X-Message-Number: 13028
From: "John de Rivaz" <>
Subject: Consciousness
Date: Fri, 31 Dec 1999 15:10:59 -0000

On the matter as to whether it can be shown on a scientific basis that there
is no continuity of consciousness, need this really concern us? We are what
we are, and we want to preserve what we are. Whatever we may be in "reality"
we want to preserve that. The main problem I see with uploading is that it
is not possible with modern technology, not is it likely to be for a while
yet. Once it is possible I am sure someone will try it and then the fun
really will start.

Wang Tilings have been mentioned as spacial (rather than temporal) systems
that compute. Fractal expert Roger Bagula has sent me these clips about them
that may interest some cryonet readers.

A Wang tile in its simplest form is a square with colored edges. To tile the
plane one has to place the tiles edge-to-edge in such a way that adjacent
colors match (no rotations of the tiles are allowed). One important question
is if there exist sets of Wang tiles admitting infinitely many tilings of
the plane, yet with no tiling being periodic. Such sets of tiles are called
aperiodic. In 1966 R. Berger discovered the fist aperiodic set of Wang
tiles, containing 20426 tiles. Today the smallest known aperiodic set of
Wang tiles contains only 16 elements. A fascinating property of these tiles
is that they can function as a Turing machine and therefore as any computer
or brain. By choosing an appropriately chosen starting row of tiles, one can
force the developing rows of tiles in such a way that they calculate
whatever one wants. An excellent introduction with real examples on how to
calculate prime numbers or Fibonacci numbers using Wang tiles can be found
in Tilings and Patterns by Branko Gruenbaum and G.C. Shephard, published by
W.H. Freeman and Company, New York.
more at this link ( a six element tiling set ):
It is easy to change such a set of Wang dominoes into polygonal tiles that
tile only nonperiodically. You simply put projections and slots on the edges
to make jigsaw pieces that fit in the manner formerly prescribed by colors.
An edge formerly one color fits only another formerly the same color, and a
similar relation obtains for the other colors. By allowing such tiles to
rotate and reflect Robinson constructed six tiles (see Figure 6) that force
nonperiodicity in the sense explained above. In 1977 Robert Ammann found a
different set of six tiles that also force nonperiodicity. Whether tiles of
this square type can be reduced to less than six is not known, though there
are strong grounds for believing six to be the minimum.
Sincerely, John de Rivaz
my homepage links to Longevity Report, Fractal Report, my singles club for
people in Cornwall, music, Inventors' report, an autobio and various other
projects:       http://geocities.yahoo.com/longevityrpt

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