Cyperales or Juncales?

[Richard Pyle]

Jim said:

> > .  We can *know* a specimen has a character or
> > combination of characters, we can know a specimen came for a  certain
place
> > at a certain time, but we can only *believe* that a bunch of specimens
is
> > of the same species

But I would say, "That depends on how you define the word 'species'."  If
you are of the mind that 'species' objectively exist in nature, and it is
the job of  taxonomists to 'discover' these objective collections of
individual organisms....then I agree with your statement.  If, on the other
hand, you are of the mind that a 'species' is merely what a taxonomist (or
community of taxonomists) says it is, then a taxonomist (or community of
taxonomists) can also "know" that a bunch of specimens are of the same
species, because that is how they have *defined* the species.

Then Tom replied:

> I disagree. "Knowing" that a specimen has a character requires an
> inference of the same kind as one makes when putting forth a phylogenetic
> hypothesis.

But I would say, "That depends on how you define the word 'character'".  It
is clear from the rest of your note that you define it strictly in the
context of "homologous" characters; whereas I imagine that Jim was defining
it in the sense of observable character (i.e., "brown stuff growing out of
[your] head"), without asserting whether there is any homology with the
brown stuff growing out of *my* head.

I think that Jacques Melot underscored the basic problem in an earlier post
to a different thread:

>     J'ai le sentiment que toutes ces discussions sont compliquees
> artificiellement par le non respect des definitions rigoureuses des
> termes techniques, non respect qui engendre des conceptions vagues ou
> fausses et rend les raisonnements parfois inextricables. Tout est
> beaucoup plus simple si l'on commence par assimiler les concepts a
> l'aide de definitions exactes.

Aloha,
Rich

Richard L. Pyle
Ichthyology, Bishop Museum
1525 Bernice St., Honolulu, HI 96817
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