Fw: Gaia theropod follow-up: a "new" phylogeny

["philidor11" <philidor11@snet.net>]

Forwarded by request.


----- Original Message -----
From: "Jeffrey Martz" <jeffmartz@earthlink.net>
To: "philidor11" <philidor11@snet.net>
Sent: Saturday, October 14, 2000 12:16 AM
Subject: Re: Gaia theropod follow-up: a "new" phylogeny


> philidor11 wrote...
> >As I read them, you're making two different points in this paragraph.
> >Both are built on an implicit answer to the question 'will a cladistic
> >analysis produce a correct answer without the intervention of the
analyst?'
> >[snip] Because your second observation assumes that the analyses can
> produce
> >inaccurate results, I think your answer would be no, that the analyst is
> >necessary.
>
>
>     No, a cladistic analysis cannot produce a correct answer without the
> analyst, and yes the analyst is neccessary...because the analyst is the
one
> who has to program the analysis in the first place.  The analyst doesn't
> just stand innocently by while PAUP programs itself and screws up its
> interpretation of the data.  Your question is a little bit like asking
"will
> a calculator produce a correct sum without the intervention of the
analyst"?
> The calculator can't press its own buttons.  If you enter in the wrong
> numbers, it isn't the calculator's fault if it spits out the wrong answer.
> And no, this potential for error, regardless of whether it is the
analyst's
> or the algorithm's fault, does not mean the method is useless (see
below)...
>
> >If the answer is yes, then you would have to assume that evolutionary
> >principles, the Universal Law, are perfectly reflected in the algorithm.
>
> >[snip] I like the observation in another post that essentially the use of
> >cladistics is to demonstrate a process of thought.
>
>
>     I'm not sure what that is supposed to mean.  I think cladistic
analysis
> is a basically a way of ordering information that helps us to see
particular
> sorts of patterns that we are looking for.
>     I think you are (somewhat disingenuously) trying to make cladistics
> sound invalid by creating the impression that cladistic analysis is has to
> omnipotently be able to program its own data without the subjective
limited
> input of a human analysts and produce perfect results in order to tell us
> anything useful.  This is balony.  Its like saying that radiometric dating
> is useless because it has a margin of error, or (perhaps a better analogy)
> that all the eyewitness accounts of a crime should be completely ignored
> because we know that eyewitnesses can make errors.  There is still
> interesting infromation to be gleaned out of an analysis, regardless of
> whether or not it gives perfectly flawless results.
>
> >The problem with that is the algorithm becomes a limitation, in that the
> >logic available to the analyst is what is available to her/him through
the
> >computer program....
>
>
>     This is a common assumption I have noticed with criticisms of
cladistics
> on this list, and is probably true of a lot of cladists; however, it is
not
> true of all cladists, and it is not implicit in cladistic analysis that
you
> can't think outside the patterns that the program gives you.  An analyst
can
> consider the effects that unidentified reversals and convergence might
have
> on the phylogeny, even if the analysis can't recognize them.  You don't
get
> a Borg implant when you buy PAUP that forces you to think only what the
> analysis gives you.
>
> >Why not abandon the cladistic structure if you have to
> >defeat it by denying it the full set of characters in order to determine
a
> >correct solution?
>
>
>     Again, cladistic analysis isn't "defeated" just because PAUP isn't an
> omnipotant and can't identify every case of reversal and convergence that
> could skew the analysis  Tweaking the data matrix is a way of trying to
get
> around the limitations of the data that the analyst programs in.
>
> LNJ
> *****************************************************************
> It is our duty to make the best of our misfortunes and not to suffer
passion
> to interfere withour interest and the public good.
> -George Washington
>
> It is your business when the wall next door catches fire.
> -Horace
> *****************************************************************
> Jeffrey W. Martz
> Graduate student, Department of Geosciences, Texas Tech University
> 3002 4th St., Apt. C26
> Lubbock, TX 79415
> http://illustrations.homestead.com/Illustration.html
>