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From: Jacques M. Mallah <jqm1584.domain.name.hidden>

Date: Fri, 15 Oct 1999 22:24:22 -0400 (EDT)

On Thu, 7 Oct 1999, Russell Standish wrote:

*> Why such interest in the cloning example? I'm sure we could come up
*

*> with a consistent framework for dealing with this example, however, at
*

*> present I don't see the point, so I deliberately exclude it from
*

*> discussion.
*

It is the reverse process of what not-100%-certain death is in QM.

*> > The truth is you won't find a definition of "stochastic" in a math
*

*> > book, except for an informal discussion in the first chapter. It is a
*

*> > primitive concept, and the human brain has an idea about it, but the math
*

*> > is forced to deal with probabilities using deterministic measure theory.
*

*> > However there should be no confusion since the distinction I made
*

*> > above is very clear. Did our observer #463 see observation #463 by
*

*> > chance? NO. In a way he *is* observation #463.
*

*>
*

*> Fine - mathematics has a habit of squeezing out conceptual markers in
*

*> the process of promoting rigour. Great for proving theorems, but lousy
*

*> for promoting understanding. Either we simply chose not to use the
*

*> words random and stochastic, and confine ourselves to dicsussion of
*

*> mathmatical theorems, or we define the terms to mean the above. I
*

*> don't see that there is anything wooly about this.
*

"Random" has a meaning, all right. But that meaning cannot be

conveyed mathematically. On the other hand I do not believe that any

randomness exists. One thing is clear though: if x=0 or x=1, and it is

chosen randomly, that is NOT the same thing as if x_0=0 and x_1=1. My

example involved a case much like the latter.

*> > > > Nor does he have any direct evidence to prove that the other
*

*> > > > observers exist. But what he can do is guess that they exist based on
*

*> > > > Occam's razor, thinking "the world would be simpler if I were one out of
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*> > > > 1000 observers".
*

*> > > > Suppose that each observer sees 10 coins. Our observer #463
*

*> > > > notices that 9 out of the 10 are tails up, 1 is heads up. He guesses that
*

*> > > > most observers see mostly tails up coins. In other words, he guesses that
*

*> > > > the effective probability for each coin to be tails up is large.
*

*> > > > To find out if this guess is correct we would "take a survey" of
*

*> > > > all the observers. Still nothing random from any point of view.
*

*>
*

*> Au contraire - the process you just described in the previous
*

*> paragraph goes by many names, such as the thermodynamic limit, the law
*

*> of large numbers etc. etc.
*

Huh? Maybe 1000 is too big a number for you to grasp. Try three.

If there are 3 guys and #1 sees up, #2 sees down, and #3 sees down, then

the effective probability of seeing up is 1/3. Nothing random, and no

large numbers to confuse you.

*> > That is complete nonsense. Of course no observer ever saw
*

*> > 'histories' with the definition of observer I have used above. You see
*

*> > one observation.
*

*>
*

*> Why not? Isn't the observation of memory traces - whether they be
*

*> within our own brain, or preserved in history books, fossil records,
*

*> computer databases and the like - an observation of a history?
*

HELL no. Maybe you never saw "Total Recall"? Or as some might

prefer, the connections in your brain _could_ be completely the result of

a very lucky series of cosmic rays. You have no way of knowing, and

that's the point, because you can not observe the history to find out.

*> > The ASSA, together with our theories of physics, very obviously
*

*> > implies that the effective probability of observing a large age is quite
*

*> > low. This is effectively a prediction, and most observers will find it to
*

*> > be correct. Using simple Bayesian reasoning, effective predictions are
*

*> > just as good as any other predictions. In particular, you can plug the
*

*> > effective conditional probabilities into the Baysian formula to update
*

*> > priors about proposed models of reality. In this case to endorse ASSA and
*

*> > reject RSSA.
*

*>
*

*> Why, when Bayesian reasoning works fine in both pictures, and neither
*

*> view is incompatible.
*

*> I disagree that ASSA predicts observers are unlikely to observe large
*

*> ages for themselves - it merely predicts that it is unlikely to come
*

*> across another observer with a large age.
*

Your above comments make no sense to me. Perhaps you should

attempt to clarify them. I will say that you seem to have missed the

point of the Bayesian analysis. It is useful because the ASSA predicts

that one is unlikely to observe a large age for oneself. The fact that

the ASSA does so is supremely obvious from the fact that at large ages the

measure is smaller.

Re: Fabric of Reality

*>Incidently, it appears that it is
*

*>possible to derive Occam's Razor, or something like it from the AUH
*

*>(as you call it - others call it the principle of plenitude). I am
*

*>currently writing this up as a paper, and will post this to LANL
*

*>eprints when ready, but it largely draws upon arguments discussed in
*

*>this email list.
*

Sounds like circular reasoning, as stated above, because the AUH

is itself justified only because of Occam's razor. A more interesting

question is whether the experimentally observed apparent simplicity of

physical laws (which leads to sucessful use of Occam's razor) is predicted

by the AUH; maybe that's what you meant. In any case I hope that in your

paper you will give full credit where it is due to those who made the

arguments.

- - - - - - -

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/

Received on Fri Oct 15 1999 - 20:02:58 PDT

Date: Fri, 15 Oct 1999 22:24:22 -0400 (EDT)

On Thu, 7 Oct 1999, Russell Standish wrote:

It is the reverse process of what not-100%-certain death is in QM.

"Random" has a meaning, all right. But that meaning cannot be

conveyed mathematically. On the other hand I do not believe that any

randomness exists. One thing is clear though: if x=0 or x=1, and it is

chosen randomly, that is NOT the same thing as if x_0=0 and x_1=1. My

example involved a case much like the latter.

Huh? Maybe 1000 is too big a number for you to grasp. Try three.

If there are 3 guys and #1 sees up, #2 sees down, and #3 sees down, then

the effective probability of seeing up is 1/3. Nothing random, and no

large numbers to confuse you.

HELL no. Maybe you never saw "Total Recall"? Or as some might

prefer, the connections in your brain _could_ be completely the result of

a very lucky series of cosmic rays. You have no way of knowing, and

that's the point, because you can not observe the history to find out.

Your above comments make no sense to me. Perhaps you should

attempt to clarify them. I will say that you seem to have missed the

point of the Bayesian analysis. It is useful because the ASSA predicts

that one is unlikely to observe a large age for oneself. The fact that

the ASSA does so is supremely obvious from the fact that at large ages the

measure is smaller.

Re: Fabric of Reality

Sounds like circular reasoning, as stated above, because the AUH

is itself justified only because of Occam's razor. A more interesting

question is whether the experimentally observed apparent simplicity of

physical laws (which leads to sucessful use of Occam's razor) is predicted

by the AUH; maybe that's what you meant. In any case I hope that in your

paper you will give full credit where it is due to those who made the

arguments.

- - - - - - -

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/

Received on Fri Oct 15 1999 - 20:02:58 PDT

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