Reasoning with Cases and Hypotheticals in HYPO

HYPO is a case-based reasoning system that evaluates problems by comparing and contrasting them with cases from its Case Knowledge Base (CICB). It generates legal arguments citing the past cases as justifications for legal conclusions about who should win in problem disputes involving trade secret law. HYPO’s arguments present competing adversarial views of the problem and it poses hypotheticals to alter the balance of the evaluation. HYPO uses Dimensions as a generalization scheme for accessing and evaluating cases. HYPO’s reasoning process and various computational definitions are described and illustrated, including its definitions for computing relevant similarities and differences, the most on point and best cases to cite, four kinds of counter-examples, targets for hypotheticals and the aspects of a case that are salient in various argument roles. These definitions enable HYPO to make contextually sensitive assessments of relevance and salience without relying on either a strong domain theory or a priori weighting schemes.