On Thu, Feb 26, 2015 at 3:01 PM, meekerdb <meeke...@verizon.net> wrote:
> On 2/26/2015 3:21 AM, Bruno Marchal wrote: > > > On 26 Feb 2015, at 05:36, meekerdb wrote: > > On 2/25/2015 7:11 PM, Jason Resch wrote: > > > > On Wed, Feb 25, 2015 at 5:28 AM, Bruce Kellett <bhkell...@optusnet.com.au> > wrote: > >> Bruno Marchal wrote: >> >>> On 24 Feb 2015, at 22:52, Bruce Kellett wrote: >>> >>> MWI simply formalizes the fact that such data are "in-principle >>>> unknowable". >>>> >>> >>> >>> Well, usually we say that the SWE formalizes that fact, and that the MWI >>> interpret this in term of many world. But I am OK with your statement, as >>> SWE implies formally the MWI, >>> >> >> Statements like this are gaining in currency these days, but this is >> strictly false. The SWE operating on vectors in Hilbert space does not >> formally imply the MWI. All that the formalism implies is the existence of >> superpositions. Schroedinger realized this very early on, hence his example >> of the cat being in a superposition of dead and alive states. Schroedinger >> thought this was effectively a reductio ad absurdum for the wave equation. >> > > I'm not so sure. I think he was more attacking the role of the observer > in creating reality. We see Einstein affirm this in a letter to Schrodinger: > > Einstein was most impressed with Schrödinger's paper, and in 1950 > wrote Schrödinger a letter of praise, saying “You are the only contemporary > physicist, besides Laue, who sees that one cannot get around the assumption > of reality, if only one is honest. Most of them simply do not see what sort > of risky game they are playing with reality—reality as something > independent of what is experimentally established. Their interpretation is, > however, refuted most elegantly by your system of radioactive atom + > amplifier + charge of gunpowder + cat in a box, in which the psi-function > of the system contains both the cat alive and blown to bits. Nobody really > doubts that the presence or absence of the cat is something independent of > the act of observation.” > > > Further, we see that later in his life, Schrodinger began to take his > theory (and the reality of the super position) more seriously: > > > “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.” > > > >> >> In order to get MWI one has to add a lot more superstructure. In >> particular one has to solve the basis problem and give a plausible account >> of the meaning of probabilities in a theory in which every possible result >> actually occurs. Both of these areas are still matters of substantial >> debate. >> >> > Tegmark shows in a large enough world, even under something like the CI, > you can't escape "all possibilities being realized", so you're faced with > the same probability "problem" whether you think the wave function > collapses or not: http://arxiv.org/abs/1008.1066 > > We study the quantum measurement problem in the context of an > infinite, statistically uniform space, as could be generated by eternal > inflation. It has recently been argued that when identical copies of a > quantum measurement system exist, the standard projection operators and > Born rule method for calculating probabilities must be supplemented by > estimates of relative frequencies of observers. We argue that an infinite > space actually renders the Born rule redundant, by physically realizing all > outcomes of a quantum measurement in different regions, with relative > frequencies given by the square of the wave function amplitudes. > > > >> >> if we define world by a structure of events close for interaction. Then, >>> using the FPI, we have a dterlministic and local account of why the data >>> appears for the observer first person (plural) point of view as >>> unknowable, indeterminist and non local. >>> >> >> Maybe the data appear indeterministic and unpredictable in principle >> because they really are that way -- the world is governed by probabilistic >> laws. We don't actually need all the superstructure of MWI. > > > What do you find more appealing, elegant, and historically more likely > to be true: > 1. A large number of objects implied to exist by a simpler theory > 2. A small or singular number of objects as described by a more complex > theory > > MW is just what's left over when you dispense with the ill-conceived and > ill-defined notion of collapse: the only phenomenon in all science that's > not time-symmetric, not time-reversible, nonlinear, discontinuous, > non-deterministic, non-local, and observer dependent. I'll take the many > worlds before I take that. > > > But without solving the measure and basis problem, MWI doesn't predict > anything - or more accurately, it predicts everything. > > > MWI predicts the same as QM+collapse. > > > Only because it assumes the Born rule applies to give a probability > interpretation to the density matrix. But Everettista's either ignore the > need for the Born rule or they suppose it can be derived from the SWE > (although all attempts have fallen short). > So it seems MW is at worst case they are on equal footing as all other interpretations similarly assume the Born rule without explaining it, and at best MW is superior in that it possibly explains the Born rule. > > It is just that MWI dispense with magic. It is local, deterministic, > realist (even if multi-realist). > > > > It simply pretends to dispense with collapse while sneaking in its > equivalent in order to use the Born rule. > > > It uses only the comp FPI, or variant. It is consciousness selection, > with relative measure. > > > But it assumes the Born rule provides the relative measure - which is more > than just the SWE. You can solve the problem of branch counting by > assuming infinitely many parallel worlds - but then that raises the problem > of defining "probability". > There's no problem defining probability. There is, however, a big problem defining collapse. > > > > > It is radically non-local. > > > It appears to be so in each branches, but is not when you look at all > branches partition, and this in any base. Paper showing that MWI is non > local adds metaphysical baggage which is not in QM, nor in Everett. > > > There are plenty of phenomenon in science that are non-linear. > > > Not in the reality, if the reality is described by quantum mechanics. > > > But QM is inconsistent with GR - so it is not a given that QM is > completely correct. > QM stands on firmer ground that GR. And is GR non-linear? Jason > But non linearity appearance is explained from inside + ignorance of the > other branches. > > > Computationalism is also discontinuous. > > > It depends of the topology. Computation = continuous with the relevant > toplogies of computer science. It is only discontinuous in topology of > reals, which is another subject. > > > The complaint was that wave function collapse is the only discontinuous > process in physics. But if you define different topologies then it too is > continuous in epistemological space (c.f. quantum bayesianism). > > Brent > > -- > 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 http://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 everything-list+unsubscr...@googlegroups.com. 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