[Taxacom] Reproducibility of descriptive data
s.thorpe at auckland.ac.nz
Thu Sep 10 22:48:50 CDT 2009
>As yet undiscovered specimens are very relevant. The taxonomist should _try_ to account for those. Although a character list and the associated descriptions can't be complete, they can be ROBUST in ways that can be defined
Robust! Another way of saying that species have a real, natural boundaries! Absolutely, yes! :)
>Which comes first, the concept or the inclusions (exemplars)?
Actually, you mean which defines the concept, the description or the inclusions (exemplars)? Jim seems to think the latter in all cases!
I think it depends on genus or species:
Genus: the description defines the genus concept
Species: the type inclusion (exemplar) defines the species objectively. The description defines what you might call the "hypothesised concept", which may be found to be incorrect if the actual natural species boundaries around the type are found to include more or less than the description does ...
From: taxacom-bounces at mailman.nhm.ku.edu [taxacom-bounces at mailman.nhm.ku.edu] On Behalf Of Mike Dallwitz [m.j.dallwitz at netspeed.com.au]
Sent: Friday, 11 September 2009 3:24 p.m.
Subject: Re: [Taxacom] Reproducibility of descriptive data
Jim Croft wrote:
"Descriptions do not 'define' a concept (at any level). They... um...
If you want a definition, you could use the list of those thing you might
include in that concept. Species in genera, specimens in species, etc."
The definition of an infinite class, or a class to which future
individuals will belong (such as a subspecies, species, or genus), can
only be done by description, not by listing its members.
"Having settled on a concept by inclusion, ..."
Which comes first, the concept or the inclusions (exemplars)? You (I
think) say the latter, I say neither (or, if that's too wishy-washy, the
former). Not that it really matters - it's only in the mind of the person
deciding on the concept. What does matter:
"... you can then go about describing it, listing the
characters/attributes that, in your mind, set the boundaries."
I.e., describing/defining the concept, so that you can convey it to others.
"It is conceivable that a taxonomist could account for all relevant
specimens, species, etc. This is, after all, why we do revisions. Any
character/attribute list is arbitrarily selected and can never be complete."
As yet undiscovered specimens are very relevant. The taxonomist should
_try_ to account for those. Although a character list and the associated
descriptions can't be complete, they can be robust in ways that can be
defined. (I can go into this in detail if anyone is interested, but
DELTA-L might be a more appropriate forum.)
By the way, I agree broadly with Pierre Deleporte's posting (and I liked
the poem), but the quoted posting attributed to me was actually from Jim
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