Re: birds?

[ucleaar <ucleaar@ucl.ac.uk>]

> >I believe in fuzzy categories, and I recognize that this example is from
> >time to time used to exemplify the notion, but I think it is not in the
> >least fuzzy.  Eagles, pigeons, penguins are all indubitably birds, and
> >bats, squirrels are indubitably not birds.  These are on a TYPICALITY
> >GRADIENT [emphasis, not yelling] but not a MEMBERSHIP GRADIENT.
> Why are the former birds, and the latter non-birds?  How do you know?
> You mean you believe a biologist?  Then tell me - is an archeopteryx a
> bird?  How about those warm-blooded dinosaurs they are now
> hypothesizing.
> To make the case clearer (or fuzzier %^), how about wolf vs. dog?  They
> have separate species names, but have fertile offspring and hence
> biologically are one species.
> In any event, biological taxonomy is not the same as linguistic
> taxonomy.  I can easily imagine some observers and cultures considering
> a bat to be more a bird than a penguin.

The relevant taxonomy in this case is linguistic. It doesn't matter
what biologists think.

In certain domains of experience, such as the natural world, the categories
*seem* to be self-evident. Here's a thought-experiment: A room contains
many small cones that have yellow spots on a blue background and tassels
on their apex, and many large cubes that have red and green stripes and
small dents over their surface and that play Fur Elise when you touch
them. I predict that put anyone from any culture in that room and they'll
come up with the same categorization of these objects into the same
two classes. Show them one of the cones & they'll all agree it belongs
in the cone class rather than the sphere class. But I don't predict
that everyone will conclude that, say, spottedness is a necessary or
sufficient criterion of membership in the cone class. If in some
areas the world seems to take care of categorization itself, we needn't
bother deciding what the criteria for membership in such categories
are. And of such categories we may believe that membership in them
is not a gradient matter. Faced with problem examples of marginal
membership, that belief may be challenged, but the whole point about
categories like these is that we aren't exposed to problems of
marginal membership.

---
And