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Re: [ontolog-forum] a skill of definition - "river"

To: "[ontolog-forum]" <ontolog-forum@xxxxxxxxxxxxxxxx>
From: "John F. Sowa" <sowa@xxxxxxxxxxx>
Date: Sun, 15 Feb 2009 14:20:47 -0500
Message-id: <49986B0F.3010209@xxxxxxxxxxx>
Mike and Mitch,    (01)

I would like to comment on the following point:    (02)

MB>> According to that definition the Okavango is not a river.    (03)

MH> The Okavango surely is a strange kind of river.
 >
 > Do you really expect to hold natural language to the same
 > strictness standards as formal ones?    (04)

This question has nothing to do with the differences between
natural languages and formal languages.  It is the result
of trying to map a continuously variable world to a discrete
set of labels (i.e., words, terms, symbols, concepts, signs).    (05)

As a continuous fluid (at least to a degree far below human
perception), there is a continuous range of ways that water
can flow across a surface.  For various purposes, people label
those ways of flowing that happen to be significant for their
interests.  The way they group them and label the groupings
depends on what they consider important in their  environment.
The kind of language, natural or artificial, is irrelevant.    (06)

This is a commonly discussed issue in philosophy:    (07)

Immanuel Kant:    (08)

    "Since the synthesis of empirical concepts is not arbitrary
    but based on experience, and as such can never be complete
    (for in experience ever new characteristics of the concept
    can be discovered), empirical concepts cannot be defined.    (09)

    "Thus only arbitrarily made concepts can be defined synthetically.
    Such definitions... could also be called declarations, since in
    them one declares one's thoughts or renders account of what one
    understands by a word. This is the case with mathematicians."    (010)

Wittgenstein's *family resemblances* :    (011)

    Empirical concepts cannot be defined by a fixed set of necessary
    and sufficient conditions. Instead, they can only be taught by
    giving a series of examples and saying "These things and everything
    that resembles them are instances of the concept."    (012)

Waismann's *open texture* :    (013)

     For any proposed definition of empirical concepts, new instances
     will arise that "obviously" belong to the category but are
     excluded by the definition.    (014)

As Kant observed, precision depends on the kind of concept, not
on the kind the language used to define the concept.    (015)

As Waismann observed, if you state a precise definition for an
empirical concept (such as 'river'), you will simply exclude
many reasonable examples, such as the Okavango River.    (016)

John Sowa    (017)



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