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Re: resources are angels, and uris are pins (Splitting vs. Interpreting)

From: Pat Hayes <phayes@ihmc.us>
Date: Mon, 22 Jun 2009 08:59:27 -0500
Cc: www-tag <www-tag@w3.org>
Message-Id: <8A5E0D8E-FB06-4A78-9859-AE8ADBA1F13E@ihmc.us>
To: Larry Masinter <masinter@adobe.com>

On Jun 19, 2009, at 10:05 PM, Larry Masinter wrote:

> The relationship between URIs and resources is intrinsically  
> ambiguous.  To ask the question of how many resources are identified  
> by a single URI is like asking how many angels can be identified by  
> a single pin.
>
> URIs by themselves do not "denote"

Yes they do. (And without scare quotes, by the way.)

> ; they are used by applications or agents to denote or identify.

The only way an agent can denote (with language) is to use a denoting  
name. Its the names that do the denoting.

> For example,
>
> * XML applications use URIs in xmlns attributes to identify  
> namespaces.
>
> * Hypertext applications such as web browsers use URIs to identify  
> which network resource should be contacted during the interaction  
> with the hypertext and how that contact is to be made.
>
> * Semantic Web applications use URIs to denote concepts.

No, they denote things. Usually fairly concrete things, such as people  
and companies and towns, things like that.

> I use "denote" as term related to, but different from, "identify".

Well, 'denotation' is a term with a well-established meaning. So far,  
in several years of reading and asking, I have never seen or heard  
anyone who can say what "identify" means.

>  Concepts do not form a set, and cannot.

Nonsense. Anything can form a set. That is, a set can contain anything.

> Concepts cannot be counted, because to count them, you would have to  
> identify them. There is no 'equality' for concepts.

There is equality for anything that anyone can talk about. Equality  
means, being the same. Things - all things - are the same as  
themselves, and not the same as anything else. End of story for  
equality. This has nothing to do with counting. Uncountable sets of,  
say, the inaccessible cardinals, still have elements which are equal  
to themselves. The only way to make sense of what you say here is to  
take it as a rhetorical way of saying that the idea of "concept" is  
broken or useless, as nobody knows what that word means. Which is not  
an unreasonable conclusion, but also not germane to anything, as URIs  
in OWL and RDFS do not denote concepts of things: they denote the  
actual things.

> Aq	`1`	12xz90-
> I believe the question asked by httpRange-14 is ill-formed, because  
> it is based on the presumption that "denotation" is a function, when  
> it is not.

It is in a given interpretation. One way to express the intent of http- 
range-14 is to express it as a constraint on interpretations: URIs  
which return 200-code http responses are required to denote (in any  
'web-legal', or maybe 'tag-approved', interpretation) a Web resource  
which emitted that response (or whatever the current http-range-14  
decision actually is.) And then, the ruling amounts to saying that  
only web-legal interpretations should be considered when asking  
questions about validity, entailment, etc. This gets neatly past the  
objection that there isn't a single unique referent to be picked out.  
There doesn't need to be: there just needs to be a well-formed  
constraint on the possible referents.

> I think somehow linking the HTTP response code returned by a server  
> as a way of changing the denotation of a URI used -- well, it's  
> ineffective, misleading, bad design.

Well, I tend to agree with that, but I also can't see any viable  
alternative. So here we are in a mess that needs to be handled  
somehow, and (as with democracy) this is a lousy idea, but all the  
other ideas are worse.

>
> I'd normally be reluctant to bring this up -- not a good use of W3C  
> TAG time in my opinion -- but I believe acknowledging the ambiguity  
> may be fundamental to making progress on some of the metadata and  
> security issues before the TAG.
>
> Metadata because metadata itself consists of assertions about media  
> resources in which the identity and scope of the metadata assertion  
> is itself a fundamental ambiguity.  The various means of associating  
> metadata with resources being discussed each carries its own model  
> of what is being described as well as the identity of the describer.

Well, that last part is probably true, but it doesnt follow that  
anything is ambiguous, only that the various means might not be in  
perfect alignment. Which is certainly an important topic to address,  
but its also important not to get it confused with other issues, like  
ambiguity. IMO ambiguity is inevitable and not centrally important,  
but this one is.

>
> Security because trust is based on the presumption of (sufficient)  
> agreement about the meaning (denotation) of the terms, and  
> disagreement about that results in trust being broken.

It results in EVERYTHING being broken, not just trust. Confucious was  
pretty clear on that point: "If names be not in accord with the truth  
of things, ... plans cannot be carried out to success"

Pat


>
> Larry
> -- 
> http://larry.masinter.net
>

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Received on Monday, 22 June 2009 14:00:39 GMT

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