Can One Really Reason about Laws?

Abstract

Precedent decides legal cases, but few precedents make the case at bar <I>res judicata</I>. Instead, analogical reasoning is used, together with canons of statutory interpretation and theories of constitutional jurisprudence. The work under review provides a model and algorithm for analogical reasoning in the legal context. Technically, the paper represents very fine work, except that in order to find the ground of a rule, some human input is required. The rule is denied and consequences of the negation are automatically derived; then, those which a person has previously marked as undesirable are candidates for the rule's ground. So this is a man-machine system, something not emphasized by the authors. Still, it is very fine work. Aside from its technical excellence and, on the other hand, an annoying number of missing articles, misplaced modifiers, and failures of agreement, the authors imply a certain understanding of law and how laws are made. The paper uses an ordinance rather than cases for analogical reasoning, after all, a practice that makes little sense unless the legislature is always perfectly consistent. Hence, the whole epistemological basis for the paper may be flawed.