Paraphyly is real (+ "strict cladist" defined)

Thomas DiBenedetto tdib at OCEANCONSERVANCY.ORG
Tue Jan 15 16:47:54 CST 2002

-----Original Message-----
From: Richard Pyle
... unless I read something that really riles me, I'll be stepping down
from the podium.
Is that an invitation?  :)
As to your points. First off, I didnt really have you in mind when I said
"y'all" -it was a general term for Ken and those who agree with him. I
realize that you have a significantly different set of views than he.
...and that is exactly what I perceive to be the primary flaw in your
position -- this assumption that the "classification system" (which we can
only interpret as the Linnaean nomenclatural system) is necessarily "based
on the principle of recognizing natural descent"
I agree that Linnaeus did not have descent as his criterion. But it seems to
have been a rather obvious step fpr systematists to adopt descent as the
criterion, beginning in a real sense with Lamarck, stated rather explicitly
by Darwin, and formalized by Hennig. Darwin of course proposed using the
ranking system to reflect anagenetic change as some sort of an overlay on a
descent-based system, an interesting proposition, but one that has proven
unworkable. In a sense, what ken is doing is simply to try to hold on to
that system.
.  This transition in the purpose of the
classification system can be seen either as a movement to bring taxonomy
into the post-nineteenth-century era; or it can be seen as one faction of
biology hijacking a system that has for centuries been shared by all. I can
probably guess what your view is, and I imagine by now that you can guess
what my view is as well.
But geez Rich, hijacking a system??? You might as well make such a charge
against Linnaeus as well - is there something wrong with a new set of ideas
taking over the practice in a particular discipline?  It is not like anyone
has a gun to their head.  It is my perception that an accurate classifcation
based on descent is far more useful to biologists than a subjective system.
So I really do think that cladistic classifications will be "shared by all"
and _used _ by all more so than older classifications.
There is a rather well developed argument that cladistic systematics is in
many ways a return to pre-Darwinian systematics (except of course for the
notion of descent) - and the "hijacking" was done by the Darwinians (what
Gary Nelson rather provacativly refers to as the "Darwinian Hundred-years
war on systematics" (are you riled yet? :) ).
The point is that consciously demarcated paraphyletic groups were not
present in pre-Darwinian systematics- they were an invention of Darwinians-
invented to confirm a (mistaken) expectation that empirical systematics
would be able to demonstrate taxa standing in an ancestor-descendant
relationship to each other (the famous "search for ancestors"). Fulfilling
this expectation became the paradigmatic goal of systematics for one hundred
years, and it was only after a century of being unable to make any such
empirical demonstrations, we have gotten back to the real purpose of
systematics - to empirically catalog the similarities and differences
between taxa and to extract the inherent hierarchical arrangement that the
characters and taxa exhibit. And now of course, we interpret that pattern as
a result of a process of descent, rather than a static expression of God's
Tom DiBenedetto

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