From: Reason (reason@exratio.com)
Date: Sat Nov 23 2002 - 23:32:26 MST
Much as I hate to muddy the waters further:
http://www.npl.washington.edu/npl/int_rep/tiqm/TI_toc.html
MWI is by no means a done deal, even if it is a major consensus
interpretation at this time. There are ways of looking at QM that do not
require MWI in order to make sense. As they say, it all comes down to what
you decide to make of the wave function collapse. In the above paper, MWI is
called the "most heroic" of current options.
The Transactional Interpretation is dismissed by those I know who are in the
know on the grounds of separate arguments against the existance of a balance
of advanced/retarded radiation in the universe. Still, it is a very elegant
explanation for the wavefunction "collapse" that completely sidesteps the
requirement for a measurement / measurer, much as MWI does.
Even if you don't like the TI, the paper has a very nice comparative
discussion of various other theories and models in it, which may be of use
to those who don't do this for a living.
Reason
http://www.exratio.com/
> -----Original Message-----
> From: owner-extropians@extropy.org
> [mailto:owner-extropians@extropy.org]On Behalf Of gts
> Sent: Saturday, November 23, 2002 9:18 PM
> To: extropians@extropy.org
> Subject: RE: the Duplication Chamber
>
>
> Lee Corbin wrote:
>
> >> Correct, and in MWI *the observer splits* when
> >> that measurement is registered in the observer.
> >> It happens at the moment of actually observing a
> >> measurement(i.e., the firing of neurons as you like
>
> >> to say.)
> >
> > Dead wrong.
>
> No, I'm dead right, I'll prove it by posting as many
> third party references as necessary, starting with the
> one below taken from the MWI faq posted at
>
> http://www.hedweb.com/everett/everett.htm
>
> I have capitalized and offset some sentences to
> high-light them.
>
> ****
> Q8 When does Schrodinger's cat split?
> Consider Schrodinger's cat. A cat is placed in a
> sealed box with a device that releases a lethal does
> of cyanide if a certain radioactive decay is detected.
> For simplicity we'll imagine that the box, whilst
> closed, completely isolates the cat from its
> environment. After a while an investigator opens the
> box to see if the cat is alive or dead. According to
> the Copenhagen Interpretation the cat was neither
> alive nor dead until the box was opened, whereupon the
> wavefunction of the cat collapsed into one of the two
> alternatives (alive or dead cat). The paradox,
> according to Schrodinger, is that the cat presumably
> knew if it was alive *before* the box was opened.
> According to many-worlds the device was split into two
> states (cyanide released or not) by the radioactive
> decay, which is a thermodynamically irreversible
> process (See "When do worlds split?" and "Why do
> worlds split?"). As the cyanide/no-cyanide interacts
> with the cat the cat is split into two states (dead or
> alive). From the surviving cat's point of view it
> occupies a different world from its deceased copy.
>
> THE ONLOOKER IS SPLIT INTO TWO COPIES ONLY WHEN THE
> BOX IS OPENED AND THEY ARE [THE ORIGINAL IS] ALTERED
> BY THE STATES OF THE CAT.
>
> The cat splits when the device is triggered,
> irreversibly.
>
> THE INVESTIGATOR SPLITS WHEN THEY OPEN THE BOX.
>
> The alive cat has no idea that investigator has split,
> any more than it is aware that there is a dead cat in
> the neighbouring split-off world. The investigator can
> deduce, after the event, by examining the cyanide
> mechanism, or the cat's memory, that the cat split
> prior to opening the box.
> ****
>
> As above, the observer does not split until him (they)
> are *altered by the states of the cat*. This means
> each of the newly created alternates are created in a
> *different state* according to the different empirical
> data they are observing.
>
> There is no time at which all the dupes in a MWI 1000
> way chamber exist in exactly the same state, because,
> as above, their variance in states is *coincidental*
> to their proliferation into 1000 alternates. Each of
> the 1000 comes into existence in a different state,
> depending on which of the 1000 outcomes he is
> experiencing.
>
> I'm not going to muddy up this message by quoting and
> replying to every paragraph of yours. We need to get
> this fact straight before we go on. I think you're
> going to owe me an apology.
>
> -gts
>
>
>
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