[Taxacom] quote of the week

Pierre Deleporte pierre.deleporte at univ-rennes1.fr
Thu Mar 20 08:44:55 CDT 2008

self-quotes of the week :

Sequences are not passing by 'pre-aligned' out there in nature;
but neither do squeletons and anatomies.

Morphologists do have 'alignment problems';
some mammals appear to have 12, 13, or 14 pairs of ribs...
and snakes can show many more
(they were likely paid by vicious molecularists for behaving such a 
tricky way). 

Aligning bird and human squeletons was an enlighting biological conjecture,
despite the frustrating fact that squeletons themselves obstinately 
refused to align spontaneously
(such a lack of cooperative spirit is absolutely baffling ...).

Homologies are concepts, inferred properties,
they are not observable material systems or processes (= changes in 

Ears exist in  nature as things protruding on living beings, not 
while homologies do not exist in themselves,
except as sequences of thought activities in human brains.

When nobody is thinking some homology, no homology is "existing" 
properly on Earth;
(which is not to say that the homology is erroneous when thought).

Confusing interpretative concepts with objectively 'observable' material 
or processes has one name (at least): naive positivism (pleonasm).


Hovenkamp, P. (Peter) wrote :
> John,
> >From your opponents you require the same infallibility that you claim
> for yourself. Both are unrealistic.
> They observe two sequences. They conjecture an alignment.
> You observe two ears. You conjecture homology.
> Same difference. 
> Peter Hovenkamp
>> Subject: Re: [Taxacom] quote of the week
>> I guess it is radical, but then it's the molecularists who have pushed
>> the distinction (and superiority) of molecules.
>> I can observe or define an ear homology as something that exists in
>> nature. When alignment is involved, as it is so often, homologies are
>> created that do not exist in nature - they are the product of one or
>> more alignment programs. So the sequences are empirical, but the cross
>> species homologies of sequences are not when they are the product of
>> alignment.
>> John Grehan
Pierre Deleporte
Université de Rennes 1
CNRS UMR 6552 
Station Biologique de Paimpont
F-35380 Paimpont   FRANCE
Téléphone : 02 99 61 81 63
Télécopie : 02 99 61 81 88

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