From: Thomas Buckner (tcbevolver@yahoo.com)
Date: Thu Dec 16 2004 - 00:25:14 MST
--- David Clark <clarkd@rccconsulting.com> wrote:
> Is there any more *proof* that multiple
> universes exist than there is
> *proof* there is a god? We understand so
> little of the universe that we
> obviously exist in, it seems a bit premature to
> believe in multi universes
> that conveniently have no way to be proved or
> disproved. To put forward a
> theory without proof is just fine so long as it
> is defined that way but to
> *believe* without any successful tests, sounds
> suspiciously like religious
> belief to me.
>
> I have not been to China but I believe China
> exists. The size of the
> conspiracy of false information that would have
> to exist if China did not
> exist could be possible but very unlikely. The
> same is not true for multi
> universes. The idea might be interesting to
> some physicists and science
> fiction writers but that doesn't mean there is
> actual evidence that multi
> universes exist. Getting the cover of
> Scientific America is no argument for
> or against any theory.
>
> David Clark
>
>
Well, here's a nutshell of what I really think is
going on:
Look at, say, a visual graph of the Mandelbrot
set, which you can zoom in on and find similar
but not identical detail at any arbitrary level,
so that the Mandelbrot set is a sort of
'information multiverse'. You could enlarge it so
much that you had a printout of a trillion
trillion square feet, and each square foot
encodes uniquely a certain amount of data, which
can be enlarged just as much again if you want.
If we analyze a single square foot, we may be
able to 'reverse-engineer' the much simpler
formula that gives rise to the whole set. It's
much simpler (Occam's razor) to conclude that
this simple formula has created the graph, and
that there are a trillion trillion other sections
making up the whole picture even if we have but
one.
Our visible universe can be expressed as a
certain amount of information. In fact, our
existence at the most elemental levels (QM) is so
'information-like' rather than 'stuff-like' that
there is nothing silly about regarding it as part
of a larger set. Insisting that we live in the
'only universe' sounds to me like saying that
75698725623 is the only number, and the others
are useful but somehow artificial.
It is easy to get around this objection by
invoking the idea that a single
complexity-generating phenomenon underwrites all
realities: perhaps a sort of Mandelbrot set-like
fractal composed of a binary arrangement of two
possible states: exist, unexist. Because no
matter how far we delve into the physics toward
unified and comprehensive theories, the biggest
mystery is still that stubborn background. Why
does anything exist at all?
If we posit only one universe, we have to explain
many, many things about it, as well as the
stubborn background. It is oddly and delicately
balanced for us to exist, against enormous odds
if several 'cosmic constants' were of different
strengths. A complexity generator that creates
all logically possible universes explains our
being as an inevitable thing.
Another way to illustrate the MWI as a logical
solution is to look at a chessboard. Now suppose
that each possible arrangement of the pieces
codes for the physical state of a very, very
small universe. You might have just enough
information to completely describe a few
elementary particles. Any micro-universe
corresponding to one of the possible meetings of
pieces in a game is a lawful universe under the
chess physics we describe. There are a few
combinations of pieces which cannot occur,
especially early in the game. You can't just move
all your pawns past your opponent's pawns without
some disruption in the line. You can't start with
your pawns lined up in front of your pieces. So
if we were using chess to run an micro-universe,
these impossible positions would be parts of the
equation that never happened in that little
universe in any possible history.
We also get the concept of time since any given
arrangement can only be lawfully derived in chess
by certain preceding moves. It can only be
followed by certain moves. How much 'free will'
does a particle coded for by a game position
have? It is free under chess physics rules to
follow any path coded for by logical paths from
that position. There will be plenty of possible
future arrangements which can never be, because
they require a series of moves that is not
allowed.
We can follow the particles through chess
universes by thinking of each succeeding possible
arrangement of the chessboard as a page in a
flipbook, and we get time by flipping the pages
with our thumbs. It's the creation of the
universe and the birth of cinema!
For amusement, watch this Java replay of perhaps
the oldest recorded game of chess (from 1475),
which just turned up in a googling of the phrase
chess universe.
http://www.chessgames.com/perl/chessgame?gid=1259987
When you hit the forward button, just think of
the pieces as elementary particles, reacting in
strict faith to the rules, as if the game were a
carefully planned dance. Chess is a pretty good
complexity generator to watch.
Other games may be found at
http://www.chessgames.com/perl/chesscollection?cid=1002168
under the following heading:
Chess is like universe ....
Compiled by arielbekarov
--*--
Even the form .... but it is only theory ....
So: Tegmark, in his article, bids to be the
Linnaeus of theoretically possible universes,
dividing the universe kingdoms into their phyla
of mathematically permitted constructions. He
isn't telling us they do exist, yet. He's talking
about what might be permitted by any possible
physics, and how to detect it. I suppose my
little chess universe is an educational toy model
of a Level IV, by the look of it.
I'll give Max Tegmark the last word:
_______________________________________________
Parallel Universes
Author:
Max Tegmark
Abstract:
I survey physics theories involving parallel
universes, which form a natural four-level
hierarchy of multiverses allowing progressively
greater diversity.
* Level I: A generic prediction of inflation
is an infinite ergodic universe, which contains
Hubble volumes realizing all initial conditions -
including an identical copy of you about
10^{10^29} meters away.
* Level II: In chaotic inflation, other
thermalized regions may have different effective
physical constants, dimensionality and particle
content.
* Level III: In unitary quantum mechanics,
other branches of the wavefunction add nothing
qualitatively new, which is ironic given that
this level has historically been the most
controversial.
* Level IV: Other mathematical structures
give different fundamental equations of physics.
The key question is not whether parallel
universes exist (Level I is the uncontroversial
cosmological concordance model), but how many
levels there are. I discuss how multiverse models
can be falsified and argue that there is a severe
"measure problem" that must be solved to make
testable predictions at levels II-IV"
__________________________________________________
Read more at
http://www.hep.upenn.edu/~max/multiverse1.html
Tom Buckner
__________________________________________________
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