[net.origins] DuBois tour de force....

mrh@cybvax0.UUCP (Mike Huybensz) (02/22/85)

References:

I'm very impressed by the amount of work you've gone to, Paul.  (Just how
many hours did you spend on this anyhow?)  And it is entertaining to see
myself cited right after Gould and Eldridge.  (Though on a matter of
argument, rather than evolution.)

However, I'm not greatly impressed by most of your arguments.  (Some were
sound, but many others dwelt on the individual trees so much that the
forest was missed.)

The most notable source of your arguments is the basic problem of describing
details of a phylogeny.

First, let's consider the question of lineage.  Lineages of species
must exist according to evolutionary theory.  Identifying them is a non-
trivial problem, because we didn't observe them.  All we have is the spotty
fossil record.  Here is a useful analogy.  Let's say I don't know my
family tree, and I find a picture of someone unmistakably in my family (there
is a strong family resemblance.)  Is the picture of my father?  My uncle?
My much older cousin?  Say I find some more pictures.  I can then arrange
them in a hypothetical family tree (network).  But have I found all the
pictures?  If I haven't, I may have deductively assigned the wrong person
as my father whose picture I haven't found yet.  (I know I had a father....)

The task in evolution is slightly simpler since there is usually only one
"parent" instead of two.  But there may be the same multitude of siblings.
How do I know that a fossil species that I find isn't an uncle rather than
a father to another species?

That's why some people will say that evolutionary lineages cannot be
reconstructed accurately.  Because we are prone to make detail mistakes.
However, the lineages exist.  And the larger the scale you look on, the
less important small details like which sibling was the parent become.
"I don't care which McCoy was his daddy, we Hatfields still hate him!"
It doesn't matter which (fill in the blank)pithecus we evolved from, we
still evolved from ape-like ancestors.

So, the "problem" of lineages, upon which you wax eloquent with many citations
is one that is well known and understood.  There is a systematist's
philosophy particularly for dealing with this task, called cladism.

Another source of your misunderstandings is the problem of at what
branching point to declare that a subgroup begins.  Assuming (for the
moment) gradualism, at what exact point does a new species appear?
The correct point is whatever we choose, because there is no clear-cut
difference from generation to generation.  Generally we choose a point
where there is a gap, because that provides a convenient distinction.
That is why there is a distinction between reptiles and birds: because there
was a gap.  When Archaeopteryx was found, it fitted somewhere in the gap.
That's why some called it reptile and some called it bird.  Now, of course,
there are two gaps, on either side of Archaeopteryx.  Perhaps not equal sizes.
If we find another gap-filler, we will then have two new gaps.

So, when creationists say "that's not a bird/reptile intermediate, that's
a bird" they are saying the equivalent of "You're not a Hatfield, because
your father was a McCoy" while not telling you that your grandmaw's
maiden name was Hatfield before she married grandpaw McCoy.  While
citing patronymy (a mere naming convention), they are concealing descent.

More after I reread...
-- 

Mike Huybensz		...decvax!genrad!mit-eddie!cybvax0!mrh