Consensus (was: Google for Internet Database of all life...)

John Grehan jgrehan at SCIENCEBUFF.ORG
Wed Mar 22 09:27:46 CST 2006

Some comments in response to Ken:

In other words, we would have a consensus
> classification, but NOT a consensus phylogeny!!!  Those workers can
> their individual phylogenies for years, but everyone else can simply
> ignore the varying codings and enjoy a consensus classification that
> very stable (and much less cluttered by the numerous intermediate taxa
> which strict cladism eventually generates).

But such a classification would seem to lack any reality - just a
classification for the sake of it?

>      I think it is pretty clear that the primary objection to the
> System is that it allows the use of paraphyletic taxa to achieve
> stability, usefulness, and consensus (while strict cladism chokes off
> very valuable, and dare I say essential, option----wherein lies strict
> cladism's widespread failure to achieve those goals). 

There is nothing inherently more stable in a paraphyletic classification
than any other. If the phylogenetic arrangement is stable then the
taxonomic units would be stable - whether mono or paraphyletic. I
understand the goal of cladistics is to achieve natural classifications
- at least in theory. In that respect cladistics is at no greater
necessary disadvantage than any other approach (not that cladistic
theory is necessarily the last word on phylogeny).

Otherwise, we face yet another 35 years of
> unproductive bickering and cladistic instability.  

Having been around for at least 35 years of systematic argument I
haven't seen the "bickering" (debates, discussions, conjectures etc -
normal scientific discourse) as unproductive. It the contrary it has
focused critical thinking and we now have, for example, far less
unjustified characters (perhaps with notable exception of hominid
systematics)and systematic arrangements. Over that time classifications
seem no more unstable now than then - except potentially for those
situations where sequence data gives radically different results to the
morphology (I say potentially because there is a problem only if the
molecular version is given automatic priority).

John Grehan

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