Real Species

[pierre deleporte]

A 10:56 27/04/2004 +0200, Zdenek Skala wrote:
>It seems to me that all the population/species distinction has been driven 
>by an overemphasis placed on (1) "almost timeless" nature of interaction 
>and (2) direct observability of concurrent events.
>Can we agree here?

I can agree with such a vision of differences between groups, populations, 
and species as coming in degrees rather than an all-or-nothing distinction. 
I think Ron argued this way with the notion of increasing time depth making 
our possible apprehension of biological connection looser and looser.
This would, in my view, allow us to put only a sharp distinction between 
individuals (anatomo-physiologically connected systems of cells) and taxa 
(populations, etc.), with the ambiguous classificatory status of coral 
colonies presented by Richard (anatonomically connected "populations").

>Richard Pyle raises another important point however:
>"Zdenek Skala refers to "natural" species (as distinguished from "taxonomic"
>species), and my question to members of this list is, can units of "species"
>(collective sets of individuals) be identified purely through "natural"
>criteria (i.e., with zero indication by a "classifying brain")?"
>
>Very good question. Indeed, no classification, despite called "natural" or 
>"taxonomic" is possible outside a classifying brain and without 
>"artificial" criteria - all the concepts like "biological species", 
>"phylogenetic species", "cohesion species" etc. are just human concepts. 
>Hence, what we really do are different conceptualizations of what is 
>"observed" (with all the necessary conceptual load even within the 
>perceptions). Then, a fully legitimate question is: why is e.g. a group of 
>interacting/mating individuals (or a monophyletic group) considered more 
>"natural" than e.g. group of individuals below 30cm in height? Possible 
>answers lead us back to the realism/nominalism distinction: either we will 
>resign to a realism (and can easily find that what we earlier considered 
>"artificial" classification can be more informative than what has been 
>considered "natural" one) or will try to develop some concept(s) of 
>"coherent wholes", "real things" etc. - with all the necessary conflicts 
>with purely formal reasoning.

I'm delighted you get this point.
At the risk of self-repetition (and to occasionally refer positively to 
Popper): all classifications, including those possibly based on "natural" 
criteria (=according to our theories about nature), are conventional but 
legitimate (informative, relevant...) provided they fit one's needs in a 
given context. Context matters ("paradigm").

Classifications are definitely not "natural things in themselves". They 
occasionally can fit a real thing (e.g. an individual's living cells) or a 
real process (e.g. a historical sketch of evolution = phylogeny, species 
being terminal taxa in such an evolutionary classification).

I really think "we"can agree in distinguishing real things from human 
constructs (however realist and scientifically plausible).

Best, Pierre.


Pierre Deleporte
CNRS UMR 6552 - Station Biologique de Paimpont
F-35380 Paimpont   FRANCE
Téléphone : 02 99 61 81 66
Télécopie : 02 99 61 81 88