Re: QM locality

From: Bruno Marchal <>
Date: Thu, 15 Jul 2004 14:48:50 +0200

Dear Jan,

Both the EPR and the Bell paper make the implicit
assumption that experiment gives univocal outputs, unlike
in the MWI.
The violation of Bell inequality, which we observe "locally"
can be explained without non-locality, and without inseparability
once we take the wave function as describing purely
relative (sub)state. The first one to explain this (concisely)
is Everett himself. It is also explained at different places in the
Everett FAQ by Michael Clive Price:

Frank Tipler wrote a very readable paper on that question:

Deutsch and Hayden wrote a more advanced paper:

That point has been under scrutiny on the for-list

It is not exaggerate to say that determinism and locality
(from an observer third person view) are the main motivation
for abandoning the collapse. Note that Many-Worlders
does not pretend Bell's inequality are not violated, only
that such a violation can be explained locally once we abandon
the wave collapse.



At 13:32 15/07/04 +0200, Jan Harms wrote:
>Dear Bruno, Dear All
>A few days ago, I was reading one of your (Bruno's) papers (I think it was
>"Computation, Consciousness and the Quantum"). You wrote that not only the
>apparent QM randomness is removed by the MWI (this point I understand) but
>also that QM becomes local if one accepts the MWI. Since then I was
>thinking about it and I could not resolve all doubt. Locality is
>quantified by the Bell inequalities. And these inequalities should still
>be applicable in the MWI since randomness per se will still exist in the
>many worlds (at least some sort of classical randomness of macroscopic
>systems). Since you say that by taking the bird perspective on the many
>worlds, we do not find any nonlocalities, my problem now is, that I do not
>see how to implement the fact that many worlds exist in order to prove
>that the Bell inequalities are always fulfilled (i.e. that QM is local).
>In other words, what is the MW bird perspective Bell inequality? Can
>someone help me? Are there papers which discuss MWI and locality?
Received on Thu Jul 15 2004 - 08:51:12 PDT

This archive was generated by hypermail 2.3.0 : Fri Feb 16 2018 - 13:20:09 PST