Re: Contexts (was Classes vs. Instances)

["John F. Sowa" <sowa@bestweb.net>]

Rolf and Avril,

I wouldn't say that the Semantic Web is totally bad,
just as I wouldn't say that the original IBM PC was
totally bad.  In fact, the PC had three very, very
good qualities:  the steel case (instead of the plastic
case of the aptly named Trash-80), the full keyboard
(instead of the upper-case-only keyboards of the TRS
and Apple PCs), and a decent, if not very exciting,
monitor that displayed 80-characters across (instead
of the 40 chars of the TV-based displays).

But the IBM Instruments Division in 1980 had produced
an engineering computer based on the Motorola 68000
with an operating system and compilers written by IBM.
It was built into a bigger and uglier box with seven
expansion slots for adding instruments and process
controllers of various kinds.

In 1981, it would have been easy to put a scaled-down
version of the 68000 system into exactly the same box
as the PC.  IBM could have delivered it with an OS and
compilers from IBM instead of QDOS (Quick and Dirty OS
-- which Bill Gates bought for $50K and sold to IBM
for one million as MS-DOS 1.0).

That's my feeling about the Semantic Web.  It has some
good features (such as Unicode, URIs, and the use of XML
for marking up documents, not for implementing languages).
But it is so much worse than it could have been if the
developers had taken account of the current state of the
art (in commercial use, even, not to mention research).

RS> Before you get too sick, have a look at:
 > 
http://www-db.research.bell-labs.com/user/pfps/publications/architecture.pdf
 >
 > A kind of fix :-) .

Thanks for the pointer.  Peter FPS makes many of the same
points I made:  RDF is a terrible base for supporting logic,
OWL demonstrates how bad RDF is, and there was much better
technology available instead of the bunch of crap that was
dumped on us by the W3C.  The main difference is that Peter
stated his points in a more diplomatic way than I did, but
I agree with his conclusion:

PFPS> It would also be possible to generalize the revised
 > Semantic Web architecture in several ways. One could lift
 > the requirement that systems handle lower levels of the
 > stack, turning the Semantic Web stack into a collection of
 > languages with a common semantic framework. One could also
 > loosen the requirement of a common semantic framework into
 > simply some sort of semantic compatibility.

My recommendation is to adopt the draft ISO standard for Common
Logic as the foundation for the Semantic Web. There are already
mappings of RDF and OWL into CL, and there is also an XML
notation, called XCL, defined in Annex C of the standard.
As for the use of XML, I would make that optional and provide
an XML tag with the option LANG=xxx in order to support better
language formats.

AS> ...  It is easier for a normal person to create an ontology
 > with a frame-based ontology editor than by using SQL tables.
 > Sure, the idea of frames existed long before SemWeb, but after
 > working with a large and messy SQL database for two long years,
 > I would welcome a frame-based SQL editor. That would surely help
 > to build and to use a database, since SQL databases are (imho)
 > very much easier to apply than RDF databases.

I certainly agree with the two main points:  SQL does not have
good tools for supporting a type hierarchy, but SQL databases
are far easier to use than RDF databases.

But you don't need frames or RDF for a good type hierarchy.
Aristotle developed that over 2300 years ago, and Porphyry
developed tree diagrams for representing type hierarchies
over 1700 years ago.  Ted Codd and Chris Date were arguing
for years that SQL should support types.

I blame IBM and Oracle for the weaknesses of SQL.  First,
IBM is to blame for not adding types, which were being
discussed by many people (including me) within IBM during
the 1970s.  My first published paper on conceptual graphs
in 1976 proposed CGs as a schema language for RDBs:

    http://www.jfsowa.com/pubs/cg1976.htm

Second, I blame Oracle for implementing the first version
of SQL that had been published in the IBM Journal of R & D
instead of the much better QUEL language that Stonebraker
had developed for Ingres.

AS> SemWeb languages have at least two good features: they
 > are frame-based and they are easily shareable. I'd be better
 > off with SQL that would accommodate these two features. Then
 > again the errors of RDF appear while one is trying to use
 > an RDFS ontology by working with e.g. JENA. It is slightly
 > amusing, but mostly painful.

I agree.  There's an old saying,

    Those who don't know history are doomed to reimplement it.

John