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Date: Sun, 11 Feb 2001 17:38:25 -0600 (CST)
From: "Jonathan R. Wagner" <znc14@TTACS.TTU.EDU>
To: Philip Cantino <cantino@ohiou.edu>
Cc: PhyloCode@ouvaxa.cats.ohiou.edu
Subject: Re: Fwd: Re: codes
At 08:02 PM 2/10/01 -0500, Philip D. Cantino wrote:
>Jonathan Wagner wrote:
>
>> Sadly, the inclusion of provisions for qualifying clauses in the
>Code falsifies this statement.
>
>How so? I don't follow your reasoning. Could you provide an example
>of how a qualifying clause falsifies David's statement?
Certainly. Under the intial precepts of phylogenetic nomenclature,
De Quieroz and Gauthier asserted that the explicit association of a name to
a particular clade assures the taxonomist that the entity to which he refers
ALWAYS exists. This is because, for any phylogenetic definition, there is
always a clade, an ancestor and all of its descendants, that it refers to.
I would note that sometimes the clade contains only one species (the
ancestor). More importantly (for our discussion) some definitional formats
(stem-based with multiple internal specifiers) must be avoided for reasons
of logic, although this latter point absolutely does not invalidate the
point De Quieroz and Gauthier make. Simply put, such a definition does not
*incontrovertably* designate a clade.
And that is where we find the problem with qualifying clauses.
Qualifying clauses, and potentially other aspect of a definition (e.g.,
multiple internal specifiers in a stem-based definition), effectively
removes the explicit assocaition of a name with an ontologically real
entity. When we allow this practice, we allow for the possibility that some
of our named clades may not exist.
While I do recognize the utility of qualifying clauses (as I have
noted), I tearfully note the passing of one of the philosophically strongest
points of phylogenetic nomenclature. I have used this point on many
occaisions to emphasize the difference between phylognetic and typological
taxa, and I have found that, once the other person wraps their head around
the idea, it can be a very attractive notion.
I am not sure if an example will be helpful, but: in the Phylocode
(11.9, example 1), Pinnepedia is defined in such a way that it may not refer
to a real clade. Of course, in hypotheses where it does not do so, it is not
a valid name. However, in contrast, I can refer to Dinosauria
(Recommendation 11A, example 1) as a real entity, whose existance is
objective, and not subject to test or falsification.
I hope this makes my point clear. If not, please feel free to ask,
and I shall try to help further.
Jonathan R. Wagner
--------------------------------------------------------------------------------
Jonathan R. Wagner, Dept. of Geosciences, TTU, Lubbock, TX 79409-1053
"Why do I sense we've picked up another pathetic lifeform?" - Obi-Wan Kenobi