Ontologies and Meta-Ontologies discussion moderated by Dr. Nicolas Rouquette (NASA/JPL) on 02/24/2005

* Discussion topic Ontologies and Meta-Ontologies: practical considerations * Moderator Dr. Nicolas Rouquette - NASA / Jet Propulsion Laboratory / California Institute of Technology * ONTOLOG forum Wiki page details http://ontolog.cim3.net/cgi-bin/wiki.pl?OntologDiscussion/MetaOntologies_And_Ontologies * Background Using the analogy associating an ontology as an analog to the concept of a reusable software library with its API, then we can look towards modern approaches of reusable software development practices as an inspiration for modular ontology development. The naive approach for modular, object-oriented software development relies heavily on subclassing as the mechanism to decouple a reusable module (i.e., the superclass) with a specific usage of that module in a given application context (i.e., the subclass that derives from the moduleandapos;s superclass). There is a growing body of evidence that this approach is inherently brittle in software engineering. (for more on this topic, see see Clemens Szyperskiandapos;s Component Software book, chapters 5 and 6 -- http://research.microsoft.com/~cszypers/Books/component-software.htm) The analogy holds for formal ontologies as well. Here, andquot;formal ontologyandquot; refers to an ontology that has rigorous formalization of some kind suitable for a reasoning process to make inferences based on the ontologyandapos;s axioms, properties and rules. Well-known examples of formal ontologies include: SUMO, PSL, DOLCE. The OntoClean methodology is an excellent case explaining the pitfalls and limitations of subsumption for organizing extensible or modular ontologies. This has led to the notion of andquot;meta-ontologyandquot;, initially used as an ontology where the (meta) ontology provides a taxonomy of concepts and properties used for capturing the meaning of things in the application-specific ontology using annotations expressed in terms of the meta-ontology. This idea has been documented in the semantic web best practices group http://www.w3.org/2001/sw/BestPractices/, e.g., with the andquot;classes-as-valuesandquot; pattern http://www.w3.org/TR/swbp-classes-as-values/ commonly used for annotation purposes.