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.

John Pollock (1940?2009) was an influential American philosopher who made important contributions to various fields, including epistemology and cognitive science. In the last 25 years of his life, he also contributed to the computational study of defeasible reasoning and practical cognition in artificial intelligence. He developed one of the first formal systems for argumentation-based inference and he put many issues on the research agenda that are still relevant for the argumentation community today. This paper presents an appreciation of Pollock's work (...) on defeasible reasoning and its relevance for the computational study of argument. In our opinion, Pollock deserves to be remembered as one of the founding fathers of the field of computational argument, while, moreover, his work contains important lessons for current research in this field, reminding us of the richness of its object of study. (shrink)

Belief formation and justification of belief is the subject of epistemology, philosophy of mind, and philosophy of action. In this article we are mostly interested in the application of analytic techniques for the explication of belief justification under uncertainty. We need to explicate this phenomenon in order to answer, at least in part, the question of what are the features of reasoning made in conditions that cause doubts, how people make decisions in such conditions. Arguments used for the justification of (...) such decisions have the status of plausible arguments. The crucial issues related to the analysis and evaluation of plausible arguments are of the acceptability of the premises and the transmission of their acceptability to the conclusion. In this article, we have focused on the transition from the premises to the conclusions of plausible arguments, on the transmission of justification of premises to the conclusions. To establish the peculiarities of such a transmission an outline of the semantics for such arguments is proposed. Its key component is the measures of the plausibility of the premises and rules of inference. A plausible argument itself does not provide the ultimate reason for accepting its conclusion. The justification of the conclusion also depends on other arguments that support or defeat it. So to establish the degree of justification of the conclusion we need to attribute the weights to the premises and rules of inference. We hope that this study provides at least a preliminary answer to the question of how the failure of the transmission of justification in plausible arguments differs from the failure of transmission in deductive arguments. (shrink)

Conciliatory views of disagreement say, roughly, that it’s rational for you to become less confident in your take on an issue in case you find out that an epistemic peer’s take on it is the opposite. Their intuitive appeal notwithstanding, there are well-known worries about the behavior of conciliatory views in scenarios involving higher-order disagreements, which include disagreements over these views themselves and disagreements over the peer status of alleged epistemic peers. This paper does two things. First, it explains how (...) the core idea behind conciliatory views can be expressed in a defeasible logic framework. The result is a formal model that’s particularly useful for thinking about the behavior of conciliatory views in cases involving higher-order disagreements. And second, the paper uses this model to resolve three paradoxes associated with disagreements over epistemic peerhood. (shrink)

En este escrito se presentan las bases de una estrategia pragmática, contextualista e inferencialista para articular una teoría que dé cuenta de los grados de justificación de nuestras aserciones. Se arguye que hay contextos de emisión de aserciones configurados con ciertos criterios inferenciales, los cuales responden a propósitos prácticos o teóricos, y conforman, en consecuencia, diferentes estándares de justificación en esos contextos. Finalmente, a partir de una caracterización de tipos de proposiciones, inferencias, compromisos asertivos y esquemas de justificación, se muestra (...) cómo determinar el grado de justificación alto, medio o bajo de una aserción con respecto a un contexto de emisión de aserciones dado. (shrink)

The article develops and justifies, on the basis of the epistemological argumentation theory, two central pieces of the theory of evaluative argumentation interpretation: 1. criteria for recognizing argument types and 2. rules for adding reasons to create ideal arguments. Ad 1: The criteria for identifying argument types are a selection of essential elements from the definitions of the respective argument types. Ad 2: After presenting the general principles for adding reasons (benevolence, authenticity, immanence, optimization), heuristics are proposed for finding missing (...) reasons, for deductive arguments, e.g., semantic tableaux are suggested. (shrink)