Re: An intuition pump

From: Jim Hendler <hendler@cs.umd.edu>
Subject: Re: An intuition pump
Date: Tue, 23 Sep 2003 13:10:27 -0400

> 
> snip
> 
> >>  >I am not against the deliberate self-imposition of a fixed common meaning
> >>  >for vocabulary terms.  Even though this is not common in human discourse,
> >>  >there are many cases where a fixed common meaning is useful, in particular
> >>  >when systems with very limited reasoning power are employed.  However, I am
> >>  >against the simple use of a vocabulary term committing one to a fixed
> >>  >common meaning, and much in favour of an explicit mechanism (e.g., imports)
> >>  >for this commitment.
> >>
> >>  this is what I cannot really understand -- it's where I'm really
> >>  looking for a use case that shows a difference --If you and I both
> >>  refer (in different places) to http://.../user/pfps#PerfectBeing we
> >>  don't need to import the page to see if we are referring to the same
> >>  thing.
> >
> >I think that we very much do need to determine what information we believe
> >about http://.../user/pfps#PerfectBeing before we can determine whether we
> >are using it to refer to compatible notions.
> 
> my point exactly - but you miss the importance of the reference in my 
> brain dead approach -- look, two scientists can know if they are 
> pointing to the same box before they look inside - however, if they 
> want to be sure they have the same cat in the box, they need to open 
> it - otherwise one may think the cat is dead, the other may think it 
> alive (or not a cat at all).   The point I make is that "which box" 
> and "what's inside" are different issues - and the first is easy on 
> the web, which makes the second possible.

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.

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.  

> >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.

> >>  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''?

> >>  Note also that a URI with nothing there (i.e. no dereferencerable
> >>  document or a non-document URI) works in the above anyway - the owner
> >>  makes no claim as to the meaning of the URI, but other systems
> >>  grounding at that URI can at least agree they are refering to the
> >>  same "box" despite it's null content
> >
> >Well, I would like to be able to have the Semantic Web concern itself with
> >something besides boxes.  Perhaps all that you mean here is a common
> >vocabulary.
> 
> I mean building common vocabulary more easily because "symbol 
> grounding" is an essentially solved problem - the main difference 
> between KR on the Web and KR in the real world IMHO

[...]

Huh?  I fail to see how the Semantic Web provides any traction here at all.
I even think that the Semantic Web makes the ``symbol grounding'' problem
harder because it beings some of the thorny issues in KR closer to the
fore.  My view is that this effort should try very hard to come up with
partial solutions that don't need to open up these cans of worms (while
still not excluding incorporation of the worms into future extensions).

Peter F. Patel-Schneider

Received on Wednesday, 24 September 2003 08:25:39 UTC