On Sat, Feb 28, 2015 at 4:27 PM, meekerdb <meeke...@verizon.net> wrote:
> On 2/28/2015 11:16 AM, Jason Resch wrote: > > > > On Fri, Feb 27, 2015 at 6:00 PM, meekerdb <meeke...@verizon.net> wrote: > >> On 2/26/2015 11:07 PM, Jason Resch wrote: >> >> Implicit in Everett's relative state formulation was an implicit >> assumption of a mechanist theory of mind. In CI there seems to be the >> assumption of a non-material, non-physical mind, which can cause/initiate >> physical changes which no other (non-conscious) physical things can do. I >> think the default position of any rationalist would be to assume that we >> (assumed to be physical objects) operate according to the same physical >> laws as everything else. >> >> >> It may not be crucial to your argument, but you repeatedly attack a >> caricature of the Copenhagen Interpretation (which is still favored over >> MWI by a majority of physicists). >> > > Perhaps among a majority of generalist physicists (who were only taught > CI), but among specialists in quantum mechanics, I doubt whether that is > still true. > > > The last poll I saw was at a symposium on quantum gravity taken by Max > Tegmark. > > But the trend is clear. CI proponents are declining while MW has been gathering steam since the 70s. Also, there seems to be a bias towards MW among the more eminent physicists: Q1 Who believes in many-worlds? ---------------------------- "Political scientist" L David Raub reports a poll of 72 of the "leading cosmologists and other quantum field theorists" about the "Many-Worlds Interpretation" and gives the following response breakdown [T]. 1) "Yes, I think MWI is true" 58% 2) "No, I don't accept MWI" 18% 3) "Maybe it's true but I'm not yet convinced" 13% 4) "I have no opinion one way or the other" 11% 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, although the suggestion is not when the poll was conducted, presumably before 1988 (when Feynman died). The only "No, I don't accept MWI" named is Penrose. > > >> Bohr held that QM was a method of predicting the statistics of the >> results of measurements; where "results" were classical values. >> > > Yes CI proponents are in denial that the world is quantum. They struggle > to maintain a classically existing world, and when that fails, > > > But it doesn't "fail". It's a theory and it predicts correctly. > It fails to describe the world as fully classical, and relegates the "quantum weirdness" to small scales and unobserved things only. Yet nothing in any of the postulates gives any hint as to why the equations shouldn't be in full effect all the time at all scales. This is what I mean by failure. > > they deny the existence of any world at all. > > >> The input to the prediction was the whole experimental setup - not just >> the microscopic part - including the recording devices. He held that this >> was necessary for scientific knowledge to exist because scientific results >> had to be shareable, and hence classical, irreversible records. This is >> what he meant by "The classcial world is logically prior to the quantum >> world." >> >> The best text on non-relativistic QM is by Asher Peres and it's available >> *free* online. >> >> >> http://www.fisica.net/quantica/Peres%20-%20Quantum%20Theory%20Concepts%20and%20Methods.pdf >> > > > Thanks. Although I find his stance on these questions dissatisfying: > > Whether or not there exists an objective “reality” beyond the > intersubjective reality may be an interesting philosophical problem, 18 but > this is not the business of quantum theory. As explained at the end of > Sect. 1-4, quantum theory, in a strict sense, is nothing more than a set of > rules whereby physicists compute probabilities for the outcomes of > macroscopic tests. > > > How are we supposed to learn more about "the thing science is supposedly > trying to learn more about" when we deny it exists at all? It's like a > recurrence of logical positivism. > > > Yes, it's less radical form of logical positivism. Does that make it > heresy? > > Not but it make the theory more intellectually suffocating by saying we shouldn't ask or think about certain questions. > > >> >> >> It, and the very good text by Leslie Ballentine, both take an >> instrumentalist/Copenhagen interpretation. So does Roland Omnes in his >> books on Quantum Philosophy. There may be a better way of looking at QM, >> but these are not ignorant or careless thinkers who are just overlooking >> the incoherencies you imagine. I suggest you read them. >> > > I never said they are idiots, but that such scientists consider a > collapse theory preferable to MW, when the former is antithetical to such a > large number of otherwise firmly-grounded scientific principals surprises > me. To accept collapse requires abandoning locality, special relativity, > determinism, time-symmetry, time-reversibility, etc. > > > > > Moreoever it's never been properly defined or described. It's not a > mathematical theory, > > > See GRW theory, or Bohmian QM, those are collapse theories. Copenhagen > and quantum bayesian interpretations are not collapse theories. The deny > the reality of the wave function, so there's nothing to "collapse". > I agree there exists various opinions as to what exactly the CI embodies, but here is what wikipedia says, I've highlighted the portions of CI that I have the most trouble with: Asher Peres <http://en.wikipedia.org/wiki/Asher_Peres> remarked that very different, sometimes opposite, views are presented as "the Copenhagen interpretation" by different authors.[11] <http://en.wikipedia.org/wiki/Copenhagen_interpretation#cite_note-11> Nonetheless, there are several basic principles that are generally accepted as being part of the interpretation: 1. A wave function [image: \Psi] <http://en.wikipedia.org/wiki/Schr%C3%B6dinger_equation> represents the state <http://en.wikipedia.org/wiki/Quantum_state> of the system. It exhausts what can be known in advance of an observation, about a particular occasion of occurrence of a system, and beyond it there are no "hidden parameters".[12] <http://en.wikipedia.org/wiki/Copenhagen_interpretation#cite_note-12> *While it is isolated from other systems*, it evolves smoothly in time, but is unobservable. 2. The properties of the system, as represented in the wave function, and in physical actuality, are subject to a principle of incompatibility. The properties occur in conjugate pairs, which cannot be jointly defined for the same time and place. The incompatibility is expressed quantitatively by Heisenberg's uncertainty principle <http://en.wikipedia.org/wiki/Heisenberg%27s_uncertainty_principle>. For example, if a particle at a particular instant has a particular definite location, it is meaningless to speak of its momentum at that instant. 3. For an occasion of observation <http://en.wikipedia.org/wiki/Measurement_in_quantum_mechanics>, the system must interact with a laboratory device. When that device is suitably constructed, for example containing a birefringent crystal, *the wave function is said to **collapse*, or irreversibly reduce <http://en.wikipedia.org/wiki/Wave_function_collapse> to an eigenstate <http://en.wikipedia.org/wiki/Introduction_to_eigenstates>, also called a pure case, of the observable <http://en.wikipedia.org/wiki/Observable> that is registered.[13] <http://en.wikipedia.org/wiki/Copenhagen_interpretation#cite_note-Heisenberg_reduction-13> 4. The registrations provided by observing devices are essentially classical, *and must described in ordinary language*. If the device is suitably constructed, its output registration makes fair sense in terms of classical physics, and consequently the ordinary language description is intelligible and useful in physics. This was particularly emphasized by Bohr, and was accepted by Heisenberg.[14] <http://en.wikipedia.org/wiki/Copenhagen_interpretation#cite_note-14> 5. A pure case wave function may be considered as a coherent superposition of other compatible pure case wave functions. This can for example describe the passage of the quantal system through a smooth classical magnetic field. Incompatible wave functions cannot be superposed. 6. *There is a distinction between an atomic or subatomic or quantal system on the one hand, and a laboratory-scale observing device on the other. *For an observation, a particular such device must be chosen, and the quantal system must then interact with it. For example, a device might test position. A different device would be needed to test momentum. One and the same device can be used, on different occasions, to test different quantal systems, and one and the same quantal system can be tested, on different occasions, with different devices. This is implicit, for example, in the discussions offered by Bohr.[15] <http://en.wikipedia.org/wiki/Copenhagen_interpretation#cite_note-15> 7. Different wave functions can be linked in a so-called tensor product. If the observing apparatus is considered in isolation, and in a quantum mechanical picture, it has its own wave function, separate from and incoherent with that of the quantal system that is being tested. In this case, when the device and the quantal system are made to interact, then two incoherent wave functions are brought into a new joint system, that needs a jointly coherent wave function, which is the tensor product. If the laboratory device has suitable carefully selected properties, then wave function collapse seems plausible. For example again the device might be based on a birefringent crystal. A wave function collapsed to a pure case by such a suitably constructed device can be interpreted as practically or nearly free of puzzles of superposition, even though the quantal system and apparatus have become entangled or coherent with one another. If the observing apparatus and the quantal system under test are considered initially and jointly only as an isolated joint entity, they have a joint wave function and must be considered as jointly coherent. In this case, of an isolated joint system, wave function collapse is inconceivable.* Only superposition is conceivable, and observation is excluded. *Two systems initially separate then interacting, and one initially joint system in isolation, provide different pictures. 8. The description given by the wave function is probabilistic. The probability of a given outcome of a measurement is supplied by the square of the modulus <http://en.wikipedia.org/wiki/Absolute_value> of the amplitude of the wave function. This principle is called the Born rule <http://en.wikipedia.org/wiki/Born_rule>, after Max Born <http://en.wikipedia.org/wiki/Max_Born>. 9. *The wave function expresses a necessary and fundamental wave–particle duality <http://en.wikipedia.org/wiki/Wave%E2%80%93particle_duality>.* This should be reflected in ordinary language accounts of experiments. An experiment can show particle-like properties, or wave-like properties, according to the complementarity principle <http://en.wikipedia.org/wiki/Complementarity_principle> of Niels Bohr <http://en.wikipedia.org/wiki/Niels_Bohr>.[16] <http://en.wikipedia.org/wiki/Copenhagen_interpretation#cite_note-16> 10. In the present state of physical knowledge, the intestinal workings of atomic and subatomic processes are not open to visualization in ordinary space-time or causal pictures. *There are also limitations on the visualizability of interactions between atomic and subatomic entities on the one hand and macroscopic apparatus on the other.* This is the fundamental reason why quantum mechanics is needed to replace the old quantum theory. It is a key concept of quantum theory, expressed in quantum mechanics by the non-separable characteristic of the wave function, that its domain is configuration space, not ordinary physical space-time. 11. When quantum numbers are large, they refer to properties which closely match those of the classical description. This is the correspondence principle <http://en.wikipedia.org/wiki/Correspondence_principle> of Bohr and Heisenberg. Jason -- You received this message because you are subscribed to the Google Groups "Everything List" group. 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