Trevor Bench-Capon, Argument in Artificial Intelligence and Law
In this talk, I shall discuss the notion of argument, and the importance of argument in AI and Law. I shall distinguish four areas where argument has been applied:
The study of argument is held to offer prospects of real progressin the field of AI and Law, and the purpose of this talk is to provide an overview of work, and the connection between the various strands.
Eveline Feteris, The rational reconstruction of legal argumentation from a pragma-dialectical perspective
This paper shows how a theory of legal argumentation can be developed from a specific dialogical approach, a pragma-dialectical approach. It demonstrates how ideas from pragma-dialectical theory on the analysis and evaluation of legal argumentation can be combined with ideas taken from legal theory. It describes how a model for the analysis and evaluation of legal argumentation can be developed and it specifies a research programme for legal argumentation from a pragma-dialectical perspective.
Jaap Hage, The functions of dialectical reasoning
Dialectical approaches to reasoning have been used for different purposes. It is possible to give dialectical presentations of 'ordinary' logics such as propositional logic (Lorenzen and Lorenz, Barth and Krabbe). Such a dialectical rendering of a logic becomes more useful if the concerned logic is non-monotonic, as for instance the logics of Pollock and of Prakken and Sartor.
It is also possible to use a dialectical approach to identify the issues between parties (Gordon), or to find a common set of premises to justify conclusions (Habermass, Alexy, Aarnio, Lodder).
Finally it is possible to use dialectics as a theory about the generation of law. This presumes that the law in a concrete case is the outcome of a process, where this process can be modelled as a dialogue. This approach was defended in Hage et al. 1994.
The presentation will detail the differences and similarities between these three approaches.
Ton van Haaften, Definitions in legal texts: a speech act perspective
This paper deals with the form, function, and use of definitions in legal texts. The theory of definition and the theory of argumentation are closely related. Defining is thought to be an important instrument for the interpretation, evaluation, and formulation of standpoints and arguments. In modern theories with a dialogical perspective on argumentation, definition is first and foremost regarded as an instrument for clarifying discussions.
According to Viskil (1994) definition is best described as a speech act by which is indicated what a term means, or how a term is used. Every single definition can be regarded as a rule of language use which indicates the meaning or the use of a term. The distinction between the different types of definition (lexical definition, stipulative definition, et cetera) can be clarified by linking them to different speech acts and by classifying these acts according to Searle's taxonomy.
In my paper, I will first give a brief introduction to a speech act perspective on definitions in general. Subsequently I will illustrate how this perspective can be used in the production and interpretation of legal texts. Two viewpoints will be distinguished: a) that of the drafters of legal rules, and b) that of the interpreters of legal rules, especially that of judges. In considering each of these viewpoints the following questions will be addressed:
Reference
E. Viskil, 'Definitions in argumentative texts', in F.H. van Eemeren & R. Grootendorst (eds), Studies in Pragma- Dialectics. Sic Sat Amsterdam 1994, pp 79-86. <\P>
Tom Gordon, The ZENO argumentation framework: argument mediation on the World-Wide Web
The Zeno Argumentation Framework is a formal model of argumentation based on and generalizing the models of Pollock, Rittel, and Toulmin. The basic elements of the model are issues, positions, pro and con arguments and preferences. Preferences are a special kind of position, and may be argued about in the same way. Using these elements, the concept of a dialectical graph is defined, for modelling the state of a debate after each move. An evaluation function on the positions in a dialectical graph, using a set of evaluation (or "proof") standards for issues of the graph, is formally defined. The evaluation function determines the current acceptability of each position and may be viewed as another formal specification of the notion of argument "validity". The evaluation function is "nonmonotonic" in the sense that extensions of a dialectical graph can cause some positions which had been acceptable to become unacceptable, and vice versa.
Zeno was designed to be used in computer systems for supporting planning amoung multiple participants with conflicting views and interests. We call such systems "mediation sytems". In the European GeoMed project, we are building a discussion forum for the World Wide Web, based on the Zeno Argumentation Model, which is to be tested in pilot projects in the domain of city and regional planning.
A software engineering perspective of the Zeno Argumentation Framework is presented, using the Object Modelling Technique (OMT). This methodology provides diagramming methods which are suitable for illustrating the data flow and dynamic aspects of dialectical processes, which are inherently procedural.
Unlike most accounts, the Zeno Argumentation Framework does not extend or adapt an existing formalization of propositional logic. We argue that the argument structure of a natural langauge text is at a different level of granularity and abstraction than its logical structure. There is no need to reduce one to the other. They are complementary; each has its own range of applications and utility. But neither is inherently more foundational, or more formal.
In the discussion, a plea will be made for a shift in emphasis of argumentation theory from the post facto analysis and evaluation of natural language texts towards providing better theoretical support for mediating argumentation processes in real time, especially for applications in the context of computer mediated communication.
Harm Kloosterhuis, Analogy argumentation in judicial decisions: a speech act perspective
This paper deals with the rational reconstruction of analogy argumentation in judicial decisions. I try to describe, analyse and explain the elements of analogy-argumentation advanced in the justification of legal decisions, to explore the criteria for the assessment of this type of argumentation, to relate that to the general theory of law and to do all that in the framework of the pragma-dialectical approach to argumentation. I will examine the problems that may arise when analysing this type of reasoning and I will discuss two perspectives in dealing with this problems. In doing this, I will try to show how use and reconstruction of analogy argumentation are interrelated.
To begin with, I will discuss the concept `rational reconstruction' in (general) argumenta-tion theory and its meaning for analogy argmentation in law. Departing from four pragma-dialectical starting points I will sketch the functional context of analogy argumen-tation. Starting point is the idea that a reconstruction of argumentation in legal decisions has to relate to the activity of the judicial application of law and to the law as a system of rules and principles. Then I will discuss a predominent logical perspective to analogy argumentation in legal theory. I will try to show that this approach does not give a proper account for the pragmatic and linguistic context of analogy- argumentation and is therefore unable to give a good account for some key questions concerning the reconstruction of this argumentation. I shall argue that a dialectical approach to analogy-argumentation is more useful for analysing and evaluating this type of argumentation.