Compromise in the air? (was: Boolean games)

[Curtis Clark]

on 2005-03-12 08:15 rjensen at SAINTMARYS.EDU wrote:
> I have to disagree with you, Curtis.  Certainly, two different views
> of where reptiles stop and birds begin can coexist - only one may be
> right, but given that we don't know which one that is, both are
> hypotheses; there are many unresolved matters involving two or more
> coexisting hypotheses.  If two alternatives could not coexist, then
> we would have no disputes in our classifications.

Sorry I didn't make myself clear: a multitude of views can and should
coexist, but only one among those views can be used at any one time in a
formal classification. Taking an example that I know a little better
than the Aves example, the evidence seems to support (monotremes
(marsupials + placentals). Let's say that someone decided that
(marsupials + placentals) constituted Class Mammalia, and that
monotremes belonged in Class Reptilia. With that view, (monotremes
(marsupials + placentals) cannot have formal taxonomic standing at any rank.

In a system without paraphyly, there is no "bully taxon" to nip the base
off of (monotremes (marsupials + placentals). In a rankless system,
establishing that taxon would be trivial. Even in a ranked system, it
could exist, either as a "superclass" or by reducing (marsupials +
placentals) to subclass.

Part of the allure of Phylocode is that it provides formalized,
widely-understood names for groups that are completely pre-empted by
intersection with widely recognized paraphyletic taxa. All other pros
and cons of Phylocode aside, it never works to deny people the
vocabulary they need to talk about their ideas.

--
Curtis Clark                  http://www.csupomona.edu/~jcclark/
Web Coordinator, Cal Poly Pomona                 +1 909 979 6371
Professor, Biological Sciences                   +1 909 869 4062