# Re: SSA (fwd)

From: Russell Standish <R.Standish.domain.name.hidden>
Date: Thu, 13 May 1999 10:09:15 +1000 (EST)

> On Wed, 12 May 1999, Russell Standish wrote:
> > Yes, I know you have explained your position many times, and each time
> > I've read such a post from you, I have thought that your argument is
> > flawed. Essentially, I suspect that you do not see the difference
> > between Bruno Marchal's first person picture, and his third person
> > picture.
>
> If the two 'pictures' give conflicting predictions, one of them is
> wrong.
> In special relativity, for example, is well that many things
> depend on what coordinate system you use; but predictions of what a given
> observer will observe are invariant. If it was not so, the theory would

And that is true in this case too. Each observer will see a different
distribution of lifetimes for their own lifetime (the first person
picture), than they will for everyone else's (the third person
picture). There is no conflict here.

> make no sense.
>
> > > From: Marchal <marchal.domain.name.hidden>
> > > To: "Gilles, Jacques, Nick..." <everything-list.domain.name.hidden>
> > > >There is no sense in counting worlds in which I do not survive.
> > > >Typicality or likelihood are relative to the observer.
> > >
> > > What about worlds on which others survive? How do you even
> > > distinguish between "you" and others to make such a distinction? And of
> > > course time should not be a consideration: Measure is NOT conserved over
> > > time! There is NOT an equal chance of finding yourself at one age as at
> > > an older age! If there was it would disprove the MWI!
> >
> > Again this depends on what picture you use (ie what filter you use to
> > loom at the universe) From the third person picture, you are quite
> > correct. From the first person picture, measure is conserved (at 1), except
> > in a catastrophic case where at some point in time, the measure
> > vanishes
>
> So according to your statement, the predictions of a theory depend
> on which 'picture' you use. That is nonsense.

It is hardly nonsense. The predictions can easily depend of the
'picture' but must be consistent with each other. Let me give a simple
example:

In one picture, observer A decides to measure the spin of an electron
in the x direction. In the other, observer B decides to measure the
spin of the electron in the y direction. Observer A will see the spin
of the electron aligned with x axis, and Observer B will see it
aligned with the y axis. Both observations are correct in the first
person picture of that observer. A "person" with the third person
perspective, sees observers A and B as inhabiting separate `worlds' of
a multiverse, each with appropriate measure that can be computed from
Quantum Mechanics.

> A theory predicts some measure distribution on the space of
> conscious observations. From the point of view of an observer, you see
> one observation drawn from that measure distribution.
> If measure were conserved for a particular individual as a
> function of time, you immediately have 2 problems:
> - How to define a particular individual? You need to, or else the
> measure of other people would count too, and would stay relatively
> constant as opposed to the rapidly diminishing measure of "you".

This is a furphy. I have no problem whatsoever in knowing that I am
who I am. If you are unsure of your identity, then that's your problem.

> - The expected value of your age would be infinite, contrary to
> observations which indicate no unusual age on your part.

Again this is based on an assumption that at each time period,
conciousness must select randomly from the set of available conscious
moments for that observer. (ie SSA of all concious moments, as opposed
to SSA of birthdates). As I mentioned earlier, I reject this
assumption as absurd, and prefer the view that conciousness must sweep
out the concious moments in the time order they are arranged, ie I
must pass through being 30 years old before I can experience being 100
or 1000 years old. Therefore being young with respect to average
lifetimes is not contradictory with expecting an infinite lifetime. I
would be very surprised if conciousness jumped from 30 yo, to 100yo
back to 10yo etc in some unordered random fashion, but of course have
no way of exactly disproving it.

>
> From: Higgo James <james.higgo.domain.name.hidden>
> >Jacques wrote:
> >>Newsflash: If a theory predicts something, and it's found to be
> >>true, that's evidence for the theory. If it's found to be false, or that
> >>what is observed is atypical of what the theory predicts, that's evidence
> >>against the theory.
> >
> >Newsflash (2): if 2 theories predict the same thing, and it is found to be
> >true, that is evidence for neither theory.
>
> Are you saying that the MWI does not predict immortality, or that
> a single world theory does predict it? The former would make sense since
> immortality is observationally false, but I didn't think you'd come around
> so easily.
>
> - - - - - - -
> Jacques Mallah (jqm1584.domain.name.hidden)
> Graduate Student / Many Worlder / Devil's Advocate
> "I know what no one else knows" - 'Runaway Train', Soul Asylum
> My URL: http://pages.nyu.edu/~jqm1584/
>
>

----------------------------------------------------------------------------
Dr. Russell Standish Director
High Performance Computing Support Unit,
University of NSW Phone 9385 6967
Sydney 2052 Fax 9385 7123
Australia R.Standish.domain.name.hidden
Room 2075, Red Centre http://parallel.hpc.unsw.edu.au/rks
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Received on Wed May 12 1999 - 18:02:28 PDT

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