re:Digital Physics web site & mailing list

From: Marchal Bruno <>
Date: Tue, 19 Nov 2002 12:26:55 +0100 (MET)

Hi Plamen,

Thanks for the info. Actually we knew about your site
since your friend Joel Dobrzelewski pointed us to it.
You can search the everything-list archives with the
keyword "cellular automata" to see
what some among us think about the use of CA for
developping a TOE. See my web page
for links to an argument showing that if "we" are
turing-emulable, then physical appearances cannot be
turing-emulable, in general.
In that sense the quantum indeterminacy confirms the
machanist hypothesis. In a nutshell, if we are machines
we cannot know which machine we are, and we cannot know
which computationnal histories we are living, and the
detailled description of our anticipable environment
relies on the infinity of computations going through
our actual states.
So if "we" are turing-emulable then the physical world
cannot be turing-emulable. Physical appearance emerges
from an relativized average on all computations.
Of course CA are very interesting per se, but misleading
for a TOE. There is a need to distinguish internal
first person appearances and external possible description.
In this list most people believe that we cannot
single out and focuse on one system, even if it is
universal, but that "every-system" must be taken into
account. If one system emerges from that, then we will
have a serious justification for it (but only then).
The evidences, both theoretical and empirical, are that
such a universal system, if it exists, cannot have
a local realist description. That is, IF the big all is
a CA, it should be a quantum CA(*).

I have read, admittedly in a quick way, your CA
explanation of EPR sort of phenomena. Er... I am
quite skeptical to be honest. An equivalent explanation
for general form of entanglement would give sort
of conspiracy variable theory ... Have you try to
CA simulate GHZ entanglement? (Greenberger, Horn, Zeilinger)

(*) cf Wim van Dam thesis "Quantum Cellular Automata",
available at


Original message by Plamen Petrov

>Dear all:
>I am reading this list since May, 2002, but only now I decided to post...
>This is to invite kindly all members of Everything-list to visit our Digital
>Physics site at:
>and (eventually) to consider subscribing to our mailing list as well (see
>Some short introductory text follows:
>Digital Physics is a relatively new scientific field somewhere on the edge
>between theoretical physics and theoretical computer science.
>The pivotal idea is that our Universe is a cellular automaton (CA), or to be
>more precise: "the Universe is something that is isomorphous to a CA".
>This proposition is known as "Fredkin's thesis", or (as Juergen Schmidhuber
>will insist!) :-) "Zuse's thesis", or "Zuse-Fredkin thesis", if you like.
>Although this idea has been around since mid 1950s, only now it got a boost
>thanks to a recently published book by Wolfram -- "A New Kind of Science"
>However, please note that our Digital Physics project is an independent
>research that has nothing to do with Wolfram's NKS, Fredkin's "Digital
>Mechanics" (DM) or Zuse's "Rechnender Raum" ("Calculating Spaces").
>This is to invite also all members of Everything-list to consider
>subscribing to our Digital Physics mailing list as well:
>Our mailing list is the oldest discussion group explicitly devoted to the
>"Universe as a CA" idea; we have been "there" since 1997 (even before Yahoo
>groups). To check out our old archives, look here:
>To subscribe to our discussion list, send message to:
>You can always unsubscribe later by posting to:
>With best regards,
>Plamen Petrov
Received on Tue Nov 19 2002 - 06:27:18 PST

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