species concepts (this is long!)

[warrena at bcc.orst.edu]

Hello,

Thanks John for the interesting commentary!  It is nice 
to consider this from a totally different perspective.  
Just a few points to follow up on these.  In general, 
my comments were from the point of view of a working 
taxonomist (I work on skippers, study their DNA, and 
describe new taxa from time to time).  From the point 
of view of someone who is not so deeply interested in 
taxonomic issues, species concepts would seem a lot 
less relevant:

> >There is certainly no concensus among
> systematists as
> >to what species concept should be used.
> 
> In which case it would seem that definitions of
> species do not matter.

If species definitions did not matter, there would not 
be an enormous body of literature dealing with the 
issue (I could cite over 100 publications here).  If 
they did not matter, people would have no reason to 
argue over them. In fact the use of various species 
concepts have huge implications in conservation (see 
Barrowclough et al. 1996)

> >All workers that use
> >subspecies have different working definitions
> of
> >subspecies,
> 
> True of species as well.

Well, this may be close to the truth in practice, but 
cannot be taken literally (read Wheeler & Meier, 
2000!).  

> 
> >All of this means that in the
> >business of taxonomy, subspecies are entirely
> >subjective.
> 
> So definitions are the foundation of
> objectivity?

I don't know about that, but without definitions for 
terms, I don't think they can be used very 
objectively.  Without a definition for a species or 
subspecies, those things simply become "whatever some 
taxonomist says they are."  

> >Workers
> >who propose subspecific names should strive to
> reach a
> >standard definition for a subspecies to remove
> some
> >subjectivity from their decisions.
> 
> If this authoritarian dictation is to be imposed
> on the use of subspecies 
> then proponents of species definition should be
> held to the same criterion.

They are working hard at it!  That is why they have 
proposed species concepts.  I know of no 
competing "subspecies concepts" in the literature.  

> 
> >The species problem is big enough!  Mayden
> (1997)
> >identified at least 22 species concepts in
> the
> >contemporary literature.
> 
> I have not read this article, but it is likely
> that most if not all fall 
> under the species as a class concept. I have
> illustrated this view below 
> with a slight re-wording of the definitions
> provided.

All of the following modified definitions of species 
concepts are VERY WRONG, way off!  These are complex 
concepts, and require many printed pages to explain and 
illustrate.  You should read the literature before 
trying to summarize these!  
> 
> >The Hennigian Species Concept (by Meier and
> Willmann),
> >The essence of species is reproductive
> isolation of natural
> >populations or groups of natural populations. 
> (I won't even pick on the 
> >"natural" criterion - another can of worms).
> 
> 
> >The Phylogenetic Species Concept (sensu Mishler
> and
> >Theriot) by Mishler and Theriot,
> >The essence of species least inclusiveness.
> 
> >  Evolutionary Species Concept (by Wiley and
> >Mayden),
> >The essence of a species is maintenance of
> identity
> >
> 
> In terms of spatio-temporal independance these
> different definitions are 
> really not all that different afterall.

Actually, yes they are.  Some of these concepts deal 
well considering contemporary and fossil taxa 
simultaneously (while some do not).  It is all 
discussed in the literature.  

> 
> >A strong proponent of any one species
> >concept should be familiar with other
> competing
> >concepts as well, to understand the strengths
> and
> >weaknesses of them all so that their own
> beliefs can be
> >better justified.
> 
> This seems to me a wishy washy kind of
> perspective.

Ok, then how are you are going to justify your opinion?

> 
> >It seems appropriate
> >to me that workers should have a defined,
> specific
> >species concept that is applied in their
> research, and
> >that the concept be consistently applied.
> 
> Since there is an abundance of competing species
> definitions that may all 
> have validity perhaps species definitions are
> really a waste of time?

I guessd I answered this already by pointing out that 
there is a huge body of literature devoted to the 
topic.  Actually, I think the abundance of species 
concepts shows how important they really are to working 
taxonomists.  I encourage you to publish your views on 
why species concepts are a waste of time!  They would 
be frequently cited, at least!

> 
> >This enables
> >workers to defend each and every taxonomic
> decision
> >they make on the grounds of their species
> concept.
> 
> Why bother having to defend one's taxonomic
> decision. If there are 
> competing views and all have validity, defense
> seems to become irrelevant.

Apply this to the real world and the legal system.  
Think about it.  If you can't defend your taxonomic 
decisions (= actions), you have no business making 
those decisions in the first place.  

> 
> >"Evolutionary" and biogeographic
> >factors are not always known with certainty,
> and only
> >add more ad hoc hypotheses to the to the theory
> of a
> >subspecies; making the hypothesis of a
> subspecies less
> >testable.
> 
> The imposition of ad hoc hypotheses in defence
> of a theoretical position is 
> a time-honored tradition in science (I include
> biology, chemistry, and 
> physics) and it can generate progress regardless
> of 'testability' (which is 
> not the only criterion for science).

I would really love to see some citations to back up 
these two statements.  You state them as facts, let's 
see the proof [or inother words, please defend your 
statements].  I would really like to see papers 
supporting these views.  

> 
> >In the eyes of many scientific philosophers
> >(as explained in works by Popper and Farris
> among
> >others) the best scientific hypotheses are
> those that
> >are the most testable,
> 
> This is just one philosophical view. Under this
> criterion witchcraft is 
> science.

I would love to see the citation for this!!!

> 
> >those with the fewest associated
> >ad hoc hypotheses (this is to say, the most
> >parsimonious exalanation is the best).
> 
> Again, just a philosophical abstraction that may
> or may not be true. Again, 
> also a good example of philosophers as the
> unpaid mercenaries of science.
> 
I cannot claim this is, strictly speaking, true.  
However, the weight of the liturature dealing with the 
topic says that the most parsimonious explanation for a 
problem is the best (from a scientific point of view). 
While not all authors on the topic agree (certainly 
anyone using maximim liklihood algorighms would not), 
this disagreement seems unique.  The more ad hoc 
principles that go into a hypothesis, the less testable 
it becomes, and therefore, the less desirable it 
becomes (as far as a scientific theory goes, even most 
ML proponents agree with this in general).  The best 
theories are the simplest and easiest to disprove.  I 
recommend reading Farris, J. S. (1983), The logical 
basis of phylogenetic analysis, along with the long 
series of commentary papers that followed it.    

> >To
> >give meaning to the above statement, a formal
> >definition of a subspecies, along with
> information on
> >what characters should be used in the
> taxonomic
> >analysis must be presented.
> 
> Again, why bother. As in species one may make up
> or accept a definition and 
> be none the wiser.

Without definitions, you can't define what you are 
doing, and it is not repeatable.  Then it is not 
science. 

Andy

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