[Taxacom] Methodological plurality [was cladistic analysis for morphological characters -- UPGMA is not cladistics]

Dan Lahr dlahr at ib.usp.br
Wed Nov 21 07:20:53 CST 2012


Hi all,

Ashley, I too feel conflicted and this: "A tree that may have good clade
support but which hangs unconnected to anything else but itself."
summarizes my attitude towards systematics (one method, multiple,
morphological, molecular, doesn´t matter).  This is too the reason why my
view is that multiple methods are meaningless -- each is showing their view
of a problem...  I advocate that science should be hypothesis testing,
which links to what Derek said: "know as much about their data as possible.
One of the benefits of using multiple methods is that doing so, and knowing
that each method has its own potential weaknesses, informs you about your
data." This is absolutely true and one great reason to experiment and
understand multiple methods.  Then you know which method applies best to
your problem.  If you have a very good reason to determine a prior in a BI
analyses, then you should do a BI.  If you´re going to end up setting a
flat prior, then you should just use ML.  They are trying to solve
different problems and are telling you different things about the world.

It is a problem with many layers.  Like someone else mentioned, this is
what makes us scientists.  Bob O'Hara has a great quote in one of his
papers that says that big questions in science are never solved, they just
dissipate as people figure out that they didn't matter, but they are
important in the development of science.  I feel this is one of those
questions.

Dan



On Tue, Nov 20, 2012 at 2:57 PM, Derek Sikes <dssikes at alaska.edu> wrote:

> know as much about their data as possible. One of the benefits of using
> multiple methods is that doing so, and knowing that each method has its own
> potential weaknesses, informs you about your data.




-- 
___________________
Daniel J. G. Lahr, PhD
Dept of Zoology, Univ. of Sao Paulo, Brazil



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