Continuity, reticulation, and classification

Ken Kinman kinman at HOTMAIL.COM
Wed Jul 25 22:52:40 CDT 2001


Tom,
      Ernst Mayr not only uses the term arbitrary, but subjective,
artificial, and other critical terminology.  He doesn't even consider them
real classifications, and in 1998 he coined the term "cladification" for the
results of cladistic classificatory algorithms.
     Mayr and Ashlock (1991) state:  "Cladists are far more subjective than
traditional taxonomists are.  They have adopted a series of arbitrary
conventions that are in complete conflict with the otherwise universally
adopted classifying principles enumerated in Chapter 6.  Indeed, a cladistic
classification is merely a phylogenetic model that lacks all the properties
one expects in a true classification.  If all a cladist wants is a
phylogeny, so be it.  Traditionally, however, a taxonomist expects more than
that from a classification."
     And Mayr (in his 1998 book) states:  "There is nothing in any theory of
classification that would require one to rely on the principle of holophyly.
  Indeed, the artificiality and heterogeneity of holophyletic taxa have been
the source of most adverse criticism of cladistics."
      The bottom line is that strictly cladistic classifications are
generally criticized by everyone except the strict cladists themselves (and
even they squabble among themselves over a variety of issues including
PhyloCode).  But I have gone beyond the other critics, and have tried to
fashion something that seeks to eliminate the major disadvantages of both
traditional eclectic classifications and strictly cladistic ones.  Not
surprisingly, many eclecticists think I'm too cladistic, and cladists think
I'm too eclectic.   So it goes for now, but someday cladisto-eclecticism
will be the norm.
          -----Ken Kinman
****************************************
>From: Thomas DiBenedetto <tdibenedetto at OCEANCONSERVANCY.ORG>
>Reply-To: Thomas DiBenedetto <tdibenedetto at OCEANCONSERVANCY.ORG>
>To: TAXACOM at USOBI.ORG
>Subject: Re: Continuity, reticulation, and classification
>Date: Wed, 25 Jul 2001 12:09:43 -0400
>
>-----Original Message-----
>From: Ken Kinman [mailto:kinman at HOTMAIL.COM]
>Any bioclassification is a construct and arbitrary. The tree of life is a
>continuity, and any cuts to divide it into taxa are arbitrary.  Cladistic
>classification is just as arbitrary in a different way, and many cladists
>believe that sister groups actually exist (which I find very troubling)
>-----
>The notion that a classification scheme is a human construct seems to me to
>be rather obvious. I note that Ken then links the word "arbitrary" to
>"construct" almost as if it were a necessary qualifier. Or at least he has
>not endeavored to make a real argument for why a cladistic classification,
>admittedly a construct, cannot also be non-arbitrary. I believe that it is.
>My dictionary defines arbitrary as "depending on individual discretion" or
>"based on or determined by individual preference or convenience rather than
>by necessity". There seems to me to be no question that an eclectic
>clssification is arbitrary - I guess Ken doesn't dispute that point. But
>cladistic classifications are not arbitrary - one simply cannot inject
>personal preferences into the process of going from a data matrix to a
>classification scheme. It is a rule-bound step - the most parsimonious tree
>that is discovered by the algorithm automatically becomes the
>classification. One cannot modify it in any way, irrespective of ones
>personal preferences, hunches, gestalts, evolutionary models etc.
>If one were to claim that all human intellectual products (constructs) are
>arbitrary, then the term becomes meaningless. The term is meant to
>distinguish those actions or concpets that are not yielded by a logical
>rule
>from those that are. There may be many steps in a systematic enterprise
>that
>one might argue are arbitrary, but the production of a cladistic
>classification from a data set is not one of them.
>In addition, I strongly disagree with the notion that "any cuts to divide
>it
>[the continuous tree of life] into taxa are arbitrary". Fundamental to the
>entire enterprise of taxonomy and systematics is the perception that life
>is
>segragated into independently evolving, discrete and distinguishable
>groups.
>One might claim that the decision that humans have made to study the
>diversity of life was an arbitrary decision (as opposed to deciding not to
>study life). But once the decision was made, I think that the subsequent
>cladistic decision to name and identify lineages by their distinctivness
>and
>historical segregation from the rest of the tree follows as logically (and
>non-arbitrarily) as the decision of taxonomists to recognize species by
>their distinctiveness and segregation from the rest of life. Cladistics is
>really nothing more than the taxonomy of groups of species. Cladists simply
>do not arbitrarily modify their empirical findings to produce
>classifications that are judged to be more useful or less up-setting than
>the findings themselves.
>
>
>Tom DiBenedetto


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