[Top] [All Lists]

Re: [ontolog-forum] CL, CG, IKL and the relationship between symbols in

To: "John Black" <JohnBlack@xxxxxxxxxxx>
Cc: "[ontolog-forum] " <ontolog-forum@xxxxxxxxxxxxxxxx>
From: Pat Hayes <phayes@xxxxxxx>
Date: Fri, 28 Dec 2007 14:31:10 -0800
Message-id: <p06230904c39af32a0771@[]>
>on Wed. Dec. 26, 2007 at 7:30 PM, Pat Hayes wrote:
>JB>>Reminds me of a question I keep having with regard to URIs in the
>>>Web Architecture. There doesn't seem to be any attempt to 
>>>distinguish between each occurrence (I sometimes call it an 
>>>utterance) of a URI and its establishment.
>PH> Indeed, there is not. On the contrary, there is an insistence that no
>>such distinction be made. To make it is an architectural error. 
>>That is the whole point of URIs, if you think about what they are 
>>mostly used for. If your browser, in its context, were to interpret 
>>a URI differently from the website it identifies, in its context, 
>>then the entire Web would stop working.
>>>  And in fact, it seems to be argued often that this is by design 
>>>and intentional, yet nowhere is are there methods for dealing with 
>>>what seems to be inevitable contextual differences between each 
>>>occurrence of a URI.
>>That is exactly the point. There should not be any such contextual 
>>differences. The CL logic is designed to eliminate them. If they, 
>>as you say, 'inevitable', then the Web must be broken. But on the 
>>whole it seems to work reasonably well.
>>>In other words, it sounds like IKL aims for the same goal
>>IKL and CL are similar in this aspect, of having globally 
>>transparent meanings for names.
>>>  but includes some machinery for achieving it, while the Web 
>>>Architecture claims that it is so by engineering design.
>>Well, URIs on the Web have a dual aspect: they provide access to 
>>"information resources" (for the meaning of this jargon, go to the 
>>W3C) and they also are used in RDF and OWL to *denote* arbitrary 
>>things. The relationships between these two roles are subtle and 
>>controversial, and not always described very clearly. But 
>>certainly, both the Web architecture and the CL logic assume that 
>>names denote uniformly, not differently in different 'local 
>I just came across this in Tarski's 1944 paper, The Semantic 
>Conception of Truth:  "...the fundamental conventions regarding the 
>use of any language require that in any utterance we make about an 
>object it is the name of the object which must be employed, and not 
>the object itself. In consequence, if we wish to say something about 
>a sentence, for example, that it is true, we must use the name of 
>this sentence, and not the sentence itself."    (01)

Quite. The same basic point was made much earlier, and more 
humorously, by Johnathan Swift, in his description of the isle of 
Laputa.    (02)

But this is not *strictly* true in human discourse. If there is some 
way to indicate the actual object without naming it, for example by 
pointing to it or brandishing it or looking pointedly at it, I can 
refer to a thing without naming it. We do this all the time. For 
example, I might pick up a vegetable in a supermarket and say to you, 
"Rutabaga?", using the vegetable itself as the object of my query. 
However, this can only be done in a setting where both you and I and 
the thing itself are equally part of the immediate common ground.    (03)

>   This reminds me of my objection (due partly to my understanding of 
>your own arguments about it) to the current attempts to describe the 
>relationship between those two roles. For I think the same could be 
>said about the object that is accessed by using a URI utterance in 
>an HTTP system. To say of a web document that it is an information 
>resource, for example, it is the name of the object (the URI) which 
>must be employed, and not the object itself. What the current 
>version of the web architecture seems to be saying is that web 
>objects, as opposed to everything else, say what they are themselves.    (04)

It would be more accurate to say that they respond in a 
characteristic way to a certain kind of action. If you stroke 
something and it purrs, you conclude it was a cat: but that doesn't 
mean that the cat itself is referring to anything. And even if it 
did, the purr itself can be viewed just as much a name as "cat" is. 
Similarly, the http response code is a symbolic signal emitted by the 
resource itself. In fact, given that the TAG ruling is that in this 
case, the URI refers to the resource, the situation is very similar 
to my calling your name while addressing a crowd, and you responding 
"yes, I'm here". Notice that this has you referring to you by using 
"I".    (05)

>In other words, to make utterances about a web object, you use the 
>web object itself (including the 200 OK), and not its name.    (06)

No, you *use* the URI that accessed that web object, to also talk 
about it (eg in RDF or OWL)    (07)

>  This would be like insisting that, when talking about a car, you 
>had to insert the car itself in your speech somehow, as the subject 
>of all propositions about it. This, of course, would seem to have 
>the great advantage that everyone would always be referring to the 
>same car - unambiguously - regardless of any local context. But 
>actually, I think this is an illusion. Objects can't insert 
>themselves into ontological categories. Agents use names to put 
>categories around objects like cars or web documents for particular 
>purposes. The universe just exists, agents say what objects are by 
>using language.    (08)

Quite. But this is irrelevant to the point we were discussing.    (09)

>So I don't agree it would break the web for each utterance of the 
>name (URI occurrence) of some web object to be used for any useful 
>purpose,    (010)

BUt wait, you have begged the question already. To say that a name is 
the name OF a given thing is to presume that all occurrences of that 
name are names of that one thing. WHich is exactly the point at 
issue. If names can change their referents on every occurrence, then 
the very notion of a "name of a thing" ceases to be meaningful.    (011)

>even if different from other uses, all while HTTP returns the same 
>object for the same URI.    (012)

Here you touch on a delicate point. IMO, there is indeed an important 
conceptual distinction to be made between the relationships of naming 
or reference, on the one hand, and 'accessing' or 'identifying' on 
the other, and many of the W3C discussions fail to make this 
distinction and so are hopelessly muddled. The http-range-14 decision 
can be summarized as: when a Web object returns a 200 response code, 
the URI which accessed it (ie the GETing of which resulted in the 
code being returned) must also be understood as denoting it. This is 
highly intuitive, so much so that many folk take it as so obvious as 
to not need saying, but it does need to be said, as it is by no means 
necessary.    (013)

Pat    (014)

>(But even as I try to wrap this up and hit the send button, I see 
>problems with this. For example, the fly (object) buzzing around in 
>front of the frog reflects light that physical changes the frogs 
>vision transducers in a distinct, fly-like way. When the frog 
>processes this as a fly, that is, when the frog's brain puts it in 
>the 'dinner' category, it appears very much like it is the very 
>essence of the fly, the fly's fly-ness that does so. Any frog that 
>arbitrarily put it in the 'mate' category, for example, would lead a 
>very short life.)
>John Black
>www.kashori.com    (015)

IHMC            (850)434 8903 or (650)494 3973   home
40 South Alcaniz St.    (850)202 4416   office
Pensacola                       (850)202 4440   fax
FL 32502                        (850)291 0667    cell
phayesAT-SIGNihmc.us       http://www.ihmc.us/users/phayes    (016)

Message Archives: http://ontolog.cim3.net/forum/ontolog-forum/  
Subscribe/Config: http://ontolog.cim3.net/mailman/listinfo/ontolog-forum/  
Unsubscribe: mailto:ontolog-forum-leave@xxxxxxxxxxxxxxxx
Shared Files: http://ontolog.cim3.net/file/
Community Wiki: http://ontolog.cim3.net/wiki/ 
To Post: mailto:ontolog-forum@xxxxxxxxxxxxxxxx    (017)

<Prev in Thread] Current Thread [Next in Thread>