Introduction (Digital Physics)

From: Marchal <>
Date: Thu Jun 14 08:16:36 2001

Hi Joel, Joel Dobrzelewski wrote:

>Hello! My name is Joel Dobrzelewski and I'm newcomer to the list.


>(I should note: Not all participants in our organization agree with this
>Plamen and me on this issue. What the larger group has in common is the
>belief that the universe is discrete, not continuous.)

Something similar happens to this list. But the problem is nuanced by some
because it has been shown that although the universe can be said discrete
from a third person or objective point of view, still it can appear (and
"be") in some sense continuous from a first person subjective point of
All this for reasons similar to those made by Everett in his
many world papers. Have you read Everett ? (or at least Tegmark?
or Deutsch?)

>So in this case, Conway's Game of Life is probably a poor example, because
>it in fact has many unreachable configurations. But at least it is the
>automaton that most people are familiar with.

Yes. (cf also:

>Without knowing anything about the "natural" world, Rule-30 (starting with a
>single non-blank bit) - all on its own - generates every possible book,
>symphony, or email message imaginable (or unimaginable!).
>Furthermore, this process is reversible - thus preserving the work done by
>the automaton and providing a mechanism for reconstructing the past (i.e.
>microscopic reversibility of nature).

Is it more impressioning than the (binary) counting algorithm, which just
counts: 0, 1, 10, 11, 100, 101, etc. It generates (after the first 1)
every strings too. And you can implement it in a reversible way with a
reversible universal turing machine.

>It is our belief that there exists a 3D version that is not only minimal
>(generates everything) but also universally computational. Meaning... it
>generates all PROGRAMS as well.

So does Schmidhuber "great programmer" or my Universal Dovetailer.

The UD generates all programs, and executes (by dovetailing) all
programs. It generates all symphony, and it generates all possible
subjective experience held by people listening to all possible symphony!
It generates your current experience, too, and infinitely very similar

>But the advantage here is that we can more easily envision the existence of
>such a miraculous object like a minimal cellular automaton than, say, a
>Universal Turing Machine. Cellular automata naturally implement physical
>universes without any interpretation.

How? Implementations are interpretations.

>The bits merely exist... and we can
>see them with our digital eyes - and the patterns they generate.


>It is my belief that the Universe we inhabit is the one mathematical object
>that all sentient creatures can deduce exists, ...

Me too. Like (indeed) most on this list. I oversimplify myself
because I don't believe that a word like "universe" is well defined.
I believe that thanks to the Post-Turing-Markov (Church) thesis
all computations exist in "Plato heaven", though.

>...and that the minimal cellular automaton is the solution.

It is not the solution. It is the problem. Your type of approach
like Schmidhuber's one is based on a naive association between the
first person view and some third person description (brain, machine,
automata). See for
an attempt to explain how non trivial the "mind body" problem
becomes when the computationalist hypothesis is taken seriously.
You can also try to tackle the Mallah's implementation problem, see
Of course these problem are still under discussion here. Some
(like Schmidhuber, and Jacques Mallah too BTW)
still doesn't see the (abyssal, though) difference between possible
(machine) *point of view*. I am not saying that cellular automata-like
approaches are wrong or uninsteresting, but they are incomplete.
Now, CA are perhaps less incomplete than "pure third person
computationalist approach" because the work by Conway and Moore (as
explained in Svozil's book, reference in my thesis, URL below)
makes possible to distinguish sort of points of view. I hope we will
discussed that later ... (Conway and Moore, like me, gives a
pure "computationalist" motivation for quantum logic).

>Well, I hope our two groups will find some common ground. From what I can
>tell, our work most closely parallels that of Mr. Juergen Schmidhuber.

Unfortunately, but hopefully only superficially :-)

Received on Thu Jun 14 2001 - 08:16:36 PDT

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