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Re: resources and URIs

From: Graham Klyne <GK@ninebynine.org>
Date: Sun, 20 Jul 2003 08:26:25 +0100
Message-Id: <>
To: Tim Berners-Lee <timbl@w3.org>
Cc: pat hayes <phayes@ihmc.us>, www-tag@w3.org


Your message below seems closer to my understanding, except your comment 
about "assumption of a single interpretation" -- maybe this is just a 
terminological slip, but if we're talking about interpretations in a model 
theoretic sense, I think it's important to not try and claim any *single* 

[Background terminology check:  An "interpretation" arbitrarily assigns a 
single value from some domain to each of a set of names.  A "denotation" of 
a name is the value assigned to that name by some given 
interpretation.  Thus, for a given name there are multiple denotations 
corresponding to each interpretation that mentions the name.]

So, picking up your line of consistency and experimentation, if an 
"identity" is derived from (is the set of denotations according to) a set 
of interpretations that are consistent to some level of observation, we 
always have the possibility that additional observations will detect 
inconsistencies, hence fragment the identity into several distinct 
"sub-identities", each derived from a subset of the interpretations of the 
original.  In this sense an "ideal" identity (e.g. in the sense 
intuitively/informally used for URIs) might be derived from the limit of 
some set of consistent interpretations as the number of observations 
considered tends to an infinitude of all possible observations.  That is, 
we can never know the identity completely, but may know it well enough for 
any given purpose.

(In saying this, I'm trying to paraphrase in non-mathematical terms the way 
that definitions of limits and continuity are used in differential calculus.)

(Reviewing what I wrote here, it seems that a corollary is that any 
identity corresponds to (or may in general correspond to) an infinite 
number of possible denotations.  I think that underscores the point about 
not assuming a single interpretation.)


At 22:38 19/07/03 -0400, Tim Berners-Lee wrote:

>Yes, I think that we are very close in making the bridge between the 
>linguistics an the engineering.
>Two agents, when they communicate, can never know what interpretation the 
>other has.   However, whenever in the communication there arises something 
>which indicates that the same URI denotes different things for the two, 
>then they can sit down and work it out until they have resolved it, and 
>they now have no more inconsistencies.
>So at any such consistent point, an agent is working with a given [set of] 
>interpretation[s], and with a set of other agents, in this state of 
>We have said that one agent can never know what interpretation another 
>agent has. However, we also know that there is nothing they have come 
>across which is inconsistent with the belief that the other agents share 
>his interpretation. So the agent may continue as though the other agents 
>do in fact have exactly the same interpretation. This assumption of single 
>interpretation works because it is not measurably wrong.
>Every time one performs some experiment to determine in another way 
>whether the agents have the same interpretation, then either one
>(This of course has string parallels in the human linguistics,  the more 
>fuzzy way in which people hone their common understandings)
>Dan's "man/most useful" could be the set of interpretations which have no 
>discernible discrepancies.  In your Fido example, the playing with Fido is 
>one of the experiments.
>On Friday, Jul 18, 2003, at 07:56 US/Eastern, Graham Klyne wrote:
>>Noting your ongoing debate, I wondered if something that Dan said [1] 
>>might be a bridge to useful progress...
>>At 17:51 16/07/03 -0500, Dan Connolly wrote:
>>>Well, it's pretty close... try taking 'identify' to mean
>>>"denote in many/most useful interpretations".
>>and ...
>>At 23:34 17/07/03 -0400, Tim Berners-Lee wrote:
>>>A dog bounds into the room. Tim says, "Here, Fido!" to the dog, and says 
>>>"Pat, meet my dog, Fido" to Pat. Tim plays with th edog. Tim asks Pat, 
>>>"Pat, would please take Fido for a walk?"
>>>Pat takes the dog for a walk.  The name seems to have been unambiguously 
>>>associated with te same dog in both there minds.
>>I think the point here is that the name here is associated with something 
>>in each mind similar enough that doing the action of "taking it for a 
>>walk" has the same observable outcome.
>>Fido might be interpreted to denote the dog, or to denote a collection of 
>>fleas that live on the dog, but to take "Fido" for a walk amounts to the 
>>same thing.
>>[1] http://lists.w3.org/Archives/Public/www-tag/2003Jul/0159.html
>>Graham Klyne
>>PGP: 0FAA 69FF C083 000B A2E9  A131 01B9 1C7A DBCA CB5E
>Graham Klyne
>PGP: 0FAA 69FF C083 000B A2E9  A131 01B9 1C7A DBCA CB5E
Received on Sunday, 20 July 2003 03:44:38 UTC

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