author: Sofia Almpani, Elena Lisanyuk, Andrew Schumann,

In this paper, we introduce the subject of the special issue Trends in Argumentation Logic. Here we mainly describe two approaches to argumentation logic with explicating monotonic and non-monotonic, or defeasible, reasoning and explain the role of artificial intelligence in applying argumentation logic. Then we give a short overview of the papers contributed to the special issue.

author: Antonis Kakas,

Can argumentation form the basis for any form of reasoning, informal or formal logical reasoning? We examine this question from the particular perspective of the recent developments in logic-based Artificial Intelligence (AI). We propose that argumentation provides the wider framework encompassing uniformly all reasoning, with strict or formal logical reasoning being a special boundary case. We also attempt to link this unifying role of argumentation with Aristotle’s original investigation of methods and formalisms for the systematic study of human reasoning.

author: Dimitra Serakioti, Petros Stefaneas,

This article is concerned with the concept of ambiguity in argumentation. Ambiguity in linguistics lies on the coexistence of two possibly interpretations of an utterance, while the role of contextual factors and background/encyclopedic knowledge within a specific society seems to be crucial. From a systemic point of view, Halliday has proposed three main language functions (meta-functions): a) ideational function, b) interpersonal function, c) textual function. Language could reflect speaker’s experience of his external and internal world, interpersonal relationships and organization of text, respectively. Lexico-grammatical choices under a micro-level perspective and context (the environment of language) may lead to inconsistent interpretations through semantic or syntactic ambiguities. In philosophy and argumentation logic, strategies of ambiguity have been investigated by Aristotle, since the first sophistic movement. In his Topics, Metaphysics and Rhetoric, has pointed out the notion of “τὸ διττῶς / διχῶς λεγόμενον”, meaning that a term can have different senses and double interpretation. In this paper we discuss how we reconstruct the meaning of an utterance in dialogue through the mechanism of interpretation and how we analyze and construe ambiguities, combining the insights of argumentation theory and text linguistics. Research results show that in case of misunderstanding, the “best interpretation” is the less defeasible one according to contextual presumptions.