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Foundations of Legal Reasoning

Objective

This Working Group aimed, by an inter-disciplinary investigation of the foundations of legal reasoning, to provide a sound basis for the application of artificial intelligence to law. By determining the extent to which the law is amenable to formal modelling, and the extent to which formal models are amenable to computation, the project aimed to identify the proper role of AI in law, and enable it to be filled.
Law has been chosen as the subject of the research for two reasons: legal reasoning exemplifies many forms of human reasoning that are of interest to AI research, and since the law is already, in its own way, a formalised system, it may lend itself to useful exploitation of this research.
A group of computer scientists, mathematical logicians, legal philosophers and jurists investigated the foundations of legal reasoning, with the aim of identifying and helping to bring about applications of artificial intelligence to legal matters.

Work has so far concentrated on the following topics:
techniques of logic programming applied to the representation of legislative texts, especially methods for preserving consistency involving the adequacy of Prolog for expressing the logic of legal sentences;
ways in which legal expert systems should take into account the problems of statutory interpretation and methods of application of laws in practice (the role of extra judicial considerations, especially policy considerations, in judicial reasoning);
the institutional theory of legal propositions, and the relation between given legal facts and the context of the legal system in which they are placed and other theories of the logic of legal sentences (the bearing of this on the adequacy of standard predicate logic for the analysis of legal arguments, and the preconditions for a successful use of deontic logic;
the general form of a legal expert system, and the prototype of a legal expert system shell.

Besides developing techniques of formal logic and settling questions of methodology a number of prototype systems have been contracted to illustrate the potential of expert system shells: CLIMS, a shell applied to contract law; INTSALE, applied to international conventions for the sale of goods; an Interstate Succession Adviser applied to problems in Scottish Law; systems applied to conditions of Austrian citizenship and to Italian matrimonial law; and an application of the Imperial College shell Ekilagi to Bologna University study benefits regulations.
APPROACH AND METHODS
The potential for formalization and computational treatment of reasoning processes in the law is investigated in relation to the following areas of application:
-Statutory interpretation and legal rationality, the use of policy arguments in statutory interpretation, the application of general rules to particular cases, and the possibility of predicting the case outcomes.
-The logic of lay justice and fact-finding, and the logic of judicial and non-judicial collective decisions.
-Questions of legal epistemology (in particular the legal classifications made by the legal system itself), and the institutional nature of legal facts.
-Philosophical and computational aspects of legal argumentation theory, and the construction of systems which will derive legal consequences.
PROGRESS AND RESULTS
Work has so far concentrated on the following topics:
-Techniques of logic programming applied to the representation of legislative texts, especially methods for preserving consistency; the adequacy of Prolog (in particular of negation as failure) for expressing the logic of legal sentences.
-Ways in which legal expert systems should take into account the problems of statutory interpretation and methods of application of laws in practice; the role of extra-judicial considerations, especially policy considerations, in judicial reasoning.
-The institutional theory of legal propositions, and the relation between given legal facts and the context of the legal system in which they are placed; other theories of the logic of legal sentences: the bearing of this on the adequacy of standard pre dicate logic for the analysis of legal arguments, and the pre-conditions for a successful use of deontic logic.
-The general form of a legal expert system, and the prototype of a legal expert system shell.
Besides developing techniques of formal logic, and settling questions of methodology, members of the group have constructed a number of prototype systems, to illustrate the potential of expert system shells: CLIMS, a shell applied to contract law; INTSALE, applied to international conventions for the sale of goods; an Interstate Succession Adviser applied to problems in Scottish Law; systems applied to conditions of Austrian citizenship and to Italian matrimonial law; and an application of the Imperial College shell Ekilagi to Bologna University study benefits regulations.
POTENTIAL
The activities of the Working Group gave rise to a further esprit exploratory action, ALDUS (5636), which investigated the technical feasibility and market potential of an AI aid to the formation of international contract of sale. This produced significant work on the technical problems of a computational approach to the conflict of laws.
Members of the group are planning further collaboration in various areas: the application of law to facts, and the processes of legal fact-finding, in relation to the formalisation of judgments of probability and of decisions under uncertainty in a legal context; exploring the relevance of neural network (connectionist) models to legal discourse and, in particular, to legal problem-solving and prediction; putting into practice some of the main findings of the previous Group, and elaborating a decision-support system for a specific area of law.

Coordinator

Machine Intelligence Ltd
Address
9 Greens Road
CB4 3EF Cambridge
United Kingdom

Participants (13)

CHRISTIAN-ALBRECHTS UNIVERSITÄT KIEL
Germany
Address
Olshausenstraße 40
24118 Kiel
Consiglio Nazionale delle Ricerche (CNR)
Italy
Address
Via Panciatichi 56/16
50127 Firenze
IMPERIAL COLLEGE OF SCIENCE, TECHNOLOGY AND MEDICINE
United Kingdom
Address
Queens Gate 180
SW7 2BZ London
Institute of Advanced Legal Studies
United Kingdom
Address
17 Russell Square
WC1B 5DR London
Istituto Universitario Europeo
Italy
Address
Via Dei Roccettini 5
50016 Fiesole Firenze
UNIVERSITAT OF THE BASQUE COUNTRY
Spain
Address

20001 San Sebastian
UNIVERSITY COLLEGE CORK
Ireland
Address
Prospect Row
Cork
UNIVERSITY OF BOLOGNA
Italy
Address
Via Zamboni 33
40126 Bologna
UNIVERSITÄT TÜBINGEN
Germany
Address
Wilhelmstraße 7
72074 Tübingen
University of Leeds
United Kingdom
Address
37 University Road
LS2 9JT Leeds
University of the West of England, Bristol
United Kingdom
Address
Coldharbour Lane Frenchay
BS16 1QY Bristol
Università degli Studi di Pisa
Italy
Address
Lungarno Pacinotti 43
56100 Pisa
Université d'Aix-Marseille III (Université de Droit d'Économie et des Sciences)
France
Address
Avenue Robert Schuman
13628 Aix-en-provence