cladism's greatest weakness
kinman at HOTMAIL.COM
Sun Sep 19 22:27:40 CDT 1999
Like some of the others, your arguments seem to be directed toward
traditional paraphyletic groups, and do not address the advantages
"semiparaphyletic" groups have over both traditional paraphyletic groups and
strictly cladistic ones.
As for art in classification (and the analyses that underlie them),
perhaps if strict cladists put a little bit of artistry back in their
approach, they may be able to get a lot more out of the data that we already
have. My experience is that additional data can sometimes make bad analyses
even worse if there isn't enough "artistic" flexibility and creativity in
the investigator's approach.
I would certainly guess this is probably true with the "mites", a group
which could turn out to be neither holophyletic or paraphyletic, but
polyphyletic. I collect spiders myself, rather than mites, but I believe
arachnid phylogenetic analyses need a serious reevaluation. The
arbitrariness in this case not being so much of the fundamental kind I was
describing in earlier postings, but arbitrariness in the form of character
choices, weighting, and interpretation. I found Shultz's cladistic analysis
of arachnids to be very disappointing, and I have yet to see any analyses
done to correct that situation.
Anyone, either cladist or eclecticist, who claims a superior approach
based on non-arbitrariness is in my opinion just fooling themselves. But
this will not become clear until cladists and eclecticists go through a
period of reconciliation (hopefully resulting in a synergistic effect), but
it is not going to be a pleasant process, and a lot of eggs will need to be
broken before that omelette can be made. Speaking of omelettes, it is
getting late here, and must get some sleep before breakfast comes around
>At 8:22 AM -0700 9/17/1999, Ken Kinman wrote:
>... As for the problem of "birdness", it is very similar to the problem we
>had and still have with "mammalness".... Unfortunately, strict cladists
>have used Hennig's assumption to mask the fact that they are just
>substituting one kind of arbitrariness for another...
>Barry O'Connor responded:
>That's a problem with "naming and ranking" which will always be arbitrary.
>Monophyletic groups which are well supported by data are not arbitrary
>within the context of that data set; paraphyletic groups, by their nature,
>are always arbitrary; i.e. which groups are excluded from the monophyletic
>group are up to the individual. This is art, not science. Thus all the
>old "ad hominem" arguments that Hennig freed us from show up in this latest
>round of "Wose/Mayr/Kinman" arguments. Anyone can criticize art, but you
>need more data or better methodologies to test hypotheses.
>At 11:42 PM -0400 9/16/1999, John Grehan wrote:
> >the primitive Leiopelmid frogs may comprise a paraphyletic assemblage,
> >but they still can show a real biogeographic pattern. The
> >same goes for the primitive paraphyletic lineages in the ghost moth
> >(Hepialidae) family that show a classic
> >Australia-Southern Africa-Eurasia/North America track.
>This is true only if you are totally up front about which lineages within
>the monophyletic group you have excluded from your discussion; i.e. there's
>really no such thing as a "paraphyletic lineage." For example, one might
>say, "the biogeographic pattern of monophyletic lineage A-idae (excluding
>genera B, N, R, Q, Y, Z, and AA) shows a classic...track." Would anyone
>think this useful if all of those excluded lineages didn't themselves form
>a smaller monophyletic group? In your above examples of "primitive
>paraphyletic lineages" which I take to mean "the monophyletic group
>excluding one single derived clade," you may be suggesting that there is an
>underlying ancestral pattern that might be masked if one included some
>large derived lineage which showed an entirely different pattern. But
>including that derived group gives a better picture of the geographic
>history of the entire lineage, even if it turns out to be more complicated
>than one would like!
> - Barry
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