Re: The physical world is real

From: Youness Ayaita <youness.a.domain.name.hidden>
Date: Mon, 24 Sep 2007 09:52:12 -0700

Thank you for your opinions and conceptual clarifications. I'll answer
separately.

Russell:

On 24 Sep., 01:36, Russell Standish <li....domain.name.hidden> wrote:
> Successor observer moments are meant to be similar to their prior
> OMs. By similar, I really mean differ by a single bit, but don't hold
> me to that. I attribute this to the "heritability" requirement of an
> evolutionary process, which I think the process of observation must be.
>
> Once you have this requirement, the probabilities of sucessive OMs are
> not all equal, and in fact I do demonstrate how the Born rule arises
> in this context (Occams Razor, my Book). Its not going to be so easy
> to distinguish realism and idealism, as the emergent reality in
> idealism also "kicks back".

I really enjoyed reading your paper "Why Occam's Razor?" and I'd never
pretend to understand your derivation of quantum mechanics better than
you do. But maybe, I have another perspective on it (or even an
addition). Explaining this will reveal why I think that the Born rule
supports materialism/realism against idealism.

>From a physicist's point of view, your derivation is complete and
doesn't require any addition. We get the postulates as they can be
found in every introductory textbook on quantum mechanics. But someone
starting from the idea of the Everything ensemble won't be completely
satisfied. You introduce an unspecified probability distribution P_psi
which is essential in the definition of the inner product. In physics,
the Hilbert space of physical states can be different for every
system; a physical theory must specify the inner product of each
Hilbert space from which we can reconstruct the distribution P_psi by
applying the Born rule. Though, if we start from a theory of
everything, we want a fundamental explanation for the specific
distribution.

The materialist approach (of the Everything ensemble) would say that
P_psi(psi_a) is given by the measure of psi_a divided by the measure
of psi. Here, the measure of psi(_a) is meant to be proportional to
the 'number' of 'worlds' forming psi(_a). More precisely, I would not
speak of a 'number' but merely of the measure in the case when equal
weight is assigned to every single world. So, with the help of the
theory of the Everything ensemble and materialism, we are able in
principle to precisely define the probability distribution P_psi.

The idealist approach may lead to a similar idea for calculating the
distribution P_psi: An idealist would not count (or measure) worlds
but observer moments. The problem that I see here is the following:
Let's suppose a system is in the state I introduced in my first
message...

|B> = |0>/sqrt(3) + |1>/sqrt(1.5)

Then, if an observer performs a measurement in the (|0>,|1>) basis,
only two observer moments will follow. One OM that sees the outcome 0
and another OM that sees the outcome 1. If we apply equal measure to
each of these OMs, we will conclude that both cases are equally
probable. But they are not. I guess that the idealist approach leads
to a probability distribution incompatible with the experiment.

Marc:

I do recognize the difference between weak and strong materialism but
it's not essential in this case. When I wrote of mapping "physical
states of the brain to states of the mind or observer moments", I did
not exclude the possibility that the map is only a concept invented by
humans.

COMP surely provides a true alternative. It is good that you mention
it. Nonetheless, it's still a little strange for me. My own thinking
has always been rather similar to Russell's concepts.

> Reflectivity (how to think about thought itself)
> is an unsolved problem in probability
> theory, the solution for which is known only to me. I have no
> intention of revealing that solution here however, since it's the key
> to AI and my opponents are undoubtably reading my postings on this
> messagelist.

Damn! I was convinced that my message would make you blab out your
important ideas :)

Youness Ayaita


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Received on Mon Sep 24 2007 - 12:52:23 PDT

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