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DISSENT GOOD, CONFORMITY BAD



"Stewart, Dwight" <Dwight.Stewart@VLSI.com> wrote:

<<Pet theories, believes, dogmas, superstitions, cherished personality
disorders are difficult nuts to crack.  This is especially true if one 
has
staked out (pun intended) a territory to defend.  But, at its worse, 
disagreement & scholarly debate is ultimately good for science.   
Whether or not it serves to enlighten any given individual is entirely 
up to them.  Never-the-less, it would be more interesting to me to hear 
a number of other Paleontologists debate Dr. Martin.  This is taking 
nothing away from Dr. Horner.>>

The origin of birds debate (just like other debates like the origin of 
tetrapods, early human evolution, and lichen origins) is a debate fueled 
by a majority of workers vs. a dissenting minority.  As Dwight notes, 
disagreement and debate are ultimately good for science since they allow 
us to look at the evidence with eyes open.  Although some workers on the 
minority side of the origin of birds debate are very... uh... we won't 
go there.... others like Larry Martin and Johann Welman are constructing 
alternative phylogenetic hypotheses based on actual evidence from 
fossils.  Sometimes it is the majority side of the bird origins debate 
that never faces the evidence and dares to evaluate it.  View the 
crocodylomorph hypothesis, never really seriously evaluated other than a 
few short reviews (one notable exception, though somewhat old is 
Tarsitano and Hecht, 1980; Gauthier, 1986 discussed it briefly but did 
not provide much contradictory evidence) and generally ignored today 
because Walker retreated from his original hypothesis.  Now, Walker's 
(1985, 1990) conclusions have never been evaluated critically (Martin, 
1991 and Witmer, 1991 commented briefly on the conclusions and decided 
that it did not change the Martin-Whetstone hypothesis), they have not 
been scrutinized against new fossils, but most recent reviews and 
authors just take his word for it (e.g., Padian and Chiappe, 1998).  I 
do not wish to sound like I am denegrating the work of Walker, his 
conclusions sound very valid to me in many cases, but without evaluation 
the debate cannot be closed.  It is interesting to note that Recent 
crocodilians and birds share several cranial features in common with 
each other than were considered convergences by Gower and Weber (1998), 
even though they admitted that the close similiarities could possibly be 
homologous.  

Do I believe that crocs are the immediate sister-group of birds?  No.  
The evidence for the theropodian hypothesis is very strong and cannot be 
ignored.  I believe though, that the crocodylomorph hypothesis needs 
critical evaulation before we dismiss it.  Without impartial, scientific 
evaluation of the evidence at hand by a worker who preferrably was not 
involved in the original debate (though it would not matter either way), 
we cannot dismiss the hypothesis like the majority has done so readily.  

Now which side is being thick-headed? 

Poring through scores of dissenter papers recently allowed me to look at 
the debate from an impartial observer.  It is hard to deny the power of 
the theropod hypothesis, and this power has put blinders over the eyes 
of several recent workers.  The various mistakes and questionable 
approaches of the minority side cause the workers of the majority side 
to ignore the evidence that is being presented.  Although most recent 
work by Feduccia and Martin (which was mainly written by Feduccia) does 
not deal with any evidence other than objections to the theropod 
hypothesis (objecting to a specific hypothesis does not necessary mean 
that it is not possible), most of Martin's work is very well written and 
researched with many valid points.  But this is ignored because of the 
different approaches that are utilized by Martin in his arguments.  This 
does not mean that you cannot evaluate his hypothesis through his 
characters, no matter what hypothesis he may have concluded from them.  
While it is true that some workers have made the origin of birds debate 
a personal vendeta, some workers have not and have thrown some 
reasonable evidence into the ring.  Rather than evaluating it however, 
most workers have ignored it because of the way the conclusions were 
found or from where (observe the complete silence, even from the 
minority, up to Gower and Weber's wondefully crafted paper of Welman, 
1995).  

I hope that I am not sounding rude or condescending but this is how I 
observe the debate.  On the positive side of things, there are great 
workers on either side of the debate lots of tangible evidence and 
hypotheses out there to be evaluated.  

Matt Troutman 
m_troutman@hotmail.com
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