a phenetic-cladistics saga (abridged) - was parapla ying (and bullies)

[pierre deleporte]

At 11:43 10/04/2004 -0500, Richard Zander wrote:
>Logic itself has some limitations. In books of logic, "inference" means
>deduction. Not induction. Maybe I'm splitting hairs here, but a
>long-standing sophistical gimmick relies on deduction alone to prove a
>point.

Guessing the past from the present state of affairs given a transformation 
law is "deduction backward" (in time); some call it abduction (after 
Peirce), others call it "hindcast". This is what phylogeny inference is all 
about (evolutionary cladistics, maximum likelihood, molecular clock 
approach...). Relative to time, it is symmetric to the classic deduction 
"forward" (deductive prediction, forecast...): given the present state of 
affairs, predict the future given a transformation (or evolutionary) law.
In both cases it's an exercise in logical consistency, and in phylogeny 
inference it's a matter of choosing the optimal topology for explaining the 
data given the law.

Phenetics consist in providing the optimal topology given some 
classificatory law, with no evolutionary dimension this time, except under 
the molecular clock transformation law.

Why not call them inference? Any problem?
I would rather equate "induction" with "mere generalization from particular 
observations". But maybe I'm wrong...

>Aquinas, according to Chesterton, promoted the idea that if you choose the
>correct first principle, then all deductions must be correct. Ergo, all
>dogma was rational and scientific.

Maybe "rational" in the restricted sense of "logically consistent" (a 
rational ontology should be materialist, in my view), but certainly not 
scientific.

>Note that induction and experimental
>verification are absent. Is there a lesson?

You're correct in pointing that logics per se can be applied outside 
science (and even dealt with just for logics' sake: see mathematics...). 
When I insist on logics as a way to "reconcile" scientific views, I 
implicitly mean logics in the context of scientific explanation, of course 
(which include scientific observations and experiments - when possible), 
not logics in other contexts (example: arithmetic exactness in counting 
angels on top a pin).
My point was that bullying or obstinating in a logically inconsistent 
position has no chance in science, because all scientists agree to apply 
logical consistency as a criterion of quality for their scientific theories.
Example: persisting in saying that characters can be phenetic" or 
"cladistic" per se, and calling "phenetic" instead of "binary" a two-state 
character or character coding, or denying the possibility of cladistically 
analysing molecular data when scientific journals are full of such 
analyses, has strictly no chance (even in the very short run... ;-).
Simply because it does not make any sense at all, logically speaking, and 
this does matter in science, beyond anybody's good or bad temper and 
personal feelings.

Pierre

>____________________
>Richard H. Zander
>Bryology Group
>Missouri Botanical Garden
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>-----Original Message-----
>From: pierre deleporte [mailto:pierre.deleporte at UNIV-RENNES1.FR]
>Sent: Friday, April 09, 2004 5:21 AM
>To: TAXACOM at LISTSERV.NHM.KU.EDU
>Subject: [TAXACOM] a phenetic-cladistics saga (abridged) - was
>paraplaying (and bullies)
>
>
>I don't believe too much in personalizing the evolution of scientific
>thought. Bullying has strictly no chance against logics in the long run (I
>hope so), we certainly have better uses for adrenalin, and possible
>"reconciliation" should strictly be a matter of logics, not personal
>feelings. Science is neither a democraty, nor a family circle.

Pierre Deleporte
CNRS UMR 6552 - Station Biologique de Paimpont
F-35380 Paimpont   FRANCE
Téléphone : 02 99 61 81 66
Télécopie : 02 99 61 81 88