Re: HARDY and Mathematical versus Physical Reality

From: Joao Leao <jleao.domain.name.hidden>
Date: Wed, 29 Oct 2003 12:31:28 -0500

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  :::  jleao.domain.name.hidden
Harvard-Smithsonian Center for Astrophysics
1815 Massachussetts Av. , Cambridge MA 02140
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Received on Wed Oct 29 2003 - 12:34:47 PST

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