Hennig XVIII

John Grehan jrg13 at PSU.EDU
Wed May 12 21:44:27 CDT 1999

I find the additional comments on Henning and Rosa intriguing and
it interests me sufficiently to look into the matter further.

Regarding Tom DiBenedetto's comment that he has heard that Croizat
 was prone to rather intemparate remarks I think that the remarks should
be directly evaluated case by case. The difficulty with Hennig explicitly
denying the charge by Croizat (where is this published?  - I was not aware
of it) is that Rosa preceeded Hennig, so a denial as such is not
very informative.

One does not have to be a "fan" of Rosa to take an interest in his
but since his work comprised "background knowledge" it affects historical
evalution of what might be considered to qualify as novel developments.
Since Rosa was not, to my knowledge, making a prediction of the future
of cladistics the term "prophet" suggested by  DiBenedetto would seem

 The comments by Humphries provide additional points. It would seem without
doubt that according to Humprhies Hennig introduced novel aspects to cladistics
that advanced the method over what Rosa and other earlier cladists developed.
It still remains an open question in my mind, however, of how much cladistics
comprised background knowledge for Hennig.

Perhaps Croizat's claims are fanciful at best, but I await to read a detailed
study on the matter. I no longer have my copy of Croizat's 1979 article
but I will rectify that, and perhaps raise some more specific questions on this
list for discussion.

Regarding Humphries claim that  Croizat tried to make Rosa into some
great hero to suit his own "Futurist" ends I would be interested to know
the source of this motive, particularly the explicit connection to Futurism.

Whether Humphries assertion that Croizat did not understand phylogenetic
systematics I am not in a position to say at this time, but it seems to me
that cladists disagree with each other over understanding cladistics, so
perhaps that's not such a great problem.

I think, however, that Humphries is incorrect to suggest Croizat was
among those who missed the cut since panbiogeography was not
re-invented independently of Croizat, and the panbiogeography of
today has a direct linear inheritance from Croizat's work - not to mention
Croizat's own explitic support for that program.

I agree with the complexity of history for ideas, and search for ancestors
of ideas
would be fruitless if one were looking for the ultimate source, but if there
is a chain of ideas and developments across both space and time, knowlwedge of
role of the various individuals may be necessary for understanding
the historical development of research programs.

John Grehan

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