Inadequacy of cladistics

Richard.Zander at MOBOT.ORG Richard.Zander at MOBOT.ORG
Fri Jan 23 11:55:58 CST 2004


Excellent thought. What is this fundamental inadequacy?

I personally think that there are two main problems:

(1) Factors involved in reconstruction need to have their chance of being
wrong (and then change the result) at least guessed at, and the chance of
all such factors (including all assumptions) being wrong must be multiplied
when determining a posterior probability. We only have a 5 percent standard
chance-of-being-wrong interval to work with, unless one insists on 1 percent
chance of being wrong before basing further work on the results, which is
worse.

(2) There is an equivocal stance where cladists talk about evolutionary
reconstruction in one breath (which requires a demonstrated high level of
reliability) and switch to classification in the next breath (which is
traditionally anything an expert says it is), then back again. This
equivocation is changing as statistical methods evolve, though such methods
often give contradictory, obscure, and mystifying results. Note that
cladists are becoming few and far between as statistical phylogenetists
publish shock and awe papers, and maybe we should no longer criticize
cladists, any more than we worry about other purveyors of out-of-date,
unprofitable theories.

On the other hand, anyone who challenges modern phylogenetic reconstruction
must do so by technical evaluation of the theory and methods from a
standpoint of familiarity with the theory and methods. Paradoxically, one
must become a phylogeneticist to criticize phylogenetics as presently
practiced. Too bad.

______________________
Richard H. Zander
Bryology Group
Missouri Botanical Garden
PO Box 299
St. Louis, MO 63166-0299
richard.zander at mobot.org <mailto:richard.zander at mobot.org>
Voice: 314-577-5180
Fax: 314-577-9595
Websites
Bryophyte Volumes of Flora of North America:
http://ridgwaydb.mobot.org/bfna/bfnamenu.htm
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http://ridgwaydb.mobot.org/resbot/index.htm




-----Original Message-----
From: Thomas G. Lammers [mailto:lammers at VAXA.CIS.UWOSH.EDU]
Sent: Friday, January 23, 2004 8:17 AM
To: TAXACOM at LISTSERV.NHM.KU.EDU
Subject: Re: [TAXACOM] Human origins


At 08:26 PM 1/22/04, Ken Kinman wrote:
>What bothers me most (as it apparently does John
>as well) is the paucity of explicit morphological
>synapomorphies for a chimp-human clade.  Although I
>must admit the molecular evidence seems rather
>convincing (from what very little I personally have
>had time to examine), the lack of rigorous cladistic
>analysis on the morphological side is very disturbing.

Here's a thought:
Perhaps this reflects some fundamental inadequacy with cladistic
methodology and its underlying assumptions ...




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