R.E. Leenes

Hard cases: a procedural approach

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.Dialogical Reason Based Logic offers a framework that makes it possible to model legal dialogues. We use Dialogical Reason Based Logic to specify hard cases in dialogical terms. Moreover, we analyse an actual Dutch hard case in terms of Dialogical Reason Based Logic, to demonstrate both the possibilities and the shortcomings of this approach.It turns out that there is no one set of rational dialogue rules. There are many concurring sets of rules that govern particular types of dialogues. The rules for legal procedures are as much part of the law as the more substantial rules. As a consequence, it is not possible to offer an universal set of dialogue rules. Dialogical Reason Based Logic rather provides a framework which can be filled with dialogue rules that determine which dialogues are valid and which ones are invalid.

A dialogue game for legal arguments

Abstract In this paper it is argued that legal reasoning should be analysed as dialogue games, rather than as logical proofs. This argument is complemented by a set of dialogue rules which define these dialogue games, and an extended example in which the working of (part of) these rules is illustrated.

Burden of proof in dialogue games and Dutch civil procedure

In recent years dialectics has become popular in Artificial Intelligence and law. A sub-branch of this field concentrates on the development of dialogue games. Many of these legal dialogue systems are fairly simple, in some respects even too simple. Among the topics dialogue games can improve on, is the division of the burden of proof. In this paper I discuss some legal dialogue games in the light of an actual legal procedure to show the shortcomings of these models. The paper shows what computational dialectics can learn form legal practice.

Abort or retry: a role for legal knowledge based systems in electronic service delivery?

Electronic service delivery is closely tied to legal decision making. Legal decision making is by nature complicated. It involves the (strict) application of rules, but it also inevitably leaves room for discretion. If the ambition of electronic service delivery is taken seriously, this means that (some) legal decisions have to be taken by computers. Legal knowledge based systems (LKBSs) capable of performing this task have been around since the early nineteen nineties. These systems, although successful, never really broke through and are somewhat forgotten. With the advent of e-Government and its focus on electronic service delivery, legal decision making systems are desperately needed. This paper argues that legal knowledge based system technology is neglected undeserved and that it offers opportunities for serious electronic service delivery.

Supporting the legal practitioner: LKBS or web?

The legal practitioner is a knowledge worker. Two distinct technologies may be of assistance to this type of professional: legal knowledge‐based system technology and Internet World Wide Web technology. In this paper we investigate the relation between legal knowledge‐based systems and the Internet. Legal knowledge‐based systems have long been surrounded by much optimism, but despite the efforts over the last 20 years, the number of practical applications actually in use is still small. On the other hand, the WWW technology, which in a practical form has been around for only a few years, is gaining momentum and is expected to have a serious impact on many fields of society, including the legal domain. We look at both technologies and try to answer the question of where the future of both technologies lies.

Douglas Walton, Appeal to Expert Opinion--- Arguments from Authority.

A new pragmatic approach, based on the latest developments in argumentation theory, analyzing appeal to expert opinion as a form of argument....

Dialogical reason‐based logic for modelling legal reasoning

Abstract A view of legal rules as fixed entities is erroneous. In legal disputes the debate is often about the rules themselves. Traditional logic‐based approaches to legal expert systems run up against difficulties when dealing with conflicts about the rules themselves. It is worthwhile to adopt a different view on the nature of legal rules. An alternative can be found in dialogical reason‐based logic (RBL). In this logic a dispute is seen as a dialogue between two parties in which reasons for or against some thesis are put forward. In RBL both rules and facts can be the objects of disputes.