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Re: Are URIs Resources? (WAS RE: Re: Non-infoset)

• To: Joe English <jenglish@f...>
• Subject: Re: Are URIs Resources? (WAS RE: Re: Non-infoset)
• From: Jan Algermissen <jalgermissen@t...>
• Date: Mon, 11 Apr 2005 22:30:46 +0200
• Cc: xml-dev@l...
• In-reply-to: <200504112008.j3BK8wK16033@f...>
• References: <15725CF6AFE2F34DB8A5B4770B7334EE07206DC1@h...> <200504112008.j3BK8wK16033@f...>
• Reply-to: algermissen@a...
• User-agent: Mozilla Thunderbird 1.0 (Macintosh/20041206)

Joe English wrote:

>Bullard, Claude L (Len) wrote:
>  
>
>>That's the critical observation for this and many other
>>threads that rely on ontological commitment to sustain
>>communications.
>>
>>Would anyone care to compare that to URIs as a unit of
>>information:
>>
>>1.  Is a URI a resource?
>>    
>>
>
>No.  There is no such thing as a "resource".
>
>To elaborate on that:  There are two groups that have
>spent a lot of time and energy trying to figure out
>what a "resource" is, and both have come to the same
>conclusion:  We don't know what a "resource" is, and we
>don't really care either.
>
>For lack of a better name I'll call these "the REST camp" and
>"the RDF camp".  In the REST camp's worldview, "resources"
>are formally and explicitly left undefined -- 
>
Hmm...IMHO, Roy has been pretty specific about what a resource is:

" More precisely, a resource /R/ is a temporally varying membership 
function /M/_R /(t)/, which for time /t/ maps to
a set of entities, or values, which are equivalent. The values in the 
set may be /resource representations/ and/or
/resource identifiers/."

http://www.ics.uci.edu/~fielding/pubs/dissertation/rest_arch_style.htm#sec_5_2_1_1

With GET you invoke the membership function.

Are you maybe confusing 'concept' (a humans interpretation what is being 
"mapped to a set of entities")
with 'resource'?

Jan


>you can GET
>a representation of one, or you can POST an entity to one,
>or do a number of other things, but you can never get your
>hands on the resource itself.  It's a convenient fiction.
>
>In the RDF camp's worldview, you don't do anything with
>resources either except Identify them and Describe them.
>REC-rdf-mt even goes so far as to say that:
>
>| The semantics does not assume any particular relationship
>| between the denotation of a URI reference and a document
>| or Web resource which can be retrieved by using that URI
>| reference in an HTTP transfer protocol, or any entity which
>| is considered to be the source of such documents. [...] The
>| things denoted are called 'resources', following [RFC 2396],
>| but no assumptions are made here about the nature of resources;
>| 'resource' is treated here as [...] a generic term for anything
>| in the universe of discourse.
>
>In other words: we don't know, and we don't really care either.
>
>
>  
>
>>2.  If it is a resource, what operations are significant?
>>    
>>
>
>See above.  There is no such thing as a resource.
>
>
>  
>
>>3.  Are URIs ever ambiguous?
>>    
>>
>
>Yes, but only if you go out of your way to make them so.
>
>You can follow the REST camp and treat them as mostly-opaque
>identifiers, perform GETs, POSTs, and DELETEs, and never
>worry at all about the shape of the URI itself except to
>ensure that it's syntactically valid, and maybe compose
>it with a relative URI here and there.  The last two
>are purely syntactic operations.  Do two different URIs
>refer to the same resource?  Who cares?  It's not important.
>
>Or you can follow the RDF camp, and treat them as opaque
>identifiers that can be compared for equality, again
>a purely syntactic operation.  Do two different URIs
>denote the same resource?  Only if there's an assertion
>somewhere that says they do.  Otherwise, who cares?  It's
>not important.
>
>Or you can follow the xml-dev approach, and continue
>to spend time and energy trying to figure out how many
>angels can dance on the head of a pin, and whether they're
>really dancing on the same pin or not.
>
>
>
>--Joe English
>
>  jenglish@f...
>
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>  
>


-- 
Jan Algermissen
Consultant & Programmer
http://jalgermissen.com

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    • From: Jan Algermissen <jalgermissen@t...>

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  • Are URIs Resources? (WAS RE: Re: Non-infoset)
    • From: "Bullard, Claude L (Len)" <len.bullard@i...>
  • Re: Are URIs Resources? (WAS RE: Re: Non-infoset)
    • From: Joe English <jenglish@f...>

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