🚀 go-pugleaf

In article <Bwt05K.70C@nic.umass.edu> 
danco@titan.ucc.umass.edu (DANIEL F COHEN) writes:

>In article <1992Oct21.170822.1775@CSD-NewsHost.Stanford.EDU>
>casley@Tarski.Stanford.EDU (Ross Casley) writes:

RC:
>>As you note, "all crows are black" and "all non-black objects are
>>non-crows" are logically equivalent.  Now it is reasonable to consider a
>>black crow as a small piece of evidence for all crows being black; collect
>>enough such instances and no counterexamples and you can consider "all
>>crows are black" as being established by observation.
>>
>>But by exactly the same reasoning finding a non-black non-crow should be a
>>small piece of evidence supporting the proposition "all non-black objects
>>are non-crows," hence it should support "all crows are black."  But this
>>obviously doesn't work.  So there's something odd about this notion of
>>evidence.  Either it doesn't respect logical equivalence, or it is not
>>possible to tell what counts as evidence for a proposition from its
>>logical form.

Having resisted entering this morass for some time, I will venture a few
remarks on its subject.  Hempel's crow paradox, as well as the closely
related "grue" paradox of Goodman, are absolutely unproblematic from a
standpoint not bound by their respective allegiance to Empiricism and
Nominalism.  Neither non-black, nor non-crow, nor indeed grue objects form
a natural kind; the latter holds in any world not characterized by abrupt
color shifts, while the former calls for an intensional reading of the
attributes, combined with a colorful, multi-species universe.  The lucky
Platonists in the audience may follow me in disembarking from this decrepit
vessel right now; with but a little confidence, you too can learn to walk
on water.  To the rest of you I heartily wish good luck in rebuilding it
while attempting to keep it afloat.  Keep the life preservers handy,
though, and remember the fate of the _Medusa_.

>>-Ross Casley

DC:
>Just for fun:
>
>If you define the universe as containing only a fixed and finite number of
>objects to which properties may be ascribed (a favorite assumption for some
>CS folks of my acquaintance), then there is a very clear way in which the
>observation of non-black non-crows provides support for the hypothesis 
>that 'All crows are black.'

Isn't it a pity, though, that favorite assumptions of your CS pals have
absolutely no bearing on the universe which they inhabit!  As if one needed
any more proof that Computer "Science" isn't... would anyone care to recall
Socrates' comparison of rhetoric to cookery?

On the last subject, I heartily recommend Julius Moravcsik's new book,
_Plato and Platonism_, which takes a place of honor in my library next to
the late Gregory Vlastos' magisterial final opus.  With more works of this
sort, we may yet succeed in decapitating the Pragmatist Hydra, which has
usurped the throne of the New World Order for over a century.

>Dan Cohen
>
>danco@philos.umass.edu
>danco@titan.ucc.umass.edu 

cordially,
mikhail zeleny@husc.harvard.edu
"Un de mes plus grands plaisirs est de jurer Dieu quand je bande."