Ontological requirements for analogical, teleological, and hypothetical legal reasoning

摘要

In 1993, Berman and Hafner criticized case-based models of legal reasoning for not modeling analogical and teleological elements. Another lesson learned since then is the role of ontologies in representing domain knowledge so that a legal reasoning system can represent and solve problems. If the reasoning involves drawing abstract analogies, reasoning teleologically about rules for deciding a case, and posing hypothetical cases to test decision rules, however, it is not clear what requirements the ontology should satisfy. This paper presents an extended example of such legal reasoning to illustrate what an ontology for case-based legal reasoning should provide. The example centers on a microworld of legal discourse, an ensemble of real legal cases, hypothetical examples, concepts, factors, principles and policies. Beginning with any case in the microworld, the system's goal is to generate arguments that a law professor and students might reasonably make in discussing the legal case in class. The example illustrates three roles the ontology should play in providing representational support for the system, distills the ontological requirements, and suggests an incremental approach to making good on Berman's and Hafner's challenge.