On Wed, Nov 15, 2017 at 02:46:21PM +1100, Bruce Kellett wrote: > On 15/11/2017 12:49 pm, Russell Standish wrote: > > On Wed, Nov 15, 2017 at 11:05:22AM +1100, Bruce Kellett wrote: > > > One of the strongest arguments for MWI was that it eliminates the concept > > > of > > > a conscious observer from the interpretation of quantum mechanics. > > I disagree. The strongest argument is that it removes the need for a > > mysterious nonunitary physical collapse process (that may or may not > > be driven by a conscious observer). > > I said "one of the strongest"! I know that you want to define QM from the > idea of observer moments. I don't think that this will work, and the usual > consensus is that one of the strengths of MWI is the elimination of the > conscious observer.
Where's your evidence that this is the usual concensus? Who argues for it? > > > A conscious observer (or rather just observer, really) is still > > required to define the branches of the MWI, be that mediated by Zeh's > > decoherence process, or otherwise. To eliminate observers entirely > > requires solving the preferred basis problem without reference to an > > observer or observation. > > That is not true. The basis problem is solved by Zurek's einselection -- the > preferred basis is the one that is stable against further > decoherence. I understand that the idea of einselection is still rather controversial, but be that as it may, I can't see how it solves the preferred basis problem. Consider an experiment where the experimenter may choose between inserting a circularly polarised file, or a linearly polarised one. The preferred basis (selected by einselection) will depend on that choice. In MWI, we normally assume that there are two branches of the universe with different choices made by the experimenter. Unless there is some sort of superdeterminism in play, where the experimenter does not have the freedom to choose. But superdeterminism is certainly not a popular idea. > Observers have nothing to do with it. In Zurek's account, it is the fact > that the results of interactions, be they measurements or not, are recorded > multiple times in the environment via decoherence, that is the mark of an > irreversible quantum event. If you put a system in contact with a completely symmetric heat bath, there will be no preferred basis selected by einselection. The only way for a basis to emerge is if there are system constraints of some sort. I would argue that the only way these constraints could arise in a Multiverse (which is symmetric by construction) is by considering the environment from the point of view of some observer, ie the basic symmetry breaking mechanism. -- ---------------------------------------------------------------------------- Dr Russell Standish Phone 0425 253119 (mobile) Principal, High Performance Coders Visiting Senior Research Fellow [email protected] Economics, Kingston University http://www.hpcoders.com.au ---------------------------------------------------------------------------- -- 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 [email protected]. To post to this group, send email to [email protected]. Visit this group at https://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout.
