[SCL] The semantics of "semantics"

[Jim Hendler]

John - it really pisses me off that every time I decide you're an 
unreasonable ogre who I could never work with, you send something 
like this...  I agree with pretty much everything you say below.
  -JH
p.s. the key to RDF is in its relation to URIs and web links, not in 
its admittedly hideous syntax - and that's covered in point 4 below, 
so I'm happy.  Amazingly, point 5 is less important to me than 4 - 
although mapping to/from will be a good test of SCL's 
expressivity/web-embedness.


At 15:53 -0500 1/16/03, John F. Sowa wrote:
>Chris, Tanel, Jim, et al.,
>
>I believe that somee recent lapses in communication have resulted
>from undefined notions of what "semantics" means.  Those of us who
>have been working with logic for some time naturally equate that
>term with "model-theoretic semantics" as defined by Ockham, Peirce,
>Tarski, Kripke, Montague, etc.
>
>An "impedence mismatch" has come to the fore in the exchange
>of notes between Chris and Tanel and my recent exchange of notes
>with Jim, which ended in a proposal for some future dinner party,
>in which they would be on the menu.
>
>To clarify the issues and the air, I would like to apologize for
>any aspersions I may have cast upon the beauty of RDF syntax or the
>semantics of the semantic web.  To avoid further misunderstandings,
>I suggest the following guidelines:
>
>  1. We should avoid using the word "semantics".  Instead, we can
>     use phrases such as "truth value" or "model theory" and talk
>     about "English definitions" or "formal definitions", where
>     "formal" implies the use of some version of logic.
>
>  2. Discussions about syntax should be raised above the level
>     of sniping criticisms about beauty or about the widespread
>     usage of one notation or another.  Instead, we should emphasize
>     that the SCL model theory is stated in terms of an abstract
>     syntax, which can be expressed in various concrete notations,
>     such as KIF, CGIF, and many variations of XML-based notations,
>     including RDF.
>
>  3. Questions about how to do the mapping from one syntax to
>     another are appropriate, but gratuitous remarks about the
>     desirability of any particular syntax should be avoided.
>
>  4. Compatibility with the W3C conventions for naming and
>     linking is a non-negotiable requirement for any and every
>     concrete syntax used to express SCL.  That requirement can
>     be most easily satisfied by providing support for the W3C
>     conventions directly in the abstract sytnax of SCL.
>
>  5. Since RDF has been designed by the W3C, it serves as a
>     critical test case for the claim that SCL is general
>     enough to specify the W3C requirements.  Therefore, we
>     should demonstrate two mappings:  first, that all of RDF can
>     be mapped to SCL, and second, that some appropriate subset
>     of SCL can be mapped to RDF.
>
>These guidelines won't prevent disagreements, but I hope that
>they can focus the discussion on the important issues.
>
>John Sowa
>
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-- 
Professor James Hendler				  hendler at cs.umd.edu
Director, Semantic Web and Agent Technologies	  301-405-2696
Maryland Information and Network Dynamics Lab.	  301-405-6707 (Fax)
Univ of Maryland, College Park, MD 20742	  240-731-3822 (Cell)
http://www.cs.umd.edu/users/hendler