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Re: aboutness and broader

From: Leonard Will <L.Will@willpowerinfo.co.uk>
Date: Wed, 4 Jun 2008 11:25:29 +0100
Message-ID: <ZlLJfnCZ2mRIFADZ@mail.willpowerinfo.co.uk>
To: public-esw-thes@w3.org

On Wed, 4 Jun 2008 at 10:30:55, Jonathan Chetwynd 
<j.chetwynd@btinternet.com> wrote
>as always with issues around logic, the reasoning isn't always 
>apparent to the outsider...
>I'm not clear about your use of "necessarily", please can you expand 
>ie what does "mammals have breasts" tell us about animals?
>or "carrots are orange" tell us about vegetables?
>other than some B can be D? but not necessarily?
>and how does that relate to "animals are motile" not telling us about 
>ie all mammals are motile? is necessarily? though...

There is a difference between defining attributes and other attributes.

"Mammals" are a type of "animals" distinguished by the characteristic 
that they produce milk to feed their young. The facts that they have fur 
and four legs are interesting, and may be included in an ontology, but 
these do not determine hierarchical relationships in a thesaurus, 
whether or not these attributes are specific to mammals.

I don't know biological taxonomy well enough to say whether being orange 
is a defining characteristic of carrots - I suspect that it is not - 
besides the problem of "vegetables" being a rather tricky category to 
define anyway . . .

Scope notes are often usefully expressed in terms of a broader concept 
and a difference that defines a sub-set of that concept, e.g.

"flower pots" are "pots" [broader concept] "for holding flowers" 

"thermometers" are "instruments" [broader concept] "for measuring 
temperature" [difference]

The fact that flower pots may be made of clay or plastic, or that 
thermometers may be graduated in Celsius or Fahrenheit, are attributes 
but not defining attributes.

In the classic example, a valid broader relationship is

"parrots" are "birds" [broader concept] "of the order Psittaciformes" 

whereas it is not valid to say

"parrots" are "pets" [broader concept] ... with any difference, because 
not all parrots are pets.

Leonard Will

Willpower Information       (Partners: Dr Leonard D Will, Sheena E Will)
Information Management Consultants              Tel: +44 (0)20 8372 0092
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Received on Wednesday, 4 June 2008 10:34:25 UTC

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