It's about NAMES, not clades (RE: Ashlock was treated badly)

Richard Pyle deepreef at BISHOPMUSEUM.ORG
Tue Jan 8 09:14:13 CST 2002

> The underlying dispute is simply the (very) old issue of
> whether or not the scientific classification of life should be aligned
> our understanding of the historical pattern of  taxic divergence - or not.

Actually, I think the real dispute is subtly different from this.  It's not
about whether paraphyletic groups are "mistakes"  or not. The dispute is
about how to apply the Linnaean *names* against a commonly-understood
phylogenetic relationship.  We can all agree on a phylogenetic
classification scheme, but still disagree how we should assign the names.
The key discussion has passed through this list before (more than once), so
I'll simply summarize:  Linnaeus devised his nomenclatural scheme before the
concept of evolution was widely understood (or perhaps even conceived). Some
time after Darwin's perspective of the origin of diversity gained widespread
acceptance, taxonomists began to assume that Linnaeus' hierarchical
nomenclatural scheme fit well with the hierarchically bifurcating pattern of
evolutionary history, and thus tended to focus their attention on using the
nomenclature to represent the evolutionary relationships.  When cladistics
began to take over much of modern taxonomic thought processes, this tendency
transformed into dictum: "The Linnaean names SHALL strictly reflect
evolutionary relationships as we currently understand them to be!"

The "resistance" (futile though it may seem to be), is fueled by two
principal concerns.  The first (and probably most significant in maintaining
the dispute) comes from a conflict between the long-held goal of stability
in nomenclature, and the early (and to some extent, current) application of
cladistic methodology.  Ultimately, this boils down to a tendency for
certain cladistic taxonomists to gain unwarranted confidence in their
phylogenetic hypotheses, so much so that they propose substantial
rearrangements in nomenclature.  Another year's worth of investigation,
however, leads them to further rearrangements of nomenclature to reflect the
new interpretation.  Multiply this by a bunch of years and a bunch of overly
confident cladistic taxonomists, and you end up with massive instability of

The second concern from the resistance camp has to do with the blind
assumption that "nomenclature" is necessarily synonymous with
"classification" (I may be wrong here, but it seems to me from the text of
yours that I've quoted above as well as other statements that you do imply
"nomenclature" when you use the word "classification").  Even with strict
adherence to monophyly (sensu Hennig), a ranked nomenclatural scheme such as
Linnaeus' will always incorporate a component of subjectivity and arbitrary
decisions on the part of the taxonomist. As such, the Linnaean nomenclatural
system is imperfect for representing phylogenetic relationships. The point
here, however, is that Linnaean nomenclature is a tool that we humans apply
to sets of biological entities so as to facilitate our ability to
communicate with each other.  Obviously, if the system was established
before the notion of evolutionary relationships even existed, then there
must be *some* function to the names *besides* representing evolutionary
history.  And in some cases, the non-evolutionary functions of nomenclature
can trump the evolutionary function, hence we still recognize the
monophyletic "Aves" as a distinct class from the paraphyletic "Reptilia"
(don't we?), because it serves a useful communicative function to do so.

The bottom line here is that the "dispute" is not about how we should or
should not acknowledge evolutionary relationships; it is about how strictly
the names should reflect those evolutionary relationships (or in most cases,
*hypothesized* evolutionary relationships).

The solution seems obvious to me, and I have previously described in in
excruciating detail within several horrendously long posts to this list (not
altogether unlike this one).  Linnaean names served a useful function in
science long before the advent of cladistics, and still serves that function
even today.  Much of its usefulness depends on its prime directive:
STABILITY. These names should continue to be used in more or less the way
they have been for two and a half centuries.  People who are interested in
elucidating and hypothesizing evolutionary relationships need, as a tool for
communication, an un-ranked system that does *not* depend on stability  --
one that can be fluid and dynamic and will explicitly represent phylogenies
without being encumbered by all the "baggage" associated with the Linnaean
system.  By golly, it seems as though the Phylocode defines exactly such a
system.  Different tools serving different functions.  What a concept!


P.S. Ken -- I know that your Kinman system has the potential to serve an
alternate solution, and I include this postscript to acknowledge that fact.
But as I've stated in earlier threads, I just don't see it as the optimal
solution for the long-run, compared to two separate systems.

P.P.S. Yes, I also acknowledge that there is a risk of confusion in
establishing two separate but seemingly similar nomenclatural schemes -- but
again, for reasons stated in earlier threads, I think the risk is low
compared to the cost of continuing down the path we presently find ourselves

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