an unavoidable consequence of the observer-independence of Planck's constant h, and entanglement is not a dynamical effect due to some nonlocal or superdeterministic or retro causal mechanism, but a kinematic fact that follows from the relativity principle and Planck's radiation law. Accordingly, QM is as complete as possible.

As Allori writes, "people favoring different theories have profoundly different motivations guiding their search for a satisfactory theory, which leads them to favor specific explanatory structures."

 

[PeterDonis]

entanglement is not a dynamical effect due to some nonlocal or superdeterministic or retro causal mechanism, but a kinematic fact that follows from the relativity principle and Planck's radiation law.

So basically, on the "principle account" view, entanglement in QM is viewed as analogous to, say, relativity of simultaneity, length contraction, and time dilation in SR.

My reservation about this is that entanglement in QM seems to have consequences that are hard to view as "kinematic", such as violations of the Bell inequalities. Those seem analogous to invariants in SR, which are not just "kinematic".

Or, to put it another way, one can make predictions in SR without ever having to make use of any "kinematic" effects like relativity of simultaneity, length contraction, or time dilation: just use something like the tensor formalism that is used in GR. But I don't see any analogous way to make predictions in QM without ever having to make use of entanglement or the properties of entangled states.

 

[RUTA]

So basically, on the "principle account" view, entanglement in QM is viewed as analogous to, say, relativity of simultaneity, length contraction, and time dilation in SR.

Exactly. Entanglement, superposition, complementarity, and randomness all follow necessarily from the relativity principle and the observer-independence of h, just like relativity of simultaneity, length contraction, and time dilation all follow necessarily from the relativity principle and the observer-independence of c.

My reservation about this is that entanglement in QM seems to have consequences that are hard to view as "kinematic", such as violations of the Bell inequalities. Those seem analogous to invariants in SR, which are not just "kinematic".

The fundamental invariant of SR is the spacetime line element and the fundamental invariant of QM is the qubit. Those invariants entail the kinematic consequences listed above.

Or, to put it another way, one can make predictions in SR without ever having to make use of any "kinematic" effects like relativity of simultaneity, length contraction, or time dilation: just use something like the tensor formalism that is used in GR. But I don't see any analogous way to make predictions in QM without ever having to make use of entanglement or the properties of entangled states.

I'm not sure what you mean by this. Please elaborate :-)

 

[Peter Morgan]

I don't see any analogous way to make predictions in QM without ever having to make use of entanglement or the properties of entangled states.

In QFT, as in SR, I take kinematics and dynamics to be merged into a single 3+1-dimensional model of the world (my feeling is that anyone can choose whether to think of that as how the world really is or as a model.) We can still distinguish kinematics and dynamics for that kind of model if we like, but we have to introduce some kind of additional structure for us to be able to do so.
Further, in QFT, entanglement only becomes a concept for us to 'use' if we introduce tensor products and partial traces; doing that is nontrivial, so I prefer to think of the physics as about measurement results in a state that is constructed as a model of part of the world by applying measurement operators to modulate a vacuum state. The vacuum state is an ideal object that is nonlocally defined to be Poincaré invariant and, it turns out, applying measurement operators to modulate that vacuum state typically also has nonlocal (but manifestly Lorentz invariant) consequences.

 

[PeterDonis]

in QFT, entanglement only becomes a concept for us to 'use' if we introduce tensor products and partial traces

I'm not sure I understand. The definition of an entangled state of a quantum system is simple: it's a state that can't be expressed as a product of states of subsystems. All you need to make that well-defined is a definition of the subsystems.

 

[Peter Morgan]

I'm not sure I understand. The definition of an entangled state of a quantum system is simple: it's a state that can't be expressed as a product of states of subsystems. All you need to make that well-defined is a definition of the subsystems.

As a tensor product of states. If we consider the Wightman axioms, they do not mention tensor products at all. There is a very weakened sense in which we can construct tensor products for 'systems' that exist only at space-like separation to each other (because the algebras of observables for regions of space-time that are at space-like separation are required to commute by the Wightman axioms), but that is not the same as the concept of a system in QM, which persists for all time.
The Wightman axioms can be discounted because they do not have any interacting models in 3+1-dimensions, however the free fields that are the starting point for perturbation theory are models of the Wightman axioms and as of now there is no accepted alternative axiomatization for interacting QFTs.
The idea of subsystems and systems is adequately defined in terms of tensor products in QM, but I feel that QFT is where we should focus our efforts at constructing natural interpretations of quantum physics. Furthermore, given the issues that arise when we consider properties of subsystems for a state that is constructed as a nontrivial sum of tensor product states of the subsystems, I have found it worthwhile to reconsider those issues in a no-systems ontology of space-time regions in QFT, where entanglement is not an available concept. OTOH, I have been thinking in terms of QFT for over 30 years and it turns out that I often fail to explain well enough how I have found that worthwhile.

 

[PeterDonis]

The idea of subsystems and systems is adequately defined in terms of tensor products in QM, but I feel that QFT is where we should focus our efforts at constructing natural interpretations of quantum physics.

Ah, I see; you're really thinking in terms of QFT, not non-relativistic QM. In QFT the whole idea of the "state" of a system is problematic, so the definition I gave for an entangled state is problematic as well. You basically have to work in the non-relativistic approximation.

 

[renormalize]

The idea of subsystems and systems is adequately defined in terms of tensor products in QM, but I feel that QFT is where we should focus our efforts at constructing natural interpretations of quantum physics.

Ah, I see; you're really thinking in terms of QFT, not non-relativistic QM. In QFT the whole idea of the "state" of a system is problematic, so the definition I gave for an entangled state is problematic as well. You basically have to work in the non-relativistic approximation.

This is a very interesting discussion. Do either of you know of references that compare and contrast standard (non-relativistic) QM with the non-relativistic limit of standard relativistic QFT? Can they possibly make differing predictions? After all, many standard QM texts "second quantize" the Schrödinger equation to arrive at the QFT of the many-particle equation for electrons. Shouldn't the electron-sector of QED limit to exactly this non-relativistic QFT and make the same predictions, including for entanglement?

 

[PeterDonis]

Do either of you know of references that compare and contrast standard (non-relativistic) QM with the non-relativistic limit of standard relativistic QFT? Can they possibly make differing predictions?

I don't see why they would. My understanding is that non-relativistic QM is the non-relativistic limit of standard relativistic QFT.

Shouldn't the electron-sector of QED limit to exactly this non-relativistic QFT and make the same predictions, including for entanglement?

My understanding is that it does, yes.

One aspect you might not be considering is that, in order to take the non-relativistic limit, you have to choose a particular frame. The usual choice is the rest frame of the experimenter's lab (in which, for example, the Stern-Gerlach devices you're going to use to measure the spins of a pair of entangled electrons, as well as the electron source and the detector screen, are at rest).

 

[pines-demon]

This is a very interesting discussion. Do either of you know of references that compare and contrast standard (non-relativistic) QM with the non-relativistic limit of standard relativistic QFT? Can they possibly make differing predictions? After all, many standard QM texts "second quantize" the Schrödinger equation to arrive at the QFT of the many-particle equation for electrons. Shouldn't the electron-sector of QED limit to exactly this non-relativistic QFT and make the same predictions, including for entanglement?

There might be some rigorous way to check, but the fact that we have many examples, makes it obvious that the two theories coincide at that limit (Dirac equation reduces to Pauli/Schrödinger equation, Mott scattering reduces to Rutherford scattering, beta decay through W boson reduces to Fermi theory, and so on.)

 

[WernerQH]

Do either of you know of references that compare and contrast standard (non-relativistic) QM with the non-relativistic limit of standard relativistic QFT? Can they possibly make differing predictions?

A while ago @bhobba pointed to an interesting paper by T Padmanabhan: "Obtaining the Non-relativistic Quantum Mechanics from Quantum Field Theory: Issues, Folklores and Facts" (https://arxiv.org/abs/1712.06605).

 

[pines-demon]

A while ago @bhobba pointed to an interesting paper by T Padmanabhan: "Obtaining the Non-relativistic Quantum Mechanics from Quantum Field Theory: Issues, Folklores and Facts" (https://arxiv.org/abs/1712.06605).

Was there a previous discussion on this paper?

 

[gentzen]

Was there a previous discussion on this paper?

bhobba first brought up that paper in 2021. What WernerQH refers too was probably in August 2025. He also brought it up on other occasions, but let's ignore those. I guess what you still remember is the occasion when I brought it up in February 2024, which was also a discussion of "the non-relativistic limit of standard relativistic QFT".

 

[WernerQH]

bhobba first brought up that paper in 2021. What WernerQH refers too was probably in August 2025. He also brought it up on other occasions, but let's ignore those. I guess what you still remember is the occasion when I brought it up in February 2024, which was also a discussion of "the non-relativistic limit of standard relativistic QFT".

Gentzen, thanks for investigating. :-) My copy of that arxiv paper is dated February 15, 2024. So I probably became aware of it also through Peter Woit's blog. But bhobba has been referring to it frequently.

 

[Herman Trivilino]

TL;DR Summary: Title

how do you differentiate between quantum entanglement simply not obeying your intuitions vs. physicists just not having a complete theory of quantum entanglement yet?

The intuitions are not obeyed because they are erroneous. There are lots of examples of intuitions being incorrect within every body of knowledge, perhaps especially in physics.

For example, intuition tells you that objects in motion, when left alone, will eventually if not immediately come to rest. But we know that being at rest is not any different from being in motion in a straight line at a steady speed. Our intuition tells us that those two things are different, but they are in fact the same. There is a seeming difference, but that difference is due only to the relative motion of the observer.

 

[syed]

The intuitions are not obeyed because they are erroneous. There are lots of examples of intuitions being incorrect within every body of knowledge, perhaps especially in physics.

For example, intuition tells you that objects in motion, when left alone, will eventually if not immediately come to rest. But we know that being at rest is not any different from being in motion in a straight line at a steady speed. Our intuition tells us that those two things are different, but they are in fact the same. There is a seeming difference, but that difference is due only to the relative motion of the observer.

Yes but we have confirmation that that intuition is wrong. In this case, we do not have a confirmation that entanglement does not have a further explanation

 

[Herman Trivilino]

Yes but we have confirmation that that intuition is wrong. In this case, we do not have a confirmation that entanglement does not have a further explanation

I thought that erroneous intuition was a claim implicit in your question:

how do you differentiate between quantum entanglement simply not obeying your intuitions

 

[syed]

I thought that erroneous intuition was a claim implicit in your question:

TL;DR Summary: Title

So my question is for the people who propose that there is nothing more to reality when it comes to quantum entanglement, or that reality is fundamentally stochastic: how do you differentiate between quantum entanglement simply not obeying your intuitions vs. physicists just not having a complete theory of quantum entanglement yet?

See quote above.

So essentially, my question is for the people who say there is no further explanation to entanglement and that it disobeys our intuitions. How does one distinguish between this and there being a further explanation?

In other words, something could be true and remain counter intuitive, but also false/incomplete which is what leads to it being counter intuitive.

 

[Herman Trivilino]

How does one distinguish between this and there being a further explanation?

I don't know. This is a philosophical question. Not physics.

In other words, something could be true and remain counter intuitive, but also false/incomplete which is what leads to it being counter intuitive.

I don't think physics can decide this for you.

 

[bhobba]

So essentially, my question is for the people who say there is no further explanation to entanglement and that it disobeys our intuitions. How does one distinguish between this and there being a further explanation?

How about Glaeson's theorem? It means the state is a vector space, which is the rock bottom of entanglement, and as an aside, why QM is probabilistic.

The paper I linked to shows that conventional QM is not the limit of QFT; it is a non-relativistic approximation to it. It can be put in an equivalent form closer to the limit of QFT:

https://faculty1.coloradocollege.edu/~dhilt/hilt44211/AJP_Nine formulations of quantum mechanics.pdf

The limit of QFT is closer to interpretation F. The issue is that it does not require antiparticles, but it would be relatively easy to incorporate them. The point is that modelling observations by operators has these 'weird' implications.

One of the issues here is that some people seem to have trouble with the idea that a mathematical implication can be an explanation.

I have pondered these profound questions for years and have gone through various phases. I understand why people discuss them. However, now, towards the end of my life (I'm 70, not in my 50s when I first started posting here), I think the math itself is the reason.

Thanks
Bill

 

[syed]

How about Glaeson's theorem? It means the state is a vector space, which is the rock bottom of entanglement, and as an aside, why QM is probabilistic.

The paper I linked to shows that conventional QM is not the limit of QFT; it is a non-relativistic approximation to it. It can be put in an equivalent form closer to the limit of QFT:

https://faculty1.coloradocollege.edu/~dhilt/hilt44211/AJP_Nine formulations of quantum mechanics.pdf

The limit of QFT is closer to interpretation F. The issue is that it does not require antiparticles, but it would be relatively easy to incorporate them. The point is that modelling observations by operators has these 'weird' implications.

One of the issues here is that some people seem to have trouble with the idea that a mathematical implication can be an explanation.

I have pondered these profound questions for years and have gone through various phases. I understand why people discuss them. However, now, towards the end of my life (I'm 70, not in my 50s when I first started posting here), I think the math itself is the reason.

Thanks
Bill

Math is a language, and in most areas of physics we combine it with theoretical constructs to give an ontological picture. Why should quantum mechanics be different: why should we be satisfied with just the math here when we expect more in other theories?

As an example, we speak of a continuous electromagnetic field that exists everywhere in space, carrying energy and momentum. The equations could be treated as mere computational tools, but the field concept gives a physical entity we can picture. Or in general relativity, weinterpret the math as a dynamical spacetime geometry (space and time themselves bend and stretch), and matter follows geodesics in that curved geometry.

 

[Nugatory]

How does one distinguish between [there is no further explanation] and there being a further explanation?

By proposing a further explanation. Until this happens there is no explanation, just as a book does not exist until someone writes it.

 

[PeterDonis]

By proposing a further explanation.

And having it confirmed by making predictions that previously were not made, and which turn out to be right.

 

[syed]

By proposing a further explanation. Until this happens there is no explanation, just as a book does not exist until someone writes it.

so are you saying that before we figured out what causes thunder, we should have assumed there's no explanation? How would we find an explanation if you assume there is none?

Before Einstein figured out a deeper explanation for gravity, he presumably first started with the assumption that an explanation exists in the first place. By telling others no explanation exists, there is no incentive to search for one. Being able to only arrive at probabilities is also a potential sign a further explanation exists, which is why Einstein believed that there was one underlying QM.

Or are you just saying that we should say there is currently no KNOWN further explanation for QM?

 

[Herman Trivilino]

so are you saying that before we figured out what causes thunder, we should have assumed there's no explanation?

I can't speak for @Nugatory but my understanding of what he said is not that we shouldn't look, but that until we succeed in finding that explanation we don't have one.

 

[dextercioby]

[...]

Or are you just saying that we should say there is currently no KNOWN further explanation for QM? [...]

This is too far, but it boils down to the infinite chain of `why' questions. So "why are the particles entangled?" cannot receive other answer than "the concept of entanglement is currently (see, this automatically means that people should not stop investigating) the best theoretical explanation we have for those particular results of experiments". You and anyone else is free to provide explanations of "Nature behavio(u)r" without entanglement. And use your own theory to assert: "your fuzzy, muddy concept of entanglement can easily be explained using this and that arguments and notions, therefore, in my theory, it's not only non-fundamental, but also useless".

 

[Nugatory]

I can't speak for @Nugatory but my understanding of what he said is not that we shouldn't look, but that until we succeed in finding that explanation we don't have one.

thank you, yes.

 

[Fra]

so are you saying that before we figured out what causes thunder, we should have assumed there's no explanation? How would we find an explanation if you assume there is none?

By creating it, rather than just finding it?

Before Einstein figured out a deeper explanation for gravity, he presumably first started with the assumption that an explanation exists in the first place. By telling others no explanation exists, there is no incentive to search for one.

Ironically, the old idea of objective hidden variables explaining outcomes (applied to QM), is conceptually similar at inference level, to the idea that the truth exists objectively before it's at hand.

As we know from Bell's theorem, the difference between how the future follow from the past, gives different results.

One might ask, in the context of evolving science, is there also a significant difference between the view that science discovers previously hidden truths of nature, or are explanations something that is created?

If we reject realism as in Bell's ansatz, is it conceptually consistent to view science as "discovering" pre-determined facts of nature? I personally lean towards a big No.

I find the idea that explanations pre-exist and that we just havent found it, is a very confused position.

/Fredrik

 

[syed]

thank you, yes.

oh okay

By creating it, rather than just finding it?

Ironically, the old idea of objective hidden variables explaining outcomes (applied to QM), is conceptually similar at inference level, to the idea that the truth exists objectively before it's at hand.

As we know from Bell's theorem, the difference between how the future follow from the past, gives different results.

One might ask, in the context of evolving science, is there also a significant difference between the view that science discovers previously hidden truths of nature, or are explanations something that is created?

If we reject realism as in Bell's ansatz, is it conceptually consistent to view science as "discovering" pre-determined facts of nature? I personally lean towards a big No.

I find the idea that explanations pre-exist and that we just havent found it, is a very confused position.

/Fredrik

There seems to be a misconception here. You are confusing the sense of an objective truth independent of measurement with the results of measurements being determined by pre-existing properties of particles independent of measurement. The latter is what Bell meant by "realism", not the former.

As Bell says in Speakable and Unspeakable in Quantum Mechanics (1987),

The results of measurements are assumed to be determined by pre-existing properties of particles, independent of the act of measurement. This is what I mean by “realism.”

Note that measurement is an active process, and at the quantum scale, even if things or states are "created" or influenced by the measurement process, it does not imply that truth isn't objective, nor does it imply that there is no explanation for why we get certain measurements.

 

[Lord Jestocost]

By the way, what exactly is meant by 'objective truth' and how might one actually arrive at 'objective truth'?

 

[Herman Trivilino]

You are confusing the sense of an objective truth independent of measurement with the results of measurements being determined by pre-existing properties of particles independent of measurement.

Can you explain where, in the passage you quoted, "objective truth independent of measurement" plays a part?

What does "objective truth" in physics even mean?

 

[syed]

Can you explain where, in the passage you quoted, "objective truth independent of measurement" plays a part?

What does "objective truth" in physics even mean?

It doesn't play a part, I was referring to the other poster. He was confusing the results of measurements independent of the act of measurement with objective truth independent of measurement.

Objective truth really just means truth, and truth with respect to reality is simply what actually, objectively, exists.

 

[Herman Trivilino]

Objective truth really just means truth, and truth with respect to reality is simply what actually, objectively, exists.

Are there things in physics that are unobjectively true?

 

[gentzen]

Are there things in physics that are unobjectively true?

The probability of rain today at 13:00 (where I live) is 20%.

 

[gentzen]

Are there things in physics that are unobjectively true?

The Dirac equation is beautiful!

 

[syed]

Are there things in physics that are unobjectively true?

there is no such thing as "subjective" truth, there is only one truth, so the idea of "unobjectively true" is incoherent, but you're asking a philosophical question at this point

 

[Herman Trivilino]

there is no such thing as "subjective" truth, there is only one truth, so the idea of "unobjectively true" is incoherent,

My point is that in the phrase "objectively true" the adverb objectively adds no meaning to the phrase.

but you're asking a philosophical question at this point

The entire concept of truth is philosophical.

Getting back to your statement:

There seems to be a misconception here. You are confusing the sense of an objective truth independent of measurement with the results of measurements being determined by pre-existing properties of particles independent of measurement.

There is no place in physics for truth especially when it's independent of measurement. The validity of a concept is established only through measurement.