Re: An intuition pump

From: Jim Hendler <hendler@cs.umd.edu>
Subject: Re: An intuition pump
Date: Wed, 24 Sep 2003 10:02:37 -0400

> At 8:25 AM -0400 9/24/03, Peter F. Patel-Schneider wrote:
> 
> >I don't think that the web is qualitatively different from even written
> >natural language in this respect.  Readers of natural languages (even
> >software) can agree on the words in an written sentence - these are, to me,
> >quite similar to the boxes you mention above.
> >
> 
> no. no, no - this is very different -- in English the string "person" 
> may have many definitions.  On the web the string 
> "http://www.../foo#person" may be said to refer to many concepts, but 
> the label is unambiguous 

I don't view it this way at all.  My view is that the English word
``person'' unambiguously labels the word ``person'', just as
"http://www.../foo#person" unambiguously labels
"http://www.../foo#person".  

- think of it as if in English I was to write
>   "No(1), No(1), No(1), this(17) is(42) very(6) different(7)"
> where each of the subscripts refers to a specific definition on a 
> specific page of a specific dictionary.   

And how is this different from

    http://...#peter (http://xmlns.org/foaf) rdf:type (http://...rdf...)
    http://www.../foo#person (http://www.../foo) .

> This would not make all 
> problems go away magically (or we wouldn't need this group), but it 
> is not the same as the first sentence I typed because you have a 
> place to reference to somehow learn more about the intended semantics.

Just as providing pointers to documents provides a place to somehow learn
about the meaning of URI references in the Semantic Web.

The situations are even closer than this.  Pointers to dictionary entries
don't provide all the meaning of a word, nor do (single) Semantic Web
documents provide all the meaning of a URI reference.

> >I do agree that there could be a qualitative difference between the
> >Semantic Web and natural languages, as the Semantic Web *could* end up with
> >many more ``words'' than even English.  (It could also end up with much
> >*fewer* ``words''.)  This could be taken as a chance to have a single-box,
> >single-meaning situation.  However, as Pat has pointed out, single meanings
> >can easily split into multiples when looked at more closely.
> >
> yes, but it would require a new URI if we then wanted to name one of 
> these new concepts.

Why?  Why would (should) a new URI be required?  Why can't (shouldn't) I
``say anything about anything''?

> >>  >When are two systems in the Semantic Web referring to exactly the same box?
> >>  >I see very, very few chances for this to happen.
> >>
> >>  whereas I see this all the time - our OWL page uses lots of links to
> >>  other people's boxes, and then displays what is there when
> >>  appropriate -- so we have a link to the W3C RSS feed without knowing
> >>  what messages will appear on our home page when that link is
> >>  exercised (via a RDF Query)
> >
> >If by box you mean URI reference, then sure, just as people use other
> >people's words.  Common meaning is, I think, another situation.
> 
> well, maybe - most people coming to http://www.cs.umd.edu/~hendler 
> seem to expect to find my web page there... common "meaning" is hard 
> to discuss, common referent seems a lot more straight forward, and 
> something to ground the meaning discussion on much more precisely 
> (See Harnad's many papers about symbol grounding and language)

I don't see a difference between referent and meaning here.

> >>  >>  So, in a sense, I interpret Tim's approach as "The owner of the URI
> >>  >>  gets to define what HE/SHE/IT means by that URI"   anyone else is
> >>  >>  welcome to say things about the owner, the predicate, the URI, etc -
> >>  >>  but they cannot change the "meaning" of that specific URI unless they
> >>  >>  do it in their space - in which case it is their claim about the
> >>  >>  meaning, not the owner's (and their URI is where they state what they
> >>  >>  claim the meaning is).
> >>  >
> >>  >I really don't understand what you could mean by ``meaning'' here.  I don't
> >>  >see that it can be ``denotation'' or ``defining information'' or anything
> >>  >else that I can relate to.
> >>
> >>  well, my point on this one is simple too - I don't understand those
> >>  either, so let's not use those words -- I still am looking for a test
> >>  case where I don't need to dereference peter:meaning to see what
> >>  breaks.
> >
> >Well, how about ``Different systems produce different results when given
> >the same initial set of information''?
> 
> I would love an operational definition like this - now can we find an 
> example? (I've been trying to create one, but keep getting stymied 
> because I'm not yet sure the implications of some of the different 
> quasi-proposals floating around)

Well, suppose I wrote a formal system that works by the strong-Tim hypothesis.
This system would be in a contradictory state if given the following
(single) premise

	<http://www-db.bell-labs.com/user/pfps/#Peter_Frederick_Patel-Schneider>
	owl:differentFrom <http://www.whitehouse.gov/president/> .

A system that implemented only RDF (or RDFS or Full OWL) would not be in a
contradictory state when given an RDF graph consisting solely of this
triple.  This should result in differing behaviour between the systems.

[...]

peter

Received on Wednesday, 24 September 2003 10:24:06 UTC