Rodolphe Hoekstra

For more than a decade constructing ontologies for legal domains, we, at the Leibniz Center for Law, felt really the need to develop a core ontology for law that would enable us to re-use the common denominator of the various legal domains. In this paper we present two core ontologies for law. The first one was the result of a PhD thesis by [Valente, 1995], called FOLaw. FOLaw speci- fies functional dependencies between types of knowledge involved in legal reasoning. Despite the fact that FOLaw was the starting point for a number of ontologies and legal reasoning systems in various (European) projects, it is rather an epistemological framework than a (core) ontology. We are not the only ones who easily confound epistemology with ontology. In the paper we present some examples and discuss whether this epistemological promiscuity in (core) ontology development is a serious problem. It is to some extent, as it limits the scope of re-use (if not leading to confusion). Therefore, we started about four years ago the development of a 'real' core-ontology for law based upon notions of common sense. The reason for a common-sense foundation is that domain independent concepts of law - the common denominator - are still tainted with a strong common-sense flavor. Moreover, domains of law refer to social activities which are generally governed by common-sense notions. This core ontology, called LRI-Core, consists of five major portions ('worlds'): physical, mental and abstract classes; roles and occurrences