Who is the postivist?

[Tom DiBenedetto]

, sylvia hope wrote:

>Tom diB wrote:

>>A synapomorphy does not support a hypothesis of homology; it IS the
>>hypothesis, left standing after the test of congruence. Neither does
>>it "support" the hypothesis of monophyly, for it IS the hypothesis of
>>monophyly, left standing after the test of congruence.

>          This is murky.  An hypothesis of homology is *arrived at* in
>          the first place by comparison of characters
>           in two or more taxa; it is *tested* or *validated* by
>          congruence with other character evidence.

gee, I'm not sure what I said that is all that murky,,,in any case I
agree with your non-murky formulation; it seems very much in line
with all I have said.

>          A synapomorphy is not an hypothesis, it is an hypothetical
>          construct

now that seems a bit murky! Not a hypothesis, but a hypothetical
construct??
(Actually I love being introduced to ever more refined levels of
semantic subtlty).

>        which results from a successful attempt to
>          validate an hypothesis of homology.

So we have a hypothesis of homology, we successfully validate it,,,it
is a conclusion (I have said all of this in the course of the last
few posts),,,but since we never stop our investigations, nor assert
that we have the absolute truth, it also remains a (corroborated)
hypothesis,,,,,,no?




Tom DiBenedetto                 http://www-personal.umich.edu/~tdib/
Fish Division                                   tdib at umich.edu
University of Michigan Museum of Zoology