A Paradox: Do LHV Theories Need the HUP?

[vanesch]

I was content letting a Bohmian and an MWIer go after it with each other, but now you're lobbed one my way!

Well, we agreed that whichever of us is right, that's in any case better than Copenhagen

The problem with Copenhagen is of course that there is this projection postulate which is 1) considered as a physical mechanism and 2) is totally non-local (it affects the states of all subsystems at a constant-time plane which is strictly spacelike)
This is not less non-local (as a theoretical mechanism) than the non-local quantum potential in Bohmian mechanics, but moreover there is no clear prescription of what exactly is a "measurement" (what physical mechanism counts as measurement). So as much as this projection is considered a physical mechanism, the principle of relativity is out.

Bohm is just as non-local in its theoretical prescription, but has at least that advantage that there is no "special mechanism" that accounts for a "measurement", apart from all known interactions. But relativity goes down the drain.

MWI at least is totally local in its prescription, but still suffers from this ambiguity of what exactly is a "measurement" (which is considered something associated to a consciousness). This makes it crazy and unreal. However, it is the ONLY way to reconsile the principle of relativity as we know it (the principle!) with the predictions of QM.

 

[selfAdjoint]

The problem with Copenhagen is of course that there is this projection postulate which is 1) considered as a physical mechanism and 2) is totally non-local (it affects the states of all subsystems at a constant-time plane which is strictly spacelike)

It only does this IF you consider it to be physical. Your whole approach leading to your enthusiasm for MWI is based on reifying the wave function as a thing that can be tracked. But it doesn't have to be given that status. I am aware of the weakness of the Information Interpretation, but that's just a matter of contingent technology. I'm willing to bet the wave function at the end of the day is more like a "bit" than an "it".

 

[ttn]

It honly does this IF you consider it to be physical. Your whole approach leading to your enthusiasm for MWI is based on reifying the wave function as a thing that can be tracked. But it doesn't have to be given that status. I am aware of the weakness of the Information Interpretation, but that's just a matter of contigent technology. I'm willing to bet the wave function at the end of the day is more like a "bit" than an "it".

Let me just note that this excellent point is, in essence, the same one made by EPR so long ago. If you don't take the collapse postulate as describing a real physical change in the state of something, that means the real physical state can be the same for two different wave functions (pre- and post-collapse). And that means there isn't a one-to-one correspondence between wave functions and actual physical states. And that is just another way (Einstein's way, actually) of saying that the wave function doesn't provide a complete description of those actual physical states.

And the problem with trying to elude the apparent non-locality associated with wf collapse by denying the completeness doctrine, is that, well, it doesn't work. You can drop the completeness doctrine and hence no longer think of wf collapse as a real physical process. But then whatever theory you put in oQM's place will have to be nonlocal if it is going to agree with experiment.

This is all precisely why J.S. Bell believed his theorem (combined with the old EPR point that OQM, considered complete, entails nonlocality) proved that *nature* (and not just some class of theories) was nonlocal.

But now I'm repeating something I've said here a gazillion times... And nobody seems able or willing to believe me... Sigh... poor old me...

 

[DrChinese]

Well, we agreed that whichever of us is right, that's in any case better than Copenhagen

The problem with Copenhagen is of course that there is this projection postulate which is 1) considered as a physical mechanism and 2) is totally non-local (it affects the states of all subsystems at a constant-time plane which is strictly spacelike)

This is not less non-local (as a theoretical mechanism) than the non-local quantum potential in Bohmian mechanics...

I don't disagree that the PP (projection postulate) seems a bit strange and to some extent a bit arbitrary. Not sure why that should be a serious negative if it works, but in general I understand and accept the criticism.

But I don't know if I agree that it is non-local in the normal sense of the word. There has been plenty of philosophical discussion of that exact point. I do not think it beneficial to try and repeat that here.

I have always thought that the Bell Locality definition was intended to get around this in a way in which it was clear that the PP did NOT violate Bell Locality per se. In other words, Bell Locality is violated when a specific effect occurs outside of the cause's light cone. That doesn't happen with the PP because there is not any specific effect. For instance, we agree that there is no change in what is observed by Alice as a result of a change in setting by Bob. Only an observer who sees both Alice *and* Bob sees anything different.

The PP isn't really non-local, anyway. It is backwards in time, not exactly the same thing. It is "AS IF" (not being literal here, just pointing out how your perspective can change according to your description):

a) When we first consider a particle in a superposition, it has no specific eigenstate and it is waiting to have that filled in;
b) When you later measure that particle, you determine the eigenstate and project its current eigenvalue to the past;
c) Subsequent observations will be consistent with this knowledge.

This applies to systems of one or many particles.

Now of course there are perspectives in which the PP seems non-local too. EPR entanglement being one. So I am really saying that it comes back to your perspective, and there is plenty of debate on all sides.

If you asked a group of physicists: you might find that most believe oQM is non-local; but they might not agree that this position has been proven and is generally accepted. Hey, that might even be my view.

 

[vanesch]

It only does this IF you consider it to be physical. Your whole approach leading to your enthusiasm for MWI is based on reifying the wave function as a thing that can be tracked. But it doesn't have to be given that status. I am aware of the weakness of the Information Interpretation, but that's just a matter of contingent technology. I'm willing to bet the wave function at the end of the day is more like a "bit" than an "it".

I agree with this. I always insisted that MWI is the way to make a story around quantum theory as we know it today, and *within that theory* there's only the wavefunction that represents the physical state of the world - the purely epistemological viewpoint that the wavefunction is just a way of writing down our *knowledge* of the world is, in my opinion, "too easy a way out", because in that case you deny your theory to describe any reality at all, but just a way of organizing what you know (of what ?). But it could of course very well be that an underlying theory with a totally different description of nature will explain us one day why the wavefunction does describe our knowledge without being a state description. However, as long as we don't have that theory, we'll have to take this as part of the ontology of the world, and I'm just trying to make a consistent picture out of that view - temporary as it may be.

cheers,
Patrick.

 

[selfAdjoint]

in that case you deny your theory to describe any reality at all, but just a way of organizing what you know (of what ?).

And I agree with this. It's not that quantum mechanics is incomplete, it's that it just doesn't address ontological questions. And why should it? Maxwell's equations describe waves but not what they're "waving in". Newton made the point: "Hypothese non fingo". To try to shortcut this situation and make physics "be" ontology leads to taking science fiction ideas seriously; parallel worlds, time travel, there's not a piece of bafflegab that isn't in somebody's interpretation. Reification is a dangerous road for physicists; mathematicians aren't tempted.

 

[ttn]

And I agree with this. It's not that quantum mechanics is incomplete, it's that it just doesn't address ontological questions. And why should it? Maxwell's equations describe waves but not what they're "waving in". Newton made the point: "Hypothese non fingo". To try to shortcut this situation and make physics "be" ontology leads to taking science fiction ideas seriously; parallel worlds, time travel, there's not a piece of bafflegab that isn't in somebody's interpretation. Reification is a dangerous road for physicists; mathematicians aren't tempted.

But you make it sound like the argument for something like nature's non-locality is simply that this has been "read off" from a particular theory. It's certainly not just because the collapse postulate in OQM "looks nonlocal" that I think we can say that nature violates Bell Locality. That would be a very bad argument, because it would rest on exactly the error you're pointing out here: namely, one shouldn't take theories seriously willy-nilly. One shouldn't accept that what a certain theory says is true, is true, without having *extremely* strong reasons to believe it. And I agree that we definitely don't have such strong reasons for, say, accepting the completeness doctrine (which is what converts the apparent non-locality associated with the collapse postulate into a real physical non-locality). So the fact that OQM has this collapse postulate -- this fact alone -- is *not* sufficient reason to think that *nature* is nonlocal.
But that isn't the argument I'm making. It's mostly because of Bell's Theorem that we know that nature is nonlocal. And this theorem does *not* say: "Here's a theory I just made up; it's nonlocal; therefore, since my theory is probably right, nature is nonlocal." That just isn't the argument at all. Bell's theorem is cool because it's *general* -- it's not even about any particular theory, but about a whole broad class of theories (namely all of those which respect Bell Locality).
So... while I agree with you that one should be careful about reifying dubious theories, I don't agree that this is a valid reason for keeping an open mind about something like non-locality.

 

[selfAdjoint]

It's mostly because of Bell's Theorem that we know that nature is nonlocal.

I am just not "in" your arguments about nonlocality. It seems to me just a semantic difference. As you agreed before, you have a tendency to say "nature is nonlocal", when you mean our best theories and experiments violate "Bell nonlocality" which turns out to mean (correct me) that the Bell inequalities for separated events are violated. That is, after the fact data, collected by local means show a violation. If this is all you mean by "Nature is nonlocal", then it is well-known and not interesting. If it is not what you mean, you should clarify, using operational terms as much as possible.

 

[ttn]

I am just not "in" your arguments about nonlocality. It seems to me just a semantic difference. As you agreed before, you have a tendency to say "nature is nonlocal", when you mean our best theories and experiments violate "Bell nonlocality" which turns out to mean (correct me) that the Bell inequalities for separated events are violated. That is, after the fact data, collected by local means show a violation. If this is all you mean by "Nature is nonlocal", then it is well-known and not interesting. If it is not what you mean, you should clarify, using operational terms as much as possible.

No, violating Bell Locality does not just mean that Bell's inequalities are violated. Bell's inequalities are derived from several assumptions, notably Bell Locality and the assumption that there exist a certain kind of local deterministic hidden variables.

I've defined Bell Locality several times here in the last couple weeks. I'll just refer you to Bell's extended discussion of this in his beautiful article "La Nouvelle Cuisine" if what I said slipped through or you want more details. But suffice it to say that Bell Locality is Bell's attempt to get at the heart of what we mean when we say things like "relativity prohibits superluminal causation". Bell Locality is Bell's attempt to translate that prose phrase into a precise mathematical condition. So I think it is extremely profound to discover that it is violated in nature. This means basically that relativity is wrong! So not at all mere semantics.

Another point that I didn't make sufficiently clear before. There are a few people who think that Bell Locality is somehow the wrong condition, that it isn't at all equivalent to what relativity is supposed to require. But these people are a vast *minority*. I know this because it's well documented that the vast *majority* of people think that Bell's Theorem is important. They usually say that it's important because it proved that "local realism" (or "the EPR program" or...) is untenable. But to whatever extent a person thinks Bell's Theorem is interesting or important, that person tacitly accpets Bell Locality as an appropriate and important test of the genuine "local-ness" of a theory.

In short: the people who applaud Bell for snuffing out the hidden variables program, yet retreat to Orthodox QM as an acceptable theory, are engaged in a deadly contradiction. You can't have it both ways. If Bell Locality really is what relativity requires, then both OQM and hidden variable theories are going to have to be rejected as inconsistent with relativity (or, we'll have to junk relativity). On the other hand, if it's OK for orthodox QM to violate Bell Locality, then it's OK for hidden variable theories to violate it as well. In which case Bell's Theorem wouldn't rule out local hidden variable theories at all, and would cease to be interesting. All I'm suggesting is that we not tolerate double standards. Anyone who rejects (say) Bohm's theory because it violates Bell Locality, ought also to reject OQM on those same grounds. And vice versa, of course.

 

[vanesch]

And I agree with this. It's not that quantum mechanics is incomplete, it's that it just doesn't address ontological questions. And why should it?

At the end of the day, it should. After all, we identify, in the lab, certain things with certain mathematical entities. This very identification is somehow ontological up to a certain level. Of course, this identification is only partial, and usually very approximative, but nevertheless, we associate a mathematical entity in our theory with a certain physical object "out there". If we do not do that, we aren't doing physics and there is no way for us to "verify experimentally" our theory. At some level, some identification between the mathematical entities in our theory (or at least, some of them) and "things out there" must be made if we are to have a theory with claims to be a physical theory, making predictions of the world.
As such, a purely epistemological viewpoint is not really tenable IMHO, because it doesn't tell us what we should know things of. What does that voltmeter I'm staring at in the lab has to do with some abstract theory ? If my abstract theory says 15V and I see the digits 2 and 3 on the screen, why on Earth would that invalidate my epistemological theory ? Maybe I just didn't interpret it well, and the 15 I get out of my epistemological theory shouldn't be read on the display of the voltmeter, but, I don't know, on the clock under my TV set or something. Where does the association between "voltmeter reading" and "number coming out of my theory" come from ? That only makes sense if we assign some ontology to this situation. So something in my theory must CORRESPOND to the real world out there (this correspondence may be erroneous, of course, because my theory is not perfect). When you can associate *this* variable in my theory with *that reading on that instrument* you've made an ontological assignment of the variable to something "out there". I don't see how you can make ANY supposition of "physical principles" if it doesn't apply to a mathematical object that has been assigned to some "reality".
Now, I'm the first one to say that probably we make errors and our theories are not the "final" ones. As such, the descriptive value of our theories is only very relative. But you should make such an assignment. You cannot hide and say that, well, after all, all those mathematical objects simply don't correspond to anything out there, but they DO correspond to the right quantities I measure. Because that's using double language: in order for them to associate to experimental quantities, you HAVE to make the link, while denying it.
When looking at quantum theory, there's only one object that makes sense (all is relative) to "map" upon a "reality" and that's the wave function. Now, I can very well accept (I even am profoundly convinced!) THAT THIS IS PROBABLY TOTALLY WRONG on a fundamental level. But we don't have anything else, and *IF* we are going to use quantum mechanics, we cannot do but make such an assignment. And who knows, maybe it is even correct!

Reification is a dangerous road for physicists; mathematicians aren't tempted.

I thought I was doing the opposite: I'm just proposing a (probably totally wrong) ontological picture that fits to a theory. I would rather think that reifying happens when you say: this is fundamentally correct, but there is no real world out there, just my knowledge, which somehow is predicted by these magical rules.
To take your example of Maxwell equations. Of course it was silly to look after the material in which the EM fields are wobbling. But nevertheless, I think that everybody agrees that there is a real EM field out there (and that that is what you're thinking about when you do classical EM). Nobody is claiming - I presume - that those E and B fields "don't really exist but tell us something about what we know about moving charges" and somehow "magically" let us calculate how other charges move, far away. You usually picture an EM pulse as something physical, traveling from A to B, and you're not surprised about the "magic" of electrons in my eyes moving around about 8 minutes after some charges moved at the surface of the sun, where the EM field was "only a mathematical tool to organize our calculations of how charges interact".

 

[DrChinese]

In short: the people who applaud Bell for snuffing out the hidden variables program, yet retreat to Orthodox QM as an acceptable theory, are engaged in a deadly contradiction. You can't have it both ways. If Bell Locality really is what relativity requires, then both OQM and hidden variable theories are going to have to be rejected as inconsistent with relativity (or, we'll have to junk relativity). On the other hand, if it's OK for orthodox QM to violate Bell Locality, then it's OK for hidden variable theories to violate it as well. In which case Bell's Theorem wouldn't rule out local hidden variable theories at all, and would cease to be interesting. All I'm suggesting is that we not tolerate double standards. Anyone who rejects (say) Bohm's theory because it violates Bell Locality, ought also to reject OQM on those same grounds. And vice versa, of course.

No, there is no contradiction to us in this category. oQM, as we all agree, is not a theory which must satisfy Bell's Inequality. The reason is that oQM does not claim that Bell Reality holds. So there is no "retreat" here.

Any local realistic theory WILL meet the conditions that trigger the Bell Inequality requirement. That is because the local realist program requires it, and by this I mean in the spirit of EPR. So the question is: would Einstein (say) have agreed with the twin requirements of Bell Locality and Bell Reality. I think he would, as most local realists do. (In fact, I have never even heard a local realist deny these as applying - although I'm sure someone must have made that argument too).

I personally consider oQM to be a local non-realistic theory. That is because oQM respects the essential tenets of relativity . I know this drives you crazy, because Bell's Theorem defines locality such that oQM is non-local. But HELLO, that definition doesn't matter at all to oQM because oQM does not require Bell Reality anyway. So Bell's Inequality - and therefore Bell's Theorem - has no applicability for oQM.

I do reject Bohmian Mechanics on the grounds that it violates special relativity. I also reject it on the grounds it is an ad hoc theory. But it is a very mild rejection on both points. If, in the future, it is developed to a point that it can be experimentally segregated from the predictions of oQM, and its predictions are superior to oQM, then I will change my mind.

 

[ttn]

I personally consider oQM to be a local non-realistic theory. That is because oQM respects the essential tenets of relativity . I know this drives you crazy, because Bell's Theorem defines locality such that oQM is non-local. But HELLO, that definition doesn't matter at all to oQM because oQM does not require Bell Reality anyway. So Bell's Inequality - and therefore Bell's Theorem - has no applicability for oQM.
I do reject Bohmian Mechanics on the grounds that it violates special relativity. I also reject it on the grounds it is an ad hoc theory. But it is a very mild rejection on both points. If, in the future, it is developed to a point that it can be experimentally segregated from the predictions of oQM, and its predictions are superior to oQM, then I will change my mind.

The only thing that drives me crazy is the inconsistency. If you decided you didn't like Bell Locality as a measure of what special relativity "really requires", I'd have no objection to your saying "I personally consider oQM to be a local... theory." But then, if you are consistent, you'd have to say that Bohmian Mechanics is a local theory too -- sure, it violates Bell Locality, but it's consistent with relativity (because it respects signal locality or whatever).

Don't you see that you are engaged in a contradiction here?

OQM and Bohm both violate Bell Locality. They both *respect* signal locality. So if you have some vested interest in making the conclusion come out a certain way (namely "Bohm is non-local, but OQM is local") you should at *least* have the courtesy to provide some kind of definition of locality according to which that statement is *true*. Otherwise you look like some kind of ignorant idealogue who just insists on OQM somehow "winning", all evidence to the contrary notwithstanding. The fact is, the two theories are on *precisely equal* footing, at least so far as Bell Locality and Signal Locality and Empirical Adequacy are concerned. Then, of course, Bohm wins hands down when it comes to clarity, precision, and not suffering from things like the measurement problem.

But if you want to just ignore all that and believe, for no reason, that "Bohm is non-local, but OQM is local"... I can't stop you.

 

[DrChinese]

Don't you see that you are engaged in a contradiction here?
OQM and Bohm both violate Bell Locality. They both *respect* signal locality. So if you have some vested interest in making the conclusion come out a certain way (namely "Bohm is non-local, but OQM is local") you should at *least* have the courtesy to provide some kind of definition of locality according to which that statement is *true*. Otherwise you look like some kind of ignorant idealogue who just insists on OQM somehow "winning", all evidence to the contrary notwithstanding. The fact is, the two theories are on *precisely equal* footing, at least so far as Bell Locality and Signal Locality and Empirical Adequacy are concerned. Then, of course, Bohm wins hands down when it comes to clarity, precision, and not suffering from things like the measurement problem.

But if you want to just ignore all that and believe, for no reason, that "Bohm is non-local, but OQM is local"... I can't stop you.

Sorry, I do not mean to mis-characterize BM. And your comment about consistency is reasonable.

I understood that BM posited explicitly non-local mechanisms. I presumed - possibly incorrectly - that it might mean that non-local effects might at some point might be distinguishable in some way. And it seems to me that there must be some element of the theory that would require some adjustment to relativity, although I guess that the fundamentals are not changing.

 

[ttn]

I understood that BM posited explicitly non-local mechanisms.

That's true -- but of course it really depends on what you mean by "non-local mechanisms." That's why we need some definite definition or definitions, so we don't get caught in the trap of defining "locality" one way when we look at one theory, and then defining it some other way when we look at another theory.

The Bohmian dynamics is explicitly non-local. What happens in one place can instantaneously affect what happens in another place. In particular, the velocity of a particle over there can be instantaneously affected (according to Bohm's theory) by some fiddling I do over here. Now, if your gut reaction to this is to say "Well that *obviously* violates relativity!", I am inclined to agree. But I will just point out that exactly the same thing is true in OQM: the state of a particle over there can be instantaneously affected (according now to OQM!) by some fiddling I do over here. So this also "obviously" violates relativity. And Bell Locality gives a precise meaning to this claim. Both theories violate Bell Locality. That is just a fact, and it is nice because it doesn't depend on anything subjective like what is "obvious", etc.

Now it is a further and separate question: can the "obviously relativity-violating" non-locality of either theory be used to send a signal FTL? The answer turns out to be No for both theories. They're both signal local. So if you think that all relativity really requires is signal locality, then there is no grounds for vetoing either of these theories.

The problem with this view, however, is clear. "Signalling" is a very human-centered concept. If relativity really prohibits superluminal signalling, that should only be because signalling is a particular kind of causal interaction (namely one that is harnessed in a certain way by humans for certain human purposes). So *really* everyone believes that relativity prohibits any kind of superluminal causation whatever. It requires "local causality."

But the problem is, if you agree with Bell and me that "Bell Locality" is a good formal definition of "local causality" (i.e., consistency with relativity), then it turns out that no empirically viable theory can be consistent with relativity! One is really *stuck* with just the kind of thing that bothers most people about Bohm's theory -- namely, that it "obviously" involves non-local mechanisms.

I presumed - possibly incorrectly - that it might mean that non-local effects might at some point might be distinguishable in some way.

You mean that if there is non-locality in the theory, that one should be able to use it to transmit information, i.e., to send signals? That just isn't necessarily true. OQM and Bohm are two examples of theories that violate Bell Locality but are nevertheless signal local. (OQM's non-locality can't be used to send signals because of the randomness involved in the collapse postulate -- although making a measurement here causes, according to OQM, a distant particle to acquire some new state, I can't *control* which state it acquires and hence can't control the causality well enough to send a signal using it. Bohm's non-locality can't be used to send signals because of uncertainty in the initial conditions: if only we knew both the initial wf *and* the initial particle positions, then we would be able to *notice* that a particle ended up in a different place than it *should* have... but alas our knowledge of those initial particle positions is given by the Born rule, so the non-local effects are washed out.)

And it seems to me that there must be some element of the theory that would require some adjustment to relativity, although I guess that the fundamentals are not changing.

Oh, I agree with you, Bohmian Mechanics *does* require some (major!) adjustment to relativity. For example, you better have some kind of preferred frame or ether or whatever in order to give *meaning* to a statement like: the velocity of a particle over there is affected *instantaneously* when such-and-such happens over here. (Or better: the formal equivalent of this which is Bohm's guidance formula for an N-particle state.) You really just can't "wed" Bohm's theory to relativity. You can keep the formalism of relativity and you can keep the Lorentz invariance *at the level of empirical predictions* -- but you can't keep *fundamental* Lorentz invariance. You have to build in some extra spacetime structure or whatever to make the theory's dynamical equations make sense.

That sounds bad, right? The problem is: you have to do the same thing in OQM, for exactly the same reasons. The dynamical equations of OQM (in particular, the collapse rule) requires some objective simultaneity slices through spacetime, and that just isn't a structure that relativity can provide.

 

[DrChinese]

Oh, I agree with you, Bohmian Mechanics *does* require some (major!) adjustment to relativity. For example, you better have some kind of preferred frame or ether or whatever in order to give *meaning* to a statement like: the velocity of a particle over there is affected *instantaneously* when such-and-such happens over here. (Or better: the formal equivalent of this which is Bohm's guidance formula for an N-particle state.) You really just can't "wed" Bohm's theory to relativity. You can keep the formalism of relativity and you can keep the Lorentz invariance *at the level of empirical predictions* -- but you can't keep *fundamental* Lorentz invariance. You have to build in some extra spacetime structure or whatever to make the theory's dynamical equations make sense.

That sounds bad, right? The problem is: you have to do the same thing in OQM, for exactly the same reasons. The dynamical equations of OQM (in particular, the collapse rule) requires some objective simultaneity slices through spacetime, and that just isn't a structure that relativity can provide.

It's not necessarily bad, and I don't mean to make it sound that way. But I am trying to identify the essential things that make me want to say "oQM could be a local theory" (I am not sure it is, mind you) and also say "BM is a non-local theory".

I don't really think I am so far off, as best as I can tell the issues I have are exactly those that are discussed in many papers - new and old. A lot depends on what you are looking at and where you are going with it.

 

[ttn]

It's not necessarily bad, and I don't mean to make it sound that way. But I am trying to identify the essential things that make me want to say "oQM could be a local theory" (I am not sure it is, mind you) and also say "BM is a non-local theory".

Not to be rude, but it seems an awful lot like "the essential thing" that makes you want to say these two things is just that lots of other people have said them. This despite the fact that they are, in fact, inconsistent with each other, as has been clarified in recent posts here.

OQM and Bohm are on equal footing in terms of locality, and the latter is a better theory on other grounds. Anybody who denies either of those things is either just confused or operating on the mindless inertia of stale history. Forget about what is popular and look at the facts.

 

[DrChinese]

Forget about what is popular and look at the facts.

The "facts", in this case, are far from clear. You of all people should know that. As to what is popular, that is a lot different from what is commonly accepted within science. It is popular opinion that the big bang is "just a theory" but science has come a lot further than that. You talk a big story but the "fact" is that you have no more new predictive medicine to prescribe than I do. Chill... there is plenty for us all to learn.

You must realize that I want to find a common ground and have worked hard to find that point. Either of us could find references to support any position about locality we care to push. I am interested in learning what makes the position of Bohmian Mechanics so interesting to you. Even if I don't change my fundamental position, I feel I have gained from the interchange. I hope you have too.

Now that I have all that feelgood stuff off my chest... would you care to give me a reference or two that will tell me a little more about BM? I have read some of Bohm's latter material, but he really didn't seem to talk about it too much. I have some of his "holographic paradigm" essays, and some other material on the relationship of causality and chance, but none of this went very far into this theory.

 

[ttn]

Now that I have all that feelgood stuff off my chest... would you care to give me a reference or two that will tell me a little more about BM? I have read some of Bohm's latter material, but he really didn't seem to talk about it too much. I have some of his "holographic paradigm" essays, and some other material on the relationship of causality and chance, but none of this went very far into this theory.

Read Shelly Goldstein's article at

http://plato.stanford.edu/entries/qm-bohm

"The Undivided Universe" (by Bohm and Hiley) is pretty good. Peter Holland's book "The Quantum Theory of Motion" is also nice. And check out Jim Cushing's "Quantum Mechanics: Historical Contingency and the Quantum Hegemony" for a historical perspective. And Bohm's 1952 papers are quite readable and clear. And you can never go wrong by reading Bell's articles, many of which discuss Bohm's theory (of which he was a huge fan).


On the touchy feely side, I assure you I'm perfectly calm about all this. But you have an annoying tendency to briefly get something, and then suddenly retreat to your old standard positions, even after they have been shown clearly to involve contradictions. And this isn't about who can cite what paper, as you keep suggesting. It's about what's true. I'm operating under the assumption that you actually understand QM and how it works, so that you can actually grasp for yourself the fact that OQM violates Bell Locality (for example). If you're just accepting that on faith from some authority, then I can understand why you would later retreat to a more comfortable position. But it seemed like you knew what you were talking about well enough to see for yourself that it is actually a fact. But then, why would you turn around and start talking again about your desire to believe that OQM is local and Bohm is nonlocal? If that just isn't true (and it isn't) and if you saw that for yourself, how could you still desire this? It makes it look like, after all, you aren't interested in finding the truth. Well, I hope I'm wrong. Check out some of the Bohm references and see what you think.