Taxa as hypotheses

[Peter Rauch]

Cross-posting of John Alroy from paleonet:

Date: Sat, 18 Mar 95 20:04:38 -0700
From: John Alroy <jack at homebrew.geo.Arizona.EDU>
To: paleonet at nhm.ac.uk
Subject: Re: Taxa as hypotheses

Further hot air, sorry all.

My earlier post was vague, probably due to computer jockeying-induced
burnout. My complaints were about the Linnean _ranks_, not about
having a taxonomic hierarchy of some kind. One literally could
identify all higher taxa as nodes on a cladogram, throwing the names
out completely (admittedly not much fun), and still have a
classification qualifying as a taxonomic hierachy. What makes the
Linnean hierarchy "Linnean" is not just the type of names that are
used or the hierarchy being a hierarchy in a literal sense, but the
use of ranks. Ranks do not qualify as hypotheses, as I'm sure Dr.
Lipps will agree. They are defined on grounds of priority or on no
grounds at all - do I call Aves a "Class," "Subclass," "Order,"
"Family," or what? Given the deeply nested position of Aves within
Dinosauria, there seems no rational basis for deciding this other
than an appeal to priority, and no sense in which a "hypothesis"
concerning this issue could be tested. This is the sort of concern
that motivates some cladists to ignore Linnean ranks - including
myself, if a person who is not entirely set against paraphyletic
groups qualifies as a cladist.