>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 Common Logic standard, which includes KIF, CGs, and OWL.
>
>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.
>
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