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From: Russell Standish <R.Standish.domain.name.hidden>

Date: Fri, 20 Aug 1999 10:21:55 +1000 (EST)

*>
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*>
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*>
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*> Russell Standish wrote:
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*> >
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*> > >
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*> > > 4. Subjective probabilities can be computed on the basis of the
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*> > > Strong SSA, and we get
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*> > > P(H, t1) = 1/2
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*> > > P(H, t2) = P(H, t3) = 2/3
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*> > > If this is the case, then I think we have to throw Tegmark's
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*> > > scheme using Bayesian statistics out the window. This option
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*> > > has severe metaphysical problems, though, in my opinion. I
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*> > > think Hal was saying, in his post, either this option, or
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*> > > option 1 above, but I'm not sure.
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*> > >
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*> > > 5. Subjective probabilities can be computed, and we should expect
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*> > > the common-sense results
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*> > > P(H, t1) = 1/2
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*> > > P(H, t2) = P(H, t3) = 1/2
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*> > >
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*> > > It's a fair coin, after all, right?
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*> > > I think this gets Gilles' and Bruno's vote (and Russell's?)
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*> > >
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*> > > 6. Subjective probabilities can be computed, and we should expect
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*> > > the nonsensical results
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*> > > P(H, t1) = 2/3
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*> > > P(H, t2) = P(H, t3) = 2/3
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*> > >
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*> >
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*> > If the probabilities can be computed, then compute them. I have
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*> > computed the probabilities as being 1/2,1/2. If you compute them as
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*> > 1/3,2/3, then you need to advance a similar computation, and then for
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*> > good measure, show me where I erred. Probability calculations are
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*> > notorious for their subtleties, so I won't take offence at being shown
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*> > wrong. At present, the only argument I can see that gives the
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*> > probabilities as 1/3,2/3 is the one based on the strong SSA - (your
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*> > point 4) - an assumption that I reject.
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*>
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*> Clearly there is not enough information to simply "compute" the
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*> probabilities from Jane's subjective perspective, without making
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*> some additional assumptions. In your computation, you assume that
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*> the measure of each branch is unaffected by its future evolution.
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True - but I think this is currently a pretty fair assumption.

*>
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*>
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*> > A reverse causality type of argument would assume that you would never
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*> > enter branches that have no escape routes. I have toyed with this
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*> > idea, but reject it - principally because I have yet to see an example
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*> > of a branch with no escape route, so in essence it becomes
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*> > meaningless
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*>
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*> This makes no sense to me. Let's rewind it -- You have yet to see a
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*> branch with no escape route. Fine, I haven't either. Let's assume there
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*> are none. The reverse causality argument would assume that you never
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*> enter branches that have no escape routes. Fine, we've just assumed that
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*> there are none. So what's the problem?
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*>
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*>
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*> >, but if there were such brances - my belief in foward
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*> > causality is so strong, I would prefer to question quantum
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*> > immortality, than to invoke reverse causality as a way of salvaging
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*> > QI.
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*>
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*> Yes, I guess I've been trying to make the point that QTI implies reverse
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*> causality. I think it does.
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*>
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Yes - but only if cul-de-sac branches exist. My point is that QTI is

not proven, and shouln't be assumed to be true. Existence of

cul-de-sac branches + absence of reverse causality would imply QTI is

false.

*>
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*>
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*> --
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*> Chris Maloney
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*> http://www.chrismaloney.com
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*>
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*> "Donuts are so sweet and tasty."
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*> -- Homer Simpson
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*>
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*>
*

----------------------------------------------------------------------------

Dr. Russell Standish Director

High Performance Computing Support Unit,

University of NSW Phone 9385 6967

Sydney 2052 Fax 9385 6965

Australia R.Standish.domain.name.hidden

Room 2075, Red Centre http://parallel.hpc.unsw.edu.au/rks

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Received on Thu Aug 19 1999 - 17:33:25 PDT

Date: Fri, 20 Aug 1999 10:21:55 +1000 (EST)

True - but I think this is currently a pretty fair assumption.

Yes - but only if cul-de-sac branches exist. My point is that QTI is

not proven, and shouln't be assumed to be true. Existence of

cul-de-sac branches + absence of reverse causality would imply QTI is

false.

----------------------------------------------------------------------------

Dr. Russell Standish Director

High Performance Computing Support Unit,

University of NSW Phone 9385 6967

Sydney 2052 Fax 9385 6965

Australia R.Standish.domain.name.hidden

Room 2075, Red Centre http://parallel.hpc.unsw.edu.au/rks

----------------------------------------------------------------------------

Received on Thu Aug 19 1999 - 17:33:25 PDT

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