ABSTRACT
H. L. A. Hart's classic article on the subject, 'The Ascription of Responsibility and Rights', Proceedings of the Aristotelian Society, in which he argued that the primary function of action sentences is to ascribe responsibility, and that even in non-legal discourse such sentences are defeasible in the manner of certain legal claims and judgements. He borrowed the term defeasible from the law of property, where it is used to refer to an estate or legal interest in land which is subject to termination or defeat in a number of different contingencies but remains intact if no such contingencies mature. Hart then extended its meaning to cover all legal claims that are regarded as provisionally established at a certain stage of the litigation process. The notion of defeasibility then is inextricably tied up with an adversary system of litigation and its complex and diverse rules governing the sufficiency and insufficiency of legal claims.
