Re: Randomness and complex organization via evolution

From: Brian D Harper (bharper@postbox.acs.ohio-state.edu)
Date: Tue Jul 11 2000 - 20:48:27 EDT

  • Next message: Chris Cogan: "Randomness and complex organization via evolution"

    At 01:18 AM 7/11/00 -0500, Chris wrote:

    >The following little essay was written for another list, but it is
    >relevant to the topic of this list, so I reproduce it here. It was
    >originally written in response to the old creationist canard that complex
    >organization cannot be obtained from random processes. The idea is that
    >this would be like the parts of a BMW miraculously assembling themselves.
    >Of course, though the evolutionary process involves a kind of randomness,
    >it is not even *remotely* like such a miraculous occurrence, as should be
    >clear from this essay, if not from ten seconds thought.
    >------------------------

    Thanks Chris, a very interesting essay. Just a few random :-[0] thoughts.

    >Why is it that processes of replication-with-variation nature that
    >generate complex organization from randomness work?
    >
    >One reason is that randomness *is* complex organization.

    I think this was stated better later on. Anyway, by most definitions I've
    seen randomness represents the upper
    end of the complexity scale. But also, according to most definitions I know
    of, random would not be organized.
    This really follows as a matter of the most usual definitions employed.

    >But, more importantly, these processes work by *accumulating* small
    >changes in organization over a number of generations of replication and
    >near-replication. Selection is not necessary. In fact, the process works
    >*better* if there is no selection at all, and every copy is saved for
    >further replication.

    Here I disagree. Selection is I believe critical for the generation of
    organization. A random element generates
    complexity, selection generates organization. In my view anyway. But I
    believe my comment here is in
    the spirit of what was written later.

    >To see how such an unintelligent process can (and does) work, imagine a
    >machine that copies strings of information, with a generally high degree
    >of accuracy.

    That a random process will generate complexity is, I believe, relatively
    obvious given the usual
    definitions. one severe problem is confusing random (technical meaning)
    with "lack of purpose" etc.

    The example is, nevertheless, a good one. There was a paper published in
    journ. theor. biol. awhile back that
    essentially does the same thing except with DNA and point mutations.

    OBTW, why is this process called unintelligent?

    [skipped details of cosmic ray detector]

    >In fact, if the input was *not* random, the process *possibly* would not
    >work as well. Consider what would happen if every input was simply an
    >instruction to set the existing bit to zero in making any copies. This
    >would ensure perfect uniformity and simplicity in the entire population,
    >even after billions of generations. Or, if the only change made was the
    >adding of a zero bit to the string, so that all strings would be strings
    >of zeroes.

    I've thought a lot about this over the years and yes, I agree. It is fairly
    common to see some bemoaning
    the fact that mutations are random wrt to the needs of an organism.
    "Wouldn't it be nice if mutations
    occurred in such a way as to benefit the organism? But we live in a cruel,
    purposeless, world. When
    we grow up we learn that things aren't always the way we want." etc.
    followed by the theme from
    hee haw "gloom despair and agony, oh me". I've seen this crap in a well
    known biology text. Embarrassing.
    But, as you say, a random process seems to be the best choice. By way of
    analogy, consider the
    engineer that uses a random search combined with selection to produce
    complex designs.

    [...]

    >Consider a world in which everything was perfectly uniform, with no
    >variations at all from one point in space to another, and no flow of
    >energy. It would be in such conditions as *this* that it would be
    >miraculous to find life somehow evolving. The rich variability (i.e.,
    >"randomness") of conditions and energy flows is the *source* of the
    >complexity of life, not a *hindrance* to achieving such complexity.

    well said.

    thanks again.

    Brian Harper
    Associate Professor
    Mechanical Engineering
    The Ohio State University
    "One never knows, do one?"
    -- Fats Waller



    This archive was generated by hypermail 2b29 : Tue Jul 11 2000 - 17:39:11 EDT