Subjective Logic and Arguing with Evidence

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The Notion of On-balance Premise Reconsidered

The notion of on-balance premise has played a crucial role in understanding the structure of conduction. It is a widely accepted view that in any third-pattern conductive argument there is always an implicit on-balance premise which represents a judgment that the positive reasons for the conclusion have outweighed the counter-considerations against it. This paper aims to provide a critical examination of the notion, and to reveal its inadequacy as a theoretical tool. First, it argues that the notion of on-balance premise has rested upon a metaphor of outweighing that is too simplistic to characterize the weighing and balancing between reasons and counter-considerations. Second, it discusses the justification of on-balance premise in third-pattern conductive arguments, and argues that the current efforts made to validate the on-balance premise as a missing premise remain to be unsuccessful

An Argumentation‐Based Analysis of the Simonshaven Case

In an argumentation approach, legal evidential reasoning is modeled as the construction and attack of “trees of inference” from evidence to conclusions by applying generalizations to evidence or intermediate conclusions. In this paper, an argumentation‐based analysis of the Simonshaven case is given in terms of a logical formalism for argumentation. The formalism combines abstract argumentation frameworks with accounts of the structure of arguments, of the ways they can be attacked and of ways to evaluate conflicting arguments. The purpose of this paper is not to demonstrate or argue that the argumentation approach to modeling legal evidential reasoning is feasible or even preferable but to have a fully worked‐out example that can be used in the comparison with alternative Bayesian or scenario‐based analyses

Marcos argumentativos etiquetados

El área de la representación del conocimiento y el razonamiento rebatible en Inteligencia Artificial se especializa en modelar el proceso de razonamiento humano de manera tal de establecer qué conclusiones son aceptables en un contexto de desacuerdo. En términos generales, las teorías de la argumentación se ocupan de analizar las interacciones entre los argumentos que están a favor o en contra de una determinada conclusión, para finalmente establecer su aceptabilidad. El objetivo principal del presente trabajo es expandir la capacidad de representación de los marcos argumentativos permitiendo representar las características especiales de los argumentos, y analizar cómo éstas se ven afectadas por las relaciones de soporte, agregación y ataque que se establecen entre los argumentos de un modelo que representa una determinada discusión argumentativa. Para ello, añadiremos un meta-nivel de información a los argumentos en la forma de etiquetas extendiendo así sus capacidades de representación, y brindaremos las herramientas necesarias para propagar y combinar las etiquetas en el dominio de la argumentación. Finalmente, utilizaremos la información proporcionada por las etiquetas para optimizar el proceso de aceptabilidad de los argumentos y brindar así resultados más refinados.Eje: Tesis doctorales. Tesis doctoral defendida por el autor en 2015, dirigida por Guillermo R. Simari y Rosanna N. Costaguta.Red de Universidades con Carreras en Informática (RedUNCI

Normative metaphysics for accountants

We use normative reasons in a bewildering variety of different ways. And yet, as many recent theorists have shown, one can discern systematic distinctions underlying this complexity. This paper is a contribution to this project of constructive normative metaphysics. We aim to bring a black sheep back into the flock: the balancing model of weighing reasons. This model is threatened by a variety of cases in which distinct reasons overlap, in the sense that they do not contribute separate weight for or against an option. Our response is to distinguish between derivative reasons and load-bearing reasons, only the latter of which contribute non-overlapping weight to an option. This distinction is close at hand for analyses of reasons in terms of the promotion of significant outcomes. But we also develop an account of this distinction for fundamentalist theories of normative reasons.Publisher PDFPeer reviewe

On a Razor\u27s Edge: Evaluating Arguments from Expert Opinion

This paper takes an argumentation approach to find the place of trust in a method for evaluating arguments from expert opinion. The method uses the argumentation scheme for argument from expert opinion along with its matching set of critical questions. It shows how to use this scheme in three formal computational argumentation models that provide tools to analyze and evaluate instances of argument from expert opinion. The paper uses several examples to illustrate the use of these tools. A conclusion of the paper is that from an argumentation point of view, it is better to critically question arguments from expert opinion than to accept or reject them based solely on trust

Examining the Modelling Capabilities of Defeasible Argumentation and non-Monotonic Fuzzy Reasoning

Knowledge-representation and reasoning methods have been extensively researched within Artificial Intelligence. Among these, argumentation has emerged as an ideal paradigm for inference under uncertainty with conflicting knowledge. Its value has been predominantly demonstrated via analyses of the topological structure of graphs of arguments and its formal properties. However, limited research exists on the examination and comparison of its inferential capacity in real-world modelling tasks and against other knowledge-representation and non-monotonic reasoning methods. This study is focused on a novel comparison between defeasible argumentation and non-monotonic fuzzy reasoning when applied to the representation of the ill-defined construct of human mental workload and its assessment. Different argument-based and non-monotonic fuzzy reasoning models have been designed considering knowledge-bases of incremental complexity containing uncertain and conflicting information provided by a human reasoner. Findings showed how their inferences have a moderate convergent and face validity when compared respectively to those of an existing baseline instrument for mental workload assessment, and to a perception of mental workload self-reported by human participants. This confirmed how these models also reasonably represent the construct under consideration. Furthermore, argument-based models had on average a lower mean squared error against the self-reported perception of mental workload when compared to fuzzy-reasoning models and the baseline instrument. The contribution of this research is to provide scholars, interested in formalisms on knowledge-representation and non-monotonic reasoning, with a novel approach for empirically comparing their inferential capacity

Senses of ‘argument’ in instantiated argumentation frameworks

Abstract Argumentation Frameworks (AFs) provide a fruitful basis for exploring issues of defeasible reasoning. Their power largely derives from the abstract nature of the arguments within the framework, where arguments are atomic nodes in an undifferentiated relation of attack. This abstraction conceals different senses of argument, namely a single-step reason to a claim, a series of reasoning steps to a single claim, and reasoning steps for and against a claim. Concrete instantiations encounter difficulties and complexities as a result of conflating these senses. To distinguish them, we provide an approach to instantiating AFs in which the nodes are restricted to literals and rules, encoding the underlying theory directly. Arguments in these senses emerge from this framework as distinctive structures of nodes and paths. As a consequence of the approach, we reduce the effort of computing argumentation extensions, which is in contrast to other approaches. Our framework retains the theoretical and computational benefits of an abstract AF, distinguishes senses of argument, and efficiently computes extensions. Given the mixed intended audience of the paper, the style of presentation is semi-formal

A Holist Balance Scale

Scale-based models of weighing reasons face challenges concerning the context-sensitivity of weight, the aggregation of weight, and the methodology for determining what the weights of reasons are. I resolve these challenges