Russell Standish wrote: > On Fri, Oct 13, 2006 at 07:03:18AM -0000, [EMAIL PROTECTED] wrote: > > > > Also see my reply to Russell below: > > > > > > >Russell Standish > > > > > >The Multiverse is defined as the set of consistent histories described > > >by the Schroedinger equation. I make the identification that a quantum > > >state is an observer moment, and the set of consistent quantum > > >histories is the set of observer histories. As such all observer > > >moments are in the Multiverse. > > > > > >But I appreciate this is not a widely held interpretation... > > > > > > Indeed so. And there's a good reason why it isn't a widely held > > interpretation, as J.barbour explained in 'The End Of Time'. In order > > to define 'the Multiverse' in terms of QM one needs a *static* > > wave-function solution for the entire universe (one which doesn't > > change) , whereas conventional QM solutions to real world problems are > > *dynamic* wave-function solutions (wave functions which evolve with > > time). No one has yet succeeded in demonstrating a static > > wave-function solution for the entire universe. > > > > I haven't read Barbour's book, but if that is what he is saying, he > would be wrong. Consider a universe of a single electron living in a > potential well V(x)=|x|^2, x\in R^3. There is a well defined solution > \psi(t,x) = \sum_j <\psu_0|j><j| exp(-iE_j t) given the initial > condition \psi_0. > > The function \psi: R x R^3 -> C is a static (time independent) > mathematical object (I wrote it the mathematicians write to emphasize > this point). Why wouldn't you identify this with the Multiverse of > that electron? > > Now I am aware that several people (Hawking included I gather) have > proposed various "wave functions of the universe", which tend to be > solutions of the Wheeler de Witt equation, which is a time independent > equation. However, I'm not so interested in following that literature.
Barbour argues the same way you do. But he does concede that his argument is not yet proven. The trouble is that in the case of, for instance, the electron, in the example you give, there is still an environment external to the electron, but for the entire universe there could be nothing external to the wave function of the universe. And the wave function of the universe, if the block-universe picture is right, would have to be a static equation as well, as I mentioned above. Apparently, none of the proposals for time-independent equations of the entire universe have yet been made to work. > > > See what I said above. If the *same* QM state could be associated with > > *different* observer moments, then observer moments would not be > > reducible to QM states and the set of consistent quantum histories > > could not be said to be fully identified with the set of observer > > histories. > > > > If the same QM state is associated with different observer moments, > you must be talking about some non-functionalist approach to > consciousness. The QM state, by definition, contains all information > that can be extracted from observation. > > Cheers > > See above. As was pointed out, functionalism allows for one-to-many relationships between conscious experiences and the physical substrates on which these experiences are instantiated. What I really mean by 'observer moment' in the fullest sense of the phrase is 'conscious experience'. Conventional QM cannot yet explain how the actual consciously observed reality is supposed to emerge from the QM wave-function. As has been pointed out, the observed reality can only be derived from QM+Additional Assumptions. There are implicit theories of consciousness in any account of how the actual observed reality is supposed to emerge from the QM wave-function and convincing explanations for how or why these assumptions are supposed to work are not yet forth-coming. How does the *observed* (classical) reality emerge from the QM wave-function? Not explained! Coarse graining, decoherence, consistent histories etc etc don't yet convincingly explain it. Until these questions are fully resolved, doubt must remain about the static timeless 'block universe' picture put forward by hard-core multiverse fans. --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Everything List" group. To post to this group, send email to email@example.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/everything-list -~----------~----~----~----~------~----~------~--~---