W3C home > Mailing lists > Public > www-rdf-interest@w3.org > April 2003

RE: Denotation of URIs

From: <Patrick.Stickler@nokia.com>
Date: Mon, 14 Apr 2003 16:10:16 +0300
Message-ID: <A03E60B17132A84F9B4BB5EEDE57957B01B90CCD@trebe006.europe.nokia.com>
To: <seth@robustai.net>
Cc: <pfps@research.bell-labs.com>, <www-rdf-interest@w3.org>



> -----Original Message-----
> From: ext Seth Russell [mailto:seth@robustai.net]
> Sent: 11 April, 2003 19:17
> To: Stickler Patrick (NMP/Tampere)
> Cc: pfps@research.bell-labs.com; www-rdf-interest@w3.org
> Subject: Re: Denotation of URIs
> 
> 
> Patrick.Stickler@nokia.com wrote:
> 
> >>Ambiguity of denotion is bad relative to what?  
> >>    
> >>
> >
> >Reliably communication. I.e. consider a recent example
> >
> >If the URI being used to denote who the first lady
> >is, is being used ambiguously, then there is no way to actually
> >test for any disagreement. I.e., I may assert that _:a denotes
> >Jane and she lives at address X, but that _:b denotes Betty and
> >she lives at address Y. If you use _:a to denote Betty and assert
> >that Betty lives at address X, I will see no contradiction, because
> >according to my understanding of _:a you are saying that Jane lives
> >at address X!
> >
> >So, disagreement about what a URI denotes prevents reliably
> >communication and even the ability to know if different folks
> >disagree about various things.
> >
> 
> Yes, I totally agree.  
> 
> >  
> >
> >>But such 
> >>ambiguity is not necessarily bad relative to 3 state logic 
> where the 
> >>third state is interperted as "Surprise" or "Error" and that state  
> >>tells us that the law of the excluded middle cannot be 
> applied in the 
> >>current context.  Is 3 state logic not a possible way out of 
> >>this morass ?
> >>    
> >>
> >
> >I don't think that the unambigous denotation of URIs has 
> anything (directly)
> >to do with binary vs. 3 state logic.
> >
> >Regardless which logic you use, your atomic primitives must 
> be consistent.
> >
> 
> Uuh ... that is not a true statement.  If someone (or even in 
> the future 
> some software agent) wisely uses the kind of human reasoning 
> that people 
> are accustomed to use with natural language, they should know 
> that their 
> "atomic primitives" need not necessarirly be consistent.  

Fair enough. And when a SW agent passes the Turing test, I'll
back off on my adamant position that ambiguity of denotation is
unnacceptable on the SW.

Until then...  it's bad, bad, bad ;-)


> >The inferences you make, by whatever logic, based on 
> assertions *using*
> >those atomic primitives is separate issue entirely. 
> >
> >URIs are the atomic primitives of the SW, and whatever model 
> of logic you
> >might apply to interpeting assertions expressed in RDF and 
> infering new
> >knowledge, those URIs should have globally consistent, unambigous
> >denotation.
> >
> 
> I agree,  "unambigous denotation of URIs" (U) and "what kind of logic 
> you use" (L) are two separate things.  I am just saying that to the 
> extent that you trust that you  have U,  then you can use a strong L 
> (like for instance one where A==A), to the extent that you do 
> not trust 
> U or even find that it leads to contradictions, you should 
> use something 
> else.   The fact is, and hopefully you will agree with me here, 
> everybody in the world  is just not going to use a URI to denote the 
> same thing across the board and in all cases;  and to assume 
> that they 
> will is going to sort out to be just down right stupid.  The 
> idea that 
> they *should* always denote the same thing is like the idea that 
> everybody *should* always obey the law.  

I fully agree, and have used examples which reflect this view. I don't
think that any of my posts have reflected anything that contradicts
this view.

But it seems that some folks would like to say that, since folks won't
obey the law, we shouldn't have any laws...

> I believe that the mentograph below does express that quite usefully.
> 
> http://robustai.net/mentography/3laws.jpg

I'll have a look.

Cheers,

Patrick
Received on Monday, 14 April 2003 09:10:22 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Monday, 7 December 2009 10:51:58 GMT