Bruno, But it seems that the Gleason Theorem assigns probabilities to the different universes in the multiverse that are not there in Everett's MWI in the first place. Richard
On Sat, Oct 27, 2012 at 9:46 AM, Bruno Marchal <marc...@ulb.ac.be> wrote: > > On 26 Oct 2012, at 15:52, Richard Ruquist wrote: > >> Well Bruno, >> >> If the "measure problem" (which I take to be the assignment of >> probabilities) is intrinsic to Everett's MWI, does that not amount to >> negating it? > > > Why? I think that it is beautifully solved by Gleason theorem, for the > Hilbert space of dim bigger or equal to 3. > > > >> I did not suggest that it negated comp, which is what you >> responded to. > > > I think comp will confirms Everett QM, and this would make our sharable > human or animal substitution level very plausibly at the Heisenberg > uncertainty level, this for surviving even a long run, without detecting any > difference. > > In that case, the Gleason solution will be the solution for comp. For this > the X and Z logics (alreeady extracted) must conforms to some desiderata, > already expressed by von Neumann, for a quantum logic, and which is that > mainly it defines the searched measure. > > I m not sure I can understand string theory or any fundamental QM without > Everett. > > I agree that the idea that we are multiplied by infinities at each instant > is not attractive, but science is not wishful thinking, and besides, I don't > take any theory too much seriously (we don't know). I also know that > different theories can happen to be equivalent. > > Of course, to be sure, comp has also many attractive features, mainly its > conceptual simplicity and naturalness. It really explains almost why there > is something instead of nothing, as it assumes only 0 and the successor and > the very simple laws, and explain from that how that very explanation > emerges in some collection of stable numbers' dream. > > Bruno > > > > > > >> Richard >> >> On Fri, Oct 26, 2012 at 9:35 AM, Bruno Marchal <marc...@ulb.ac.be> wrote: >>> >>> Richard, >>> >>> On 25 Oct 2012, at 18:42, Richard Ruquist wrote: >>> >>>> Bruno, >>>> >>>> Doesn't the Gleason Theorem negate MWI by assigning probabilities? >>>> Richard >>> >>> >>> >>> On the contrary. Gleason theorem solves the "measure problem" intrinsic >>> in >>> the Everett MWI, it makes the probabilities into comp (or weakening) >>> first >>> person indeterminacies. >>> >>> Unfortunately, comp necessitates a version of Gleason theorem for all >>> comp >>> states, not just the quantum one, as the quantum law must be derived from >>> the 1p indeterminacies, occurring in arithmetic. >>> >>> The advantage is that comp provides the theory of both quanta and qualia >>> (and a whole theology actually). >>> Unfortunately, it is not yet clear if those quanta behave in a >>> sufficiently >>> quantum mechanical way, like making possible quantum computers, hydrogen, >>> strings may be, etc. >>> >>> Bruno >>> >>> >>> >>> >>>> >>>> On Thu, Oct 25, 2012 at 9:38 AM, Bruno Marchal <marc...@ulb.ac.be> >>>> wrote: >>>>> >>>>> >>>>> >>>>> On 24 Oct 2012, at 19:53, meekerdb wrote: >>>>> >>>>> On 10/24/2012 4:31 AM, Bruno Marchal wrote: >>>>> >>>>> >>>>> On 23 Oct 2012, at 14:50, Roger Clough wrote: >>>>> >>>>> Hi meekerdb >>>>> >>>>> There are a number of theories to explain the collapse of the quantum >>>>> wave >>>>> function >>>>> (see below). >>>>> >>>>> 1) In subjective theories, the collapse is attributed >>>>> to consciousness (presumably of the intent or decision to make >>>>> a measurement). >>>>> >>>>> >>>>> This leads to ... solipsism. See the work of Abner Shimony. >>>>> >>>>> >>>>> >>>>> >>>>> 2) In objective or decoherence theories, some physical >>>>> event (such as using a probe to make a measurement) >>>>> in itself causes decoherence of the wave function. To me, >>>>> this is the simplest and most sensible answer (Occam's Razor). >>>>> >>>>> >>>>> This is inconsistent with quantum mechanics. It forces some devices >>>>> into >>>>> NOT >>>>> obeying QM. >>>>> >>>>> >>>>> No, it's only inconsistent with a reified interpretation of the wf. >>>>> It's >>>>> perfectly consistent with an instrumentalist interpretation. >>>>> Decoherence >>>>> is >>>>> a prediction of QM in any interpretation. It's the einselection that's >>>>> a >>>>> problem. >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> But instrumentalism is just an abandon of searching knowledge. There is >>>>> no >>>>> more what, only how. >>>>> An instrumentalist will just not try to answer the question of betting >>>>> if >>>>> there is 0, 1, 2, ... omega, ... universes. >>>>> >>>>> And the einselection is not a problem at all, in QM + comp. It is >>>>> implied. >>>>> And, imo, the QM corresponding measure problem is solved by Gleason >>>>> theorem >>>>> (basically). >>>>> >>>>> And then, keeping that same 'everything' spirit, the whole QM is >>>>> explained >>>>> by comp. We have just to find the equivalent of "Gleason theorem" for >>>>> the >>>>> "material hypostases". >>>>> >>>>> Bruno >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> 3) There is also the many-worlds interpretation, in which collapse >>>>> of the wave is avoided by creating an entire universe. >>>>> This sounds like overkill to me. >>>>> >>>>> >>>>> This is just the result of applying QM to the couple "observer + >>>>> observed". >>>>> It is the literal reading of QM. >>>>> >>>>> >>>>> >>>>> >>>>> So I vote for decoherence of the wave by a probe. >>>>> >>>>> >>>>> You have to abandon QM, then, and not just QM, but comp too (which can >>>>> only >>>>> please you, I guess). >>>>> >>>>> Bruno >>>>> >>>>> >>>>> http://iridia.ulb.ac.be/~marchal/ >>>>> >>>>> >>>>> >>>>> -- >>>>> You received this message because you are subscribed to the Google >>>>> Groups >>>>> "Everything List" group. >>>>> To post to this group, send email to everything-list@googlegroups.com. >>>>> To unsubscribe from this group, send email to >>>>> everything-list+unsubscr...@googlegroups.com. >>>>> For more options, visit this group at >>>>> http://groups.google.com/group/everything-list?hl=en. >>>> >>>> >>>> >>>> -- >>>> You received this message because you are subscribed to the Google >>>> Groups >>>> "Everything List" group. >>>> To post to this group, send email to everything-list@googlegroups.com. >>>> To unsubscribe from this group, send email to >>>> everything-list+unsubscr...@googlegroups.com. >>>> For more options, visit this group at >>>> http://groups.google.com/group/everything-list?hl=en. >>>> >>> >>> http://iridia.ulb.ac.be/~marchal/ >>> >>> >>> >>> -- >>> You received this message because you are subscribed to the Google Groups >>> "Everything List" group. >>> To post to this group, send email to everything-list@googlegroups.com. >>> To unsubscribe from this group, send email to >>> everything-list+unsubscr...@googlegroups.com. >>> For more options, visit this group at >>> http://groups.google.com/group/everything-list?hl=en. >>> >> >> -- >> You received this message because you are subscribed to the Google Groups >> "Everything List" group. >> To post to this group, send email to everything-list@googlegroups.com. >> To unsubscribe from this group, send email to >> everything-list+unsubscr...@googlegroups.com. >> For more options, visit this group at >> http://groups.google.com/group/everything-list?hl=en. >> > > http://iridia.ulb.ac.be/~marchal/ > > > > -- > You received this message because you are subscribed to the Google Groups > "Everything List" group. > To post to this group, send email to everything-list@googlegroups.com. > To unsubscribe from this group, send email to > everything-list+unsubscr...@googlegroups.com. > For more options, visit this group at > http://groups.google.com/group/everything-list?hl=en. > -- You received this message because you are subscribed to the Google Groups "Everything List" group. 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