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From: throopw@rtp47.UUCP (Wayne Throop)
Newsgroups: net.origins
Subject: Evolution predicts nothing by predicting everything
Message-ID: <43@rtp47.UUCP>
Date: Thu, 23-May-85 14:33:46 EDT
Article-I.D.: rtp47.43
Posted: Thu May 23 14:33:46 1985
Date-Received: Sun, 26-May-85 20:53:19 EDT
References: <1126@uwmacc.UUCP>
Organization: Data General, RTP, NC
Lines: 38

There have been several postings to the effect that evolution predicts
nothing by virtue of predicting everything.  So summarize, quoting
Paul DuBois on what evolution says organisms will "do":

> They'll get more complex.  Or they'll get simpler.  Or
> they'll stay the same.  Some prediction.
> Or did you have something else in mind?

Examining these seperate predictions, we find that indeed evolution
predicts complex organisms will develop from simple ones, if the
environment gives advantage to complexity.  Similarly, the prediction is
that organisms will "get simpler" when the environment gives advantage
to simplicity.  And, oddly enough, they will stay the same when the
environment gives advantage to stasis (or gives no advantage for
changing).

Therefore I think that the problem that Paul points out is a
non-existant one.  Evolution predicts that species will evolve in
response to the environment.  Paul's objection is similar to saying that
Newton's laws are non-predictive because they predict that objects will
"Proceed in straight lines.  Or they'll curve.  Or they'll stay
still.  Or they'll accelerate.  Some prediction."

Note that even when the environment is known to some degree, evolution
can give ambiguous predictions in complex, real-world cases, for about
the same reason that simple application of Newston's laws aren't of much
help with three-or-more body problems in astronomy.  In each case the
"environment" is too complex for simple analysis.

Evolutionary predictions as stated by Paul seem arbitrary, but seem
quite reasonable to me when qualified by the addition that they are
predictions of response to environmental change by natural selection.
As I see it, the claim that evolution is not predictive because it
predicts everything is not valid.

Or did Paul have something else in mind?
-- 
Wayne Throop at Data General, RTP, NC
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