Re: Introduction (Digital Physics)

From: Marchal <>
Date: Thu Jun 21 09:38:06 2001

Joel wrote:

>What is the mind-body problem?

The formulations are as numerous than the philosophical systems.

For a materialist the problem is to explain what are the necessary
and sufficient conditions for having the feeling of pain in a leg.

For an idealist the problem is to explain what are the necessary
and sufficient conditions for having the feeling that there exists
things like electrons, waves, chairs, and neurons...

For an dualist the problem is to explain the relationship between
mind and matter. (cf Descartes "modern" formulation).

In general the mind body problem is tackle by religion.
Some "scientist" does not believe there is a mind body problem
because they are unaware that they believed in the "matter religion".
The mind body admit a lot of subproblem, like what is free-will, is
there an afterdeath, what is the nature of qualia, etc.

>What does "first person" and "third person" mean?

I know from your post that you are computationalist, i.e. you
can imagine that our consciousness is can be retrieved from the
working of a pure finite computation (by a universal minimal
cellular automaton for instance).

Then you agree that in principle you are duplicable (at some level
of description).

Suppose you take on you a intime diary where you note the result
of your "personal" experience.

Now I make here (at Brussels) a copy of your actual description, then
I annihilate you, and then I make you reconstituted at both
Washington and Moscow.

A first approximation of the "first person" is given by the
content of your diary. Because you keep your diary with you, it
will be duplicated too. It will contain either "I wake up
in Moscow, what a nice city, etc.", or "I wake up
in Washington, what a nice city, etc.".

A third person description is a verifiable one by an external
(not duplicated) observer. It can contain something like "Joel
wakes up successfully in both Washington and Moscow. It has been
confirmed by two phonecalls, etc."

This gives a striking illustration of the difference between the
two discourses. What is an "and" (Moscow "and" Washington) in the
3-description becomes an "or" (I wake up in Moscow or in Washington)
in the 1-description.

It is easy (for some at least!) to realise that (with comp) we
cannot predict the "result of experience" for self-multiplication
experiments. This indeterminacy can be shown not depending of
the contingent feature of the reconstitutions. Look at the UDA for
a description of the consequences of that proposition. It entails
a priori explosive sets of possible 1-continuations.

There is a kind of complementarity/duality between
1-3 description versus discrete/continuum. If we can be "captured"
by a finite discrete code, then we cannot avoid some confrontation
with the continuum under one form or another.

Sometimes I summarise that view on the foundation of math by
paraphrasing Kronecker : God creates the Natural Numbers, all
the rest are ... dreams by Natural Numbers".
(Kronecker says "... all the rest are human inventions; I generalise
Kronecker by replacing human by universal turing machines).
Now, with comp dreams obeys the laws of dreams (the laws of
the consistent computational extensions), and the appearance of
the physical must be explained by the logical structures of those
sheaves of dreams.

If your cellular automata generates everythings it will do it in
an extraordinary terrible redundant way. The computational
indeterminacy must be quantified on the set of *all* consistent

Received on Thu Jun 21 2001 - 09:38:06 PDT

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