Message 2001-02-0060: Re: Codes

Mon, 12 Feb 2001 12:54:07 -0600

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Date: Mon, 12 Feb 2001 12:54:07 -0600
From: "David M. Hillis" <>
Subject: Re: Codes

Now I have the rest of Gerry Moore's message. All I can say is that 
his experiences are very different than mine. The only objections I 
hear when I explain the PhyloCode are from people who worry about the 
possibility of two competing, parallel systems of nomenclature (a 
point to which I fully agree). I cannot believe that anyone wants 
that...two different names for everything, and no one able to 
understand the other side. Sounds like nomenclatural hell to me, and 
I suspect that we'd lose a lot more people like me if we went that 
route than we would lose by making an upgraded, single, comprehensive 
code. And, if people did not go alone at first with an upgraded, 
universal Code, it really wouldn't matter, because their names could 
still be incorporated into the new system seamlessly (as long as we 
have forward- and reverse-compatibility). There are always people who 
say they won't upgrade any given program, but it eventually becomes 
necessary if they want to communicate with their colleagues. I'm 
think the PhyloCode will also be like that.

The only other point that I didn't already respond to was:
>Hillis was critical of the existing system, noting that it required 
>"diagnoses of taxa rather than phylogenetic definitions, and the 
>diagnoses don't even have to be correct." However under the 
>PhyloCode one can define taxon names under a phylogenetic hyopthesis 
>that is also later proven incorrect.

The difference is that the diagnosis doesn't have any required 
connection to the name under the existing codes, so even if the 
diagnosis is accurate, someone else is free to apply the name to a 
group that doesn't fit the diagnosis. There has to be a diagnosis, 
but it doesn't have to be correct, and it doesn't carry any weight in 
assigning the name to a group of organisms. That decision is entirely 
subjective, as long as the group contains the type species. Under the 
PhyloCode, the definitions are formulated in such a way that they 
unambiguously apply to a single clade in the Tree of Life. Our 
understanding of phylogeny may change, but the definition always 
points to a single, unambiguous clade, no matter what the 
phylogenetic hypothesis may be.

David Hillis

David M. Hillis
Director, School of Biological Sciences
Director's office: 512-232-3690 (FAX: 512-232-3699)
Alfred W. Roark Centennial Professor
Section of Integrative Biology
University of Texas
Austin, TX 78712
Research Office: 512-471-5792
Lab: 512-471-5661
FAX: 512-471-3878


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