W3C home > Mailing lists > Public > www-rdf-comments@w3.org > January to March 2004

Re: Media types and assertions

From: Pat Hayes <phayes@ihmc.us>
Date: Thu, 11 Mar 2004 21:43:08 -0600
Message-Id: <p06001f0bbc76e07b30d2@[]>
To: Mark Baker <distobj@acm.org>
Cc: www-rdf-comments@w3.org

>On Thu, Mar 11, 2004 at 03:04:42PM -0600, Pat Hayes wrote:
>>  >If somebody on the Web can't distinguish between an RDF message which
>>  >says "Mark hates bananas" versus one that says "Mark hates bananas (but
>>  >not really)" (aka unasserted),
>>  But that isn't the right way to express the distinction. "Mark hates
>>  bananas" means what it means in either case, and its this bare
>>  propositional meaning that the specs talk about and which is
>>  identified by the media type (I actually think that media type isn't
>>  the right tool even for this, but I know I'm in a minority on this
>>  issue and so don't press the point). Not asserting something isn't
>>  asserting it with a qualification: it is just, well, not asserting it.
>Sorry, I should have been clearer.  What I meant by "but not really"
>was "not asserted".
>>  >then there is a failure to communicate.
>>  Communicate about what? The content is communicated accurately.
>As it would be if it were transferred with text/plain or

Not at all. Unless you know it is RDF, you don't even have a chance 
of getting at the content. Conveying it as text/plain doesn't even 
tell you how to parse the logical form.

>The Web is concerned with more than content, it's concerned with being
>able to serialize up meaning at one end of the pipe, and have it
>accurately reconstituted at the other end.  The media type tells us what
>spec to use to extract meaning from the document encapsulated in a Web
>message, and so is arguably the most important piece of metadata used in
>this process.

Ok, no argument with that. That's why one needs an RDF media type, to 
inform the engines that this is RDF rather than plain XML or plain 
text. But all that is basically about what syntax level to parse it 
at, so one can get at the semantics. Asserted or not asserted, it is 
still RDF rather than plain text.

>  > The
>>  intent of the publisher is not communicated: but where is that
>>  communicated anywhere on the Web?  Publishers of commercial websites,
>>  Blogs and webcams may all have very different intentions and goals,
>>  but they all publish HTML, which is all that the web protocols
>>  concern themselves with.
>And they all publish their HTML using text/html.  If they published it
>with text/plain, then they're publishing different information.

They are publishing different information about the FORM of the 
publication itself, about what kind of textual stuff it is. They 
aren't publishing different information about their intentions. 
Information is one thing, intention about what should be done with 
the information, or what promises are being made by publishing the 
information, are another thing altogether.


>Mark Baker.   Ottawa, Ontario, CANADA.        http://www.markbaker.ca

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Received on Thursday, 11 March 2004 22:43:10 UTC

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