[Taxacom] Reproducibility of descriptive data

Mike Dallwitz m.j.dallwitz at netspeed.com.au
Thu Sep 10 22:24:16 CDT 2009

Jim Croft wrote:

"Descriptions do not 'define' a concept (at any level). They... um... 
describe it.

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 

Mike Dallwitz
Contact information: http://delta-intkey.com/contact/dallwitz.htm
DELTA home page: http://delta-intkey.com

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