"Fuzziness" (Continuity and classification)

Richard Pyle deepreef at BISHOPMUSEUM.ORG
Wed Jul 25 22:19:47 CDT 2001

> Is the 'separation' of mother and child really defined by the break at the
> umbilical cord? That's just one physical event of many in the
> differentiation process. Perhaps one could argue that the
> umbilical cord is
> an artifact of a separation that has already taken place. Perhaps the
> separation of individuality (whatever that may be) is just as fuzzy as for
> species.

While I take your point that the snipping of the umbilical cord between a
newborn human and its mother may not necessarily represent *the* moment of
distinction between the two entities; I have to agree with Ken that the
analogy between the divergence of an offspring individual from a parent
individual, and the differentiation of two populations of individuals into
two distinct "species", is a weak one.  Two populations of individual
organisms (or, more correctly, their gene pools) may follow two isolated
paths towards "speciation", but then later re-merge when reproductive
barriers are bridged. A human progeny, once begun, is not apt to later
re-merge with its parent to restore the uniformity of the original whole.
Even an Oedipus situation in humans would represent a merger of two
"populations" (of one individual each), while the parent and offspring would
still maintain their distinctness.

Bottom line:  The boundaries between "species" (populations of individuals)
will always be more "fuzzy" and subject to human interpretation than the
boundary between a parent individual and its offspring individual.

> If the criteria for "good" classifications  resides only within one's
> personal preference there is nothing to debate.

Well, I think there is something to debate, and I think the focus of the
debate boils down to "collective" personal preference.  We, as a community
of taxonomy nerds, must decide how the implementation of nomenclature and
its influence on critter/weed/microbe classification will best suit our
needs.  It is the personal preference of some that the nomenclature and
classification should represent strict phylogenies.  It is the personal
preference of others that the nomenclature and classification should take
other factors into account.  I think that it is in all of our best interests
to resolve this dispute, to minimize ambiguity in the meaning of the "words"
[names] in our "language(s)" [nomenclature and classification scheme(s)].
Several different paths to a resolution seem to have been advocated:

1) Maintain the existing (Linnaean) system as the only "language", and
implement it in the same way that it has been utilized for decades before
the advent of cladistic analysis (as generally advocated by "classical"

2) Maintain the existing (Linnaean) system as the only "language", but
implement it in a way that represents a strict phylogenetic interpretation
of evolutionary relationships (as generally practiced by modern cladistic

3) Modify the existing (Linnaean) system as the only "language", and
implement it in a way that satisfies both needs (as advocated by Ken

4) Dump the existing (Linnaean) system altogether, and replace it with a new
"language" (e.g., Phylocode) designed to more ably accomodate strict
phylogenetic classification (not sure if anyone actually advocates this
right now, but perhaps could be the ultimate end-game for taxonomy);

5) Maintain the existing (Linnaean) nomenclature and classification system
as one "language" implemented in the same way that it has been utilized for
decades before the advent of cladistic analysis; and also introduce a new,
concurrent "language" (e.g., Phylocode) designed to more ably accomodate
strict phylogenetic classification (as generally advocated by a number of
level-headed folk, myself included..... :-)  )

While I certainly recognize the potential for confusion in maintaining two
concurrent "languages", as I have stated previously I don't forsee that
confusion as being any more disruptive to communication than the current
situation of using a single "language" with ambiguous meaning. As I have
also previously stated, the confusion of two "languages" can be mitigated by
a few (seemingly) simple precautions, such as unambiguous denotation of the
"words" [names] of the new "language" [Phylocode] by some sort of consistent
symbol.  I think confusion would also be mitigated by restricting the use of
the new "language" to higher levels of classification for the first few
years of its life.

In any case, we'll never really be able to guage the level of confusion that
would ensue from having two separate "languages" until the second "language"
is actually put to real use.  It will either gain ever-broadening support,
or it will wither and die.  Let natural selection decide.


P.S. How I managed to divert a message that began with the snipping of a
human umbilical cord into yet another soapbox tirade about Phylocode and
Linnaean nomenclature elludes even me, but I nevertheless apologize for its

Richard L. Pyle
Ichthyology, Bishop Museum
1525 Bernice St., Honolulu, HI 96817
Ph: (808)848-4115, Fax: (808)847-8252
email: deepreef at bishopmuseum.org
"The views expressed are the author's, and not necessarily those of Bishop

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