Re: PhyloCode

[David Marjanovic <david.marjanovic@gmx.at>]

> Ok my rule can be dropped in such cases such as in this case in which note
> must be taken that if you tell people they have eaten dinosaur or reptile
> when they eat bird they will take it that you lied to them as the usage 
> was
> not meant for that context.

As the president (Kevin de Queiroz) said: The word "bird" will not 
disappear. The word "Aves" will not disappear either. Under current 
classifications, you can already tell people they have eaten vertebrate for 
dinner without being wrong -- and this doesn't any damage to "bird" or 
"Aves".

> All well and fine but for other cases my principle should be applied. No
> word can even in theory be strictly speaking defined 100% because you 
> can't
> as Quantum Mechanics teaches give a perfect measurement to anything 
> without
> the act of measurement altering what is being measured. What's a 
> measurement
> hasn't even been defined according to everyone. We can define things even
> without knowing much at all about it. What is a human being?

Here in biological nomenclature, we don't care at all what a human being is. 
We're not trying to measure. Nomenclature (unlike phylogenetics!!!) consists 
_purely_ of _arbitrary definitions_. Just like mathematics. "1 + 1 = 2" is 
absolutely true _because and only because_ of the ways "1", "+", "=" and "2" 
are _defined_. In the same way, it is an absolute truth* that Dinosauria 
consists of "the most recent common ancestor of *Megalosaurus bucklandii* 
and *Iguanodon bernissartensis*, and all its descendants". Why? Simply 
because we say so and call that a definition.

Now what a dinosaur is, which organisms are and are not descendants of that 
common ancestor, or what that (currently unknown) "most recent common 
ancestor" is, _this_ is left to science. To solve these questions, we need a 
phylogeny -- that is, a phylogenetic _hypothesis_, a phylogenetic tree, to 
which we can _apply_ the nomenclature. Making and disproving phylogenetic 
hypotheses is the job of the science of phylogenetics. Being a science, it 
does not make definitions; it applies them.

* Well, it's not, because the PhyloCode is not yet in effect.

> We still haven't completed figuring out every last piece of genetic
> information on that question.

If we had, we'd have a very good understanding of phylogeny. But this is not 
needed for phylogenetic _nomenclature_. The very idea of phylogenetic 
nomenclature is that the resulting names should be applicable to _every_ 
imaginable phylogenetic tree.

> You can say that a spider scientifically is not an insect.
> You cannot say a dog is an insect.

These are (or at least could be) examples of applications of phylogenetic 
definitions to a particular phylogenetic hypothesis. :-)

> Words have to be viable. PhyloCode cannot fully win in science if all it 
> has
> conquered are the scientists.

Here I agree. The makers of definitions must think through the potential 
consequences of the definitions they want to coin. There are several rules 
and recommendations in the current draft of the PhyloCode that are concerned 
with this. As I've mentioned, some of those can already be interpreted as 
not allowing the currently (in narrow circles) "popular" definition of 
Reptilia.