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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Best Wishes,
Rick (016)
blog: http://phaneron.rickmurphy.org
web: http://www.rickmurphy.org
phone: 703.201.9129 (017)
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