Thanks for these quotes. Bell's comparison still rings true. I think. He was indeed enthusiastic about the GRW foray but that one also has problems of its own.
-Joao scerir wrote: > "The Everett (?) theory of this section will simply be the pilot-wave > theory without trajectories. Thus instantaneous classical configurations > x are supposed to exist, and to be distributed in the comparison class of > possible worlds with probability |psi|^2. But no pairing of configurations > at different times, as would be effected by the existence of trajectories, > is supposed. And it is pointed out that no such continuity between present > and past configurations is required by experience." > [...] > "Now it seems to me that this multiplication of universes is extravagant, > and serves no real purpose in the theory, and can simply be dropped > without repercussions. So I see no reason to insist on this particular > difference between the Everett theory and the pilot-wave theory - where, > although the *wave* is never reduced, only *one* set of values of the > variables x is realized at any instant. Except that the wave is in > configuration space, rather than ordinary three-space, the situation > is the same as in Maxwell-Lorentz electron theory. Nobody ever felt > any discomfort because the field was supposed to exist and propagate > even at points where there was no particle. To have multiplied universes, > to realize all possible configurations of particles, would have seemed > grotesque." > > -J.S.Bell, "Quantum Mechanics For Cosmologists", in "Quantum Gravity 2", > eds. C.Isham, R.Penrose, D.Sciama, Oxford U.P., 1981, pp. 652-653. > > Here Bell seems to prefer the pilot-wave. According to D.Zeh later he > discarded the pilot-wave (just because it was too similar to the > Everettian approach) and took the GRW model, the 'spontaneous collapse', > which was 'relativistic'. -- Joao Pedro Leao ::: [EMAIL PROTECTED] Harvard-Smithsonian Center for Astrophysics 1815 Massachussetts Av. , Cambridge MA 02140 Work Phone: (617)-496-7990 extension 124 VoIP Phone: (617)=384-6679 Cell-Phone: (617)-817-1800 ---------------------------------------------- "All generalizations are abusive (specially this one!)" -------------------------------------------------------
