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Re: [ontolog-forum] mKR (was Thing and Class)

To: "[ontolog-forum]" <ontolog-forum@xxxxxxxxxxxxxxxx>
From: Rick Murphy <rick@xxxxxxxxxxxxxx>
Date: Fri, 12 Sep 2008 21:44:04 -0400
Message-id: <48CB1AE4.9050707@xxxxxxxxxxxxxx>
Chris & All:    (01)

Glad to see model theory come up again. I have a keen interest in better 
understanding how model theory differentiates meaning from truth.    (02)

My current understanding is that Tarski claims to provide a semantic 
conception of truth in his paper of the same name where truth is defined 
in terms of material adequacy and formal correctness. He does not claim 
to provide a theory of meaning as I mention here ...    (03)

http://phaneron.rickmurphy.org/?p=25    (04)

I also understand that when Pat Hayes wrote the RDF semantics document 
for W3C, he chose to exclude a theory of meaning from the scope of the 
document.    (05)

I am also especially interested in some decisions made by Tim BL & Co in 
the linked data activity that relate to material adequacy. My current 
understanding is that non-information resources gets a 303, then a 
redirect to another uri which is a representation of the non-information 
resource that can be later rendered by a browser.    (06)

These decisions seem to imply the need to revise the existing RDF model 
theory with regards to material adequacy in that information and 
non-information resources are now specified. My intuition is that the 
issue here is more with material adequacy as interpretation than 
possible worlds.    (07)

I need to get back to Soames's refutation of the Davidsonian program 
which attempted to derive a theory of meaning from Tarski's semantic 
conception of truth. I had previously referenced this paper ...    (08)

http://www-rcf.usc.edu/~soames/forthcoming_papers/Truth_and_Meaning.pdf    (09)

and wondered whether anyone was interested in sharing their thoughts ?    (010)

Christopher Menzel wrote:
> On Sep 12, 2008, at 6:04 PM, Richard H. McCullough wrote:
>> Chris
>>
>> I would appreciate some pointers on how to do that. The things that  
>> I have read say that a formal semantics maps the "meaningless"  
>> symbols of formal logic to the "meaningful" symbols of English.
> 
> No, that is nothing like a formal semantics; that is at best an  
> informal semantics, which is generally pretty useless for the central  
> purposes of KR.  The point of a formal semantics is (a) to provide  
> interpretations of the non-logical primitives of a language and (b)  
> to  provide a *systematic* account of how the meanings of complex  
> expressions in a language are determined by the meanings assigned to  
> their component parts.  This, in particular, is what is missing from  
> mKR.    (011)

But my understanding, as I state above is that a) equates with material 
adequacy and b) equates with formal correctness from which we get truth, 
but not meaning.    (012)

> (b) has to do primarily with the interpreting the logical components  
> of your language -- boolean operators, modal operators, quantifiers,  
> etc.  You can learn about this in any good text on mathematical  
> logic.  (And just note: It appears to me that your language is  
> completely lacking the apparatus of propositional and first-order  
> logic.  These are essential to any modern KR language.)
> 
> In regard to (a), many of your important non-logical primitives --  
> e.g., "action", "context", "part", "attribute", "relation", "time",  
> etc -- are left utterly uninterpreted.    (013)

So how does common logic do this ? Where does it differentiate supposito 
formalis and suposito materialis ?  Or, how does common logic ensure 
that the snow really is white ? Or is common logic just another 
simulacra as Baudrialliard cautions.    (014)

> Try replacing them with "foo,  
> bar, baz, etc" and you get an idea of how useful your language is for  
> KR.  The notions above are ambiguous and difficult.  They need to be  
> nailed down by a semantics that fixes (as far as possible) their  
> properties and the logical connections.  For instance, what is the  
> relation between "action" and "time"?  Intuitively, the two are  
> *intimately* connected.  A good formal semantics will do that: for  
> example, it might represent time as the real line and will map each  
> action to an interval.  Alternatively, if one has ≠ discrete  
> processes in mind, a semantics might represent time by the integers  
> and assign to each action a start point and a (later) endpoint.   
> Again, what is an attribute?  Can you combine different attributes  
> like "red" and "smooth" into a single attribute?  A good semantics  
> will represent attributes as functions of some ilk, or as objects with  
> extensions, or perhaps extensions at possible worlds, or whatever.   
> But however, it is done, it will be perfectly clear what you do and do  
> not mean by "attribute".  See the idea?  You might have a look at the  
> NIST Process Specification Language for a good example of a language  
> whose non-logical primitives are rigorously interpreted in a formal  
> semantics, and how those interpretations are reflected in the PSL  
> axioms.  Or, for that matter, have a look at the model theory for RDF  
> and OWL on the W3C web site.
> 
>> But mKR propositions are paraphrases of English. mKR is composed of  
>> English words and phrases, not "meaningless" symbols of formal logic.
> 
> But the symbols of formal logic are not meaningless *at all*.  They  
> are given very rigorous interpretations in any standard semantics  
> (a.k.a model theory) for a given formal language -- of which any  
> useful KR language is a species.
> 
>> I haven't seen any formal semantics for English.
> 
> Sure thing, but neither is English anything like a KR language; indeed  
> it is the very opposite of a KR language.  It is informal, imprecise,  
> fraught with ambiguity, and impossible for computers to process  
> (without severe restrictions).  It is WHY we have KR languages; it is  
> WHY we build ontologies.  KR exists precisely because you can't rely  
> on informal, intuitive understandings of English when you want to  
> share and process information, and use computers to aid significantly  
> in the process.
> 
> -chris
> 
>  
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>      (015)

Best Wishes,
Rick    (016)

blog:   http://phaneron.rickmurphy.org
web:    http://www.rickmurphy.org
phone:  703.201.9129    (017)

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