Argumentation and Defeasible Reasoning in the Law

Different formalisms for defeasible reasoning have been used to represent knowledge and reason in the legal field. In this work, we provide an overview of the following logic-based approaches to defeasible reasoning: defeasible logic, Answer Set Programming, ABA+, ASPIC+, and DeLP. We compare features of these approaches under three perspectives: the logical model (knowledge representation), the method (computational mechanisms), and the technology (available software resources). On top of that, two real examples in the legal domain are designed and implemented in ASPIC+ to showcase the benefit of an argumentation approach in real-world domains. The CrossJustice and Interlex projects are taken as a testbed, and experiments are conducted with the Arg2P technology

Some Artificial Intelligence Tools for Argument Evaluation: An Introduction

Even though tools for identifying and analyzing arguments are now in wide use in the field of argumentation studies, so far there is a paucity of resources for evaluating real arguments, aside from using deductive logic or Bayesian rules that apply to inductive arguments. In this paper it is shown that recent developments in artificial intelligence in the area of computational systems for modeling defeasible argumentation reveal a different approach that is currently making interesting progress. It is shown how these systems provide the general outlines for a system of argument evaluation that can be applied to legal arguments as well as everyday conversational arguments to assist a user to evaluate an argument

Argumentation schemes in AI and Law

In this paper we describe the impact that Walton’s conception of argumentation schemes had on AI and Law research. We will discuss developments in argumentation in AI and Law before Walton’s schemes became known in that community, and the issues that were current in that work. We will then show how Walton’s schemes provided a means of addressing all of those issues, and so supplied a unifying perspective from which to view argumentation in AI and Law.</jats:p

Discurso Web, Modelos Teóricos e Sistemas de Argumentação: Implicações para a Tomada de Decisão

A crescente importância atribuída pelas organizações à tomada de decisão em contexto web requer que sejam definidos e implementados mecanismos mais eficientes para apoiar as atividades da mesma. As redes sociais, enquanto espaços de colaboração, permitem que os atores sociais interajam entre si independentemente do local e espaço onde se encontram. Um aspeto importante dos ambientes virtuais é que, de uma forma ou de outra, se verifica a existência de discussão argumentativa e nesse sentido a web constitui-se como uma excelente ferramenta para apoiar a representação, divulgação e recuperação do conhecimento, pois pode realçar a expressão argumentativa, devido à sua omnipresença e abertura. Através da captura e análise do discurso web, é possível obter informação relevante que reflete a opinião e a manifestação de pontos de vista que podem ser úteis para a tomada de decisão. Para o efeito, é importante identificar e perceber a estrutura da rede de atores sociais, a comunicação, contexto, linguagem, linguística e conteúdo do discurso web, visto que as palavras e frases estão sempre carregadas de sentidos e intenções, que podem ser definidas de forma diferente.A argumentação tem o seu foco nos diálogos com o objetivo de aumentar ou diminuir a aceitação de um ponto de vista, a fim de chegar a uma conclusão através de um raciocínio lógico. Nesse contexto, temos assistido a um aumento importante no desenvolvimento de sistemas de colaboração centrados na web, que funcionam como facilitadores da argumentação. Nestes, diferentes pontos de vista podem ser apresentados, contestados e avaliados, e a tomada de decisão colaborativa é efetuada através de debates e negociações entre um grupo de indivíduos. Tendo em conta este novo paradigma, este trabalho objetivou consolidar conhecimentos associados ao discurso web, à argumentação e decisão, aos modelos teóricos de argumentação e aos sistemas de argumentação computacional para a web.The growing importance given by organizations to decision-making in the web context requires more efficient mechanisms to be defined and implemented, in order to support its activities. Social networks whilst collaboration spaces, enable social actors to interact regardless of their location. An important aspect of virtual environments is that, one way or another, argumentative discussions exist and the web is constituted as an excellent tool to support representation, dissemination and knowledge retrieval, as it can enhance the argumentative expression due to its ubiquity and openness. By capturing and analyzing web discourses, organizations can obtain relevant information reflecting the expression of viewpoints that might be useful for decision-making. To achieve this goal, and since words and phrases are always charged with meanings and intentions that might be defined in different ways, it is important to identify and understand the structure of the actors’ social network, communication, context, language, linguistics and content of web discourse. Argumentation has its focus on dialogues, aiming to increase or decrease the acceptance of a point of view in order to reach a conclusion through logical reasoning. In this context, we have seen a significant development of web-centric collaboration systems, which act as argumentation facilitators. Within these systems, different viewpoints can be presented, challenged and evaluated, while collaborative decision-making is carried out through debates and negotiations between groups. Given this new paradigm, this study aims to consolidate existing knowledge on web discourse, argumentation and decision, argumentation theoretical models and argumentation computational systems for the web.info:eu-repo/semantics/publishedVersio

A framework for relating, implementing and verifying argumentation models and their translations

Computational argumentation theory deals with the formalisation of argument structure, conflict between arguments and domain-specific constructs, such as proof standards, epistemic probabilities or argument schemes. However, despite these practical components, there is a lack of implementations and implementation methods available for most structured models of argumentation and translations between them. This thesis addresses this problem, by constructing a general framework for relating, implementing and formally verifying argumentation models and translations between them, drawing from dependent type theory and the Curry-Howard correspondence. The framework provides mathematical tools and programming methodologies to implement argumentation models, allowing programmers and argumentation theorists to construct implementations that are closely related to the mathematical definitions. It furthermore provides tools that, without much effort on the programmer's side, can automatically construct counter-examples to desired properties, while finally providing methodologies that can prove formal correctness of the implementation in a theorem prover. The thesis consists of various use cases that demonstrate the general approach of the framework. The Carneades argumentation model, Dung's abstract argumentation frameworks and a translation between them, are implemented in the functional programming language Haskell. Implementations of formal properties of the translation are provided together with a formalisation of AFs in the theorem prover, Agda. The result is a verified pipeline, from the structured model Carneades into existing efficient SAT-based implementations of Dung's AFs. Finally, the ASPIC+ model for argumentation is generalised to incorporate content orderings, weight propagation and argument accrual. The framework is applied to provide a translation from this new model into Dung's AFs, together with a complete implementation

A framework for relating, implementing and verifying argumentation models and their translations

Computational argumentation theory deals with the formalisation of argument structure, conflict between arguments and domain-specific constructs, such as proof standards, epistemic probabilities or argument schemes. However, despite these practical components, there is a lack of implementations and implementation methods available for most structured models of argumentation and translations between them. This thesis addresses this problem, by constructing a general framework for relating, implementing and formally verifying argumentation models and translations between them, drawing from dependent type theory and the Curry-Howard correspondence. The framework provides mathematical tools and programming methodologies to implement argumentation models, allowing programmers and argumentation theorists to construct implementations that are closely related to the mathematical definitions. It furthermore provides tools that, without much effort on the programmer's side, can automatically construct counter-examples to desired properties, while finally providing methodologies that can prove formal correctness of the implementation in a theorem prover. The thesis consists of various use cases that demonstrate the general approach of the framework. The Carneades argumentation model, Dung's abstract argumentation frameworks and a translation between them, are implemented in the functional programming language Haskell. Implementations of formal properties of the translation are provided together with a formalisation of AFs in the theorem prover, Agda. The result is a verified pipeline, from the structured model Carneades into existing efficient SAT-based implementations of Dung's AFs. Finally, the ASPIC+ model for argumentation is generalised to incorporate content orderings, weight propagation and argument accrual. The framework is applied to provide a translation from this new model into Dung's AFs, together with a complete implementation