We've had the MW vs collapse debate many times on this list, as well as on FOAR and Extropy-Chat lists. I might suggest searching the history of these groups to see some of the points and counter points to each issue as I see many of them repeated here. I'm including a summary of some of the common points/arguments here from previous discussions on this list and others.
*On Bell's Inequality:* On Wednesday, November 30, 2016, Adrian Tymes <[email protected]> wrote: > > Someone earlier stated Bell's Inequality implies we have to give up one > of: locality, determinism, or realism. This list is incomplete, we must > give up one of: locality, determinism, realism, or counterfactual > definiteness. > > > > Counterfactual definiteness means experiments have only one outcome. MWI > gives up counterfactual definiteness and retains locality, determinism and > realism. > But experiments do have only one outcome, as experienced and observed by > the experimenters. Any alternate worlds are immeasurable and may as well > not exist. > That's not quite what's meant by counterfactual definiteness though. Realism, in QM also implies something different from whether or not something is observable. According to Bohr, only measurements are real. This view dispenses with a reality external from observers. In MWI, the universal wave function is real independent of observers or observation. It is why Einstein asked someone who believed in the Copenhagen Interpretation "Do you really believe the moon only exists when you're looking at it?" In MW, the moon definitely does exist, even when no one is looking at it, so it is a theory that maintains/restores realism to QM. All of Einstein's criticisms of QM, that it abandoned realism, locality, and determinism, are issues that are resolved by MW. I think Einstein would have enthusiastically embraced it, had he lived to see it. *On observability of other branches:* On Wed, Nov 30, 2016 at 10:48 PM, Adrian Tymes <[email protected]> wrote: > On Wed, Nov 30, 2016 at 7:36 PM, Rafal Smigrodzki <[email protected]> wrote: > On Wed, Nov 30, 2016 at 5:56 PM, Adrian Tymes <[email protected]> wrote: >> But experiments do have only one outcome, as experienced and observed by >> the experimenters. Any alternate worlds are immeasurable and may as well >> not exist. > > ### If you were to say that only the observed experimental outcomes exist, > then you imply there is something qualitatively different between the part > of the wavefunction we do experience and the parts that we don't. > Science is all about observability, measurement, and what actually exists. If you wish to speculate that something that is never measurable, observable, or otherwise detectable must still exist, you need evidence. The other universes are detectable and they do effect our universe, e.g. interference patterns. Furthermore, you must accept the reality of the wave function (and all its branches) in order to explain how quantum computers work. Whether we can directly observe some phenomenon or not is irrelevant, we can't observe the inside of black holes, beyond the cosmological horizon, the future, things outside our light cone, etc., yet we would all agree those things exist. What matters is whether these other universes are predicted to exist and consequences of our best theories. The evidence for these other branches includes all the evidence we have for quantum mechanics. Indefensible mental gymnastics are required to believe in both QM but deny the reality of the wave function and its many histories. *On quantum computers:* “Schrödinger also 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.” -- David Deutsch > > Furthermore, you must accept the reality of the wave function (and all > its > branches) in order to explain how quantum computers work. > The wave function works just fine in a single world too. The wave function is a system of many universes, as Feynman said that that a universal wave function: “must contain amplitudes for all possible worlds depending on all quantummechanical possibilities in the past and thus one is forced to believe in the equal reality of an infinity of possible worlds.” and Stephen Hawking regarded the MWI as “self-evidently correct”. When the British actor Ken Campbell, asked him “all these trillions of universes of the multiverse, are they as real as this one seems to be to me?” Hawking answered, “Yes.... According to Feynman's idea, every possible history [of Ken] is equally real.” The way single-worlders get around this is by saying the wave function doesn't refer to anything real, that it is just a useful calculating device. But how does this non-real "useful calculating device" enable a table-top device to factor semi-prime numbers of millions of digits, when such a calculation would take more time than then the heat death of the universe to run on a conventional computer, even if all matter in the observable universe were turned into computers? *On Occam's Razor/Simplicity of theory:* > The evidence for these other branches includes all the evidence we have > for > quantum mechanics. Indefensible mental gymnastics are required to believe > in > both QM but deny the reality of the wave function and its many histories. > They are only indefensible if you take MWI as a postulate. If you do not presuppose MWI, then you might see that things look the same whether there are multiple worlds or just the one. MW is not a postulate, it is barebones QM. Copenhagen = QM postulates + collapse postulate Many Worlds = QM postulates It is a theory with fewer assumptions, and it explains more. It explains why you get the appearance of collapse, something Copenhagen had to assume. By Occam, it should be preferred, the only reason it isn't is people are uncomfortable with the idea that the universe is bigger than it seems. It's okay, humanity has gone through this before, with the discovery of other planets besides Earth, with the discovery of other stars besides the sun, with the discovery of other galaxies besides the Milky Way. We are just in the middle of a more recent awakening to the idea that reality is bigger than we previously thought. It took 100 years for Copernicus's heliocentric idea to become accepted, it's only been 60 years since Everett. In fact, there's been no reason to believe in Copenhagen Interpretation since Everett used the assumption of no collapse to show how the math of the theory produces the illusion of collapse. You can't get a more clear cut case for Occam's razor's preference for MW over CI than this: explains more, while assuming less. John Clark [email protected] via <https://support.google.com/mail/answer/1311182?hl=en> lists.extropy.org 12/31/16 to ExI On Sat, Dec 31, 2016 at 7:48 PM, Adrian Tymes > > As is the theory that the other parts of the superposition were real > > and continue to exist forever, just somehow shifting to some other > > "world" that did not exist before that moment. QM contains no > > provision for any of that. On the contrary, if you assume Schrodinger's Wave Equation means what it says then it does indeed exist forever, the mathematics say nothing about it collapsing. MWI unquestionably makes the fewest assumptions, everybody assumes the Schrodinger Wave Equation (or the equivalent Heisenberg Matrices) is correct but in addition Copenhagen assumes the act of observation does mysterious things even though it can't say exactly (or even approximately) what a measurement is. And Pilot Wave assumes a thing that can not be directly measured somehow guides things around almost like the finger of God. And Transactional assumes the future can change the past. But MWI assumes none of that, all MWI assumes is Schrodinger's Wave Equation and Heisenberg Matrices mean what they say the y mean. That's it. Paul Davies describes MWI as being "cheap on assumptions, but expensive on universes". Schrodinger Wave Equation (or the equivalent Heisenberg Matrices) is correct but in addition Copenhagen assumes the act of observation does mysterious things even though it can't say exactly (or even approximately) what a measurement is. And Pilot Wave assumes a thing that can not be directly measured somehow guides things around almost like the finger of God. And Transactional assumes the future can change the past. But MWI assumes none of that, all MWI assumes is Schrodinger's Wave Equation and Heisenberg Matrices mean what they say the y mean. That's it. Paul Davies describes MWI as being "cheap on assumptions, but expensive on universes". *Regarding falsifiability / status as a theory:* You'd need an observer that can report results when dead - i.e., when not making more observations. Unless you mean something far more trivial, in which case why hasn't that experiment been run yet? The AI is assumed to be a conscious observer. It makes a which-way observation of a particle in a two slit experiment, records the fact that it measured a definite result but does not record which slit it passed through. The computation of that conscious AI observer is then reversed (quantum erasing it), which should, in theory, restore the interference pattern. This experiment, if it were run and produced the results I described, would serve to disprove "consciousness/observation causes collapse"-type theories. One of MWI's strongest advocates is David Deutsch <https://en.wikipedia.org/wiki/David_Deutsch>.[84] <https://en.wikipedia.org/wiki/Many-worlds_interpretation#cite_note-deutsch98-84> According to Deutsch, the single photon interference pattern observed in the double slit experiment <https://en.wikipedia.org/wiki/Double_slit_experiment> can be explained by interference of photons in multiple universes. Viewed in this way, the single photon interference experiment is indistinguishable from the multiple photon interference experiment. In a more practical vein, in one of the earliest papers on quantum computing,[85] <https://en.wikipedia.org/wiki/Many-worlds_interpretation#cite_note-deutsch85-85> he suggested that parallelism that results from the validity of MWI could lead to "*a method by which certain probabilistic tasks can be performed faster by a universal quantum computer than by any classical restriction of it*". Deutsch has also proposed that when reversible computers <https://en.wikipedia.org/wiki/Reversible_computing> become conscious that MWI will be testable (at least against "naive" Copenhagenism) via the reversible observation of spin.[65] <https://en.wikipedia.org/wiki/Many-worlds_interpretation#cite_note-davis86-65> Everett’s theory is more than an interpretation of the quantum mechanical effects we see (such as collapse). On the contrary, it is the very (and so far only) explanation for them. On this matter, Deutsch said that talking about Everett’s theory as an interpretation “*would be like talking of dinosaurs as the ‘interpretation’ of fossil records, rather than the things in the theory that explain them.*" The cosmologist Max Tegmark concurs, saying, “*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.*” So it is not that MW is formulated to be unfalsifiable, it's that the alternatives are not mathematical theories offering any explanation or specification of how they work. CI doesn't explain how collapse or observation are related or happen, and Superdeterminism doesn't specify how photon pairs can know to offer the correct statistics according to how you will choose to measure them at the time they are created. Jason On Sun, Nov 26, 2017 at 8:37 PM, <[email protected]> wrote: > > > On Monday, November 27, 2017 at 12:55:24 AM UTC, John Clark wrote: >> >> On Sun, Nov 26, 2017 at 6:36 PM, <[email protected]> wrote: >> >> >>> > >>> Feynman, who wasn't an MWI enthusiast >>> [...] >>> >> >> *"Political scientist" L David Raub reports a poll of 72 of the >> "leading cosmologists and other quantum field theorists" about the >> "Many-Worlds Interpretation" [...] Amongst the "Yes, I think MWI is true" >> crowd listed are Stephen Hawking and Nobel Laureates Murray Gell-Mann and >> Richard Feynman. Gell-Mann and Hawking recorded reservations with the name >> "many-worlds", but not with the theory's content. Nobel Laureate Steven >> Weinberg is also mentioned as a many-worlder" * >> >> https://www.hedweb.com/everett/everett.htm#believes >> > > Your source is fact-challenged. Weinberg thinks MULTIVERSE may have merit, > but NOT the MWI, which he characterized as "repellent". AG > > >> >> But to be fair, Feynman wasn't exactly an enthusiast, I think he >> believed Many Worlds was the the least bad quantum interpretation but he >> wasn't really a fan of philosophy and had sympathy for the "shut up and >> calculate" quantum interpretation. >> >> >>> >>> > >>> no human observer is necessary to perform a quantum experiment. >>> >> >> Hey you don't have to convince me that an observer is not needed for >> something to exist in one definite state, but then I'm not a fan of >> Copenhagen. >> > > You keep making the same error. The only way to understand double slit > experiment is via superposition of states, which means no definite state > before measurement! Does NOT apply to macro objects where interference does > not manifest. I won't say it again! AG > >> >> >> >> >>> > >>> If the detector is designed for a which-way measurement, the >>> interference is destroyed. >>> >> >> If the which way information is retained the interference pattern is >> destroyed, if the information >> is destroyed then you have interference, and that is what Many Worlds >> predicts. >> > > ??? No interference in which-way experiment. AG > >> >> >> >>> >> >>>> The very heart the Copenhagen interpretation is that things do not >>>> have definite properties >>>> before >>>> they are measured, >>>> >>> >>> > >>> Wrong. >>> >> >> * "According to the Copenhagen interpretation, physical systems >> generally do not have definite properties prior to being measured"* >> >> https://en.wikipedia.org/wiki/Copenhagen_interpretation >> > > You're cherry picking. The statement refers (or should refer) to quantum > experiments which manifest interference effects and where the system being > measured is in a superposition of states. AG > >> >> >>> > >>> Your claim only applies in a special situation of quantum experiments >>> which manifest interference effects. >>> >> >> I agree, interference effects >> only manifest in special circumstances, when a world splits become >> different and then the two evolve in such a way that the two become >> identical again and so merge back together, and that is only likely to >> happen if the difference between the two worlds is very small; that's why >> we don't see weird quantum stuff in our macro world, like in the Earth Moon >> system >> > > But since the many worlds are disjoint, we don't SEE anything. Moreover, > they can't become identical if they differ in what's measured! You have > embraced a nonsense theory; not even "physics". AG > > > >> . >> >> John K Clark >> >> >> >> >> >>> >> -- > 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 [email protected]. > To post to this group, send email to [email protected]. > Visit this group at https://groups.google.com/group/everything-list. > For more options, visit https://groups.google.com/d/optout. > -- 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 [email protected]. To post to this group, send email to [email protected]. Visit this group at https://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout.
