The authors describe a logic programming approach to the representation of legislative texts. They consider the potential uses of simple systems which incorporate a single, fixed interpretation of a text. These include assisting in the routine administration of complex areas of the law. The authors also consider the possibility of constructing more complex systems which incorporate several, possibly conflicting interpretations. Such systems are needed for dealing with ambiguity and vagueness in the law. Moreover, they are more suitable than single interpretation (...) systems for helping to test proposed legislation and for helping to give citizens advice. (shrink)

Stephen Cole Kleene was one of the greatest logicians of the twentieth century and this book is the influential textbook he wrote to teach the subject to the next generation. It was first published in 1952, some twenty years after the publication of Godel's paper on the incompleteness of arithmetic, which marked, if not the beginning of modern logic. The 1930s was a time of creativity and ferment in the subject, when the notion of computable moved from the realm of (...) philosophical speculation to the realm of science. This was accomplished by the work of Kurt Gode1, Alan Turing, and Alonzo Church, who gave three apparently different precise definitions of computable. When they all turned out to be equivalent, there was a collective realization that this was indeed the right notion. Kleene played a key role in this process. One could say that he was there at the beginning of modern logic. He showed the equivalence of lambda calculus with Turing machines and with Godel's recursion equations, and developed the modern machinery of partial recursive functions. This textbook played an invaluable part in educating the logicians of the present. It played an important role in their own logical education.". (shrink)

The Concept of Law is the most important and original work of legal philosophy written this century. First published in 1961, it is considered the masterpiece of H.L.A. Hart's enormous contribution to the study of jurisprudence and legal philosophy. Its elegant language and balanced arguments have sparked wide debate and unprecedented growth in the quantity and quality of scholarship in this area--much of it devoted to attacking or defending Hart's theories. Principal among Hart's critics is renowned lawyer and political philosopher (...) Ronald Dworkin who in the 1970s and 80s mounted a series of challenges to Hart's Concept of Law. It seemed that Hart let these challenges go unanswered until, after his death in 1992, his answer to Dworkin's criticism was discovered among his papers. In this valuable and long-awaited new edition Hart presents an Epilogue in which he answers Dworkin and some of his other most influential critics including Fuller and Finnis. Written with the same clarity and candor for which the first edition is famous, the Epilogue offers a sharper interpretation of Hart's own views, rebuffs the arguments of critics like Dworkin, and powerfully asserts that they have based their criticisms on a faulty understanding of Hart's work. Hart demonstrates that Dworkin's views are in fact strikingly similar to his own. In a final analysis, Hart's response leaves Dworkin's criticisms considerably weakened and his positions largely in question. Containing Hart's final and powerful response to Dworkin in addition to the revised text of the original Concept of Law, this thought-provoking and persuasively argued volume is essential reading for lawyers and philosophers throughout the world. (shrink)

We discuss several aspects of legal arguments, primarily arguments about the meaning of statutes. First, we discuss how the requirements of argument guide the specification and selection of supporting cases and how an existing case base influences argument formation. Second, we present,our evolving taxonomy of patterns of actual legal argument. This taxonomy builds upon our much earlier work on argument moves and also on our more recent analysis of how cases are used to support arguments for the interpretation of legal (...) statutes. Third, we show how the theory of argument used by CABARET, a hybrid case-based/rule-based reasoner, can support many of the argument patterns in our taxonomy. (shrink)

Much work on legal knowledge systems treats legal reasoning as arguments that lead from a description of the law and the facts of a case, to the legal conclusion for the case. The reasoning steps of the inference engine parallel the logical steps by means of which the legal conclusion is derived from the factual and legal premises. In short, the relation between the input and the output of a legal inference engine is a logical one. The truth of the (...) conclusion only depends on the premises, and is independent of the argument that leads to the conclusion.This paper opposes the logical approach, and defends a procedural approach to legal reasoning. Legal conclusions are not true or false independent of the reasoning process that ended in these conclusions. In critical cases this reasoning process consists of an adversarial procedure in which several parties are involved. The course of the argument determines whether the conclusion is true or false. The phenomenon of hard cases is used to demonstrate this essential procedural nature of legal reasoning. (shrink)

C. C. W. Taylor presents a clear and faithful new translation of one of the most famous and influential texts in the history of Western thought, accompanied by an analytical and critical commentary focusing on philosophical issues. In Books II to IV of the Nicomachean Ethics Aristotle gives his account of virtue of character, which is central to his ethical theory as a whole and a key topic in much modern ethical writing.

The authors describe a logic programming approach to the representation of legislative texts. They consider the potential uses of simple systems which incorporate a single, fixed interpretation of a text. These include assisting in the routine administration of complex areas of the law. The authors also consider the possibility of constructing more complex systems which incorporate several, possibly conflicting interpretations. Such systems are needed for dealing with ambiguity and vagueness in the law. Moreover, they are more suitable than single interpretation (...) systems for helping to test proposed legislation and for helping to give citizens advice. (shrink)

This paper discusses some engineering considerations that should be taken into account when building a knowledge based system, and recommends isomorphism, the well defined correspondence of the knowledge base to the source texts, as a basic principle of system construction in the legal domain. Isomorphism, as it has been used in the field of legal knowledge based systems, is characterised and the benefits which stem from its use are described. Some objections to and limitations of the approach are discussed. The (...) paper concludes with a case study giving a detailed example of the use of the isomorphic approach in a particular application. (shrink)