Schutzenberger and simulation

From: Wesley R. Elsberry (welsberr@inia.cls.org)
Date: Tue Oct 17 2000 - 05:28:00 EDT

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    I find it amusing that work on genetic algorithms is critiqued
    as not providing a complete simulation of all the nuances of
    biological reality when the same critics apparently wish us to
    accept Schutzenberger's even less nuanced simulations as
    relevant. The irony there is precious.

    Of course, if it hadn't been for Bradbury, I might have missed
    out on that dose of irony completely. I've put Jones in an
    "archive-unread" filter, as well as "DNAunion".

    The quote with Waddington saying that he wasn't interested in
    Schutzenberger's computers is often quoted out of context.
    In isolation, it makes it look like some distressed non-techie
    biologist is simply frustrated with an elegant argument given
    by Schutzenberger. In fact, though, Waddington had another and
    better reason for being short with Schutzenberger, which was that
    Schutzenberger was digressing away from a concrete biological
    counter-example given by Lewontin. Waddington's interjection
    comes at Schutzenberger's fifth "reply" to Lewontin, which
    nonetheless failed to answer Lewontin's direct question.

    Dr. Alex Fraser contrasted Schutzenberger's simulation scenario,
    which did not work, with a version that did work.

    [Quote]

    Dr. Fraser: Can I contrast one computer with another? You
    have a computer programmed to examine the statement, "All I am
    allowed to do is change letters and I hope I produce a
    program. Any kind of program will do." This doesn't work.
    We now turn around and set up another computer, and we tell it
    a basic genetic system of plus-minus alleles in which we are
    saying, "Can it produce information?" The decision on whether
    the information is useful will be a selective one of "survive
    or not survive." This is the same kind of decision-making;
    the programs look very similar to those which are being
    constructed to try to produce information-containing programs.
    The principles are very similar.
      However, in the genetic one, the system is that there are
    multiplicities of pathways to suitable answers. The machine
    can gradually, step by step, get there; each step takes it
    toward the answers, and it produces them when all we have fed
    into the machince is a genetic system of essentially complete
    simplicity. What is surprising is how fast rational information
    is produced by the machine within the meaning of the original
    context.
      So, if you are going to take a program space and say, "We cannot
    transform it," but leave out of it the means of combination
    and recombination in between and of evolution by selection,
    I am certain that your program will not produce sense; but if
    you put it in there the machine gets there so fast it is
    surprising.

    [End Quote - Dr. A Fraser, discussion of Schutzenberger's paper,
    "Mathematical challenges to the Neo-Darwinian interpretation of
    evolution", p.80]

    Wesley



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