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

To: "Pat Hayes" <phayes@xxxxxxx>
Cc: "[ontolog-forum] " <ontolog-forum@xxxxxxxxxxxxxxxx>
From: "John Black" <JohnBlack@xxxxxxxxxxx>
Date: Fri, 28 Dec 2007 21:14:00 -0500
Message-id: <029801c849c0$7a236e70$6601a8c0@KASHORI001>
on Fri. Dec. 28, 2007 at 5:31 PM, Pat Hayes wrote:
> >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 contexts'.
>>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."
> Quite. The same basic point was made much earlier, and more humorously, by 
> Johnathan Swift, in his description of the isle of Laputa.
> 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.    (01)

I believe this is true of web objects. If I mention a URL to you then both 
of us can use HTTP to access the same object at nearly the same time.    (02)

>>   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.
> 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".    (03)

Perhaps this is so, but how will this make it into RDF or OWL? Doesn't this 
require that axioms be added to the specification? Doesn't this make it a 
special case? With that ruling, a large set of URI must be understood to be 
members of the class "Information Resource" and furthermore, that class must 
be understood to be disjoint with all sorts of other classes.    (04)

>>In other words, to make utterances about a web object, you use the web 
>>object itself (including the 200 OK), and not its name.
> No, you *use* the URI that accessed that web object, to also talk about it 
> (eg in RDF or OWL)
>>  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.
> Quite. But this is irrelevant to the point we were discussing.
>>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,
> 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.    (05)

I see what you mean about saying "...name of some web object...", but it 
looks like I begged the question by assuming what I am disputing! more like 
self-destructing than begging....  On the other hand, I thought by hedging 
with "useful" I avoided such cases of extreme variability as would render it 
meaningless - oh well.    (06)

But seriously, I feel like I must be missing something again about names and 
contexts. Here is the problem. My name is "John", a good proper name, which 
in the presence of my immediate family, nails me precisely, and very 
efficiently. In another family, occurrences of the same name, "John", refer 
equally well to other referents, with equal precision and efficiency. This 
use of the term "context" appears to me very trivial and ubiquitous. Isn't 
this type of context the same as a "namespace" that occurs frequently in 
programming languages? It permits names to change their referents, if not on 
*every* occurrence, at least on every change of context (or namespace). Or 
am I missing something?    (07)

>>even if different from other uses, all while HTTP returns the same object 
>>for the same URI.
> 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.    (08)

And again, doesn't it need to be pounded into RDF and OWL somehow?    (09)

> Pat
>>(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
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