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
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