Argumentation Framework Research Articles

On the Decomposition of Abstract Dialectical Frameworks and the Complexity of Naive-based Semantics

Abstract dialectical frameworks (ADFs) are a recently introduced powerful generalization of Dung’s popular abstract argumentation frameworks (AFs). Inspired by similar work for AFs, we introduce a decomposition scheme for ADFs, which proceeds along the ADF’s strongly connected components. We find that, for several semantics, the decompositionbased version coincides with the original semantics, whereas for others, it gives rise to a new semantics. These new semantics allow us to deal with pertinent problems such as odd-length negative cycles in a more general setting, that for instance also encompasses logic programs. We perform an exhaustive analysis of the computational complexity of these new, so-called naive-based semantics. The results are quite interesting, for some of them involve little-known classes of the so-called Boolean hierarchy (another hierarchy in between classes of the polynomial hierarchy). Furthermore, in credulous and sceptical entailment, the complexity can be different depending on whether we check for truth or falsity of a specific statement.

Comparing logic programming and formal argumentation; the case of ideal and eager semantics

The connection between logic programming and formal argumentation has been studied starting from the landmark 1995 paper of Dung. Subsequent work has identified a standard translation from logic programs to (instantiated) argumentation frameworks, under which pairwise correspondences hold between various logic programming semantics and various formal argumentation semantics. This includes the correspondence between 3-valued stable and complete semantics, between well-founded and grounded semantics and between 2-valued stable (LP) and stable (argumentation) semantics. In the current paper, we show that the existing translation is able to yield the additional correspondence between ideal semantics for logic programming and ideal semantics for formal argumentation. We also show that correspondence does not hold between eager semantics for logic programming and eager semantics for formal argumentation, at least when translating from logic programming to formal argumentation. Overall, the current work should be seen as completing the analysis of correspondences between mainstream admissibility-based argumentation semantics and their logic programming counterparts.

A logic of defeasible argumentation: Constructing arguments in justification logic

In the 1980s, Pollock’s work on default reasons started the quest in the AI community for a formal system of defeasible argumentation. The main goal of this paper is to provide a logic of structured defeasible arguments using the language of justification logic. In this logic, we introduce defeasible justification assertions of the type t : F that read as “t is a defeasible reason that justifies F”. Such formulas are then interpreted as arguments and their acceptance semantics is given in analogy to Dung’s abstract argumentation framework semantics. We show that a large subclass of Dung’s frameworks that we call “warranted” frameworks is a special case of our logic in the sense that (1) Dung’s frameworks can be obtained from justification logic-based theories by focusing on a single aspect of attacks among justification logic arguments and (2) Dung’s warranted frameworks always have multiple justification logic instantiations called “realizations”. We first define a new justification logic that relies on operational semantics for default logic. One of the key features that is absent in standard justification logics is the possibility to weigh different epistemic reasons or pieces of evidence that might conflict with one another. To amend this, we develop a semantics for “defeaters”: conflicting reasons forming a basis to doubt the original conclusion or to believe an opposite statement. This enables us to formalize non-monotonic justifications that prompt extension revision already for normal default theories. Then we present our logic as a system for abstract argumentation with structured arguments. The format of conflicting reasons overlaps with the idea of attacks between arguments to the extent that it is possible to define all the standard notions of argumentation framework extensions. Using the definitions of extensions, we establish formal correspondence between Dung’s original argumentation semantics and our operational semantics for default theories. One of the results shows that the notorious attack cycles from abstract argumentation cannot always be realized as justification logic default theories.

Deductive and abductive argumentation based on information graphs

In this paper, we propose an argumentation formalism that allows for both deductive and abductive argumentation, where ‘deduction’ is used as an umbrella term for both defeasible and strict ‘forward’ inference. Our formalism is based on an extended version of our previously proposed information graph (IG) formalism, which provides a precise account of the interplay between deductive and abductive inference and causal and evidential information. In the current version, we consider additional types of information such as abstractions which allow domain experts to be more expressive in stating their knowledge, where we identify and impose constraints on the types of inferences that may be performed with the different types of information. A new notion of attack is defined that captures a crucial aspect of abductive reasoning, namely that of competition between abductively inferred alternative explanations. Our argumentation formalism generates an abstract argumentation framework and thus allows arguments to be formally evaluated. We prove that instantiations of our argumentation formalism satisfy key rationality postulates.

Para além dos direitos humanos

Diante da necessidade crescente de se olhar o Direito sob uma ótica internacionalizada, o presente artigo de natureza básica tem como objetivo analisar se é possível encarar o controle jurisdicional de convencionalidade, como um instrumento de proteção aos Direitos da Personalidade. É cógnito que os Direitos Humanos são alvo da salvaguarda pelo controle que compatibiliza normas internas com os tratados internacionais que versam sobre esses direitos, mas há a necessidade de observar se a referida conjuntura também se estende aos direitos de natureza personalíssima, tendo em conta a relevância que tais direitos possuem e a necessidade, que deles emerge, de discussões científicas sobre o tema. Dessa forma, por meio do método de abordagem hipotético-dedutivo e mediante a utilização do método de procedimento bibliográfico e observacional, é possível compreender primeiramente que, a proteção destinada aos Direitos Humanos por intermédio do controle de convencionalidade, também pode alcançar alguns Direitos da Personalidade e em segundo lugar, qual o arcabouço argumentativo para tanto.

Complexity of Nonempty Existence Problems in Incomplete Argumentation Frameworks

Abstract argumentation frameworks (AFs) are a prevailing model for the formal representation of argumentations in AI research. The generalized model of incomplete AFs extends the basic model by allowing for the representation of unquantified uncertainty about the existence of elements in an argumentation. For this extended model of AFs, we formally define a natural generalization of the nonempty existence problem, which asks whether there exists a nonempty set of arguments satisfying the conditions specified by a given semantics. Focusing on the fundamental semantics for incomplete AFs and considering a possible and a necessary variant of the nonempty existence problem, this yields a family of related problems, and we provide a full analysis of their computational complexity.

Epistemic Argumentation Framework: Theory and Computation

The paper introduces the notion of an epistemic argumentation framework (EAF) as a means to integrate the beliefs of a reasoner with argumentation. Intuitively, an EAF encodes the beliefs of an agent who reasons about arguments. Formally, an EAF is a pair of an argumentation framework and an epistemic constraint. The semantics of the EAF is defined by the notion of an ω-epistemic labelling set, where ω is complete, stable, grounded, or preferred, which is a set of ω-labellings that collectively satisfies the epistemic constraint of the EAF. The paper shows how EAF can represent different views of reasoners on the same argumentation framework. It also includes representing preferences in EAF and multi-agent argumentation. Finally, the paper discusses complexity issues and computation using epistemic logic programming.

Valid attacks in argumentation frameworks with recursive attacks

The purpose of this work is to study a generalisation of Dung’s abstract argumentation frameworks that allows representing recursive attacks, that is, a class of attacks whose targets are other attacks. We do this by developing a theory of argumentation where the classic role of attacks in defeating arguments is replaced by a subset of them, which is “extension-dependent” and which, intuitively, represents a set of “valid attacks” with respect to the extension. The studied theory displays a conservative generalisation of Dung’s semantics (complete, preferred, stable and grounded) and also of its principles (conflict-freeness, acceptability and admissibility). Furthermore, despite its conceptual differences, we are also able to show that our theory agrees with the AFRA interpretation of recursive attacks for the complete, preferred, stable and grounded semantics and with a recent flattening method.

A principle-based robustness analysis of admissibility-based argumentation semantics

The principle-based approach is a methodology to classify and analyse argumentation semantics. In this paper we classify seven of the main alternatives for argumentation semantics using a set of new robustness principles. These principles complement Baroni and Giacomin’s original classification and deal with the behaviour of a semantics when the argumentation framework changes due to the addition or removal of an attack between two arguments. We distinguish so-called persistence principles and monotonicity principles, where the former deal with the question of whether a labelling or extension of an argumentation framework under a given semantics persists after a change, and the latter with the question of whether new labellings or extensions are created after a change. We furthermore show in which sense labelling-based and extension-based semantics lead to subtly different principles and results. Our results can be used for choosing a semantics for a particular application, or to guide the search for new argumentation semantics, but they have been used also in the design of algorithms.

An experimental analysis on the similarity of argumentation semantics

In this paper we ask whether approximation for abstract argumentation is useful in practice, and in particular whether reasoning with grounded semantics – which has polynomial runtime – is already an approximation approach sufficient for several practical purposes. While it is clear from theoretical results that reasoning with grounded semantics is different from, for example, skeptical reasoning with preferred semantics, we investigate how significant this difference is in actual argumentation frameworks. As it turns out, in many graphs models, reasoning with grounded semantics actually approximates reasoning with other semantics almost perfectly. An algorithm for grounded reasoning is thus a conceptually simple approximation algorithm that not only does not need a learning phase – like recent approaches – but also approximates well – in practice – several decision problems associated to other semantics.

On argument acceptability change towards legal interpretation dynamics

We propose a formal theory built upon an abstract argumentation framework for handling argumentation dynamics. To that end, we analyze the acceptability dynamics of arguments through the proposal of two different kinds of sets of arguments which are somehow responsible for the acceptability/rejection of a given argument. We develop a study of the consequences of breaking the construction of such sets towards the acceptance of an analyzed argument. This brings about the proposal of a novel change operation which allows to determine which arguments should be removed from the framework so that another particular argument becomes accepted. Finally, the proposed model is formalized in the light of the theory of belief revision by characterizing the corresponding operations through constructive definition and an axiomatic characterization, connecting them through the corresponding representation theorem. The theoretical proposal constitutes the fundamentals for a system implementation in many dynamic domains of application. In particular, we show its application for handling the dynamics of legal interpretation. In that sense, this proposal constitutes a fundamental approach and theoretical justification to handle the dynamics of legal arguments through changes of interpretative canons. We show a possible concretisation of our abstract theory for the legal domain by analysing a real legal case from the Argentinean jurisprudence. Such a system would be capable of suggesting alternative critical points in the current state of affairs of a legal case towards pursuing a specific goal for which the case is being investigated.

Representation, justification, and explanation in a value-driven agent: an argumentation-based approach

Ethical and explainable artificial intelligence is an interdisciplinary research area involving computer science, philosophy, logic, and social sciences, etc. For an ethical autonomous system, the ability to justify and explain its decision-making is a crucial aspect of transparency and trustworthiness. This paper takes a Value-Driven Agent (VDA) as an example, explicitly representing implicit knowledge of a machine learning-based autonomous agent and using this formalism to justify and explain the decisions of the agent. For this purpose, we introduce a novel formalism to describe the intrinsic knowledge and solutions of a VDA in each situation. Based on this formalism, we formulate an approach to justify and explain the decision-making process of a VDA, in terms of a typical argumentation formalism, Assumption-based Argumentation (ABA). As a result, a VDA in a given situation is mapped onto an argumentation framework in which arguments are defined by the notion of deduction. Justified actions with respect to semantics from argumentation correspond to solutions of the VDA. The acceptance (rejection) of arguments and their premises in the framework provides an explanation for why an action was selected (or not). Furthermore, we go beyond the existing version of VDA, considering not only practical reasoning, but also epistemic reasoning, such that the inconsistency of knowledge of the VDA can be identified, handled, and explained.

THE IMPLEMENTATION OF RELIGIOUS PLURALISM VALUES OF ISLAMIC LAW ON ARTICLE 156A OF THE CRIMINAL CODE

<em>Religious freedom in Indonesia is based on the abundant presence of Godliness that is the religious values embraced in Indonesia. The religions are Islam, Christianity, Catholicism, Hinduism, Buddhism and Confucianism mentioned in the Presidential Decree No. 1 of 1965 on the defamation/blasphemy, and stipulation of Article 156a to become a part of Article 156 Criminal Code. The essence of the blasphemy law is to realize a harmonious religious life. This is in line with the Islamic law that is universal and dynamic. Islam does not deny the diversity of the universe, diversity of knowledge, diversity of tribes and cultures, and diversity of religions and beliefs. Because the messenger of the Prophet was to improve the morality of his followers by carrying the value of Rahmatan lil-aalamiin (a blessing for the universe). In this study, the values of Islamic law implicit in Article 156a of the Criminal Code were examined by applying a normative method as well as religious text approach as a framework for argumentation. In addition to applying a policy-oriented approach, this research also applied a value-oriented approach. Because the position of Islamic law is one source of material law as well as very relevant to the pluralistic style of Indonesian society.</em>

The Linguistic Formulation of Fallacies Matters: The Case of Causal Connectives

While the role of discourse connectives has long been acknowledged in argumentative frameworks, these approaches often take a coarse-grained approach to connectives, treating them as a unified group having similar effects on argumentation. Based on an empirical study of the straw man fallacy, we argue that a more fine-grained approach is needed to explain the role of each connective and illustrate their specificities. We first present an original corpus study detailing the main features of four causal connectives in French that speakers routinely use to attribute meaning to another speaker (puisque, étant donné que, vu que and comme), which is a key element of straw man fallacies. We then assess the influence of each of these connectives in a series of controlled experiments. Our results indicate each connective has different effects for the persuasiveness of straw man fallacies, and that these effects can be explained by differences in their semantic profile, as evidenced in our corpus study. Taken together, our results demonstrate that connectives are important for argumentation but should be analyzed individually, and that the study of fallacies should include a fine-grained analysis of the linguistic elements typically used in their formulation.

No false grounds and topology of argumentation

Abstract We integrate Dung’s argumentation framework with a topological space to formalize Clark’s no false lemmas theory for solving the Gettier problem and study its logic. Our formalization shows that one of the two notions of knowledge proposed by Clark, justified belief with true grounds, satisfies Stalnaker’s axiom system of belief and knowledge except for the axiom of closure under conjunction. We propose a new notion of knowledge, justified belief with a well-founded chain of true grounds, which further improves on Clark’s two notions of knowledge. We pinpoint a seemingly reasonable condition which makes these three notions of knowledge collapse into the same one and explain why this result looks counter-intuitive. From a technical point of view, our formal analysis driven by the philosophical issues reveals the logical structure of the grounded semantics in Dung’s argumentation theory.

On the upscaling approach to wind tunnel experiments of horizontal axis hydrokinetic turbines

In this work, we proposed an upscaling methodology to extrapolate results from wind tunnel experiments with small-scale model to the full-size hydrokinetic turbine. Small-scale 1:20 wind tunnel experiments ( $${\hbox {Re}}\sim 10^4$$ ), with a three-blade horizontal axis turbine, were carried out looking to identify the characteristic curves of a full-size turbine operating in water ( $${\hbox {Re}}\sim 10^6$$ ). The lack of dynamic similarity due to unmatched Reynolds numbers is analyzed in the framework of blade element momentum theory arguments. A new semi-empirical power-law equation is achieved, uniquely based on the BEM theory which relates the power coefficients of model and full-size turbine to the Reynolds numbers and a power factor, specific to each turbine. Computational fluid dynamic CFD simulations for the same rotor geometry, simulating different runners with varying diameters from small-scale model to full-scale turbine are carried out to validate the upscaling arguments, and to verify the accuracy of the power coefficient curves predicted by proposed methodology.

On the Semantics of Abstract Argumentation Frameworks: A Logic Programming Approach

AbstractRecently there has been an increasing interest in frameworks extending Dung’s abstract Argumentation Framework (AF). Popular extensions include bipolar AFs and AFs with recursive attacks and necessary supports. Although the relationships between AF semantics and Partial Stable Models (PSMs) of logic programs has been deeply investigated, this is not the case for more general frameworks extending AF.In this paper we explore the relationships between AF-based frameworks and PSMs. We show that every AF-based framework Δ can be translated into a logic program PΔ so that the extensions prescribed by different semantics of Δ coincide with subsets of the PSMs of PΔ. We provide a logic programming approach that characterizes, in an elegant and uniform way, the semantics of several AF-based frameworks. This result allows also to define the semantics for new AF-based frameworks, such as AFs with recursive attacks and recursive deductive supports.

A probabilistic deontic argumentation framework

What does it mean that something is probably obligatory? And how does it relate to the probability that it is permitted or prohibited? In this paper, we provide a possible answer by merging deontic argumentation and probabilistic argumentation into a probabilistic deontic argumentation framework. This framework allows us to specify a semantics for the probability of deontic statuses. The deontic argumentation part builds on standard concepts from the study of computational models of argument: rule-based arguments, argumentation graphs, argument labelling semantics and statement labelling semantics. We then encapsulate this deontic composition with the approach of probabilistic labellings to probabilistic argumentation, in order to associate deontic statements with probability values. The framework is illustrated with a scenario featuring a violation and a contrary-to-duty obligation.

Organização dos trabalhadores, a pandemia, a educação e o Programa de Transição / Workers’ Organization, the Pandemic, Education and the Transition Program

O presente artigo tem por objetivo principal destrinchar as possibilidades teóricas e programáticas que se depreendem do texto elaborado em 1938, quando da fundação da IV Internacional, por Leon Trotsky. Através da revisão de literatura disponibilizada online nesse período pandêmico e de obras que antecedem cronologicamente os dias atuais, procurou-se construir um arcabouço argumentativo que culminasse na demonstração da necessidade, atualidade e (re)elaboração de um programa transicional que abarque as necessidades que já estavam postas desde antes da crise econômica e sanitária vigente, mas que, em alguma medida, têm sido modificadas em intensidade neste período. Ao final ousou-se propor algumas linhas que possam servir de pontapé inicial para o que possa ser considerado um programa de transição para a educação, em especial, para um futuro ainda incerto, dado o profundo desconhecimento sobre o vírus causador da situação que ainda vigora.

Argumentação e pensamento crítico na educação científica: análise de estudos de casos e problematizações conceituais

O objetivo geral deste artigo é apresentar uma breve revisão da literatura sobre um recorte específico do estado da arte em relação à presença do referencial teórico da argumentação e do pensamento crítico no ensino de ciências. Na primeira parte é realizada uma espécie de mapeamento prévio disponível em alguns artigos científicos de educação científica que se utilizem desta ferramenta. Nessa perspectiva, foram selecionados, através de busca no portal de periódicos da CAPES, alguns estudos de casos específicos para exposição e discussão de seus resultados a respeito dos usos da argumentação e seu potencial no aprendizado em ciências. Em um segundo momento, faz-se uma análise conceitual da importância e da contribuição, na educação científica e na formação de professores, que a utilização da argumentação e do pensamento crítico pode trazer vislumbrando uma aprendizagem fundamentada no entendimento crítico de temáticas científicas. Embora o escopo desta revisão seja bastante delimitado, nossa análise permite assumir que o uso da argumentação e pensamento crítico no ensino de ciências constitui-se em uma estratégia pedagógica potencial, que a literatura endossa ser possível utilizá-la tanto na educação básica como na formação de professores de Física e de Ciências, tornando a aprendizagem dos conteúdos mais significante e reflexiva.