Re: What do the ontologists want

At 10:44 AM 5/15/01 -0500, pat hayes wrote:
>>'Jon says "The sky is blue."' ?
>
>It is logically exotic, if I may be forgiven the terminology, since it 
>refers to a sentence by ostention, rather than by denotation. Actually, 
>even this is relatively harmless, as long as you simply quote. However, in 
>order to be useful, one usually has to be able to move between a quoted 
>sentence or expression and the use of that sentence or expression as part 
>of the language itself, and this 'reflexion' is what is really arcane and 
>tricky. Simple quotation is relatively harmless, I concede, but largely 
>useless: it is simply a way of referring to character strings.
>For example, would you want to be able to infer, from your example, that 
>Jon said that the sky is blue? It doesnt follow from it, however, unless 
>you provide some machinery to de-quote a quoted string. Seems to me that 
>the latter is much more useful than the former: the relationship between 
>an agent and the *content* of what they say is more interesting, usually, 
>than the relationship between the agent and the *form of character 
>strings* that they use (except of course when the mapping between form and 
>meaning is central to the discussion, as it is in some legal settings; but 
>again, this seems exotic for our purposes.) To refer to the content of an 
>expression, however, one does not quote it: one simply uses it.

Something that I very much wish to be able to do is something like this:

   'Jon says "The sky is blue"'
   'I believe Jon'
=>
   'I believe (the sky is blue)'

Or:

   'Jon says "The sky is blue"'
   'My oracle says "Jon is reliable"'
=>
   'The sky is blue'

I've deliberately not tried to state this rigorously, as I'd probably miss 
the mark if I did.  I hope the general intent is reasonably clear.

Maybe there is a way of formulating this that doesn't rely on logical 
exotica.  But it does seem to rely on some form of "reflexion" -- a 
statement is used both as an object about which other statements are made, 
and as an assertion in its own right.

#g


------------
Graham Klyne
GK@NineByNine.org

Received on Tuesday, 15 May 2001 15:55:27 UTC