Re: tautology

From: Jacques M. Mallah <>
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
> > > > 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

                         - - - - - - -
              Jacques Mallah (
       Graduate Student / Many Worlder / Devil's Advocate
"I know what no one else knows" - 'Runaway Train', Soul Asylum
            My URL:
Received on Fri Oct 15 1999 - 20:02:58 PDT

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