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Re: Back to HTTP semantics

From: Pat Hayes <phayes@ihmc.us>
Date: Mon, 15 Jun 2009 15:21:57 -0500
Cc: Jonathan Rees <jar@creativecommons.org>, David Booth <david@dbooth.org>, AWWSW TF <public-awwsw@w3.org>
Message-Id: <57EDBCFE-1645-4337-89A0-BD04C173F6F8@ihmc.us>
To: "Williams, Stuart (HP Labs, Bristol)" <skw@hp.com>

On Jun 15, 2009, at 12:18 PM, Williams, Stuart (HP Labs, Bristol) wrote:

> Hello Jonathan,
>
>> -----Original Message-----
>> From: Jonathan Rees [mailto:jar@creativecommons.org]
>> Sent: 15 June 2009 17:17
>> To: Williams, Stuart (HP Labs, Bristol)
>> Cc: Pat Hayes; David Booth; AWWSW TF
>> Subject: Re: Back to HTTP semantics
>>
>> On Mon, Jun 15, 2009 at 10:56 AM, Williams, Stuart (HP Labs,
>> Bristol)<skw@hp.com> wrote:
>>> the meme that RDF interpretration of URI are constrained
>> by what might be called the Web natural interpretation is not
>> original to me. Whilst I can understand and appreciate the
>> denial that you mention in RDFMT with respect to the
>> formalism presented there in - leaving interpretation
>> unconstrained by the web itself - I think there are many who
>> see interpretation implicitly constrained in that way when
>> one joins the logical system RDF with the pragmatics of the
>> web. Eg. If in RDF one were to use http://www.w3.org as a
>> reference to my left foot, there would be an inconsistency in
>> the total system even that were not so from the RDF
>> interpretation alone.
>>
>> I was not talking about memes or implicit constraints, which are a
>> different matter. This is sort of like saying people should only use
>> the C programming language for programming computers. It's  
>> empirically
>> mostly true, and why would you want to use it for any other reason?  
>> So
>> what's the problem?
>>
>> If you can find a *normative* statement explicitly connecting RFC2396
>> "identification" to RDF "interpretation" I'll give you 10 quid (next
>> time I see you).
>
> I think that your 10 is safe :-).
>
> I think that for some people (principally from a web background),  
> the connection is so obvious that it hardly needs stating

Which is a large part of the problem. That obviousness of the non- 
obvious has been the single most corrosive influence on TAG-level  
theorizing, IMO. It lies behind almost all the large conceptual  
mistakes that we are still trying to deal with, such as conflating  
naming and accessing under the single term 'identification', and then  
getting that muddled idea further muddled up with notions of identity,  
or (God help us) Platonic ideals.

<noise>Grrrrrr.</noise>

> ; whilst for others it is obvious to neatly (and explicitly)  
> decouple a formal RDF interpretation form a "web-interpretation"  
> rendering not particular significance to the choice of using URI as  
> a naming system.

AAaaargh.  URIs are NOT a naming system. Programming identifiers are  
NOT names. If someone declares "a" to be a real and writes "a :=  
43.27", that does not give a name to a number, nor even to a container  
of a number.  (If "a" names anything, it would probably be a  
continuant, a second-order function from states to state-state  
functions; but even that sense of naming is really little more than a  
metaphor.) When I was asked to invent a model theory for RDF, I asked  
about this quite explicitly and carefully, and got an unequivocal  
answer. RDF is not a programming system, with a semantics suited to  
such a system. RDF is not about identifiers with values in states, and  
functions on those states, or about containers and file systems and  
network traffic. RDF is supposed to be a general descriptive logic.  
Weak, but general. It has to have a logical semantics, which talks  
about what names denote. I asked: how does the use of URIrefs to be  
names restrict or qualify what those names denote? And again, the  
explicit answer from Tim and DanC and others was, none. There are no  
constraints: A URIref can refer to anything at all. At one early stage  
I actually suggested that we say normatively, as part of the  
semantics, that URIs denote Web pages (or whatever), and that idea was  
immediately squashed like a bug. What URIrefs refer to, which the RDF  
semantics was supposed to address, has got **nothing at all** to do  
with Web pages or containers or files, etc..

> I suspect that few from the GOFW world will have picked up on the  
> explicit denial in RDFMT that Pat referred us to.

Well, someone would have to be very dense to have read the MT document  
and not had this made pretty clear. But then I suspect that very few  
people in the GOFW world have, or ever will, read the RDF MT :-)

Pat

>
>> I don't count AWWW, which quietly assumes the
>> connection in two inconspicuous spots. It is not prescriptive on this
>> point, and it's not clear that it would be normative even if it were
>> prescriptive.
>
> :-)
>
>> I'm not saying that making the connection is necessarily a bad thing
>> (although it might be); just that it hasn't been done. I've already
>> suggested that introducing a new kind of RDF interpretation called a
>> "webarch-interpretation" might be a way to do it, although this
>> obviously takes us outside the realm of logical semantics and into
>> much more treacherous waters.
>>
>> Jonathan
>>
>
> Stuart
> --
>

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Received on Monday, 15 June 2009 20:22:38 GMT

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