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KR-2002 Panel/Debate. Are Upper-Level Ontologies worth the effort? Chris Welty, IBM Research. What is Ontology? [Smith & Welty, 2001]. A discipline of Philosophy Meta-physics dates back to Artistotle Ontology dates back to 17th century The science of what is One universe - one ontology
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KR-2002 Panel/Debate Are Upper-Level Ontologies worth the effort? Chris Welty, IBM Research
What is Ontology?[Smith & Welty, 2001] • A discipline of Philosophy • Meta-physics dates back to Artistotle • Ontology dates back to 17th century • The science of what is • One universe - one ontology • Borrowed by AI community • McCarthy (1980) calls for “a list of things that exist” • Evolution of meaning • Now refers to domain modeling, conceptual modeling, knowledge engineering, etc.
a set of general logical axioms a collection of taxonomies a catalog a glossary a set of text files a collection of frames a thesaurus complexity without automated reasoning with automated reasoning What is an Ontology?[Welty, Uschold, Gruninger, Lehmann & McGuinness, 1999]
What is an Upper Level Ontology? • The most general classifications of entities • Domain independent • High reusability, utility • “Common reference” ontology • The most basic building blocks (foundation) of ontologies, e.g. • Properties: Event/object, abstract/concrete, … • Relations: Isa, part, instance, …
Examples of Upper Level Ontologies • Wordnet Upper Level [Miller, Fellbaum] • Cyc Upper Level [Lehmann, Klein] • IEEE SUO […] • OntoClean Top Level [Guarino, et al] • GOL [Smith, et al]
What an Upper Level Ontology is not • Necessarily large • Necessarily part of any system that uses it • Necessarily goal-independent • Necessarily language dependent • Easy
Pro Nicola Guarino CNR, Italy Brandon Bennett U. Leeds, UK Con Alan Rector U. Manchester, UK Jim Hendler U. Maryland, USA Panelists
Panelist IntroductionNicola Guarino • Background • Ontology, Formal Ontology • Recent Work • OntoClean, restructuring WordNet • Goal • Bring together CS, Philosophy, and Linguistics • Ontology • Account of intended meaning of terms
Panelist IntroductionBrandon Bennett • Background • Spatial and temporal reasoning • Recent Work • Axiomatic systems for space/time, vagueness [VUG] • Goal • A unifying foundational ontology • Ontology • Rigorous definition of concepts
Panelist IntroductionAlan Rector • Background • Medical terminologies, description logics • Recent Work • GALEN, part/whole reasoning, drug info • Goal • Integration of clinical systems with decision support, indexing of evidence • Ontology • Implementation of the formal representation of concepts needed for a collection of information resources
Panelist IntroductionJim Hendler • Background • Scaleable KR Systems, Interoperability, Agents • Recent Work • DAML, DAML+OIL, W3C webont chair • Goal • A semantic web • Ontology • A web of nested terminologies
Points Against • No “The” • Agreement impossible • On the scale of the web, ridiculous • Standardizing syntax OK, but not semantics • Cognitive systems differ, even within people • Different cog system, different “ontology” • Consequences of decisions hard to predict, but important • Middle level easier, more important • Upper level development often gets bogged down • Takes time away from more critical parts of a system • No way to evaluate quality • Easy to teach someone middle-level concepts • Upper level often too opaque to explain • Some domains require different levels of complexity depending on the needs
Points for • Standardizing upper level is no different than standardizing syntax, its just the next step • to establish consensus, there must be some common ground • We don’t know how to argue • Need tools to support argumentation • We must understand when we disagree
Other points • What is upper level? • Abstract, or simple? • Where is the evidence to support upper level notions? • Time: easy or hard? • How relevant is philosophical ontology? • What is the value of legislation? • Role of logic, category theory • How do we learn how to communicate • Upper ontology similar to language creation?