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Re: Social meaning discussion 6th March

From: Tim Berners-Lee <timbl@w3.org>
Date: Fri, 28 Feb 2003 15:34:59 -0500
Message-ID: <3E5FC7F3.1080501@w3.org>
To: Dan Brickley <danbri@w3.org>
CC: Brian McBride <bwm@hplb.hpl.hp.com>, Jeremy Carroll <jjc@hplb.hpl.hp.com>, pat hayes <phayes@ai.uwf.edu>, Bijan Parsia <bparsia@isis.unc.edu>, Graham Klyne <GK@ninebynine.org>, RDF Core <w3c-rdfcore-wg@w3.org>

Dan Brickley wrote:

>* Tim Berners-Lee <timbl@w3.org> [2003-02-28 11:47-0500]
>  
>
>>I am concerned that you have thrown out the baby with the bathwater.
>>And still left some bathwater. ;-)
>>Our views do seem rather different
>>
>>What is required, and easy, is to say what an RDF document means.
>>
>>What is not required and a bad idea is to explain how to use it.
>>
>>1. The meaning of an RDF document is that of the statements.
>>2. The meaning of the statement is defined by the definition
>>of the predicate, as applying to the subject and object identified by the
>> definition of the subject and object terms.
>>    
>>
>
>This for me is the crux: do we mean the machine oriented 'definition'
>in RDFS or OWL or N3, or some more rounded/scruffy/social notion of 
>definition.
>  
>
Whatever is available.  It tends to depend on the term.

>Use case: I want to add 'foaf:uncle' to my FOAF vocabulary at 
>http://xmlns.com/foaf/0.1/ and intend to express as much of the conventional
>meaning of 'uncle' as I can with the technology available, ie. RDFS + 
>OWL + N3 + HTML/prose. In the case of 'uncle', most of the meaning is invisible
>to RDF/S and OWL. But most of it could be handled by N3 rules, assuming 
>we had foaf:parent, foaf:sibling, gender vocab etc.
>  
>
Well, that is a big assumption.    So let's be sepcific

{ ?x :uncle ?y } log:iff  {  ?x   :parent  [  :brother ?y ] }.

is a precise definition of the term for someone for whom parent and brother
are defined.  But this of course doesn't really help us as somewhere the
thing has to be grounded in english.

'"?x :uncle ?y" indicates that y is the uncle of x'

is an english definitoin which will do for a lot of people.
I would expect a good spec to have both.
The formal  information is a useful axiom.

>So when you say 'the definition of the predicate', that to me is where 
>our problem lies. (I'm happy btw having predicates drive the meaning 
>of statements, though I think this is something we stipulate rather than 
>show). Which 'definition' of the predicate sets the meaning?
>  
>
One would expect that any maths given with an english definition would be
consistent with it.

Tim


>Dan
>
>  
>
>>That then hands off to the relevant specs the right and the duty to
>>define their bit.
>>
>>Tim
>>sans chapeau.
>>    
>>
Received on Friday, 28 February 2003 15:36:15 EST

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