An Automated System for Argument Invention in Law Using Argumentation and Heuristic Search Procedures*

Abstract

Abstract. A heuristic search procedure for inventing legal arguments is built on two tools already widely in use in argumentation. Argumentation schemes are forms of argument representing premise-conclusion and inference structures of common types of arguments. Schemes especially useful in law represent defeasible arguments, like argument from expert opinion. Argument diagramming is a visualization tool used to display a chain of connected arguments linked together. One such tool, Araucaria, available free at http://araucaria.computing.dundee.ac.uk/, helps a user display an argument on the computer screen as an inverted tree structure with an ultimate conclusion as the root of the tree. These argumentation tools are applicable to analyzing a mass of evidence in a case at trial, in a manner already known in law using heuristic methods (Schum 1994) and Wigmore diagrams (Wigmore 1931). In this paper it is shown how they can be automated and applied to the task of inventing legal arguments. One important application is to proof construction in trial preparation (Palmer 2003).

Legal Electronic Institutions and ONTOMEDIA: Dialogue, Inventio, and Relational Justice Scenarios

“…As we will see, these inferences are conceived to be "rationally binding" between the participants engaged in any dialogue [42]. This approach fits particularly well in a judicial perspective, in which either the judge or the lawyer have to find new and convincing arguments to sustain proof.…”

“…According to Walton's proposal, the gap between logic and rhetoric may be filled up leaning gradually on the identification, analysis, and evaluation processes (dialectic), and on the innovative one (rhetoric). Heuristics are used to find new arguments, but the crucial point is called dialectic relevance, a method of chaining both forward and backward to get the chain of argumentation to match up in the middle [23,42]. The whole process is recursive and iterative, going from (i) acceptable premises to (ii) rules of inference, and (iii) a chaining recursive device.…”

“…Along with fallacies, these constitute precisely the points chosen by Walton to reelaborate the problem of innovation and creation of new arguments [23,42]. This goes directly to the core of one of more pervasive and persistent problems of cognitive sciences and philosophy.…”

Advances in the Theory of Argumentation Schemes and Critical Questions

“…So, in the project of analysis, argument schemes serve as models of comparison during the initial identification of the type of reasoning at work in an argument, and further provide a complete profile of all the required components of the argument once such an identification is made. Finally, we note in passing that argumentation schemes also can play an important role in argument invention (or the generation and composition of argument) (Walton 2005a).…”

Argument from Expert Opinion as Legal Evidence: Critical Questions and Admissibility Criteria of Expert Testimony in the American Legal System*

“…The second is the growing literature in argumentation theory on argument from expert opinion as an argumentation scheme, or defeasible form of argument . The third is the flowering of recent work in artificial intelligence and law (Schum 1994;Sartor 1996, 2003), using argumentation schemes to represent forms of reasoning in law that are modeled in artificial intelligence (Walton 2005;Bex et al 2003). In recent work of this sort, argument from expert opinion is the scheme most commonly taken as the leading case for studying how to identify, analyze and evaluate forms of argument used in law (Gordon 2005).…”