Is there any hope at all for Locality?

[harrylin]

The impact of Bell is that it tells us: "No physical theory of local hidden variables can ever reproduce all of the predictions of quantum mechanics." [..] such is the scientific method [..]

It would be an awful lot of work to test all proposed models for all predictions. That would be needed to test full correspondence with QM, but it is not needed to test Bell's theorem or Herbert's proof. Instead, to test their proofs it suffices to test for the one or two predictions that according to Bell and Herbert cannot be reproduced. Such is the scientific method! Compare Popper

 

[stevendaryl]

It would be an awful lot of work to test all proposed models for all predictions.

I think that the twin-pair EPR experiment is good enough. Pretty much all the strangeness of quantum mechanics is captured by that one experiment. If there were a local realistic explanation for that, I think most people would find it believable that the rest of quantum mechanics could be explained along the same lines.

 

[DrChinese]

It would be an awful lot of work to test all proposed models for all predictions. That would be needed to test full correspondence with QM, but it is not needed to test Bell's theorem or Herbert's proof. Instead, to test their proofs it suffices to test for the one or two predictions that according to Bell and Herbert cannot be reproduced. Such is the scientific method! Compare Popper

Please note that the question is whether a local realistic theory can reproduce all of the predictions of QM. What good, may I ask, is one that is 50% correct (useful)? Sorry, that is the scientific method! You can't compare QM to such a theory and expect it to be taken seriously. And the reason this criteria is important is that most local realistic models start with unphysical assumptions that will obviously never fly. So they are DOA.

But as stevendaryl says, one successful prediction would be a good start. But there are none currently on the table. Again, for a simulation to be considered, it must postulate a hypothesis (mechanism) that will itself be subject to test. (Which again will almost certainly render it useless.)

-----------------------

Sometimes it is easy to forget where things started. EPR thought QM was an approximation to a better theory which would be both local and realistic. Bell essentially says that a local theory will not agree to QM in critical respects, specifically it cannot be context independent per EPR. In fact, even a non-local theory will not be context independent. Any way you look at it, for the entangled particle pair scenario to work, the nature of the measurement on Alice changes the statistics for Bob instantaneously and without regard to distance. No local model can account for that, obviously.

 

[RUTA]

Sometimes it is easy to forget where things started. EPR thought QM was an approximation to a better theory which would be both local and realistic. Bell essentially says that a local theory will not agree to QM in critical respects, specifically it cannot be context independent per EPR. In fact, even a non-local theory will not be context independent. Any way you look at it, for the entangled particle pair scenario to work, the nature of the measurement on Alice changes the statistics for Bob instantaneously and without regard to distance. No local model can account for that, obviously.

Time-symmetric views of QM are local and realistic because they exploit a loophole in Bell's theorem, i.e., they use information about detector settings to explain the correlations.

 

[bhobba]

Time-symmetric views of QM are local and realistic because they exploit a loophole in Bell's theorem, i.e., they use information about detector settings to explain the correlations.

I can't quite understand that. If you have 'influences' traveling back in time how can that be local? That means influences can effectively travel at any speed - even infinite.

Thanks
Bill

 

[bhobba]

EPR thought QM was an approximation to a better theory which would be both local and realistic. Bell essentially says that a local theory will not agree to QM in critical respects, specifically it cannot be context independent per EPR

That's an interesting view - and of course was Einsteins. It is often forgotten that Einstein after his debates with Bohr accepted QM as correct - but incomplete in the sense it was an approximation to a theory that conformed to his intuition. But being an approximation means it is not QM - but a theory from which QM emerges - a sub quantum theory. Such theories have been proposed eg Primary State Diffusion:
http://arxiv.org/pdf/quant-ph/9508021.pdf

Bells theorem applies to QM - it may or may not apply to a sub quantum theory. But I find it very hard to accept QM, being not local and realistic, can emerge from one that is.

Thanks
Bill

 

[RUTA]

I can't quite understand that. If you have 'influences' traveling back in time how can that be local? That means influences can effectively travel at any speed - even infinite.

Thanks
Bill

Non-local interactions are represented by space-like worldlines (superluminal speed). The causal paths in TSQM are time-like (subluminal speed).

 

[RUTA]

Bells theorem applies to QM - it may or may not apply to a sub quantum theory. But I find it very hard to accept QM, being not local and realistic, can emerge from one that is.

Thanks
Bill

QM is not necessarily non-local or non-realistic. In order for that to obtain, one must subscribe to all of the assumptions of Bell's theorem. One assumption of Bell's theorem is that future detector settings are not to be used in explaining the correlations. If you get rid of that assumption, then QM can be understood as local and realistic.

 

[bhobba]

Non-local interactions are represented by space-like worldlines (superluminal speed). The causal paths in TSQM are time-like (subluminal speed).

Hold on here. If future settings can influence the past, those influences are tachyon like traveling faster than light and hence non local.

I personally am not enamored with the transactional interpretation but local I think it aren't.

Thanks
Bill

 

[bhobba]

QM is not necessarily non-local or non-realistic. In order for that to obtain, one must subscribe to all of the assumptions of Bell's theorem. One assumption of Bell's theorem is that future detector settings are not to be used in explaining the correlations. If you get rid of that assumption, then QM can be understood as local and realistic.

If future settings influence the past that is explicitly FTL and non local.

Added Later:
From my recollection articles I read on the transactional interpretation always stated it must be non local, as from its assumptions it must be, unless my understanding of SR is somehow drastically mistaken (not out of the question though). So I hunted down an article on it:
http://www-users.york.ac.uk/~mijp1/transaction/TI_30.html
'With these goals in mind, we now present the transactional interpretation of quantum mechanics (TI). We will find that the TI, which is objective and explicitly nonlocal, satisfies each of these goals. It provides a description of the state vector as an actual wave physically present in real space. It provides a mechanism for the occurrence of nonlocal correlation effects through the use of advanced waves. The collapse of the state vector in the TI is the formation of a transaction which occurs by an exchange of retarded and advanced waves. The transaction model provides a way of clearly visualizing and developing intuition about the quantum phenomena which have remained mysterious and counter-intuitive for half a century.'

It must be - its based on the Wheller-Feynman model and that is well known and obviously nonlocal.

Thanks
Bill

 

[bohm2]

I can't quite understand that. If you have 'influences' traveling back in time how can that be local? That means influences can effectively travel at any speed - even infinite.

This link on fqxi may help:

Retrocausality gives a means to decompose that spooky non-local action into two local actions, the first one backwards in time," said Price. In other words, according to Price, the properties of the entangled particles are correlated backwards in time, from the point in spacetime where the measurement is made, to the point in spacetime where they become entangled, allowing the correct hidden variables to be encoded into the pair of particles. "In a case with retrocausality, the measurement that one observer makes affects her particle ‘backwards’ to the point where they are together," says Price. "There’s a zigzag path connecting the two particles through time and space and no need for instantaneous action at a distance.

Time to Go Retro
http://fqxi.org/community/articles/display/170

 

[RUTA]

If future settings influence the past that is explicitly FTL and non local.

Thanks
Bill

That's not correct. See the beable in Figure 5 of this paper for example http://arxiv.org/pdf/1001.5057v3.pdf

 

[bhobba]

This link on fqxi may help:

Even the article on the TI states it plainly - the TI is nonlocal - as it must be right from the very foundations of SR. If influences can travel back in time locality is broken. If its an issue for SR is another matter - if it can't be used to send information to sync clocks then SR remains intact. What the TI proposes is like that so its not an issue for SR - but locality goes down the tube.

Thanks
Bill

 

[bhobba]

That's not correct. See the beable in Figure 5 of this paper for example http://arxiv.org/pdf/1001.5057v3.pdf

Sorry - don't agree with you, and it is clearly and obviously nonlocal. Even the link I gave states it plainly - it is a nonlocal theory.

Added Later:
Something occurred to me. I am basing this on the Transactional Interpretation of QM - I believe RUTA is advocating the RBW interpretation which is different. But if it has the feature of detector settings affecting the past can't see how it is local. Perhaps he can explain the key difference - why is the Transactional nonlocal and the RBW isn't? That is if that's what's going on - if RUTA is talking about the Transactional Interpretation then I am bemuseed - the guy that put forth the interpretation clearly states its nonlocal.

Thanks
Bill

 

[harrylin]

Please note that the question is whether a local realistic theory can reproduce all of the predictions of QM. [..] .

That's not what I was talking about: I talked about testing Bell's and Herbert's proofs. That would be an essential step in the direction of answering the bigger question.

 

[bohm2]

Even the article on the TI states it plainly - the TI is nonlocal - as it must be right from the very foundations of SR. If influences can travel back in time locality is broken.

There are local and non-local retrocausal models, as I understand it. Yes, TI is stated as being non-local but Price's model is local and the differences are kind of glossed over in the article I posted previously, I think:

As we shall explain, the new argument shows that quantization makes a crucial difference. Time-symmetry alone doesn't guarantee that causation ever works backwards, but quantization gives us a new kind of influence, which -assuming time-symmetry- must work in both temporal directions. This new kind of influence is so subtle that it can evade spooky nonlocality, without giving us an even more spooky ability to send signals into the past. One of the striking things about the apparent action at a distance in quantum mechanics (QM) is that it, too, is subtle in just this way: there's no way to use it to build a "Bell Telephone", allowing superluminal communications. The argument hints how this subtlety might arise, as a consequence of quantization, from an underlying reality that smoothly links everything together, via pathways permitted by relativity...

As we noted earlier (see Box 1), there are several retrocausal proposals on the table. But some, like the Aharonov-Vaidman Two State proposal, or the earlier Transactional Interpretation, try to build their retrocausal models with the same kind of elements that Einstein objected to-wave functions not properly located in space and time. If we want to stay close to the spirit of Einstein's program, then, we'll need to start somewhere else.

Dispelling the Quantum Spooks-a Clue that Einstein Missed?
http://arxiv.org/pdf/1307.7744.pdf

So retrocausality does not imply non-locality nor superdeterminism, for that matter. See links.

 

[bhobba]

So retrocausality does not imply non-locality nor superdeterminism, for that matter. See links.

Even though I am heavily into math I am kind of a simple guy.

Would someone explain to me clearly, not linking to an article, but in clear language the subtlety here. Why is the TI nonlocal and what Ruta advocates isn't? Right from the foundations of SR if you have influences traveling back in time you break causality. The TI interpretation states it explicitly and logically, from the foundations of SR it must be so.

So exactly what is the difference - what is this very subtle point that makes this massive change in perspective and allows Bell to be violated. For if it's true, like De Brogle-Bohm was to Von Neumann we have a specific counter example to Bell - and I sense an immediate Nobel Prize in the wind.

Thanks
Bill

 

[wle]

I think that the twin-pair EPR experiment is good enough. Pretty much all the strangeness of quantum mechanics is captured by that one experiment. If there were a local realistic explanation for that, I think most people would find it believable that the rest of quantum mechanics could be explained along the same lines.

If you're talking specifically about EPR or EPR-Bohm correlations (as opposed to, say, CHSH-type correlations), then they don't violate any Bell inequality and it's a fairly simple exercise to come up with a toy local model that reproduces them.

 

[RUTA]

Sorry - don't agree with you, and it is clearly and obviously nonlocal. Even the link I gave states it plainly - it is a nonlocal theory.

Thanks
Bill

Did you look at Figure 5? Where are the space-like causal paths in that figure? Maybe you mean something else by nonlocal?

 

[RUTA]

Would someone explain to me clearly, not linking to an article, but in clear language the subtlety here. Why is the TI nonlocal and what Ruta advocates isn't? Right from the foundations of SR if you have influences traveling back in time you break causality. The TI interpretation states it explicitly and logically, from the foundations of SR it must be so.

Thanks
Bill

I don't think causality need be defined as you specify, but that's semantics. We're talking about locality here and by that I simply mean space-like causal influences.

Maybe you're thinking about the ambiguity of temporal ordering for space-like worldlines and conflating causality with locality in that sense? In other words, that A causes B when B precedes A in some frame means there must be a frame in which A precedes B, therefore A and B are space-like related and the causal connection is nonlocal.

 

[bhobba]

Maybe you're thinking about the ambiguity of temporal ordering for space-like worldlines and conflating causality with locality in that sense? In other words, that A causes B when B precedes A in some frame means there must be a frame in which A precedes B, therefore A and B are space-like related and the causal connection is nonlocal.

Thats exactly it.

Its in just about every book on SR I have ever read (eg Rindler - Relativity which is my goto book) if you have speeds greater than C then you find frames where causality is broken just like is being proposed here ie 'influences' going back in time. These are not local - meaning normally we notice influences affect something nearby which affects something nearby that and so on. If you have things from the future affecting the past then the is explicitly breaking locality. I now realize you are not necessarily talking about the transactional interpretation (TI) but in that interpretation it is explicitly stated its not local.

What I would like to understand is why what you are proposing, which seems pretty much the same as the TI, is local and the TI is not.

Also if you really have a model that is real and local then that is BIG news. Again every single textbook I have read on QM, including my goto book Ballentine, states it is simply not possible. I was just watching some online lectures on QM the other day and the lecturer said it outright - there is nothing more well established in physics these days that you can't have a model of QM that is local and real. Now I do not 100% agree with that because that is for QM and a sub quantum theory may or may not obey Bells theorem, but to me that is really clutching at straws and I doubt its even possible, but I am willing to concede it.

What my gut is telling me is you are referring to the ability to send information which is what's really required to violate SR - QM non locality doesn't do that so you don't have a problem. Is that it?

Thanks
Bill

 

[RUTA]

Thats exactly it.

Its in just about every book on SR I have ever read (eg Rindler - Relativity which is my goto book) if you have speeds greater than C then you find frames where causality is broken just like is being proposed here ie 'influences' going back in time. These are not local - meaning normally we notice influences affect something nearby which affects something nearby that and so on. If you have things from the future affecting the past then the is explicitly breaking locality. I now realize you are not necessarily talking about the transactional interpretation (TI) but in that interpretation it is explicitly stated its not local.

What I would like to understand is why what you are proposing, which seems pretty much the same as the TI, is local and the TI is not.

Also if you really have a model that is real and local then that is BIG news. Again every single textbook I have read on QM, including my goto book Ballentine, states it is simply not possible. I was just watching some online lectures on QM the other day and the lecturer said it outright - there is nothing more well established in physics these days that you can't have a model of QM that is local and real. Now I do not 100% agree with that because that is for QM and a sub quantum theory may or may not obey Bells theorem, but to me that is really clutching at straws and I doubt its even possible, but I am willing to concede it.

What my gut is telling me is you are referring to the ability to send information which is what's really required to violate SR - QM non locality doesn't do that so you don't have a problem. Is that it?

Thanks
Bill

In Figure 5 of the paper by Evans, Price and Wharton the causal paths are null, not space-like, so there is no ambiguity in temporal ordering and no FTL relationships. However, causation in their interpretation is not ordered, just relational, so the future causes the past as much as the past causes the future. I’m not an advocate of this view for reasons I will not go into, but it illustrates an interpretation which is local (no FTL causation) and real (quantum objects have definite properties). You will hear physicists claim QM is either non-local or non-real or both, but they seldom tell you their assumptions. One of those assumptions is that information from the future, such as detector settings, is not available to quantum entities in the present. That’s how this TSQM interpretation avoids that conclusion.

 

[DrChinese]

You will hear physicists claim QM is either non-local or non-real or both, but they seldom tell you their assumptions. One of those assumptions is that information from the future, such as detector settings, is not available to quantum entities in the present.

Even in standard QM: when Alice and Bob choose measurement settings, there is no sense that Alice's selection is in any way preferred over Bob's - even when she makes her observation first. What seems fundamental in all Bell compliant interpretations is the overall *context*, which includes both Alice and Bob - regardless of "where" and "when" they are.

 

[RUTA]

Even in standard QM: when Alice and Bob choose measurement settings, there is no sense that Alice's selection is in any way preferred over Bob's - even when she makes her observation first. What seems fundamental in all Bell compliant interpretations is the overall *context*, which includes both Alice and Bob - regardless of "where" and "when" they are.

Exactly, it's spatiotemporally holistic. That's the point Evans et al is trying to make in their paper. The action characterizes a spatiotemporal block of facts and the action for Figures 4 and 5 is the same. Thus, that Figure 5 is mysterious when Figure 4 is not represents a temporal bias. That is, we experience Nature in time-evolved form, but Nature is fundamentally a spatiotemporal whole.

 

[audioloop]

Exactly, it's spatiotemporally holistic. That's the point Evans et al is trying to make in their paper. The action characterizes a spatiotemporal block of facts and the action for Figures 4 and 5 is the same. Thus, that Figure 5 is mysterious when Figure 4 is not represents a temporal bias. That is, we experience Nature in time-evolved form, but Nature is fundamentally a spatiotemporal whole.

Mr. Stuckey or Mr. Silberstein, like that:

http://arxiv.org/ftp/quant-ph/papers/0503/0503065.pdf
"In BW all observers’ histories are treated democratically, unless we ‘add
something’ to pick out a preferred frame. No frame is physically distinguished from any
other. No set of measurement records, derived in any frame of reference, is more
veridical than any other. With this radical democracy of histories comes a radical
democracy of spatiotemporal events. The essence of BW is that all observers’ futures,
pasts and presents are equally ‘real’."
.

 

[RUTA]

Mr. Stuckey or Mr. Silberstein, like that:

http://arxiv.org/ftp/quant-ph/papers/0503/0503065.pdf
"In BW all observers’ histories are treated democratically, unless we ‘add
something’ to pick out a preferred frame. No frame is physically distinguished from any
other. No set of measurement records, derived in any frame of reference, is more
veridical than any other. With this radical democracy of histories comes a radical
democracy of spatiotemporal events. The essence of BW is that all observers’ futures,
pasts and presents are equally ‘real’."



.

That's from our first publication on RBW, 8 years ago. We've made a lot of progress since then, but this part hasn't changed

 

[rkastner]

My understanding is that the RBW gives up the 'being thus' of individual systems. That can be seen as a kind of nonlocality, since no given 'system' can be local in the sense of occupying a finite spacetime region -- it is defined by its relationships with all other systems, and relationships are basically nonlocal. Either one allows systems themselves to be nonlocal in this sense, or one allows influences between localized systems to be nonlocal (i.e. FTL) (or both). So QM descibes something decisively nonlocal, in my view. The question is whether one should see QM as describing a dynamical reality or an a-dynamical block world. I think that the dynamical interpretation is better because it makes use of more of the mathematical apparatus of the theory, and in my view therefore better explains, in physical terms, why the theory works as well as it does. TI in particular gives a much more elegant physical account of the Born Rule.

 

[RUTA]

My understanding is that the RBW gives up the 'being thus' of individual systems. That can be seen as a kind of nonlocality, since no given 'system' can be local in the sense of occupying a finite spacetime region -- it is defined by its relationships with all other systems, and relationships are basically nonlocal. Either one allows systems themselves to be nonlocal in this sense, or one allows influences between localized systems to be nonlocal (i.e. FTL) (or both). So QM descibes something decisively nonlocal, in my view. The question is whether one should see QM as describing a dynamical reality or an a-dynamical block world. I think that the dynamical interpretation is better because it makes use of more of the mathematical apparatus of the theory, and in my view therefore better explains, in physical terms, why the theory works as well as it does. TI in particular gives a much more elegant physical account of the Born Rule.

Hi Ruth, Mark Stuckey here. Silberstein may weigh in later, too.

We don't have FTL worldlines in RBW, so we're local in that sense. In the context of the mean spacetime manifold of GR, we can have spacetimesource blocks directly connecting distant regions as in quantum graphity. This is local at the level of the graph, so the term used in the literature is “disordered locality.” Caravelli, F., & Markopoulou, F.: Disordered Locality and Lorentz Dispersion Relations: An Explicit Model of Quantum Foam (2012) http://arxiv.org/pdf/1201.3206v1.pdf; Prescod-Weinstein, C., & Smolin, L.: Disordered Locality as an Explanation for the Dark Energy. Physical Review D 80, 063505 (2009) http://arxiv.org/pdf/0903.5303.pdf.

 

[rkastner]

Hi Mark, thanks for the update. Again a lot depends on how one defines 'locality'. Einstein included the idea of 'being thus' in his concept of locality. Here's an excerpt:

"..if one asks what is characteristic of the realm of physical ideas indepen-
dently of the quantum theory, then above all the following attracts our at-
tention: the concepts of physics refer to a real external world, i.e. ideas are
posited of things that claim a `real existence' independent of the perceiving
subject (bodies, fields, etc.), and these ideas are, on the other hand, brought
into as secure a relationship as possible with sense impressions. Moreover, it
is characteristic of these physical things that they are conceived of as being
arranged in a spacetime continuum. Further, it appears to be essential for this
arrangement of the things introduced in physics that, at a specific time, these
things claim an existence independent of one another, insofar as these things
`lie in dfferent parts of space'. Without such an assumption of mutually inde-
pendent existence (the `being-thus') of spatially distant things, an assumption
which originates in everyday thought, physical thought in the sense familiar to
us would not be possible..." (A. Einstein. Quanten-Mechanik und Wirklichkeit.
Dialectica, 2:320{324, 1948.) I added the italics.Of course, the interesting thing is that QM seems to demand that the world is not like this. What I propose in my book is that we should question the assumption in first passage I italicized -- I think QM is telling us about sub-empirical entities not necessarily contained in spacetime, while the spacetime theatre of events is emergent from that. And you and Michael are exploring keeping spacetime as fundamental while giving up the assumptions in the second italicized passage. In any case, the course of science has always been to expand our world view, and QM is forcing us to do that. I personally welcome this; I think that trying to hold on to 'local realism' is not the way to move forward.

Best wishes
Ruth

 

[RUTA]

Hi Mark, thanks for the update. Again a lot depends on how one defines 'locality'. Einstein included the idea of 'being thus' in his concept of locality. Here's an excerpt:

"..if one asks what is characteristic of the realm of physical ideas indepen-
dently of the quantum theory, then above all the following attracts our at-
tention: the concepts of physics refer to a real external world, i.e. ideas are
posited of things that claim a `real existence' independent of the perceiving
subject (bodies, fields, etc.), and these ideas are, on the other hand, brought
into as secure a relationship as possible with sense impressions. Moreover, it
is characteristic of these physical things that they are conceived of as being
arranged in a spacetime continuum. Further, it appears to be essential for this
arrangement of the things introduced in physics that, at a specific time, these
things claim an existence independent of one another, insofar as these things
`lie in dfferent parts of space'. Without such an assumption of mutually inde-
pendent existence (the `being-thus') of spatially distant things, an assumption
which originates in everyday thought, physical thought in the sense familiar to
us would not be possible..." (A. Einstein. Quanten-Mechanik und Wirklichkeit.
Dialectica, 2:320{324, 1948.) I added the italics.


Of course, the interesting thing is that QM seems to demand that the world is not like this. What I propose in my book is that we should question the assumption in first passage I italicized -- I think QM is telling us about sub-empirical entities not necessarily contained in spacetime, while the spacetime theatre of events is emergent from that. And you and Michael are exploring keeping spacetime as fundamental while giving up the assumptions in the second italicized passage. In any case, the course of science has always been to expand our world view, and QM is forcing us to do that. I personally welcome this; I think that trying to hold on to 'local realism' is not the way to move forward.

Best wishes
Ruth

We liked that quote so much we just put it into a paper based on our Foundations of Physics 2013 talk. Thanks That paper is going into an IOP book on QG this fall. I'll provide a link here when it's done later this week, but I will say that we have finally turned RBW into the physics of theory X (as Wallace calls it). It provides quite a different take on unification and QG, but it does totally vindicate the Standard Model of particle physics (as a higher-level theory). Here is Silberstein's response to your last post:

Einstein appears to conflate (or at least highlight) several different notions of “local” in said passage, including but not limited to, (1) local as localized in spacetime, (2) local as possessing primitive thisness with intrinsic properties, (3) local as in no faster than light interactions and (4) local as in being otherwise independent (e.g., statistically) of entities at other points in spacetime. Our beables (spacetimesources) are only local in the first and third senses. Our beables are of spacetime but not in spacetime. That is, spatiotemporal relations and observables (source values) are completely co-existent on our view. For us, classical spacetime also emerges from something more fundamental, but the sense of emergence isn't dynamical it's statistical, and the fundamental reality isn't a dynamical process. For us fundamental explanation is given in terms of adynamical global constraints-a self consistency criterion. As for your claim that dynamical interpretations of the quantum are more in keeping with the formalism of quantum mechanics, it depends on which of the many formalisms you have in mind. In our case it isn't Schrodinger dynamics and wave functions, but rather path integrals, discrete path integrals over graphs. We argue this lends itself more naturally to an adynamical interpretation. As for other motivations for going adynamical, we would also include quantum entanglement, delayed choice experiments, quantum liar experiments and all of relativity theory. But let's be honest, all the formalisms in question can be interpreted either way with appropriate effort, so at the end of the day the choice of interpretation ought to depend on what it buys you both in physics and conceptually. In the case of RBW, in return for rejecting dynamism and realism about configuration space and wave functions, you get an answer to the nature of quantum entanglement, a resolution to the measurement problem, answers to most of the major conceptual problems plaguing quantum field theory such as renormalization, a deflation of dark energy and, as Stuckey just said, an account of unification and quantum gravity.