Katie Atkinson

Practical reasoning as presumptive argumentation using action based alternating transition systems

In this paper we describe an approach to practical reasoning, reasoning about what it is best for a particular agent to do in a given situation, based on presumptive justifications of action through the instantiation of an argument scheme, which is then subject to examination through a series of critical questions. We identify three particular aspects of practical reasoning which distinguish it from theoretical reasoning. We next provide an argument scheme and an associated set of critical questions which is able to capture these features. In order that both the argument scheme and the critical questions can be given precise interpretations we use the semantic structure of an Action-Based Alternating Transition System as the basis for their definition. We then work through a detailed example to show how this approach to practical reasoning can be applied to a problem solving situation, and briefly describe some other previous applications of the general approach. In a second example we relate our account to the social laws paradigm for co-ordinating multi-agent systems. The contribution of the paper is to provide firm foundations for an approach to practical reasoning based on presumptive argument in terms of a well-known model for representing the effects of actions of a group of agents.

Computational Representation of Practical Argument

In this paper we consider persuasion in the context of practical reasoning, and discuss the problems associated with construing reasoning about actions in a manner similar to reasoning about beliefs. We propose a perspective on practical reasoning as presumptive justification of a course of action, along with critical questions of this justification, building on the account of Walton. From this perspective, we articulate an interaction protocol, which we call PARMA, for dialogues over proposed actions based on this theory. We outline an axiomatic semantics for the PARMA Protocol, and discuss two implementations which use this protocol to mediate a discussion between humans. We then show how our proposal can be made computational within the framework of agents based on the Belief-Desire-Intention model, and illustrate this proposal with an example debate within a multi agent system.

A dialogue game protocol for multi-agent argument over proposals for action

We present the syntax and semantics for a multi-agent dialogue game protocol which permits argument over proposals for action. The protocol, called the PARMA Protocol, embodies an earlier theory by the authors of persuasion over action which enables participants to rationally propose, attack, and defend, an action or course of actions (or inaction). We present an outline of both an axiomatic and a denotational semantics, and discuss an implementation of the protocol for two human agents.

Using Computational Argumentation to Support E-participation

Internet-based tools that encourage public participation in debates concerning policy issues have been recognized as a good way to engage the electorate with political issues. In addition, such systems for e-participation can gather, make available, and analyze the publics contributions to political debate. In this article we discuss a system called Parmenides, which we designed to exploit technological developments to bring democratic processes into the online world. Parmenides is primarily a forum by which government bodies can present policy proposals to the public so that users can submit their opinions on the justification presented for the particular policy. Within Parmenides, the justification for action is structured to exploit a specific representation of persuasive argument based on the use of argumentation schemes and critical questions.

A Dialogue Game Protocol for Multi-Agent Argument over Proposals for Action

Abstract.We present the syntax and semantics for a multi-agent dialogue game protocol which permits argument over proposals for action. The protocol, called the Persuasive Argument for Multiple Agents (PARMA) Protocol, embodies an earlier theory by the authors of persuasion over action which enables participants to rationally propose, attack, and defend, an action or course of actions (or inaction). We present an outline of both an axiomatic and a denotational semantics, and discuss implementation of the protocol, in the context of both human and artificial agents.

Persuasion and Value in Legal Argument

In this paper we consider legal reasoning as a species of practical reasoning. As such it is important both that arguments are considered in the context of competing, attacking and supporting arguments, and that the possibility of rational disagreement is accommodated. We present two formal frameworks for considering systems of arguments: the standard framework of Dung, and an extension which relates arguments to values allowing for rational disagreement. We apply these frameworks to modelling a body of case law, explain how the frameworks can be generated to reconstruct legal reasoning in particular cases, and describe some tools to support the extraction of the value related knowledge required from a set of precedent cases.

Arguing about cases as practical reasoning

In this paper we apply a general account of practical reasoning to arguing about legal cases. In particular, we describe how the reasoning in one very well known property law case can be reconstructed in terms of our account. We begin by summarising our general approach which uses instantiations of an argumentation scheme to provide presumptive justifications for actions, and critical questions to identify arguments which attack these justifications. These arguments and attacks are organised into argumentation frameworks to identify the status of individual arguments. Different beliefs about, and perspectives on, the issue are represented by different agents based on the Belief-Desire-Intention model, and conditions under which these agents may advance justifications and attack them are described. We model the different views of our case in these terms, describe the resulting argumentation frameworks, and relate them to the original majority and dissenting opinions. We contend that this approach both shows the worth of the general approach and its applicability to the legal domain.

Algorithms for decision problems in argument systems under preferred semantics

For Dung@?s model of abstract argumentation under preferred semantics, argumentation frameworks may have several distinct preferred extensions: i.e., in informal terms, sets of acceptable arguments. Thus the acceptance problem (for a specific argument) can consider deciding whether an argument is in at least one such extensions (credulously accepted) or in all such extensions (skeptically accepted). We start by presenting a new algorithm that enumerates all preferred extensions. Following this we build algorithms that decide the acceptance problem without requiring explicit enumeration of all extensions. We analyze the performance of our algorithms by comparing these to existing ones, and present experimental evidence that the new algorithms are more efficient with respect to the expected running time. Moreover, we extend our techniques to solve decision problems in a widely studied development of Dung@?s model: namely value-based argumentation frameworks (vafs). In this regard, we examine analogous notions to the problem of enumerating preferred extensions and present algorithms that decide subjective, respectively objective, acceptance.

Semi-Automated Argumentative Analysis of Online Product Reviews.

Argumentation is key to understanding and evaluating many texts. The arguments in the texts must be identified; using current tools, this requires substantial work from human analysts. With a rule-based tool for semi-automatic text analysis support, we facilitate argument identification. The tool highlights potential argumentative sections of a text according to terms indicative of arguments (e.g. ‘suppose’ or ‘therefore’) and domain terminology (e.g. camera names and properties). The information can be used by an analyst to instantiate argumentation schemes and build arguments for and against a proposal. The resulting argumentation framework can then be passed to argument evaluation tools.

Abstract Argumentation and Values

Argumentation and Values Trevor Bench-Capon and Katie Atkinson