on Mon Dec 24, 2007 at 4:18 PM, Pat Hayes wrote: (01)
> >Please forgive me, in advance, for my spotty knowledge of some of the
> >topics
>>in this post. My interest in these ideas often exceeds my understanding.
>>
>>First, congratulations to all on the ISO adoption of CL as a standard. I
>>believe it will prove to be an invaluable addition to the spread of
>>interoperable knowledge representation technology. It is an important
>>achievement. I am doubly excited by this because it includes, at long
>>last,
>>an ISO standard for Conceptual Graphs. CGs was the first knowledge
>>representation formalism I encountered. I read the CG1984 book several
>>times, worked on an implementation in prolog of a linear form, and then
>>had
>>the pleasure to participate for a short time in 1997 on work towards the
>>CGIF standard specification. More recently, having decided that semantics
>>is
>>heavily dependent on contexts, and searching for material concerning that
>>subject, I came across IKL and the startling claim that "Every occurrence
>>of
>>an IKL name has the same meaning." This is something I find highly
>>desirable, but which as I said, I had just recently decided was not
>>possible.
>
> I think you may be reading more into this than was intended. It does not
> say that every occurrence of an IKL name has the same unique referent in
> the actual world. It says that every such name occurrence maps to
> referents in all interpretations in the same way. But there may be many
> possible interpretations: there almost always are. (02)
I'm confused. I understand that there may be many interpretations. Lets
consider the case of two network nodes. If the referent of a name 'A' is X
in one interpretation and is Y in another interpretation, then in what sense
are these name occurrences mapped "...in the same way."? From what you say
later, I suppose you mean that all the same statements are true of both X
and Y. (03)
>>The topic I am particularly interested in discussing here now, is this
>>claim
>>and a similar statement in the CL requirements section 5.1.4.b., "Any
>>piece
>>of Common Logic text should have the same meaning, and support the same
>>entailments everywhere on the network. Every name should have the same
>>logical meaning at every node of the network."
>
> Right. Note, *logical* meaning. One might reasonably say that the meaning
> of "Patrick J Hayes" is me, in this particular world, but that is not its
> logical meaning. Its logical meaning is a mapping from interpretations
> (aka possible worlds) to an individual in that interpretation's universe. (04)
I have never gotten comfortable with the idea of sorts or types of meaning
(formal, social, natural, logical, etc. etc.). Never-the-less, I take you
mean that the requirement is that the same set of statements will be true of
all referents of the name in all interpretations, not that the name will
necessarily have the same referent in all interpretations. Is that right?
This is quite a different result from what I was reading it to say. (05)
>> Yet in the version of the
>>Common Logic (CL) specification I have, in section 1 I read "The following
>>are outside the scope of this standard: ... Computer-based operational
>>methods of providing relationships between symbols in the logical
>>'universe
>>of discourse' and individuals in the 'real world'".
>
> Right.
>
>>
>>This topic, the operational relationship between symbols in logic and
>>individuals in the world, happens to be my particular interest of late.
>>Actually, come to think of it, I have been interested in this for some
>>time
>
> Join the club :-) Seriously, this is a very large and interesting topic.
> One has to recognize, however, that it goes beyond the scope of logic as
> usually construed: certainly beyond the scope of Tarskian logical
> semantics.
>
>>and I recall that one of the many things that impressed me about John
>>Sowa's
>>first book on Conceptual Structures in 1984 was the chapter on
>>Psychological
>>Evidence, including the discussion of perceptrons.
>
> Perceptrons or perceptions? Perceptrons were a very early idea in what is
> now called neural networks. (06)
My mistake - two in fact - very embarrassing!
The term used was "percepts", not "perceptrons" and it is found in chapter 3
titled "Conceptual Graphs" not in chapter 2, "Psychological Evidence". (07)
>>That section was, at
>>least an initial attempt, to address the question.
>
> ? How does a perceptron (or a neural network more generally) address the
> question of how names come to be attached to their referents? I see no
> connection at all. (08)
Right, my error, see previous section. He uses "percepts" differently, in
terms of neuroscience rather than neural networks. In section 3.1 "Percepts
and Concepts" of Chapter 3, he says "For concrete entities like cats and
tomatoes, the brain has percepts for recognizing the entity and concepts for
thinking about it..... (09)
3.1.3 Assumption. For every percept p, there is a concept c, called the
interpretation of p. the percept p is called the image of c. Some concepts
have no images...." (010)
That there is something which aids the recognition of an entity (referent)
which a (named) concept is about - that is the connection I see. (011)
John Black (012)
>>So here is my first question: If the semantics of CL starts out with a
>>mapping from the vocabulary of a CL text to individuals in the universe of
>>discourse
>
> Better say, in *a* universe of discourse. There is one universe for each
> interpretation, and there may be many equally correct interpretations.
>
>>, but this mapping is nowhere encoded or included in the CL text
>
> It cannot be encoded in text, being a mapping from text to what may well
> be non-textual things.
>
>>,
>>then how can you be sure that one agents mapping to individuals at one
>>node
>>of the network will be the same as the mapping of another agent at some
>>other node of the network?
>
> You can't. The best you can do is to be sure that all the possible
> mappings that are consistent (using that word informally) with the
> conclusions that the second agent can draw, are also consistent with those
> that the originating agent can draw. That is a (rather convoluted) way of
> saying that they are both using the same logic and both respecting the
> notion of entailment that is supports. This is the best that any logical
> semantics can possibly guarantee.
>
> Pat Hayes
>
>>
>>John Black
>>www.kashori.com
>>
>>
>>
>>
>>
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> (013)
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