>
> On Thu, 13 May 1999, Russell Standish wrote:
> > everything-list.domain.name.hidden
>
> What's that?
A typo :)
> >
> > 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.
>
> On the contrary, this is a textbook example of the way I said it
> works. The theory predicts some measure distribution of observers; an
> individual observer sees an observation drawn from that distribution.
> There are no different sets of predictions for different pictures, just
> the measure distribution and the sample from it.
It sounds to me like you don't think the prediction changes according
to what the observer chooses to observe? An electron cannot have its
spin aligned with the x axis and the y axis at the same time. Once the
experimenter has chosen which direction to measure the spin, the
history of that particular is observer is constrained by that fact,
and the predictions of QM altered accordingly. This is true both in
MWI and the Copenhagen interpretation, and is the "spooky" nature of QM.
I used to think that QM gave predictions in terms of distributions,
and that because one didn't see isolated particles, rather ensembles
of such particles, I didn't see a problem. The properties of an
ensemble are well defined.
However, the ability of experimenters to isolate a single particle,
such as a photon, or an atom, means we have to take this "spookiness"
seriously.
>
> > > 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.
>
> Nature must have a mathematical criterion for it, if it is going
> to figure in a theory of physics.
>
Quite agreed. However, I don't believe this to be much of a
problem. Most mathematical treatments of such take it to be some kind
of projection operator.
> > > - 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.
>
> The above paragraph is rather meaningless since you haven't
> defined 'yourself'. If 'you' are some extended implementation of a
> computation, you are not immortal: the number of implementations will
> decrease over time. I take one time step as the most logical unit but
> that is irrelevant to the conclusion.
>
This para still indicates that you are falling for this rather absurd
sampling assumption mentioned above. Give me one good reason why you
would expect conciousness to sample randomly from the set of all such
"concious points", rather than in an ordered (and potentially
unbounded) sequence of self-consistent points (ie a history).
> From: Higgo James <james.higgo.domain.name.hidden>
> Subject: RE: SSA
>
> >Jacques wrote:
> >> 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.
>
> > Good grief, Jacques - for the umpteenth time: of course it does not
> >predict immortality any more than classical physics does. But you will
> >end up as one of those exceedingly unlikely, one in 10E500000...Jacques's that
> >happen to survive for an aeon. Even then you will have no better proof of
> >MWI than you do now.
>
> Let me get this straight. It doesn't predict immortality, but it
> does; I will find myself to be old due to the MWI, but since it's not
> really a prediction of the MWI I won't have evidence for the MWI based on
> that. Your doublethink continues to amaze me.
>
> > Immortality is no more 'observationally false' than the statement
> >'you will become a petunia in six minutes'. After six minutes, you may
> >challenge that statement (in those universes in which you are not a petunia
> >and have not lost your power of communication in another way). And after
> >infinity you may challenge my statement that you are immortal.
>
> Ever hear of statistics? All use of empirical evidence is based
> on it.
>
> > If anything, the fact that you are alive lends support to the
> >hypothesis that you will not die. You have never been observed to die in
> >the past.
>
> That's the kind of Basic Stupidity (BS) that undeservedly gave
> induction a bad name. I've had enough of your BS.
>
I think the above few arguments are floccinauccinihilpilication. Yes,
living to ages much larger than human average would be empirical
support of QTI, at least for the person so involved. However, you
would probably have a hard time convincing all the other individuals
(who would probably be aged 0-100 years, assuming no great advances in
Medicine).
Of course someone may come up with mathematical theorem limiting human
lifetime - this is about the strength of what is required to disprove QTI.
The "observationally false" statement that Jacques makes is based on his
ergodic SSA on concsious sampling. As I stated earlier, I find this
difficult to believe, and Jacques obviously finds it so obvious that
he doesn't feel the need to defend it.
Cheers
----------------------------------------------------------------------------
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 Sun May 16 1999 - 18:35:23 PDT