W3C home > Mailing lists > Public > www-rdf-logic@w3.org > May 2001

Re: Desirata for Symbols (was Re: What do the ontologists want)

From: Sandro Hawke <sandro@w3.org>
Date: Sun, 20 May 2001 08:25:09 -0400
Message-Id: <200105201225.IAA11225@hawke.org>
To: pat hayes <phayes@ai.uwf.edu>
cc: www-rdf-logic@w3.org

pat:
> sandro:
> >What possible advantage does "urn:elvis" (or any other URI-like thing)
> >have over "elvis" as a logic symbol?
> >
> >1.  We can prevent unintentional re-use.   This is like
> >    com.sun.SomeJavaClass or w3c_some_C_library_function.  Doing this
> >    allows us to skip a symbol translation stage in reasoning about
> >    two different expressions.
> 
> Several problems with this include the fact that often, with names, 
> one NEEDS to have 're-use' in order to refer to something. That is 
> largely what names are for in social use of language, if you think 
> about it. But I have argued this to death in earlier threads.

Er yes -- that's why I said "prevent UNINTENTIONAL re-use."

In logic terms, I believe this feature lets you make skolum
functions/constants.


> >    I think there are cases, with agents communicating in a multi-path
> >    network, where the translation problem becomes impossible to solve
> >    without at least a mechanism for generating unique agent (or
> >    document) identifiers.  And if you need that generation mechanism
> >    for agents, you might as well make it available for all objects.
> 
> Not all names are identifiers!  Most objects do not have identifiers 
> in this sense.
> A name-clash of identifiers is a computational error. Re-use of names is not.

Ah, sorry -- I remember you arguing about the distinction between
names and identifiers earlier, but I have neither understood nor
started using it.   When I'm writing primarily to you, I try to use
the term "symbol."  

> >2.  There are some social mechanisms in place to designate who has
> >    authority to define the denotation of the symbol.  The clearest is
> >    probably urn:oid, which involves a whole mechanism in
> >    international law deligating denotational authority.  (I don't
> >    know how well it works, but I've heard it tries.)
> 
> Denotational authority? Wow. You and I definitely live in different 
> universes. There are no laws about denotational authority. The only 
> person who has "denotational authority" (impossible to type this 
> without smiling) over the words I use is me.

I'm not saying denotational authorities work well, just that some
people try to create them.  Certainly bodies of law do define certain
terms.  In Massachusetts, I beleive I can be thrown in jail for
calling myself a "doctor" or "lawyer" (in certain situations), but I'm
certainly free to call myself a "shmoctor" or "arguer".

> >    I have no idea how this actually helps, beyond the functionality
> >    in point #1.  Who cares if symbols starting urn:oid:1.2.840.113556
> >    may only legally be "defined" by Microsoft?  How do we use that
> >    fact?
> >
> >3.  Some URIs can point humans and/or machines to some definitional
> >    text, possibly even some permanent definitional text.  But is
> >    there an advantage to
> >        "elvis according to the formal definition at http://example.com/elvi
> s"
> >        (aka "http://example.com/elvis#elvis")
> >    over
> >        "elvis234234"        [elvis with some uniqueness mechanism]
> >       with the nearby assertion
> >        ("elvis234234", formal_definition_website, "http://example.com/elvis
> ")
> >
> >    The later form gives us much more flexibilty to explore approaches
> >    to "definition", whatever that means.
> 
> The denotation of my name is me, not a definitional text.

Of course.  But some people think the symbol one uses in public for a
thing should be text which includes instructions for finding out more
about the thing.  Is that useful?

   -- sandro
Received on Sunday, 20 May 2001 08:25:13 UTC

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