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Darwin-L Message Log 6:97 (February 1994)

Academic Discussion on the History and Theory of the Historical Sciences

This is one message from the Archives of Darwin-L (1993–1997), a professional discussion group on the history and theory of the historical sciences.

Note: Additional publications on evolution and the historical sciences by the Darwin-L list owner are available on SSRN.


<6:97>From ahouse@hydra.rose.brandeis.edu  Thu Feb 24 16:46:38 1994

Date: Thu, 24 Feb 1994 17:48:54 -0500
To: darwin-l@ukanaix.cc.ukans.edu
From: ahouse@hydra.rose.brandeis.edu (Jeremy Creighton Ahouse)
Subject: Re: Reconstructing backwards

        I think that cladistics is in part in the situation that Popperian
falsification fell/wandered/was thrust into.  The basic ideas were/are
crystaline and beautiful.  Now with all of the work making the tacit
assumptions of different methods explicit much of the easy insight
insisting on the importance of shared derived characters gets muddied.
        I am not sure that the lack of penetration with the evolutionary
taxonomists was due to their blinkered pig ignorance or their prescient
immediate understanding that a detailed hypothesis of evolution was implied
by methodology used to implement the cladistic insight.
        Initially the criteria that lead to skipping information about the
details of the roots and using fossil/amber... individuals as just another
terminal taxon was that this treatment would not mislocate them (in terms
of most recent shared ancestor) and there was no reason to privelege them.
There was also the (important) recognition that in a bounded branching
process (where the probablity of having and ancestor is exactly 1 and the
probability of having descendants is < 1) that the chances of a particular
fossil actually "being" the direct ancestor to anything extant was slim
indeed.
        Jeffrey's initial question about the knowledge of the details of
the tree come into play in the claim that linneage eveolution is a
branching process that proceeds by splitting off, bifurcations (rather than
many simultaneous new originations), by the insistence that there is a
continuity in the ancestor descendent relation (that they would share even
more ancestral characters), and then in the use of many particular pieces
of information; mitochondrial DNA (used in Eve hypothesis because it is
maternally passed), super-oxide dismutase (used in looking at protist
evolution because its function is vital and seems to be available early),
hemoglobin genes to look at mammal groups... there are many others.  I
don't know if knowledge of the root can be said in these cases to help
choose the traits under consideration or if it is really the other way
round that a certain level of stability is required so that we can
compare... and this feeds back on itself (like using flower part characters
to define angiosperm families, or jaw parts for understanding major
divisions in the tetrapods).
        In these details lie all of the monsters...

        - jeremy

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