8 An Overview of OntoClean Nicola Guarino1 and Christopher A. Welty2 1Laboratory for Applied Ontology (ISTC-CNR) Polo Tecnologico, Via Solteri 38, 38100 Trento, ITALY
[email protected] 2IBM Watson Research Center 19 Skyline Dr., Hawthorne, NY 10532, USA
[email protected] Summary. OntoClean is a methodology for validating the ontological adequacy of taxonomic relationships. It is based on highly general ontological notions drawn from philosophy, like essence, identity, and unity, which are used to characterize relevant aspects of the intended meaning of the properties, classes, and relations that make up an ontology. These aspects are represented by formal metaproperties, which impose several constraints on the taxonomic structure of an ontology. The analysis of these constraints helps in evaluating and validating the choices made. In this chapter we present an informal overview of the philosophical notions in- volved and their role in OntoClean, review some common ontological pitfalls, and walk through the example that has appeared in pieces in previous papers and has been the basis of numerous tutorials and talks. 8.1 Introduction The OntoClean methodology was first introduced in a series of conference-length papers in 2000 [Guarino and Welty, 2000a-c; Welty and Guarino, 2001], and re- ceived much attention and use in subsequent years. The main contribution of On- toClean was the beginning of a formal foundation for ontological analysis. Alan Rector, a seasoned veteran at ontological analysis in the medical domain, said of OntoClean, “…what you have done is reduce the amount of time I spend arguing with doctors that the way I want to model the world is right…” [Rector, 2002].