Richard,
Bruno,I do not find Deutsch's introduction of a rational decision maker convincinge.g.: http://arxiv.org/ftp/quant-ph/papers/9906/9906015.pdf nor Wallaces elaboration on that theme e.g.: http://arxiv.org/pdf/0906.2718v1.pdf. My belief is that a rational decision maker, somewhat like a god,would following Leibniz, always chose the best quantum state in any interaction to become physical in a single universe. In fact that seems to be exactly what Wallaces rational decision maker does. I think Deutsch has snookered us all.Richard
I don't want to be technical about this, as I "believe" in the many dreams at the start. By comp they are just the search of existing or non existing solution to diophantine equation, or arithmetical problem.
But technically, from some of its paper at least, Wallace seems to me the closer to comp Everettian, i.e. closer to the kind of physics which has to emerge from the distribution of the possible dreams/ persons in arithmetic, as implied by the comp assumption.
The comp mind-body problem forces us to mega-generalizes Everett, on the whole of the arithmetical truth, and physics is "reduced" to arithmetic, like the carbon-based biology can be said to be be reduced to chemistry today.
Bruno
On Mon, Oct 29, 2012 at 11:28 AM, Bruno Marchal <marc...@ulb.ac.be> wrote:Hi Richard, On 28 Oct 2012, at 21:01, Richard Ruquist wrote:Bruno, But it seems that the Gleason Theorem assigns probabilities tothe different universes in the multiverse that are not there in Everett's MWI in the first place. Richard?I don't see that, nor why you say so. can you elaborate? Gleason theorem just makes unique the usual Born rule, and justify a literal reading of thequantum amplitude as relative (infinite) proportions. It is quite similar to the Deutsch Hayden justification, in decisiontheoretical terms, of such amplitude reading, in the Heisenberg picture.BrunoOn 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 ofprobabilities) is intrinsic to Everett's MWI, does that not amount tonegating it?Why? I think that it is beautifully solved by Gleason theorem, for theHilbert 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 sharablehuman or animal substitution level very plausibly at the Heisenberguncertainty level, this for surviving even a long run, without detectingany difference.In that case, the Gleason solution will be the solution for comp. Forthisthe X and Z logics (alreeady extracted) must conforms to some desiderata, already expressed by von Neumann, for a quantum logic, and which is thatmainly it defines the searched measure.I m not sure I can understand string theory or any fundamental QM withoutEverett. I agree that the idea that we are multiplied by infinities at each instantis not attractive, but science is not wishful thinking, and besides, Idon'ttake any theory too much seriously (we don't know). I also know thatdifferent 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 whythereis something instead of nothing, as it assumes only 0 and the successorandthe very simple laws, and explain from that how that very explanationemerges in some collection of stable numbers' dream. BrunoRichard 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?RichardOn the contrary. Gleason theorem solves the "measure problem" intrinsicinthe Everett MWI, it makes the probabilities into comp (or weakening)first person indeterminacies.Unfortunately, comp necessitates a version of Gleason theorem for allcompstates, not just the quantum one, as the quantum law must be derivedfrom 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. BrunoOn 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 meekerdbThere are a number of theories to explain the collapse of the quantumwave 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 devicesinto NOT obeying QM.No, it's only inconsistent with a reified interpretation of the wf.It's perfectly consistent with an instrumentalist interpretation. Decoherence isa prediction of QM in any interpretation. It's the einselectionthat's a problem.But instrumentalism is just an abandon of searching knowledge. Thereis 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 isimplied.And, imo, the QM corresponding measure problem is solved by Gleasontheorem (basically).And then, keeping that same 'everything' spirit, the whole QM isexplainedby comp. We have just to find the equivalent of "Gleason theorem" forthe "material hypostases". Bruno3) There is also the many-worlds interpretation, in which collapseof 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 (whichcan only please you, I guess). Bruno http://iridia.ulb.ac.be/~marchal/ --You received this message because you are subscribed to the GoogleGroups "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. 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