RE: experiments and MWI

From: Higgo James <james.higgo.domain.name.hidden>
Date: Tue, 8 Dec 1998 12:55:29 -0000

Hi, Rainer.

I am pleased to be in a universe in which your plane did not crash.

On your first point, thanks - agreed. Also, Vic seems to imply that there
are two types of system - quantum and non-quantum. A 'quantum effect' can
make a difference to a hot, wet classical system. I have cc'd this to Vic
Stenger's list.

On point 2, I have to concede that you are right, and we must hope that an
experiment such as the one you proposed could be undertaken to prove the
valifity of MWI. That doesn't mean that the exploration of the consequences
of MWI is not a useful pursuit here and now.

On point 3, my quantum theory of immortality would make vacuum decays, no
matter how common, imperceptible to us as we continue in those universes in
which there has been no decay. This is an interesting avenue to pursue.

James

> -----Original Message-----
> From: Rainer Plaga [SMTP:plaga.domain.name.hidden]
> Sent: 08 December 1998 12:29
> To: james.higgo.domain.name.hidden
> Subject: experiments and MWI
>
> Hello James,
>
> 1.
> Vic's criticism seems justified in the
> sense that you didn't prove immortality,
> only extreme longevity seems very plausible.
> On the other hand I do not understand his
> point about mixtures. There are no
> ``true mixtures'' in the MWI, only one
> pure state of which we perceive a very small
> part. So he seems to be outside
> strict MWI with his argument.
>
> 2.
> I thought about your point that
> you don't need experimental evidence
> in favor of MWI, that it's (undisputed) elegance
> is sufficient.
>
> In the end I find this point of view
> (which seems close to the one of Max)
> sterile, it can hamper progress.
>
> Imagine people would have been content
> in 1890 with the ``elegance'' of Boltzmann's
> indirect thermodynamical evidence in favour
> of atoms.
> The wish to find direct evidence
> in favor of single atoms was an important
> driving force in the early days of quantum physics.
>
> In other words: I'm convinced that direct
> evidence for MWI will lead to a qualitatively new
> understanding of the quantum world.
> I doubt that purely theoretical or philosophical
> work on the MWI will ever lead to this, the
> problems are too complicated.
>
> 3.
> Counterexample to a theorem ``direct experimental evidence
> against alternatives to the MWI'' can't be found
> (like one Max seems to have in mind: ``Copenhagen
> always leads to the same phenomenology'').
>
> There exist parameter regions in the Standard Model
> of particle physics
> where the vacuum is metastable. Single
> quantum events, which raise the energy density
> (e.g. particle collisions) then lead
> to the decay of our vacuum to a more
> stable form: this would kill humanity.
>
> Normally this is taken as evidence that
> the SM does not have such parameters.
> In the MWI this argument does not hold
> of course. Each vacuum decay
> has only a certain probability, so there
> are always surviving humanities.
> (This is very close to my ``atom bomb''
> alteration of Max's suicide test of MWI).
> In other words: if future research on the SM
> would prove that the parameters are such
> that the vacuum is metastable, this would
> be direct (and non byzantine or
> macabre) evidence for the MWI.
>
> Of course it might well be that such paramters are not found,
> however any general theorem about the untestability of MWI
> is doubtful.
>
> All the best Rainer
Received on Tue Dec 08 1998 - 05:00:59 PST