which should win?

[MorpheusSandman]

The assumptions are tested, "judged", by the logical results, that is, "where it ends up".

Well, yes, we often find ways to test assumptions, hypotheses, and theories by where they lead. There's no way to directly observe things like common descent in evolution, but if common descent is true, we expect to see certain things in the fossil record, when we look at DNA of various species, etc., and we do, indeed, see those things. However, this is not always the case. Sometimes the assumptions themselves are directly testable (more on this later).

What I meant by what I said is that you can't look at the conclusions, the logical results, and say that that conclusion is too complicated, that it's counter-intuitive, that you're uncomfortable with it, etc. and use THAT to argue against the interpretation, hypothesis, or theory. To use my evolution example, if someone proposed the mechanism for biological change we call evolution, it would not be fair for an opponent to say "but, if we take that to its conclusion, that would mean man came from the same place as modern apes" and then reject evolution because those implications either can't be observed, or they make the opponent uncomfortable or they seem counter-intuitive or too complex.

The latter is what has happened with you (and, to be fair, a great many others) regarding Many Worlds. You don't even look at the assumptions being made, you look at the end result (the many worlds themselves) and say that they're unfalsifiable, counter intuitive, and needlessly complex. Just as it's unfair to look at the end result of evolution and argue these things, it's unfair to look at the end result of MW (the interpretation) and argue these things.

In many worlds nothing seems falsifiable. Do an experiment and in one set of worlds you get one answer. In another set of worlds you get another answer. Why bother?

YesNo, I've mentioned many times how MW is falsifiable. It's true that we can not test/contact the other worlds, but, following what I said above about assumptions being directly testable, MW's assumptions are falsfiable. MW's essential assumption is that all reality functions according to QM, so there is no "split" between the quantum and macro worlds. This assumption is falsifiable. If we are ever able to put multiple particles in a state of superposition and find that some of those particles are not in that state, then that will falsify MW. CI is all about the "split" between quantum and macro world via the collapse. If all particles are superpositioned, then there is no split, no collapse, everything is QM, and MW is true, and the many worlds themselves are the result of that basic truth. I've also mentioned that, thus far, over 2000 particles have been observed to be in superposition simultaneously, so if there is that split/collapse that CI says there is, it is not to the 2000th or less particle.

I want to make one more, parable-like point about what I mean by judging MW by its logical conclusion. Here's the parable:

Two extra-dimensional beings discover the existence of our dimension. However, they can not see or investigate too deeply into that dimension. These beings live in a dimension where there is almost a complete lack of matter. In fact, these beings are almost pure, disembodied intelligence, meaning the only matter they're made of is what is requires to produce intelligence. These beings do get a glimpse into the quantum fields of our universe, but do not understand it and doesn't know what it is.

Being 1: Based on our observance, perhaps those fields are really fundamental forms of matter, we'll call them quanta, and that these quanta obey equally fundamental laws that govern their movement. I like this hypothesis as both what they are and what they do are extremely simple and consistent with what we observe.

Being 2: Yes, the matter and movement may be simple, but think about the logical conclusions! If this thing is what you say it is and behaves how you say it does, this simplicity will quickly explode into forms of great complexity, from huge matter-sucking holes, to giant balls of gas, to organic beings with neurological systems! Surely all of this is much too complex, counter-intuitive, and non-falsifiable! I much prefer that we add the notion that it's our observation that's causing the movement and objects we see. In fact, if we don't observe it's not there and it doesn't move! While there's no basis for this in our observance or models, it makes far more sense than proposing that this matter is real and behaves via models independent of what we see, since the end result of that assumption is a universe far too complex, counter-intuitive, and unfalsifiable.

Being 1: Well, that makes more intuitive sense; but, look, we have this screen here. If we turn away from this universe we can observe its affects on this screen. So we can see the affects of this matter and its movement on this mirror without us observing it at all. So far, every time we check its affects, it seems to be and function like we'd expect it to without our observance interfering. So, if your hypothesis is correct, at what point are we supposed to see something different on this screen?

Being 2: No comment.

[Delta40]

And now, some light musical entertainment: A Capella Science Bohemian Gravity.

http://www.youtube.com/watch?v=2rjbtsX7twc

[YesNo]

And now, some light musical entertainment: A Capella Science Bohemian Gravity.

http://www.youtube.com/watch?v=2rjbtsX7twc

That video might be the best thing that has come out of string theory to date.

Well, yes, we often find ways to test assumptions, hypotheses, and theories by where they lead. There's no way to directly observe things like common descent in evolution, but if common descent is true, we expect to see certain things in the fossil record, when we look at DNA of various species, etc., and we do, indeed, see those things. However, this is not always the case. Sometimes the assumptions themselves are directly testable (more on this later).

What I meant by what I said is that you can't look at the conclusions, the logical results, and say that that conclusion is too complicated, that it's counter-intuitive, that you're uncomfortable with it, etc. and use THAT to argue against the interpretation, hypothesis, or theory. To use my evolution example, if someone proposed the mechanism for biological change we call evolution, it would not be fair for an opponent to say "but, if we take that to its conclusion, that would mean man came from the same place as modern apes" and then reject evolution because those implications either can't be observed, or they make the opponent uncomfortable or they seem counter-intuitive or too complex.

I'm sure there are people who question evolutionary descent and natural selection, however, I suspect most people accept those things. It is the explanations for them that cause the problem.

For example, did chance plus selfish genes cause all of this? That would imply a smooth fossil record, but the fossil record looks more in line with punctuated equilibrium and the "selfishness" of the gene implies consciousness no matter how one wants to hand wave it out. But why not include consciousness as part of the cause? I don't mean intelligent design, but just intelligent organisms at various levels making choices, some of them working, some of them not.

My point is that disagreements surrounding evolutionary theory are not comparable to the disagreements surrounding MW.

What one ends up with if one accepts MW does not agree with our experience and so one has to ask what is wrong with the assumptions or the logic leading to that conclusion. What one ends up with in evolution and natural selection is accepted. The similarity between species and the strata in sedimentary deposits is easily seen. It is the cause of these end results that leads to the questions.

The latter is what has happened with you (and, to be fair, a great many others) regarding Many Worlds. You don't even look at the assumptions being made, you look at the end result (the many worlds themselves) and say that they're unfalsifiable, counter intuitive, and needlessly complex. Just as it's unfair to look at the end result of evolution and argue these things, it's unfair to look at the end result of MW (the interpretation) and argue these things.

Let me summarize my objections to MW:

1) We have no evidence of MW except what comes from the mathematics of the Schrodinger equation. My understanding of Roland Omnes is that this mathematics does not force one logically to accept many worlds. One world is fine. That means, the mathematics itself, the only evidence for MW, is not adequate to reach a MW conclusion.

2) MW removes the assumption that provides for the Born probabilities, but claims it could generate them. So far it hasn't. As an interpretation, we both admit it is not complete. From my perspective, there is no reason to even consider an interpretation that is not complete.

3) The original objections to Copenhagen's "wave function collapse" have been resolved in Consistent Histories (aka Copenhagen done right) using decoherence theory. So there exists an interpretation that is complete, resolves the issues about "wave function collapse" and does not require many worlds.

4) It is unclear that one could actually split reality in the way MW claims it can be split. True, mathematically one can split the superimposed sine or cosine functions by subtracting them out just as one added them in to the Schrodinger wave function, but can one do that in reality? The experiments showing that Bell's inequality are broken seem to show that these particles cannot be split apart even if one separates them a great distance. I don't see how MW can be local, deterministic and real and still account for the experimental evidence.

If we are ever able to put multiple particles in a state of superposition and find that some of those particles are not in that state, then that will falsify MW.

I don't follow what you are saying here. There are no "particles". (Nor are there any "waves".) The "superpositions" are only a mathematical model (or, metaphor, like the "selfishness" of genes) that works. In some ways I think the experiments to show that the Bell inequality is broken are the falsification for MW, but MW is so unclear that one can't pin anything on it.

[Delta40]

That video might be the best thing that has come out of string theory to date.

Lol. I was hoping somebody would appreciate it!

[Nick Capozzoli]

I guess the demon would be providing an energy source to do the work. http://en.wikipedia.org/wiki/Maxwell's_demon

It does make me wonder how if everything runs down, gets entropy, what is the physical law that allows something to lose entropy overall in a closed system, not just transfer less entropy from one part to the other? Chance isn't going to work here. Chance is what increases entropy.

A possible solution to the paradox would be to consider that the demon, in order to change the temperature of the two compartments, must be able to perceive the speed and direction of the particles approaching the gate from his side of the chamber in order to "decide" whether or not to open the gate and let them pass to the other side. Lets assume that this precise perception is physically possible (i.e., let's forget about quantum mechanics and completely ignore the Uncertainty Principle, and try to answer the paradox using only thermodynamics).

Well, the necessary demon would have to be quite small, yet he would also have to be capable of perceiving and making decisions based on what he perceives. In order to do this, it's reasonable to assume that he would have to possess a certain amount of complex internal structure. Now one of the measures of system entropy is the relative structural "complexity." A complexly organized demon would have lower entropy than a randomly organized demon. Since the demon exists, by the conditions of the experiment, in only one of the two chambers, his (negative) entropy would have to be calculated into the entropy of his chamber, and would allow him, without violating the Second Law, to effect a temperature change. His ability to effect the temperature change, without violating the Second Law, would be limited by just how much his "negative entropy value" allows him to raise the temperature of the particles in the "demonless" chamber. This could be calculated. There are other considerations that need to be factored in. A major one is that the demon can't observe particles on the other side of his gate. As he allows more and more faster moving particles to the other side, there will be a greater likelihood that when he opens the gate he will let a fast moving particle back into his chamber. This is a statistical/kinetic issue.

I'm not an expert in physics. I took some undergraduate physics and mathematics courses in college on my way to medical school. I came up with this "solution" to the Maxwell's Demon Paradox when it was presented in one of my undergraduate physics courses more than 35 years ago. I think it offers a plausible explanation for how the demon could effect the temperature change without violating the Second Law, and without having to resort to anything else than classical thermodynamics.

[MorpheusSandman]

My point is that disagreements surrounding evolutionary theory are not comparable to the disagreements surrounding MW.

Absolutely, but I was not making the comparison between the actual disagreements in evolution VS the actual disagreements about MW; rather, I was noting what the equivalent would be between the common disagreements about MW are and evolutionary theory. When someone proposes the mechanism behind evolutionary theory, you cannot criticize it because the end-result consequences are too complex, counter-intuitive, or non-testable. What you're saying about the fossil record are legitimate disagreements about what the actual mechanism predicts; the equivalent in MW would be if someone found the supposed "split" between the micro and macro world.

What one ends up with if one accepts MW does not agree with our experience and so one has to ask what is wrong with the assumptions or the logic leading to that conclusion.

Many Worlds actually DOES agree with our experience in that it explains why we experience what we do. What you're really saying is that MW does not agree with our intuitive interpretation of our experience. Gravity and a spherical Earth doesn't agree with our intuitive interpretations of experience either. Throughout scientific history, the truth has been frequently been clouded by the hidden assumptions/interpretations we make regarding our experiences, rather than illuminated by it.

Let me summarize my objections to MW:

1) There is no "evidence" in the form of scientific testing for any interpretation of QM; that's why they're "interpretations" and not "theories" or even "hypotheses." All of the "evidence" is found in the history of science and via epistemic rationality. For the former, we have no examples of mathematical models modeling non-real things, so the fact that mathematical models have always modeled what is real would favor MW, because MW treats the QM equations as real representations of real things. For the latter, MW abides by Occam's Razor and does not unnecessarily add anything to those equations, like the WF collapse, for which there is no explanation or evidence for anywhere, and for which creates contradicts with everything else we know.

2) This is the only legitimate complaint about MW; but your statement about not even considering an interpretation that is incomplete is absurd. This means you don't accept Evolution and General Relativity! Even if you look at Newtonian mechanics, it was obviously incomplete very early on, in that it couldn't account for the orbit of Mercury. Did this mean Newton was "wrong?" No, what it meant was that Newtonian mechanics was incomplete, and this incompleteness was "fixed" by Einstein; and Einstein was proven "incomplete" via the discovery of QM. All of these theories were "incomplete," but were rightly accepted in their time as being the best theoretical model at the time. Even if you were to argue (fairly) that MW lacks the experimental results of the above physics, MW is, at the very least, compatible with older physics.

3) I am no expert on CH, but from what I can gauge it seems to be a "middle-ground" between CI and MW, one which keeps the decoherence of the latter but, like the former, seems to propose that the wave-function is non-real, or, at least, the other worlds are non-real. I really don't see how this is CI "done right," since it removes the fundamental element of the collapse in CI. It still has the problem of explaining why only PART of the WF would be real (the part that ends up as our world when measured).

4) As I said in an early post, there really isn't any "splitting." In MW, all of the other worlds are already "there." Decoherence is really more of a "pairing off" between observer and observed. Interference patterns are evidence of all the worlds already present at singular point. I don't really know what you mean by the splitting happening "in reality." MW proponents think that the wavefunction IS reality. You seem to be talking about reality as our perception of a singular world, and perception is not reality (the map is not the territory). I'm not quite sure what you mean in the Bell part either. It still seems to me like you subtracting the observer from the equation, you're still forgetting that one observer in one location makes one observation and observer and observed decohere; yet, from a long ways off, you have the same observance and the same process. From the one world both observers and observed end up in, it seems as if locality has been violated, but if you take into account that there are now two separate worlds, they have not been. The violation is a result of our perception, of our not being able to be in both worlds at once.

I don't follow what you are saying here. There are no "particles". (Nor are there any "waves".) The "superpositions" are only a mathematical model (or, metaphor, like the "selfishness" of genes) that works.

This is just you making the "non-real" assumptions of CI. We can see the effects of these wave-particles in the double-slit experiment. This is what we mean by observing superposition. Tests have been done that have placed entire molecules with over 2000 particles in a superpositioned state. Eventually, via CI, there SHOULD be a point where those particles AREN'T superpositioned, as CI proposes a "split" between the micro and macro worlds. If they are superpositioned from one single particle all the way up to groups of molecules, even to the point of making up living things, then one of MW's assumptions (all particles in all things are superpositioned, including us) is correct. While such observances could never confirm that the wavefunction is actually real, it's Occam's razor that tells us there's no reason to treat it as unreal, and your (and others') distaste for MW's implications is not a good reason.

[YesNo]

A possible solution to the paradox would be to consider that the demon, in order to change the temperature of the two compartments, must be able to perceive the speed and direction of the particles approaching the gate from his side of the chamber in order to "decide" whether or not to open the gate and let them pass to the other side.
...
Well, the necessary demon would have to be quite small, yet he would also have to be capable of perceiving and making decisions based on what he perceives.

It looks like what is needed is for something to be able to make a choice. That implies consciousness of some sort. I wonder if I can conclude if I observe objects with less entropy that implies the previous work of some form of consciousness that made a choice?

I don't know enough about physics to be able to say if that solution of Maxwell's demon paradox actually resolves it or not.

[YesNo]

All of the "evidence" is found in the history of science and via epistemic rationality. For the former, we have no examples of mathematical models modeling non-real things, so the fact that mathematical models have always modeled what is real would favor MW, because MW treats the QM equations as real representations of real things.

Ptolemy had mathematical models for astronomy that got the right results, but those models are not the way we see reality today: http://en.wikipedia.org/wiki/Ptolemy

I am no expert on CH, but from what I can gauge it seems to be a "middle-ground" between CI and MW, one which keeps the decoherence of the latter but, like the former, seems to propose that the wave-function is non-real, or, at least, the other worlds are non-real. I really don't see how this is CI "done right," since it removes the fundamental element of the collapse in CI. It still has the problem of explaining why only PART of the WF would be real (the part that ends up as our world when measured).

I'm reading Roland Omnès's Quantum Philosophy again to see if it makes more sense now. I don't know much about Consistent Histories either: http://en.wikipedia.org/wiki/Consistent_histories

As I said in an early post, there really isn't any "splitting." In MW, all of the other worlds are already "there."

If wave function collapse is a problem for CI, splitting is a problem for MW. Hopefully, Consistent Histories will resolve both.

I'm not quite sure what you mean in the Bell part either.

Although Frank Tipler would disagree (http://arxiv.org/pdf/quant-ph/0003146v1.pdf), he does describe the problem that I think MW has with the experimental results showing Bell's inequality was surpassed.

Basically, the problem is this. Experimenters showed some "non-locality" features of quantum mechanics in the process of testing Bell's inequality. That data now needs to be explained by these interpretations. If MW accepts the data, then it is non-local. If it doesn't then it violates QM. Tipler thinks there's a way out of this, but I don't think he's right.

[MorpheusSandman]

Ptolemy had mathematical models for astronomy that got the right results, but those models are not the way we see reality today:

Yeah, but nobody is proposing that astronomy is about things that aren't real. I don't know exactly what you mean about his mathematical models "getting the right results," but the fact remains he was trying to model real things, not non-real things.

If wave function collapse is a problem for CI, splitting is a problem for MW. Hopefully, Consistent Histories will resolve both.

"Splitting" is basically "decoherence," and this is not a problem for MW at all because decoherence is what's in the math; if you take the math as describing something real.

Basically, the problem is this. Experimenters showed some "non-locality" features of quantum mechanics in the process of testing Bell's inequality.

They've shown these "non-locality" features while assuming both collapse and a single-world. The moment you factor in the observer's role in MW, the apparent non-locality is explained in local terms. I'm not sure why you don't understand this. All of the non-locality in Bell and Bell-like tests RELY ON THE COLLAPSE AND SINGLE-WORLD ASSUMPTION to be non-local. If there is no collapse, if the wavefunction is real, and if humans function just like aggregate wavefunctions, then we get many worlds and locality, but the appearance of non-locality due to us being part of the system we're observing.

[Nick Capozzoli]

It looks like what is needed is for something to be able to make a choice. That implies consciousness of some sort....

That was my point about the Demon, that he would have to be "conscious," i.e., able to perceive the speed and direction of the particles approaching the gate on his side of the two chambers, and he would need to be able to either open or close the gate depending on what he perceived. The Demon does not behave just like any other "simple" particle in his system. He has to have some sort of "complex" organization (such as what we think of as a nervous system in macroscopic organisms) that would allow him to behave "consciously." It's difficult to imagine what sort of "nervous system" could exist in a Demon of the microscopic dimensions required for Maxwell's thought experiment. Nonetheless, the Demon must be able to do what is required of him, and this would require that he have a complex organization. We would therefore need to calculate the Demon's entropy value (a more or less large negative value due to his organizational complexity) into the entropy values of the two chambers at the start of the thought experiment. Let's assume (as the thought experiment requires) that the two chambers are at the same temperature, and there is this "conscious" gate-controlling Demon in one of the chambers. Could this Demon effect a temperature difference between the two chambers, in apparent violation of the Second Law of Thermodynamics?

The answer is that the Demon could effect a temperature difference, but only within limits, without violating the Second Law. The limit of the Demon's ability to effect an inter-chamber temperature difference would depend on just how much the Demon's complexity (negative entropy) would allow this to occur.

IMHO, one of the neatest things about classical thermodynamics compared to, say, quantum mechanics, is that thermodynamics always makes theoretical "common" sense and always seems to jibe with "common sense reality." Maybe this has something to do with the fact that the thermodynamic "laws" are primarily statistical and based on common experience. For example, there is nothing in thermodynamics that would absolutely preclude a glass of water at room temperature from suddenly turning into ice, though that would be extremely unlikely... It's possible to "explain away" the Maxwell's Demon paradox and understand that it really doesn't "violate" the Second Law. There is nothing at all "spooky" about Maxwell's Demon, as there is with lots of QM paradoxes, like Schrodinger's cat.

I will go so far as to say that as far as "scientific" ways of understanding the behavior of the Universe go, thermodynamic theory seems to be "always true." The only other scientific theory that seems to be "always true" is the theory of natural selection.

[cacian]

I will go so far as to say that as far as "scientific" ways of understanding the behavior of the Universe go

I am not sure I like the expression ''the behaviour of he universe''. I think to say it behaves one could almost predict it will misbehave. I would say the universe is platonic in that it is strictly ironic not one scientist can a grip on it. it is very simple yet science likes to skim to around to avoid it in a way. what you see is what you get with the universe and what you do not it is because you can't. that is the bottom line it is not because the universe likes to play hide and seek. it is because the naked eye cannot be in two places at one. the universe is a vast multifaceted visually and science is anything but that.
a tool in a lab a cannot abrase the mechanism of how the universe challenges us because the sheer of it cannot compare to the way scientist thinks or behaves. I put it down to the scientist behaviour and not the universe.

thermodynamic theory seems to be "always true." The only other scientific theory that seems to be "always true" is the theory of natural selection

I am not too familiar about thermodynamics and I sure think natural selection lags behind. it is not natural it is patron selection to me. in other words it is patronising.

[YesNo]

That was my point about the Demon, that he would have to be "conscious," i.e., able to perceive the speed and direction of the particles approaching the gate on his side of the two chambers, and he would need to be able to either open or close the gate depending on what he perceived. The Demon does not behave just like any other "simple" particle in his system. He has to have some sort of "complex" organization (such as what we think of as a nervous system in macroscopic organisms) that would allow him to behave "consciously." It's difficult to imagine what sort of "nervous system" could exist in a Demon of the microscopic dimensions required for Maxwell's thought experiment. Nonetheless, the Demon must be able to do what is required of him, and this would require that he have a complex organization. We would therefore need to calculate the Demon's entropy value (a more or less large negative value due to his organizational complexity) into the entropy values of the two chambers at the start of the thought experiment. Let's assume (as the thought experiment requires) that the two chambers are at the same temperature, and there is this "conscious" gate-controlling Demon in one of the chambers. Could this Demon effect a temperature difference between the two chambers, in apparent violation of the Second Law of Thermodynamics?

I suspect anything that's alive is conscious in some way with or without a nervous system. For all I know, even something that is not alive could be "conscious" in some sense. If it can make a choice it must be conscious enough to make that choice.

The answer is that the Demon could effect a temperature difference, but only within limits, without violating the Second Law. The limit of the Demon's ability to effect an inter-chamber temperature difference would depend on just how much the Demon's complexity (negative entropy) would allow this to occur.

That makes sense.

IMHO, one of the neatest things about classical thermodynamics compared to, say, quantum mechanics, is that thermodynamics always makes theoretical "common" sense and always seems to jibe with "common sense reality." Maybe this has something to do with the fact that the thermodynamic "laws" are primarily statistical and based on common experience. For example, there is nothing in thermodynamics that would absolutely preclude a glass of water at room temperature from suddenly turning into ice, though that would be extremely unlikely... It's possible to "explain away" the Maxwell's Demon paradox and understand that it really doesn't "violate" the Second Law. There is nothing at all "spooky" about Maxwell's Demon, as there is with lots of QM paradoxes, like Schrodinger's cat.

I'm reading Roland Omnes, Quantum Philosophy. He tries to bring back common sense to QM. Regarding Schrodinger's cat he notes that the wave function of a dead cat could not interfere with the wave function of a live cat anyway, so there is no such thing as a cat that is both dead and alive. Or to use his own words (page 201):

If a cat is dead, its internal wave function will never regain the fine phase tuning of a living-cat wave function. Adding a dead=cat wave function and a live=cat one in a sum Ψ1(x,y)+Ψ2(x,y) is like adding sea waves and the bubbling of a whale: they do not interfere, they ignore each other, they stay apart.

That was enough to demystify the cat for me although the example would still work with entities whose wave-functions could interfere.

I will go so far as to say that as far as "scientific" ways of understanding the behavior of the Universe go, thermodynamic theory seems to be "always true." The only other scientific theory that seems to be "always true" is the theory of natural selection.

I was reading Rupert Sheldrake recently (The Science Delusion) and he suggested moving away from always true laws. His basic argument is that the universe changes more like an organism than a machine. Why shouldn't the "constants" and "laws" change as well depending on place and time. They wouldn't be able to change too much or we wouldn't be able to make assumptions about what is happening elsewhere in the universe or in the past.

Yeah, but nobody is proposing that astronomy is about things that aren't real. I don't know exactly what you mean about his mathematical models "getting the right results," but the fact remains he was trying to model real things, not non-real things.

The quantum stuff is real. It is just not real the way Einstein defined reality. For him the property of something is real only if one could know it for certain.

"Splitting" is basically "decoherence," and this is not a problem for MW at all because decoherence is what's in the math; if you take the math as describing something real.

Decoherence does not require many worlds. It could be used by both CI and MW.

They've shown these "non-locality" features while assuming both collapse and a single-world. The moment you factor in the observer's role in MW, the apparent non-locality is explained in local terms. I'm not sure why you don't understand this. All of the non-locality in Bell and Bell-like tests RELY ON THE COLLAPSE AND SINGLE-WORLD ASSUMPTION to be non-local. If there is no collapse, if the wavefunction is real, and if humans function just like aggregate wavefunctions, then we get many worlds and locality, but the appearance of non-locality due to us being part of the system we're observing.

Roland Omnes describes the non-locality that was observed to decide that Bell's inequality as a "non-separability" between entangled entities, not a full non-locality which involves faster than light communication. Consistent Histories doesn't have a problem with this data and it doesn't have a collapse model that I could see. There is only one world for CH.

The reason I think this data may be enough to falsify MW is because there are two parts to it, entanglement and interference: One has two entangled particles each representing an interference between two different spin choices. Separate them far enough apart and measure them close enough in time to fulfill separability conditions. The measurements induce a split at both of the particles. This generates 4 worlds, 2 for each particle. The data shows the entanglement correlation between the measurements. How does MW stitch these 4 worlds back together so there are only 2 which show the correlation? Tipler thinks he has a way by claiming the comparison check is another measurement event, but that is where he becomes unclear. My conclusion is that either MW is non-separable (non-local) or it does not model the data.

I think to say it behaves one could almost predict it will misbehave.

I like the idea that the universe could "misbehave" when it doesn't follow one of our laws. The universe is not deterministic, so our laws have to account for that.

[MorpheusSandman]

The quantum stuff is real. It is just not real the way Einstein defined reality. For him the property of something is real only if one could know it for certain.

You say the "quantum stuff is real," but both CI and CH define the wavefunction as non-real. It's only MW that assumes it's real.

Decoherence does not require many worlds. It could be used by both CI and MW.

Decoherence + realism requires MW. Decoherence can't work in CI because of CI's collapse (the collapse and decoherence are mutually exclusive). If you assume decoherence but non-realism you get CH, apparently.

The measurements induce a split at both of the particles. This generates 4 worlds, 2 for each particle. The data shows the entanglement correlation between the measurements. How does MW stitch these 4 worlds back together so there are only 2 which show the correlation?

What in the world makes you think MW has to have only two worlds? Keep in mind that in the double-slit experiment with one particle, through different trials you have the particle going through either, both, or neither slit. Since MW takes the wavefunction as real, this would itself imply 4 distinct "worlds" (possibilities) within the wavefunction (within that test, at least). Besides, you have to keep in mind General Relativity in terms of measurement; there is no universal "now," merely different perspectives in space. So no two measurements of the same particle could be simultaneous since there is no simultaneous time. One observation has to happen "first" (Implying one is first shows the limitations of the language keeping in mind the perspective aspect of GR), and once it happens decoherence happens locally; so the other observer is no longer observing the same wavefunction of the same particle. The apparent affect happens as a result of decoherence.

[YesNo]

You say the "quantum stuff is real," but both CI and CH define the wavefunction as non-real. It's only MW that assumes it's real.

Whether the wavefunction is real or not is not the question. That is the mathematics that represents it. Personally, I don't think it is real, but it doesn't matter. The quantum stuff, things like electrons and photons, are real in the common sense definition of real. Some of the properties about them are not certain. That is what makes these properties unreal, but the underlying stuff that could have these properties is "real".

Decoherence + realism requires MW. Decoherence can't work in CI because of CI's collapse (the collapse and decoherence are mutually exclusive). If you assume decoherence but non-realism you get CH, apparently.

I'll stick with CH to avoid using the wave function in these discussions.

I claim that if realism requires determinism, not even MW can provide this since the facts of the matter are the quantum stuff is not deterministic. MW hopes it will one day get around the problem that the facts present, but it has yet to produce an interpretation that is complete enough to generate even one wave function.

Perhaps it is important to make explicit just what it means to not be able to produce the Born probabilities. What that means is that MW cannot produce the coefficients for even the simplest wave function.

The only interpretation I am aware of that is deterministic and complete enough to generate a wave function is Bohm's interpretation which is superdeterministic (we are in the Matrix without any Zion-like resistance movement) and deliberately non-local.

What in the world makes you think MW has to have only two worlds? Keep in mind that in the double-slit experiment with one particle, through different trials you have the particle going through either, both, or neither slit. Since MW takes the wavefunction as real, this would itself imply 4 distinct "worlds" (possibilities) within the wavefunction (within that test, at least). Besides, you have to keep in mind General Relativity in terms of measurement; there is no universal "now," merely different perspectives in space. So no two measurements of the same particle could be simultaneous since there is no simultaneous time. One observation has to happen "first" (Implying one is first shows the limitations of the language keeping in mind the perspective aspect of GR), and once it happens decoherence happens locally; so the other observer is no longer observing the same wavefunction of the same particle. The apparent affect happens as a result of decoherence.

Because the two particles are entangled, once the data from the two observers is matched a correlation needs to be observed to account for the quantum facts. How is that accomplished in MW?

I've tried to find how this might be answered and so far have only found three kinds of answers.

1) Claim that the experimental data showing non-locality is incorrect. This would avoid the problem entirely for all interpretations. I understand that the tests are still being refined to eliminate any loopholes, so there is a slight possibility this might work. Of the three, this is the only valid argument.

2) Claim that it can't happen in MW, but not explain why. For example, here is Lev Vaidman's comment (http://plato.stanford.edu/entries/qm-manyworlds/)

The most celebrated example of nonlocality was given by Bell 1964 in the context of the Einstein-Podolsky-Rosen argument. However, in the framework of the MWI, Bell's argument cannot get off the ground because it requires a predetermined single outcome of a quantum experiment.

However, after the data was collected, not only did it "get off the ground", but now MW has to get off its butt and account for it.

3) Claim that there is some third measurement that patches all this together. Here is Frank Tipler's comment (http://arxiv.org/pdf/quant-ph/0003146v1.pdf):

Furthermore, this ignored third measurement is actually of crucial importance: it is performed after information about the orientation of the second device has been carried back to the first device (at a speed less than light!). The orientation is coded with correlations of the spins of both electrons, and these correlations (and the linearity of all operators) will force the third measurement to respect the original split.

How does this happen in MW? That is the problem. It is not enough to just state that it all works out in the end.

[MorpheusSandman]

YesNo, I propose we cease this QM discussion. It's not that I can't answer your points/questions, it's just that I'm realizing that this will be at least the third, if not the fourth, thread that we've been through this; and not only am I doubting that anyone else is reading by this point (if any objective third party wants us to continue, feel free to chime in), I'm tiring of having to type the same things ad nauseam only to have you make points/posts that act as if I've never addressed them. Half of the time, you're (still) making invalid objections to MW that only reveal that either you (still) don't know what MW is, or that you're very desperate to latch on to anything you feel could discredit it, and you don't care if those objections are invalid or not. I thought I made it very clear that MW's inability to derive the Born rule is the ONLY valid objection to MW; Bell is not a valid objection as all Bell experiments assume the truth of CI's single-world collapse. That you don't think whether one thinks the wavefunction is real or not is important is also very telling, as the different assumptions of realism VS non-realism are one of the defining elements that separate the various interpretations.

It also occurs to me that the reason I've been pulled back into these conversations after the first thread was your continuing insults that MW was invented by atheistic metaphysicians that are inventing fantasies to support their a priori beliefs. That is nothing but a steaming, heaping pile of wombat crap. Ignoring the fact that no interpretations are inherently "better" for any (a)theistic metaphysical philosophy, MW was proposed by a guy who, like ALL post-QM physicists, thought the seemingly irreconcilable paradoxes that CI produced needed solving. His solution was to assume realism and remove the collapse; to, essentially, treat the wavefunction as encompassing all of reality, including observers. The many worlds came about as a result of following those assumptions to their conclusion. Under those two assumptions you get an interp. that is local, deterministic, real; that can't derive the Born rule; and had diddly squat to do about any metaphysical system, atheistic or otherwise. If you don't understand why MW is local and deterministic, then all that means that you still don't understand MW, and I'm sick to death of explaining it.