Re: Many Worlds invalidated?

From: Hal Finney <>
Date: Mon, 26 Apr 2004 11:14:32 -0700

Jeff Bone forwards:
> Many Worlds theory invalidated
> Kathryn Cramer breaks the story on a to-be-presented Harvard talk on an
> experiment that appears to invalidate both the "Many Worlds" and
> "Copenhagen" theories of quantum mechanics. Kathryn is the daughter of
> John Cramer, a physicist whose "Transactional Interpretetation"
> hypothesis is the only one left intact by the experiment's findings.

This is nonsense. It's nothing but sophistry and playing with language.
Neither the Copenhagen nor the Many Worlds interpretations says what
she claims. The CI has always been vague about what constitutes a
measurement, and it looks to me like this experiment falls through the
cracks. The MWI merely says that experimentally unrealized quantum worlds
exist just like ours, it makes no absolute claims about distinguishable
worlds lacking interference. The MWI is just the quantum formalism minus
wave function collapse and is therefore perfectly compatible with this
experiment, since the experiment is itself compatible with the quantum

Hal Finney

> It has been widely accepted that the rival interpretations of quantum
> mechanics, e.g., the Copenhagen Interpretation, the Many-Worlds
> Interpretation, and my father John Cramer's Transactional
> Interpretation, cannot be distinguished or falsified by experiment,
> because the experimental predictions come from the formalism that all
> such interpretations describe. However, the Afshar Experiment
> demonstrates in an interaction-free way that there is a loophole in
> this logic: if the interpretation is inconsistent with the formalism,
> then it can be falsified. In particular, the Afshar Experiment
> falsifies the Copenhagen Interpretation, which requires the absence of
> interference in a particle-type measurement. It also falsifies the
> Many-Worlds Interpretation which tells us to expect no interference
> between "worlds" that are physically distinguishable, e.g., that
> correspond to the photon's passage through one pinhole or the other.
> Link (Thanks, Kathryn!)
Received on Mon Apr 26 2004 - 14:57:35 PDT

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