Hello Simon,

SimonJAnthony@... wrote:

> In a message dated 15/07/03 20:17:11 GMT Daylight Time, m@...
> writes:
>
>
> > So if I can show that for each term in the superposed state, there
> is
> > one relative state, will I have answered the question?
> >
>
> I realise that I run the risk of being seen as obstinate in the
> extreme,
> particularly in a forum devoted to MWI, but there are still two
> principal issues
> which, due to my own slowness of brain, I haven't grasped:
>
> 1: Why is one basis rather than another preferred in MWI?

The basis by which to decompose the wavefunction is the one appropriate
to the interaction involved. Specifically, you're going to need to
break it down into a set of eigenfunctions for the operator
corresponding to the observable or interaction in question. You might
as well be asking why the position or momentum operators have the form
they do. I'm not saying that this isn't a valid question, but it does
apply equally to CI and MWI.

> 2: Decoherence diagonalizes the density matrix but the same
> resulting
> matrix can be produced by many distinct wave functions. How therefore
> does MWI
> select one of those states rather than another? In other words, why
> don't we
> see superpositions?

MWI does not select one state over any other. Rather, all states are
selected, with versions of the observer seeing each possible result.
The possible results and eigenstates are those appropriate to the
interaction/measurement operator. There's only one relative state per
eigenstate. We don't experience superpositions because the linearity of
the SWE ensures that relative states cannot interact, and evolve
separately after interacting with the superposed system. It would
therefore be impossible to create an entity whose consciousness is
informed by multiple relative states.

> What I mean by the first issue I think is clear to you. I can explain
> the
> second in more detail but it would probably be more clear if you read
> it in, eg,
> Ch 6 "Quantum Theory and Reality" of Penrose's book "Shadows of the
> Mind".
> If those questions can be answered satisfactorily (and there's the
> catch? - but
> I'll not be unreasonable) I'll willingly and gratefully accept that
> MWI is
> the "best" available interpretation of QM.

How am I doing?

Matt.

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When God plays dice with the Universe, He throws every number at once...

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