[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: Synapomorphy Wars

Dinogeorge@aol.com wrote:
> In a message dated 97-08-04 14:54:59 EDT, smithjb@sas.upenn.edu (Joshua
> Smith) writes:
> << Also, just because an animal has a condition, does not mean that 
>  its ancestors necessarilly possessed that condition (sauropod feet, for 
>  example).  I agree that dinosaurian feet were probably pentactyl at some 
>  point, but this can not be taken as a theory.  It is still mearly a 
>  hypothesis--and one that need not be true.   HOW many times have wings 
>  evolved? >>
> If the number of pedal digits is free to vary in any manner whatsoever, then
> so is any other character at any locus, and therefore all cladistic analysis
> is completely meaningless. This is the content of your message. Not even I
> can agree to that.
        That was not what I was implying. However, since you brought it up:

        Just because we have a fancy new toy does not mean that it works 
the way that we think it does.  We are all proud of ourselves at our 
cleverness and are quick to pat ourselves on the back and say "yes, what 
a good job we have done, we have a method here that is really going to 
shape up the way people do phylogeny work."  That is also what R.S. Lull 
thought when he created the coordinate analysis method of doing ichnology 
in 1901 and nobody today has even heard of that.

        There is no way to tell if our little technological marvel here 
will stand the test of time except to test it WITH time.  Test it and 
test it and test it.  That is what science does.  We have been studying 
evolution for about a hundred years.  That is a pathetically short amount 
of time, and we are going to be arrogant enough to say we have a handle 
on how it works?  Whatever.  To say that something in evolution cannot 
work because it will invalidate the claditistic methodology is akin to 
breaking the tails of certain hadrosaurian dinosaurs in a certain museum 
in London because we of course knew at the time more about the anatomy of 
the dinosaurs we were mounting than the dinosaurs did.

        I am NOT defending against your interpretation of my statement 
(i.e., that the number of pedal digits is free to vary in any manner), I 
am arguing against the rationality by which you argued your point.  I 
have no data to support or reject the hypothesis of the number of pedal 
digits and the manner in which they vary (which WAS my original point (I 
think, it has now been a while...)).  What I am saying is that to say 
that pedal digits cannot vary in that manner because if they do it will 
invalidate a semiquantitative operational method that we have created
is not valid.  It might even be considered ridiculous...

Josh Smith
Department of Geology
University of Pennsylvania
471 Hayden Hall
240 South 33rd Street
Philadelphia, PA  19104-6316
(215) 898-5630 (Office)
(215) 898-0964 (FAX)