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. http://www.amazon.com/exec/obidos/ISBN=0716719983/longevitybooksA/ more at this link ( a six element tiling set ): http://www.scientium.com/drmatrix/progchal.htm 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 Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=13028