On Sun, Jun 17, 2018 at 6:24 PM, Bruce Kellett <bhkell...@optusnet.com.au> wrote:
> From: Jason Resch < <jasonre...@gmail.com>jasonre...@gmail.com> > > > On Sun, Jun 17, 2018 at 6:42 AM, Bruce Kellett < > <bhkell...@optusnet.com.au>bhkell...@optusnet.com.au> wrote: > >> From: Jason Resch <jasonre...@gmail.com> >> >> On Sun, Jun 17, 2018 at 12:12 AM, < <agrayson2...@gmail.com> >> agrayson2...@gmail.com> wrote: >> >>> >>> >>> * why do you prefer the MWI compared to the Transactional >>> Interpretation? I see both as absurd. so I prefer to assume the wf is just >>> epistemic, and/or that we have some holes in the CI which have yet to be >>> resolved. AG * >>> >> >> >> 1. It's the simplest theory: "MWI" is just the Schrodinger equation, >> nothing else. (it doesn't say Schrodinger's equation only applies >> sometimes, or only at certain scales) >> >> >> Well no, it is an interpretation of the SE, involving the reification of >> the wave function. So it is not 'just' the Schrödinger equation. >> > > It is a theory, in that it is fully mathematical and makes predictions. > Other so called interpretations CI etc. are not mathematical theories > because they don't say when or why or under what circumstances > Schrodinger's equation stops working. As Max Tegmark said: > > “I disagree that the distinction between Everett and Copenhagen is ‘just > interpretation’. The former is a mathematical theory, the latter is not. > The former says simply that the Schrödinger equation always applies. The > latter says that it only applies sometimes, but doesn't given an equation > specifying when it doesn't apply (when the so-called collapse is supposed > to happen). If someone were to come up with such an equation, then the two > theories would be mathematically different and you might hope to make an > experiment to test which one is right.” > > > Decoherence theory effectively answers such objections. > Yes and if you accept Decoherence as an explanation for the appearance of wave function collapse, then you should elide the "wave function collapse" postulate from your theory (as it has already been explained from the other existing postulates). And what is QM without the wave function collapse postulate? It's just the Schrodinger equation, applying at all times and all scales. > > > > You speak of reification of the wave function as if it is something > special. In what other physical theory is something postulated one theory, > and a different theory is when that same thing is postulated, but is also > "really real"? Is the theory of quarks distinct from another theory of > quarks that holds them to be really real? > > David Deutsch comments on the absurdity of this: > > “Schrödinger also”, David Deutsch notes, “had the basic idea of parallel > universes shortly before Everett, but he didn't publish it. He mentioned it > in a lecture in Dublin, in which he predicted that the audience would think > he was crazy. Isn't that a strange assertion coming from a Nobel Prize > winner—that he feared being considered crazy for claiming that his > equation, the one that he won the Nobel Prize for, might be true.” > > > Schrödinger was also the originator of the idea of a collapse of the wave > function. He saw that his wave function necessitated a collapse of his wave > to a point particle interaction in the majority of measurements. > When he, and all other physicists were still under the spell of believing there must only be one universe that remains real. He and other physicists at the time believed otherwise it would lead to a "jellificiation" of states. It was only later in life he began to appreciate the full implications of his theory. And Decoherence in 1952, provided a means to avoid that jellification of states. See: https://goo.gl/49xwzJ > > > > 2. It explains more while assuming less (it explains the appearance of >> collapse, without having to assume it, thus is preferred by Occam's razor) >> >> >> Maybe the collapse is real. >> > > > But to assume this is like assuming there are invisible and undetectable > "motive demons" operating within a car engine that are necessary to make > the car engine work, when we have another perfectly valid way of explaining > everything the car engine does without having to assume these motive > demons. I don't see the point when we have a theory that explains all the > facts before us. > > > Maybe it just means that we don't yet fully understand the collapse. There > are plenty of possibilities that don't resort to magic. > > I agree. But what facts about our observations of collapse are not already fully explained by Decoherence? In other words, what is left to solve about it? I thought Decoherence solved this (back in 1952 with Bohm). > > 3. Like every other successful physical theory, it is linear, reversible >> (time-symmetric), continuous, deterministic and does not require faster >> than light influences nor retrocausalities >> >> >> MWI is still a non-local theory. FTL influences or not, QM is >> intrinsically non-local. >> > > > When you say non-local what type of non-locality do you mean? It is a > local theory in the sense that physical objects interact only with other > physical objects in their proximity, and carry information only at luminal > or subluminal speeds. See Q12 on <http://www.anthropic> > http://www.anthropic-principle.com/preprints/manyworlds.html > > > Price's argument here has been shown to be invalid -- he surreptitiously > relies on non-locality. > > Care to explain this non-locality and where it appears in a MWI explanation of the EPR paradox, for example? I've provided explanations on this list before of how EPR/Bell operates under MWI without FTL influences. So if you think they are required I would be interested to know where you think they appear and are necessary. John Clark often says MWI is non local because the branches are not local to each other, but I think this is a redefinition of the common sense use of the term locality in physics. Is this what you mean by MWI being non local? > > 4. Unlike single-universe or epistemic interpretations, "WF is real" with >> MWI is the only way we know how to explain the functioning of quantum >> computers (now up to 51 qubits) >> >> >> Rubbish. The functioning of quantum computers is not dependent on MWI. >> Many worlds is, after all, only an interpretation. Not the reality of >> anything at all. >> > > How do you explain the finite computational resources of a table-top > quantum computer factoring a prime number in seconds when it would take a > classical computer the size of the solar system 10^100 years to do the same > calculation? > > David Deutsch notes that quantum computers present a strong challenge to > defenders of single-universe interpretations, saying “When a quantum > computer delivers the output of such a computation, we shall know that > those intermediate results must have been computed somewhere, because they > were needed to produce the right answer. So I issue this challenge to those > who still cling to a single-universe world view: if the universe we see > around us is all there is, where are quantum computations performed? I have > yet to receive a plausible reply.” > > > That might be Deutsch's opinion, but plenty of others think differently. > Quantum computers can easily be understood in a single world account. > > But it can't be explained in non-realist views of the wave function. For example, those that say it is nothing but a convenient tool for computing probabilities. The reason is, here this "convenient tool" is computing results for us that we have no hope of ever computing ourselves. How is something which isn't real, and isn't really there, yielding results of computations? You say others think differently, but don't allude to who those other thinkers are or what their thoughts are. Do you have an explanation for quantum computers that works with the assumption the wave function is not real? What would you say about a conscious AI implemented on a quantum computer? Would it or would it not be capable of existing in and experiencing "many simulations"? > > 5. Unlike copenhagen-type theories, it attributes no special physical >> abilities to observers or measurement devices >> >> >> Which version of the CI are you referring to? There are as many >> "Copenhagen Interpretations" as there are citizens of Copenhagen. Bohr's >> original theory did not refer to observers or make experiments central. He >> merely thought that quantum phenomena were understandable only in the >> context of a classical world. >> > > By CI theories here, I mean those that include collapse of the wave > function (an irreversible, random, instantaneous event) being triggered by > some nebulously defined measurement, observation, consciousness, etc. > > > Most of these objections to CI are answered by decoherence theory. > > Do you subscribe to decoherence theory? > > > 6. Most of all, theories of everything that assume a reality containing >> all possible observers and observations lead directly to laws/postulates of >> quantum mechanics (see Russell Standish's Theory of Nothing >> <http://www.hpcoders.com.au/theory-of-nothing.pdf>, Chapter 7 and >> Appendix D). >> >> >> Unfortunately, Russell's attempt to derive quantum mechanics from the >> plenum of all possible bit strings failed at the first step. So you don't >> have much support from this. >> > > I would be very interested to see this, do you recall the subject or time > frame of this discussion? > > > Not off-hand. But you could search the archives of this list. It was > probably late last year that we had this discussion. > Thank you. > > > In any case, if Russell's derivation failed, there are other results that > are other clues (e.g. from Bruno's UDA) which from the assumption of an > infinite reality predicts several quantum phenomenon, including apparent > randomness, non-clonability of matter, and evidence of infinite > computations at work when we look at sufficiently small scales > > > Bruno's so-called successful predictions of quantum phenomena are no more > than clutching at straws. He has not derived any sensible physics. > > > It will take a lot of work under his approach, but I am not aware of any other system proposed by anyone, which even has a chance at this. My belief is that any such system can only take us so far, because I think there are many possible structures that permit conscious life, and so there is no unique law of physics, aside from really basic principles like first person indeterminacy, always being conscious, and always having finite memory, etc. But I don't expect any system to give us the mass of the electron, as I think there are other beings living in other structures where the mass of the electron could be different from our "electrons". > Given #6, we should revise our view >> >> >> But we don't have #6. See the discussion I had with Russell on this list >> some time ago. He had to admit that his derivation of QM failed. >> >> It is not MWI and QM that should convince us of many worlds, but rather >> the assumption of many worlds (an infinite and infinitely varied reality) >> that gives us, and *explains *all the weirdness of QM. >> >> >> No, the weirdness of the violation of the Bell inequalities and >> non-locality remains, even in MWI. >> > > Bell had an implicit assumption in his reasoning, which is that only a > single definite result is obtained by all parties for any given measurement > (including those not performed). This is not true under MWI so Bell's > reasoning that there must be non-locality fails for MWI, as many-worlds > lacks contra-factual definiteness. > > Again from: http://www.anthropic-principle.com/preprints/manyworlds.html > > > > > > > *To recap. Many-worlds is local and deterministic. Local measurements > split local systems (including observers) in a subjectively random fashion; > distant systems are only split when the causally transmitted effects of the > local interactions reach them. We have not assumed any non-local FTL > effects, yet we have reproduced the standard predictions of QM.* > > > > > > > > > > > *So where did Bell and Eberhard go wrong? They thought that all theories > that reproduced the standard predictions must be non-local. It has been > pointed out by both Albert [A] and Cramer [C] (who both support different > interpretations of QM) that Bell and Eberhard had implicity assumed that > every possible measurement - even if not performed - would have yielded a > *single* definite result. This assumption is called contra-factual > definiteness or CFD [S]. What Bell and Eberhard really proved was that > every quantum theory must either violate locality *or* CFD. Many-worlds > with its multiplicity of results in different worlds violates CFD, of > course, and thus can be local.* > > > As I said above, Price has an invalid argument. If Bell's theorem does not > apply to MWI, why is it that no one has been able to give a simple, clear, > local account of the violations of the Bell inequalities? > Let me try: In the EPR experiment, a pair of photons is created. Each photon is in a super position of every possible polarization, and because it is created as a pair, it's dual in the superposed state always has exactly the opposite polarization (rotated 180 degrees). When you perform a measurement of your left-traveling photon on Earth, you become entangled (correlated) with it, and all the possible states of that photon, when measured, leak into the room, starting with the measuring device, then your eyes, then your brain, then your notebook, etc. until now everything is in the room, and soon Earth is now in many states which contagiously spread from that photon. Also, because the photon you measured was entangled (correlated) with its pair in the superposition, whatever result you measure for the photon's polarization tells you immediately what the polarization of its pair is (in your branch at least). So any future communication you get from me on Pluto will necessarily align with the result you measured. Effectively, "single" hidden variables don't work under Bell's inequality, but many hidden variables do. > Maudlin concludes his discussion of many worlds by questioning whether > sense can be made of correlations if all outcomes occur at both ends of a > Bell-type experiment. He concludes: "If some sense can be made of the > existence of correlations, we have to understand how. In particular, if > appeal is made to the wave-function to explicate the sens e in which, say, > the "passed" outcome on the right is paired with the "absorbed" outcome on > the left to form a single "world", then we have to recognize that this is > not a *local* account of the correlations since the wave-function is not > a local object. (Quantum Non-Locality & Relativity, 3rd Edition.) > > To see why it is local you need to trace the event back to the creation of the paired photons. Each photon, in a sense, has already measured each other. If the photons are always created in opposite aligned pairs, knowing one you already know the other. You know you have ended up in the branch of the wave function where my photon has the opposite angle of yours the moment you measure your photon, because both photons were created in a way that has such a property. Also, both of these photons, which already measured each other, traveled at no more than the speed of light to reach you and me. When we measured them, the branching of the wave function was entirely local. Starting with the polarization screen, then the photon detector, then the light flash, then your retina, the nerves along your optic nerve, then your brain. Nothing happened instantaneously across space or time, and nothing exceeded the speed of light in this process. > > This should overwhelmingly convince us of MWI-type everything theories >> over any single-universe interpretation of quantum mechanics, which is not >> only absurd, but completely devoid of explanation. With the assumption of a >> large reality, QM is made explainable and understandable: as a theory of >> observation within an infinite reality. >> >> >> I think other possibilities are still available, and generally more >> acceptable. >> >> MWI has problems of its own. Particularly with the preferred basis >> problem and the derivation of Born's rule from within many worlds in a >> non-circular way. >> >> > Other theories don't even offer an explanation for Born's rule. MWI at > least offers several plausible answers, such as Gleason's Theorem. > > > Gleason's theorem is not the complete answer to the origin of the Born > rule. > > But you see it as a partial answer? That is more than can be said for any other interpretation of QM, is it not? > Regarding preferred bases, both of the papers I provided which began this > thread address that question: > > https://arxiv.org/pdf/1104.2324.pdf > >> * Note that quantum interferences between different terms in Eq. (39) are >> extremely small, since overlaps between macroscopically different >> configurations, such as and , are suppressed by the huge dimensionality of >> the corresponding Hilbert space. In fact, for any observables constructed >> out of local operators, matrix elements between macroscopically distinct >> states are highly suppressed, This, therefore, provides preferred bases for >> any macroscopic systems.* > > > and > > https://arxiv.org/pdf/1105.3796.pdf > >> *Decoherence Decoherence1 explains why observers do not experience >> superpositions of macroscopically distinct quantum states, such as a >> superposition of an alive and a dead cat. The key insight is that >> macroscopic objects tend to quickly become entangled with a large number of >> “environmental” degrees of freedom, E, such as thermal photons. In practice >> these degrees of freedom cannot be monitored by the observer. Whenever a >> subsystem E is not monitored, all expectation values behave as if the >> remaining system is in a density matrix obtained by a partial trace over >> the Hilbert space of E. The density matrix will be diagonal in a preferred >> basis determined by the nature of the interaction with the environment* > > > *This preferred basis is picked out by the apparatus configurations that >> scatter the environment into orthogonal states. Because interactions are >> usually local in space, ρSA will be diagonal with respect to a basis >> consisting of approximate position space eigenstates. This explains why we >> perceive apparatus states |0iA (pointer up) or |1iA (pointer down), but >> never the equally valid basis states |±iA ≡ 2 −1/2 (|0iA±|1iA), which would >> correspond to superpositions of different pointer positions.* >> > > That is just the explanation that Schlosshauer gives. And as I have > pointed out, it is circular. One could justify any Quantum operator at all > as the position operator on this basis -- physics would be different. But > then, what is required is an account of why physics is as it is. > > Could you explain to me what is the expected observational difference between QM and MWI, under the "preferred basis problem"? What does eliminating collapse of the wave function cause that you see as leading to MWI being ruled out by either any experiment or observation that has been performed? Jason -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To post to this group, send email to everything-list@googlegroups.com. Visit this group at https://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout.
