1. KR-2002 Panel/Debate Are Upper-Level Ontologies worth the effort? Chris Welty, IBM Research

2. 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.

3. What is an Ontology? [Welty, Uschold, Gruninger, Lehmann & McGuinness, 1999] complexity a catalog a set of general logical axioms a glossary a set of text files a thesaurus a collection of taxonomies a collection of frames with automated reasoning without automated reasoning

4. 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, …

5. 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]

6. What an Upper Level Ontology is not Necessarily large Necessarily part of any system that uses it Necessarily goal-independent Necessarily language dependent Easy

7. Panelists Pro Nicola Guarino CNR, Italy Brandon Bennett U. Leeds, UK Con Alan Rector U. Manchester, UK Jim Hendler U. Maryland, USA

8. Panelist Introduction Nicola Guarino Background –Ontology, Formal Ontology Recent Work –OntoClean, restructuring WordNet Goal –Bring together CS, Philosophy, and Linguistics Ontology –Account of intended meaning of terms

9. Panelist Introduction Brandon 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

10. Panelist Introduction Alan 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

11. Panelist Introduction Jim 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

12. Are upper-level ontologies worth the effort?

13. 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

14. 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 dont know how to argue –Need tools to support argumentation –We must understand when we disagree

15. 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?