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

RichardOn 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"intrinsic inthe Everett MWI, it makes the probabilities into comp (orweakening) firstperson indeterminacies.Unfortunately, comp necessitates a version of Gleason theorem forall compstates, not just the quantum one, as the quantum law must bederived fromthe 1p indeterminacies, occurring in arithmetic.The advantage is that comp provides the theory of both quanta andqualia(and a whole theology actually).Unfortunately, it is not yet clear if those quanta behave in asufficientlyquantum 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 thequantumwave 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 somedevices intoNOT obeying QM.No, it's only inconsistent with a reified interpretation of thewf. It'sperfectly consistent with an instrumentalist interpretation.Decoherenceisa prediction of QM in any interpretation. It's the einselectionthat's aproblem.But instrumentalism is just an abandon of searching knowledge.There isno more what, only how.An instrumentalist will just not try to answer the question ofbetting ifthere 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 explainedby 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 canonly please you, I guess). Bruno http://iridia.ulb.ac.be/~marchal/ --You received this message because you are subscribed to theGoogle 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 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. 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 GoogleGroups"Everything List" group.To post to this group, send email to everything-l...@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 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.For more options, visit this group at http://groups.google.com/group/everything-list?hl=en.

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