Re: Proposed issue: What does using an URI require of me and my software?

On Tuesday, September 23, 2003, at 04:07  PM, Graham Klyne wrote:

> At 14:49 23/09/03 -0400, Bijan Parsia wrote:
>> ---- Original message ----
>> >At 11:00 23/09/03 -0400, Bijan Parsia wrote:
>> >>The main line is "that use of a URI in RDF implies a commitment to  
>> its
>> >>ontology".
>
> [...]
>
>> >I originally read that statement loosely as meaning something like  
>> "Using
>> >the URI in RDF is to make statements about what the owner of the URI
>> claims
>> >it to identify".
>>
>> See Pat's claims that this kind of separation doesn't work for  
>> concepts and
>> relations.
>
> If you're referring to Pat's earlier posting to this list, I didn't  
> observe any such claim.   (Quite possibly my oversight.)

 From  
http://lists.w3.org/Archives/Public/public-sw-meaning/2003Sep/0047.html:

"""Not strictly analogous, because you are not a concept. Your date of  
birth is just a fact, which can be misrepresented by a falsehood.  
Concepts are not real things that have crisp edges beyond which  
falsehoods can be discerned. If I say that marriage means a social  
union between two consenting adults, and Joe says that marriage is a  
pact between a man and a woman made before God, do Joe and I disagree  
about a question of fact or about the meaning of the word "marriage"? I  
think the latter is the only option that makes sense.""""

I read your claim as being similar to the suggestion I made that a URI  
which is, say, rdf:type owl:Class "identifies" *some thing*. The URI  
owner can make assertions about it (e.g., that it is rdfs:subClassOf  
wordnet:woman) and so can other people (e.g., that it is  
owl:complementOf wordnet:woman).

(I don't endorse this view, but I was surprised, given the RDF model  
theory, that Pat didn't endorse something like it.)

> My perspective is that there are, quite clearly in my mind, (at least)  
> two kinds of "meaning" associated with RDF, or indeed any descriptive  
> data:
>
> (1) that which is defined in formal terms, and which can be subjected  
> to formal analysis. ("formal meaning")
>
> (2) that which exists by virtue of consensus between people. ("social  
> meaning")

Uh...And you do think that 1 is a subset of 2, yes? Or what has RDF  
Core been doing?

Perhaps worse as i ordinarily think of meanings as getting  
*formalized*. Thus, all meaning is subject to (more or less successful)  
formal analysis.

> If one takes a purely formalistic stance, then the second kind is no  
> meaning at all.

I think this is on a wrong track.

>  But surely there's more to life, the web and everything than  
> formalism?  In particular...
>
>> Plus, your reading seems pointless. Operationally, what does it  
>> affect?
>
> ... it affects the ways that people might write software to process  
> RDF containing said URI.

Yes, that's what I'm after. But I want to know what those ways are. I  
wouldn't mind formalizing them, if at all possible. owl:imports (at  
least according to pat) isn't formalized (or even semantically clear).  
But it specifies SOMETHING. And it makes a difference when writing owl  
reasoners...believe me.

>  (Does writing a program to process some URI in RDF is a particular  
> way give some added formal meaning to the URI?  Whatever the answer, I  
> don't see that it helps us to formally reason more thoroughly about  
> the thing referenced.)

I'm really not sure what it *is* to "reason formally".

But it still seems red herringland. Right now, I want to know if I have  
to reason over the transitive closure of the set of documents  
retrievable by the set of URIs in some RDF document, rather than over  
the statements in the RDF document alone, or over some specifiable  
subset of that transitive closure. And then, there's the freshness of  
the closure.

It seems to me that this is the kind of thing you can put in a spec.  
"Yes, grab that closure." Yes, it's a good idea, but you don't have  
to." "No, are you nuts?" "No,not for mere use, but if you have an  
owl:imports, then yes"

Well, ok, they'll go into an unhappy spec since there's a ton more to  
figure out.

> I perceive this debate arose because there is more meaning in RDF  
> expressions than is captured by the formal semantics, but we couldn't  
> agree how to describe the nature of that meaning.

Well, I thought it arose because Tim, specifically, though that there  
was *less* such meaning :) The fear of meaninglessness!

> One might take a view that if can't be formalized we've no business at  
> all trying to describe this "social meaning".  I don't subscribe to  
> that view.  If we don't try to describe the meaning that can't be  
> formalized, then we have no basis to judge whether a program that  
> operates on certain data in a certain way is behaving as we humans  
> believe it should do.

Describing is a kind of formalizing. Specifying is a kind of  
formalizing.

> Also, an informal description may often, I believe, be a precursor to  
> formal definitions that capture more (but never all) of the intended  
> "social meaning".

Since I've not provided a formal analysis of owl:imports, consider my  
presentation to be that precursor :)

>> > By this, using a URI *formally* means nothing.
>>
>> My understanding, both from looking at the text (see my earlier  
>> reading)
>> and from conversation, is that this is not the case.
>>
>> I don't see how to read "committment to an ontology" in this context  
>> that
>> *doesn't* have an effect on the formal meaning.
>
> Well, maybe.  I don't want to get hung up on that text.  I don't think  
> we're here to create new aspects of formal meaning.  We've got two  
> working groups doing that already.

Well, that, itself, is at issue. I don't see how to read tim's issue  
statement otherwise. *I'm* not the one to be convinced! But if we don't  
beat up on the concrete proposals, especially the ones with status, we  
risk doing nothing at all. It seems to me Tim cares about his view.

>> I mean, really, what does this "identify what the URI claims it  
>> identifies"
>> *mean*? Is it even true?
>
> Er, I don't recognize that statement.  What I said was "Using the URI  
> in RDF is to make statements about what the owner of the URI claims it  
> to identify", which explicitly appeals to a human as opposed to a  
> formal judgement of meaning.  Maybe you refer to something else?

Sorry, I meant yours.

But I still deny your distinction, between appeals to human vs. formal  
judgement of meaning. I don't know what the latter is.

I want to know the *practical* consequences of this notion of meaning.  
Specifically, that URIs have a meaning and that meaning is "under the  
control of the URI owner" and that I (document author or RDF software  
writer) should, in some sense *respect* that meaning.

What must I do to exhibit that respect. What does web/semantic web  
architecture require of me? (Nothing, imho, but others disagree.) What  
do we intend (as a community) to *specify* one must do to so respect  
that meaning.

Tim claims that we're engages in prescription rather than description.  
I want to know what I'm going to be told to *do*. If we're just  
theorizing about how the web or semantic web actually works, well,  
that's a different task. And, I say this as a philosopher, who cares?  
Why is the W3C spending money on this, or our member organizations that  
aren't universities? The W3C probably isn't THAT sort of research  
entity (nor does it seem especially well equipped to do this sort of  
research).

Cheers,
Bijan "The Sleepless" Parsia.

Received on Wednesday, 24 September 2003 05:05:47 UTC