© 2001 by Oxford University Press
Defeasibilism
1 Oriel College, Oxford
The author suggests that law is best represented, understood, and taught in the form of open-ended, defeasible, normative, conditional propositions. The meaning, role, and significance of defeasibility is explained by presenting three ‘canonical forms’ and by distinguishing exceptions and overrides. The role of equity in the law of contract, as understood by the author, is taken as an exemplar of override and parallels are drawn with policy in the English law of tort and with mercy in the criminal law of England and Wales. The third and preferred canonical form is sequenced and internally differentiated and seeks a satisfactory middle way between all-or-nothing rules and wild-card discretion and a reconciliation of the surface demands of legal rules and the deeper values embedded in law. The suggested approach therefore resists closure and seeks a conceptual restructuring of law which opens it up to the influence of notions such as justice and equity and locates them as open-ended conditions of defeasance inhabiting the express or implied ‘unless...’ clause which is taken to be an element in every fully-formed statement of law. This approach accommodates law as a locus not only of traditional rule-based reasoning, but also of open-ended internal moral reasoning invoking deeper values inherent in law and only imperfectly captured and implemented by formal legal rules.