Re: Random processes create meaning

From: Doug Hayworth (
Date: Thu Sep 21 2000 - 13:00:37 EDT

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    In response to Glenn Morton's post, David Campbell wrote:
    >Probably much more important is that natural selection makes evolution
    >highly non-random. A favorable mutation has greatly increased probability
    >of becoming established; a detrimental one has a greatly decreased chance
    >of becoming established. The pattern of mutation does appear random in
    >some senses of the word, but superimposed on that is the directional
    >component of selection. If anyone wants more details, any population
    >genetics text will give formulas.
    >The illustration of the puzzled codebreaker does illustrate another aspect
    >overlooked in the quotes disparaging the effectiveness of random
    >processes. Lots of random arrangements will give coherent sentences; many
    >more will give comprehensible approximations of sentences. The
    >codebreaker by providing the selective pressure of a search for a military
    >meaning eliminates numerous unsuccessful interpretations of the
    >message. As long as the codebreaker picks an interpretation that pleases
    >his superior officer, even if it is not exactly the message sent, he will
    >keep his job. Likewise, there are generally numerous ways to get a
    >protein to do a particular job.

    I think an important component to add to discussions of random processes is
    the use of qualifiers that make explicit their randomness *with respect to
    x*. Without such a qualifier, in some sense nothing is random; even point
    mutations are *determined* by some actual physical/chemical environment
    (such as the availability of nucleotides, the conformation of the extending
    strand, etc.). In this sense, the environment that causes genetic mutation
    is as nonrandom as the environment which causes natural selection in
    populations of organisms. The important point is that most genetic
    mutations are clearly random with respect to subsequent fitness, whether of
    the DNA molecule itself or the organisms it ends up in.

    Such qualifiers are critical in discussions relating natural and
    theological sciences, since the meaning of words in these two spheres are
    so very easily muddled together and confused. By contrast, within
    population genetics or evolutionary biology alone, the qualifiers are not
    usually necessary since references to random events are generally
    understand by the context.


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