[SCL] Lenat agrees to support CL

[John F. Sowa]

Folks,

Last week, there was a two-day review of Cyc in Austin.
On the next day, I gave a talk at a Mitre Technical Exchange
Meeting on "Ontology and the Semantic Web".  Since the topics
discussed in Austin were relevant to the Mitre talk, I included
some slides about Cyc.  I extracted the Cyc slides and put them
at the end of this note in plain text.  The full set of slides
for my talk at Mitre can be found at

   http://www.jfsowa.com/talks/mitre.htm

In particular, note the slide with Lenat's statement about
the proposed CL standard.

John Sowa
_________________________________________________________________

                             CYC REVIEW

Two-day DARPA-sponsored review of Cyc on June 10th & 11th
with about two dozen AI experts.

Consensus:

 * Cyc is a unique and valuable resource:  Since 1984,
   650 person years and $65 million to define and axiomatize
   about 600,000 concept types.

 * Support for Cyc should be continued.

 * Cyc should be freely available for research purposes.

 * Many questions about the relationship of Cyc to other
   R & D efforts.
__________________________________________________________________
                        LEXICAL RESOURCES

Developers of WordNet (George Miller) and FrameNet (Chuck Fillmore)
were also present.

Consensus:

 * Lexical resources are complementary to Cyc.

 * Extremely valuable for natural language projects.

 * Desirable to integrate contributions from various sources.

 * Integration would require relatively modest funding.

 * Word senses (synsets) can be linked to the concept types
   of Cyc and other axiomatized ontologies.

 * Further questions to be explored.

___________________________________________________________________

                         COMMON LOGIC (CL)

Abstract syntax and model theory for logic-based languages.

Currently supported:  KIF, conceptual graphs, and OWL.

Other notations can be supported:  Z, UML Object Constraint Language,
and traditional predicate calculus.

Lenat agreed

 * CycL is very close in expressive power to CL.

 * Defining CycL in terms of CL abstract syntax is important
   for knowledge interchange.

 * Doing so would give CycL a model-theoretic semantics.

___________________________________________________________________
                      FEIGENBAUM'S QUESTION #1

Ed Feigenbaum asked a question:

 * Lenat had claimed that when the KB reached a critical size,
   new knowledge could be added much faster.

 * Recently, the size of the KB has increased significantly.

 * Has Cyc now reached a critical mass that would support
   an exponential increase in size?

Fritz Lehmann's response:  The major reason for the recent increase
is a managerial decision by Lenat.

___________________________________________________________________

                      FEIGENBAUM'S QUESTION #2

Feigenbaum asked another question:

 * In 1961, I. J. Good made a prediction:

      It is more probable than not that, within the twentieth
      century, an ultraintelligent machine will be built and
      that it will be the last invention that man need make.

 * Why hasn't Good's prediction come to pass?

 * Is there some missing ingredient that the AI community
   hasn't discovered?

 * What is it?  Could it be added to Cyc?

____________________________________________________________________

                           SOWA'S ANSWER

The missing ingredient is analogical reasoning:

 * All human thinking is based on analogies.

 * All aspects of logic -- induction, deduction, and abduction
   -- are highly disciplined, special cases of analogy.

 * A high-speed analogical reasoner would be more flexible
   than Cyc.

 * And it could call Cyc as a subroutine.

This answer generated more squabbles than consensus.

___________________________________________________________________

          SLIDES ON ANALOGICAL REASONING HAVE BEEN OMITTED

For that information, see the paper by John Sowa and Arun Majumdar:

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

____________________________________________________________________

                   SUPPORTING MULTIPLE ONTOLOGIES

 * Cyc supports microtheories, which are subontologies that
   may be inconsistent with one another.

 * Example:  microtheories about vampires or Greek mythology.

 * Cyc currently has 6,000 microtheories.

 * Cyc can create new microtheories dynamically to represent
   modalities or some agent's knowledge and belief.

 * But there is a need for different microtheories even at the
   upper levels of the ontology.

____________________________________________________________________

                          EXAMPLE FROM CYC

A sample story used by the Cyc ontologists:

   Jim, a car dealer, saw a tornado approaching the lot where
   all his cars were located.  Shortly thereafter, the tornado
   swept through the lot and destroyed all his cars.

Implications of the Cyc ontology:

 * If a tornado approaches, it is an object.

 * If a tornado destroys something, it is an event.

 * But objects and events are disjoint.

 * Therefore, there must be two distinct entities:  TornadoAsObject
   and TornadoAsEvent.

___________________________________________________________________

                      PRECISION AND VAGUENESS

Precision is sometimes bad:

 * Essential for computability and logical deduction.

 * But highly inflexible:  an advantage in some cases, but
   a disadvantage in other cases.

 * A precise ontology may force undesirable choices.

Vagueness is sometimes good:

 * Inevitable starting point for planning, design, research,
   and any kind of sincere negotiation.

 * Some things -- such as tornadoes, glaciers, and clouds --
   may be both objects and events.

____________________________________________________________________

                 CYC INTERMEDIATE LANGUAGE (I-CYCL)

 * I-CycL uses the same syntax and logical operators as CycL.

 * But I-CycL uses concept types that map directly to the words
   of natural languages.

 * The concept type Tornado, for example, could be used in I-CycL.

 * But in the mapping from I-CycL to CycL, the constraints
   imposed by the Cyc ontology would replace Tornado with
   either TornadoAsObject or TornadoAsEvent.

___________________________________________________________________

                     MAPPING LANGUAGE TO LOGIC

The I-CycL approach has also been used with other logic-based
languages, including conceptual graphs:

 1. The first stage of mapping language to logic uses labels taken
    from lexical resources, such as WordNet and FrameNet.

 2. Usually, there is a one-to-many mapping from the lexical labels
    to the names of the concept types and relations in the ontology.

 3. The selection of specific concept types and relations depends
    on constraints derived from axioms and definitions in the ontology.