Re: [ Jacques Mallah]

From: russell standish <>
Date: Mon, 9 Feb 2009 13:47:54 +1100

On Sun, Feb 08, 2009 at 09:34:30PM -0500, Jesse Mazer wrote:
> > Date: Mon, 9 Feb 2009 13:02:31 +1100
> > From:
> > To:
> > Subject: Re: [ Jacques Mallah]
> >
> > All I have ever said was that effective probability given by the
> > squared norm of the projected eigenvector does not follow from Born's
> > rule. It can't follow, because Born's rule says nothing about what the
> > normalisation of the state vector after observation should be. It is a
> > conditional probability only.
> I still don't understand the connection you're making. When people say the effective probability is equal to the amplitude squared, it doesn't require you to assume anything about the state vector *after* observation (in particular you don't have to assume an objective collapse), it's just the square of the norm of the vector you get when you project the system's (normalized) state vector at the instant *before* observation onto an eigenvector.
> Jesse

Sure. What you've just said is just an interpretation-free description of the
mathematics. Whether it is a helpful description is another matter.

But Jacques Mallah is making a metaphysical claim when saying it is
equal to the squared amplitude of the branch. Which is a completely
different beast. He must have some model in mind which tells us how
the "amplitude" of the branches relates to the "amplitude" of the
original state.


A/Prof Russell Standish                  Phone 0425 253119 (mobile)
UNSW SYDNEY 2052         
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Received on Sun Feb 08 2009 - 21:48:22 PST

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