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Re: The need for RDF in Linked Data

From: Gregg Reynolds <dev@mobileink.com>
Date: Mon, 17 Jun 2013 04:01:38 -0500
Message-ID: <CAO40MimD2CBzyCjumBN0seeVTvEDrEf=Wf2arRufyiH9ab1s3A@mail.gmail.com>
To: David Booth <david@dbooth.org>
Cc: semantic-web@w3.org
On Mon, Jun 17, 2013 at 12:26 AM, David Booth <david@dbooth.org> wrote:
> There seems to be some persistent misunderstanding about the role of RDF in
> Linked Data, as evidenced by comments like the following:
>
>   "RDF is just one implementation of Linked Data"
>
> If Linked Data is intended to support the goal of the Semantic Web, then
> unless the Semantic Web is re-architected with a new foundation, RDF is
> *essential* to Linked Data -- not optional, and not merely one potential
> choice among many.  the reason is that the Semantic Web critically relies on
> the use of *both* a standard universal identification convention (URIs) for
> its vocabulary, *and* a standard universal information model (RDF) for
> making statements.

This whole issue goes away if you move to general language:  LD means
naming things and making claims.  You could make a slogan from it:
"Name 'n Claim!"

An example of LD is the a tag in HTML:  <a href="http://...">foo</a>
implicitly claims that the IRI-designated resource is about foo.
"Implicitly" because the semantics are baked-in to HTML.  (Use of an
HTTP IRI also makes an implicit claim, namely "you could look it up".)
 RDF extends this by making it possible to express relation claims
explicitly.

That RDF is essential - i.e. necessary - to LD practice is patently
untrue.  The web evolves; it will not be surprising of other ways of
expressing claims using IRIs (or something else) emerges.  An obvious
possibility is to use a pair of IRIs to express predication.
Discouraging innovation by insisting "RDF now and forever!" seems
unwise.

>
> For example, suppose the client application dereferences a URI and obtains a
> comma-separated-values (CSV) document.  unless the client application knew
> how to interpret that file, it would not be able to make meaningful use of
> that data.

First line contains headers.  Client displays data in tabular form.
Seems like a meaningful use of data to me.  Make the headers IRIs and
you can follow the links.  No RDF.  No universal info model.

>
> why couldn't other sufficiently powerful information models achieve the same
> Semantic Web goal just as well, and be used in addition to RDF? Because that
> would fragment the web.  instead of one web we would have many webs, each
> one its own walled garden,

I don't have a problem with multiple webs.  I think it would be a good
thing.  If they were all open and useful, they would learn to play
nicely with each other.

> If the term Linked Data is "hijacked" by a broader population to mean *any*
> sort of data that is linked -- not necessarily RDF -- then this will be a
> major loss to the Semantic Web community, because it is very hard to come up
> with simple ways to communicate the essence of the Semantic Web.

Naming and claiming seems pretty simple to me.

Selling JSON-LD as a LD and/or RDF solution seems unobjectionable to
me, but it's a separate issue from whether use of RDF is a necessary
condition for calling something LD.

Cheers,

Gregg
Received on Monday, 17 June 2013 09:02:08 UTC

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