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Re: Arbitrary science further ...
In a message dated 6/8/99 7:29:10 PM Eastern Daylight Time,
<< We all have opinions, biases, etc., and total objectivity is impossible,
but this is what we shoot for, to practice science as best as is humanly
However, regardless of the people doing the work, I'd suggest that
paleontology can be considered arbitrary in two areas. The first, as we've
discussed, is in naming. As you know, I wish that brontosaur was still in
scientific use and that dinosaurs and birds (?) had escaped classification
under reptiles. The rules are consistent and openly applied, but the outcome
could have been different without being in contradiction of fact.
The other area is shown in Mr. Headden's posting about Caenagnathus:
<< Okay, by 1972 we've got a happy little bunch of theropods (or birds,
considering Joel Cracraft's past take on Caena).
Currie and Russell (1988) synonymized Macro with Chiro on the basis on a new
skeleton; no more Macro.
Paul (1988) synonymized Chiro and Elmi on the basis of the tarsometatarsi;
relatively sound, seconded (in a sense) by Currie (1989)
-->. Currie (1989) synonymized "O." elegans with Elmi based on the
similarity of the tarsometatarsi compared to Chiro (more later); no more
"O.", now E. elegans.
Sues (1997) synonymized Caena and Chiro, long suspected but improvable until
then; no more Caena.
This made all Caena's species Chiro's...
Sues took E. elegans elegans and made it a species of Chiro, arguing that he
percieved no great distinction between the two species,
and promptly, on basis of size, synonymized C. sternbergi and E. elegans; the
latter, by facter of being named first, became the valid name.
Currie (1989) placed E. elegans with Elmi on basis of distinct fused distal
tarsals forming a cap over the metatarsus, and by possessing a posteromedial
(E. rarus is larger, more robust, and has a posterior ridge on the distal
tarsals, rather like *Avimimus* and parvicursorids (see Osmolska, 1971)).
Relative slenderness in elegans as compared to rarus and [Chiro] pergracilis
argues for some distinction from either as a species, but closer to rarus
than to pergracilis, despite that it's N.American, not Asian.
Such stratigraphic separation is not sufficient (given LK transitional
Berring bridges) for combining N.Amer. species into a genus.
C. sternbergi jaws are different from C. pergracilis in that they have a
articular face, and relatively deeper and wider surangular (e.g. more
"robust") coupled with smaller size and similar degree of fusion between the
elements. Refered jaw _may_ or _may not_ belong to the species, but
Cracraft's reasons to naming a new
species seem to me to be valid (based on proportions).
So, therefore, I'm more inclined to believe the following to be closer
This is a bravura display of erudition and judgement!
Consider the bases for decision. Only the first mentioned is based on new
data (a new skeleton). The rest are based on tarsometatarsi ('relatively
sound'), no perceived distinction between species, size, 'distinct fused
distal tarsals forming a cap over the metatarsus, and... a posteromedial
"tongue"', relative slenderness, NOT stratigraphic separation, jaws with 'a
shorter, wider articular face, and relatively deeper and wider surangular
(e.g. more "robust") coupled with smaller size and similar degree of fusion
between the elements', and proportions.
This list includes items of detailed anatomy and gross observations. Is it
possible that another paleontologist could look at this list and find other
compelling reasons for a different set of relationships among the fossils?
That is, has judgement, as opposed to universal rules, been applied? From
this distance, it appears that some of the distinctions do appear arbitrary,
though based on great knowledge and skill.
Some time ago I read that physicians in emergency rooms now have available to
them a computer program which is able to develop a prognosis for patients
which is at least as good as the one developed by the doctors themselves.
Apparently it is possible to develop invariable rules which have predictive
value. In the absence of prediction as a test, is it possible to reduce to
indifference the amount of judgement inherent in identifying relationships
As we have discussed, there are established principles, such as parsimony,
which allow choice among the various alternatives. Aren't there close calls
in at least some situations? How do you weight a factor like geography, as
in the discussion above where one animal was closer to animals a continent
away than to its neighbors?
To me, paleontology, like chess, has an element of art to it no matter what
the computers do. This art, or arbitrariness, is part of my interest.