FWD>certainty/un

[Warren Lamboy]

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Meredith Lane writes:

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Date: 28/07/1995 17:41
From: Meredith A. Lane
>If ecology and animal behavior tolerate uncertainty, that is their
>>business,and is hardly a justification for systematics doing so.


Mediocre spirits demand of science the kind of certainty which it cannot
give, a sort of religious satisfaction. Only the real, rare, true
scientific minds can endure doubt, which is attached to all our knowledge.
          -- Sigmund Freud

As an adolescent I ... craved factual certainty ... so I became a
scientist.  This is like becoming an archbishop so you can meet girls.

        -- M. Cartmill

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And Warren responds:

   Whether I am judged to be a "mediocre spirit" or quite similar to an
"adolescent" [as might be concluded from the above quotes posted in response
to my original posting quoted in the first few lines] is for everyone else to
decide.  It is very difficult to answer previous posts, and then have someone
else nit-pick away at the details of my responses.  I did not mean that I
would not tolerate any uncertainty as a scientist; what I have been saying all
along is that the total uncertainty in phylogeny reconstruction methods is so
great that it exceeds my capacity to accept it.  I might mention that I was
originally trained as a mathematician, later as a statistician, and finally as
a botanist, and I use statistical methods almost daily and certainly weekly in
analyzing RAPD data (see my papers in PCR Methods and Applications 1994, Vol.
4: 31-37 and 4:38-43) and data from SSRs (simple sequence repeats).
   It is not uncertainty in phylogeny reconstruction methods that I object to.
 It is the inability to test the methods empirically against real data.  I
mean, even astrology takes real data (birth place, date, and time), carries
them thru a complex and sophisticated procedure [beyond the ken of most of us,
I am sure, just like phylogeny reconstruction appears to many], and comes up
with predictions and recommendations.  And astrology has the added benefit
that it can be compared to reality to see how well it works!
   When I am wearing my statistician hat, I am generally concerned with
minimizing two things:  variance + bias.  As I decease the variance, my
estimates become more precise (have smaller standard errors) -- although the
estimates themselves may differ wildly from the true value, if the estimates
are biased.  I would conjecture that as we pile up more and more data sets and
different types of data from a specific phylogenetic group of interest we do
decrease the variance, but we do not know how biased the results are, nor what
we can do about it.  Extinction has a tremendous effect on how well we are
able to reconstruct phylogenetic trees, and I'll bet it has occurred in almost
all but the very most recent plant groups.  This source of difficulty can
never be removed from the picture.

-Warren