Striking a balance, weighting and Cladistics

[Thomas Lammers]

At 10:40 PM 2/14/01 -0800, you wrote:

>This is probably amply discussed in the literature but has never managed
>to penetrate my thick skull:  why is there a desire to weight characters a
>priori, unless to influence the outcome of an analysis away from results
>driven by parsimony?

Well, I suppose this IS the reason.  But it is motivated by the knowledge
that there is absolutely no reason to assume that evolution has been
parsimonious.  Parsimony is simply the best default in the absence of other
data.  Occam's Razor does not say that the simplest explanation is always
right; just that in the absence of other data it is a safer bet than any
convoluted hypothesis.

I think what is hoped with weighting is that we can discover which
characters are indeed most indicative of the pathways of evolution, i.e.,
which are genuine synapomorphies.  Whether that is possible or not, I'll
leave to wiser heads to debate.


Thomas G. Lammers, Ph.D.

Assistant Professor and Curator of the Herbarium (OSH)
Department of Biology and Microbiology
University of Wisconsin Oshkosh
Oshkosh, Wisconsin 54901-8640 USA

e-mail:       lammers at uwosh.edu
phone:      920-424-1002
fax:           920-424-1101

Plant systematics; classification, nomenclature, evolution, and
biogeography of the Campanulaceae s. lat.
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