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The pragma-dialectical approach to argumentation aims to provide a sound integration of both dialectics — the study of critical exchanges — and pragmatics — the study of language use in actual communication. Pragma dialectics thus combines a dialectical view of argumentative reasonableness with a pragmatic view of the verbal moves made in argumentative discourse. This paper provides an overview of the current state of the pragma-dialectical approach, insofar as this can be done adequately in a single paper, and provides many pointers to the full range of work in this area.

In this paper we introduce a logic of abstract argumentation capturing Dung’s theory of abstract argumentation, based on connectives for attack and defend. We extend it to a modal logic of abstract argumentation to generalize Dung’s theory and define variants of it. Moreover, we use the logic to relate Dung’s theory of abstract argumentation to more traditional conditional and comparative formalisms, and we illustrate how to reason about arguments in meta-argumentation.

Argumentation has received steadily increasing attention in the multi-agent systems community over the past decade, with particular interest in the use of argument models from the informal logic community. The of such argument systems is a necessary step if they are to be successfully deployed, and their properties rigorously understood. However, there is as yet no widely accepted approach to the formalisation of argument systems. In this paper, we take as our starting point the view that arguments and dialogues are inherently , and that any proper formalisation of argument must embrace this aspect of their nature. For example, a statement that serves as a justification of an argument is is statement an argument: the argument for which the justification serves must itself be referred to in the justification. From this starting position, we develop a formalisation of arguments using a hierarchical first-order meta-logic, in which statements in successively higher tiers of the argumentation hierarchy refer to statements further down the hierarchy. This enables us to give a clean formal separation between object-level statements, arguments made about these object level statements, and statements about arguments.

In this paper we describe a framework in which the grounds for one argument’s defeat of another is itself subject to argumentation. Hence, given two conflicting arguments, each of which defeat the other, one can then determine the preferred defeat and hence the preferred argument. We then apply this nested argumentation to selection of an agent’s preferred ‘instrumental’ arguments, where each such argument represents a plan of actions for realising an agent’s goals.

Systems of argumentation or ’computational dialectic’ are emerging as a powerful means of structuring inter-agent communication in multi-agent systems. Individual systems of computational dialectic have been suggested and implemented to tackle specific problems but no comprehensive and comparative assessment has been made of such systems. This paper introduces Scenario, a framework for the implementation and testing of a wide range of computational dialectic systems. Scenario has a range of benefits for both theoretical and practical work in computational dialectics, including: a means to test arbitrary dialectic systems using a unified knowledge base; a means to determine standard metrics by which dialectic systems can be measured and compared; enabling a body of example dialogue to be assembled for each dialectic system to demonstrate their qualities.

Argumentation plays a key role in finding a compromise during a negotiation dialogue. It may lead an agent to change its goals/ preferences and force it to respond in a particular way. Two types of arguments are mainly used for that purpose: and . For example, if an agent receives a threat, this agent may accept the offer even if it is not fully “acceptable” for it (because otherwise really important goals would be threatened).

The contribution of this paper is twofold. On the one hand, a logical setting that handles these two types of arguments is provided. More precisely, logical definitions of threats and rewards are proposed together with their weighting systems. These definitions take into account that negotiation dialogues involve not only agents’ beliefs (of various strengths), but also their goals (having maybe different priorities), as well as the beliefs about the goals of other agents.

On the other hand, a “simple” protocol for handling such arguments in a negotiation dialogue is given. This protocol shows when such arguments can be presented, how they are handled, and how they lead agents to change their goals and behaviors.

(ABN) provides agents with an effective means to resolve conflicts within a multi-agent society. However, to engage in such argumentative encounters the agents require the ability to generate arguments, which, in turn, demands four fundamental capabilities: a schema to reason in a social context, a mechanism to identify a suitable set of arguments, a language and a protocol to exchange these arguments, and a decision making functionality to generate such dialogues. This paper focuses on the first two issues and formulates models to capture them. Specifically, we propose a coherent schema, based on social commitments, to capture social influences emanating from the roles and relationships of a multi-agent society. After explaining how agents can use this schema to reason within a society, we then use it to identify two major ways of exploiting social influence within ABN to resolve conflicts. The first of these allows agents to argue about the validity of each other’s social reasoning, whereas the second enables agents to exploit social influences by incorporating them as parameters within their negotiation. For each of these, we use our schema to systematically capture a comprehensive set of social arguments that can be used within a multi-agent society.

Recent years have seen an increasing interest of multiagent system research in employing the theory of for the development of communication protocols. While significant progress has been made in formalising argument-based communication, (possibly ) agent-level as a integration of rational agent reasoning and inter-agent argumentation dialogues have received fairly little attention. In this paper we propose the use of the InFFrA framework in argument-based negotiation. This framework allows for a strategic and adaptive communication to achieve private goals within the limits of bounded rationality in open argumentation communities. The feasibility of the approach is illustrated in an agent-based web linkage scenario, showing that its performance is comparable to that of simple proposal-based negotiation while accommodating much stricter constraints regarding “what can be said” like those used in argumentation.

One form of argument-based negotiation is when agents argue about why an offer was rejected. If an agent can state a reason for a rejection of an offer, the negotiation process may become more efficient since the other agent can take this reason into account when making new offers. Also, if a reason for rejection can be disputed, the negotiation process may be of higher quality since flawed reasons may be revised as a result. This paper presents a formal protocol for negotiation in which reasons can be asked and given for rejections and in which agents can try to persuade each other that a reason is or is not acceptable. The protocol is modelled as a persuasion dialogue game embedded in a negotiation protocol. It has a social semantics since the protocol does not refer to the internal state of negotiating agents.

Much work in the area of argumentation-based dialogues between agents has been based on the influential taxonomy of dialogue types developed by Walton and Krabbe. In this paper we re-examine the Walton and Krabbe framework, concentrating on the preconditions for different types of dialogue and analyzing them in a systematic way. Doing so identifies a number of new kinds of dialogue missing from the framework. We discuss some of the more interesting of these and develop protocols for them.