Fish with mild (Sheesh spinoff)

["A.P. Hazen" <a.hazen@philosophy.unimelb.edu.au>]

Mike  Taylor wrote:
	I hate to disagree with you, Tom, but -- well -- I disagree.
	I don't see how this is any different from asking "I wonder
	why no fish developed the ability to suckle their young".
	If someone asked that question, I wouldn't expect to see
	responses saying "One subclade did", referring to Mammalia.
I'm sorry, I don't recall the specifics and can't give a reference, 
but I believe there is a FISH (in the unreconstructed pre-cladistic 
usage of the term; I believe also in the clade Actinopterygia, which 
does NOT include tetrapods) that has essentially evolved that: 
parents (no, I don't know if of one sex or both) secrete something 
from their skin which the babies eat.

   [[[It's something with a bit of a footnote in philosophical 
history.  Philosophers of language back in the  1960s were concerned 
with the relation  between the MEANINGS of words  and the BELIEFS (or 
THEORIES) accepted by the users of the words: there seem to be 
grounds for thinking that meaning is derivative  from the contexts in 
which a word  is used, so...  And one example often discussed was the 
question of whether the MEANING of the word FISH changed when people 
decided that whales weren't fish.  One of the better papers on the 
topic
	Michael Slote, "The theory of important criteria," in
	"Journal of Philosophy" v. 63 (1966), pp. 211-224
proposed a definition of FISH -- every clause, I seem to remember, 
would have excluded some Actinopterygian species.  A sobering lesson 
on the complexity of our understanding of ordinary language and -- to 
bring things a bit back to the DML's topic -- a demonstration that 
names of "kinds" of animal HAVE to be interpreted as referring to 
lineages and not to groups defined in terms of common features.]]]

Allen Hazen
Philosophy Department
University of Melbourne