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Re: The Ordered List Ontology

From: Sandro Hawke <sandro@w3.org>
Date: Thu, 01 Jul 2010 00:16:22 -0700
To: Pat Hayes <phayes@ihmc.us>
Cc: Harry Halpin <hhalpin@ibiblio.org>, Dan Brickley <danbri@danbri.org>, Toby Inkster <tai@g5n.co.uk>, Graham Klyne <GK@ninebynine.net>, Bob Ferris <zazi@elbklang.net>, Linked Data community <public-lod@w3.org>, Semantic Web <semantic-web@w3.org>
Message-ID: <1277968582.2036.523.camel@waldron>
On Thu, 2010-07-01 at 01:53 -0500, Pat Hayes wrote:
> On Jun 30, 2010, at 6:24 PM, Harry Halpin wrote:
> 
> > On Wed, Jun 30, 2010 at 8:17 PM, Pat Hayes <phayes@ihmc.us> wrote:
> >>
> >> On Jun 30, 2010, at 1:15 PM, Dan Brickley wrote:
> >>
> >>> On Wed, Jun 30, 2010 at 6:34 PM, Pat Hayes <phayes@ihmc.us> wrote:
> >>>>
> >>>> On Jun 30, 2010, at 6:45 AM, Toby Inkster wrote:
> >>>>
> >>>>> On Wed, 30 Jun 2010 10:54:20 +0100
> >>>>> Dan Brickley <danbri@danbri.org> wrote:
> >>>>>
> >>>>>> That said, i'm sure sameAs and differentIndividual (or however  
> >>>>>> it is
> >>>>>> called) claims could probably make a mess, if added or removed...
> >>>>>
> >>>>> You can create some pretty awesome messes even without OWL:
> >>>>>
> >>>>>       # An rdf:List that loops around...
> >>>>>
> >>>>>       <#mylist> a rdf:List ;
> >>>>>               rdf:first <#Alice> ;
> >>>>>               rdf:next <#mylist> .
> >>>>>
> >>>>>       # A looping, branching mess...
> >>>>>
> >>>>>       <#anotherlist> a rdf:List ;
> >>>>>               rdf:first <#anotherlist> ;
> >>>>>               rdf:next <#anotherlist> .
> >>>>>
> >>>>
> >>>> They might be messy, but they are *possible* structures using  
> >>>> pointers,
> >>>> which is what the RDF vocabulary describes.  Its just about  
> >>>> impossible to
> >>>> guarantee that messes can't happen when all you are doing is  
> >>>> describing
> >>>> structures in an open-world setting. But I think the cure is to  
> >>>> stop
> >>>> thinking that possible-messes are a problem to be solved. So,  
> >>>> there is
> >>>> dung
> >>>> in the road. Walk round it.
> >>>
> >>> Yes.
> >>>
> >>> So this is a point that probably needs careful presentation to new
> >>> users of this technology. Educating people that they shouldn't  
> >>> believe
> >>> any random RDF they find in the Web, ... now that is pretty easy.
> >>> Still needs doing, but it shadows real world intuitions pretty well.
> >>>
> >>> If in real life you think the Daily Mail is full of nonsense, then  
> >>> it
> >>> isn't a huge leap to treat RDFized representations of their claims
> >>> with similar skepticism (eg. see
> >>> http://data.totl.net/cancer_causes.rdf for a great list of Things  
> >>> The
> >>> Daily Mail Say Might Cause Cancer).
> >>>
> >>> *However* it is going to be tough to persuade developers to treat a
> >>> basic data structure like List in the same way.
> >>
> >> Sure.  But what they need to grok is that RDF does not have ANY data
> >> structures in it (except maybe triples). It describes data  
> >> structures, just
> >> like it describes everything else. It does not PROVIDE data  
> >> structures.
> >> Maybe it should - make the case! - but then it will need to change  
> >> rather
> >> drastically in its very foundation. Triples describing lists are  
> >> not the
> >> same as triples-plus-lists.
> >
> > The issue is here that RDF started as a metadata format to "describe"
> > data I believe, and at this point with the Linked Data is now being
> > transformed into a generic language *for* data, period.
> 
> Is this really the case? I wasn't part of the very first RDF  
> initiative, but ever since I've been involved with it, its purpose was  
> pretty explicitly supposed to be for representing information - call  
> it data if you like - rather than anything "meta". I've never read  
> anything that suggest that RDF is supposed to be describing data. It  
> is supposed to be describing the world.

I agree.  See one of the inputs to RDF, MCF:
http://www.w3.org/TR/NOTE-MCF-XML-970624/

"There is no useful distinction between the representational needs of
data and metadata."

> >  The lack of
> > lists (and hashes, and other things programmers are used to dealing
> > with) in a reasonable (read "non-XML") syntax is one of the primary
> > reasons the developer community has moved towards JSON.
> 
> Well, Im all for JSON, but JSON is a programming language, not a  
> language for stating facts in. If anything, JSON would be the  
> metalanguage here, being used to do things to RDF syntax, I presume.

Well, JSON is a syntax for serializing some kinds of data used in
programming languages; it's not a programming language itself.  I expect
W3C will be doing some more work in bridging RDF and JSON soon; my most
recent (unofficial) attempt is here:

http://decentralyze.com/2010/06/04/from-json-to-rdf-in-six-easy-steps-with-jron/

In that, I don't go into the difference between a data structure
language and a KR language, because it doesn't seem to me to be a
distinction most people need to worry about.  

   -- Sandro
Received on Thursday, 1 July 2010 07:16:40 UTC

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