Re: Introduction (Digital Physics)

From: Fred Chen <flipsu5.domain.name.hidden>
Date: Tue, 19 Jun 2001 20:11:07 -0700

Hi Joel,

I have not corresponded with the distribution in quite a while. Your posting
below seems to have caused some furor.

You wrote:
>
> Anyway, I represent a small group of people who believe that in fact all
> universes do exist and are computed by some very simple structures known
as
> "minimal cellular automata".
>

I tend to feel that the position that our universe is a digital cellular
automaton is vulnerable, mainly because it implies that we can create
universes containing self-aware structures (SAS's) that our much simpler
than the one we inhabit, by using some multi-dimensional analogue to Rule-30
below.

>
> 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).
>
> 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.

A resolution to the White Rabbits problem accepted by most on the
distribution requires us to insist that we live in the simplest possible
universe containing SAS's. So it would be impossible or highly improbable
that we can create universes with SAS's (e.g., by constructing cellular
automata). If you could, and you could prove that you have created a
universe inhabited by SAS's, that would indeed be some achievement, and it
would force a change of thinking in many.

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

Whether our universe is digital or continuous is harder to decide. Even with
a set of quantized universes, we could have a continuum of 'different sized'
quanta building blocks, though it may not affect the physics for each of the
universes.

Fred
Received on Tue Jun 19 2001 - 20:17:34 PDT