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Re: Stratigraphy, biogeography & cladograms

>>Taken at face value, this comment means that any old method of
providing testable hypotheses is as good as cladistics, as long as the
hypotheses really are testable.>>

Right, I agree with you on this point: in the context of the origin of
birds I guess I am arguing that the alternative proposals do not fulfil
the criterion of testability no.

>>If you believe we cannot ever know the truth, then why would you
bother making hypotheses at all?>>

I think this comment must be read within the context of the fossil
record in question and its inherent incompleteness ... I think we would
all accept that it is unlikely that we have all the relevant fossil
information such that our phylogenetic hypotheses will really be _the
truth_, if you see that I mean ... perhaps if we all worked on forams,
the picture would be somewhat different !.

>>After a while, after you've tested a hypothesis in all manner of ways,
after you've discarded allalternatives, what remains--the hypothesis
that passes all the tests--must be the truth. Starting with, say, all 50
theoretically possible phylogenies, once you have discarded 49 of them,
the one that remains must be true. So truth is attainable, even in
phylogenetic analysis.>>

I agree again with you, of course, but _only_ in the presence of a 100%
complete fossil record ... 


Gareth J. Dyke
Dept of Earth Sciences
University of Bristol
Wills Memorial Building 
Queens' Road
Bristol BS8 1RJ UK

www: http://palaeo.gly.bris.ac.uk/