Floris Bex

Utrecht University | UU · Department of Information and Computing Sciences

We define and study the notions of stability and relevance for precedent-based reasoning, focusing on Horty’s result model of precedential constraint. According to this model, precedents constrain the possible outcomes for a focus case, which is a yet undecided case, where precedents and the focus case are compared on their characteristics (called...

We extend the result model for precedent-based reasoning with incomplete case bases. In contrast to regular case bases, these consist of incomplete cases for which not all dimension values need to be specified, but rather each dimension is assigned a set of possible values. The outcome of cases then applies for each (combination of) the possible di...

We explore the computational complexity of justification, stability and relevance in incomplete argumentation frameworks (IAFs). IAFs are abstract argumentation frameworks that encode qualitative uncertainty by distinguishing between certain and uncertain arguments and attacks. These IAFs can be completed by deciding for each uncertain argument or...

This paper presents ORLA (Online Reinforcement Learning Argumentation), a new approach for learning explainable symbolic argumentation models through direct exploration of the world. ORLA takes a set of expert arguments that promote some action in the world, and uses reinforcement learning to determine which of those arguments are the most effectiv...

De groeiende digitale voetafdruk van de samenleving levert de politie grote uitdagingen op. Grote hoeveelheden data doorzoeken op opsporingsindicaties, belastend en ontlastend bewijs en intelligence vereist een enorme hoeveelheid mentale arbeid, en de komende jaren gaan duizenden medewerkers van de politie met pensioen. Mede hierom is er bij de pol...

We explore the computational complexity of stability and relevance in incomplete argumentation frameworks (IAFs), abstract argumentation frameworks that encode qualitative uncertainty by distinguishing between certain and uncertain arguments and attacks. IAFs can be specified by, e.g., making uncertain arguments or attacks certain; the justificatio...

The first issue of Artificial Intelligence and Law journal was published in 1992. This paper provides commentaries on nine significant papers drawn from the Journal’s second decade. Four of the papers relate to reasoning with legal cases, introducing contextual considerations, predicting outcomes on the basis of natural language descriptions of the...

In argument-based inquiry, agents jointly construct arguments supporting or attacking a topic claim to find out if the claim can be accepted given the agents’ knowledge bases. While such inquiry systems can be used for various forms of automated information intake, several efficiency issues have so far prevented widespread application. In this pape...

There has recently been talk of algorithms that predict decisions in legal cases being used by the judiciary to improve the predictability and consistency of judicial decision making. We argue that their use may minimise the error rate of decisions in the long run, but that this would require not only major technical advances but also major changes...

As AI systems are increasingly applied in real-life situations, it is essential that such systems can give explanations that provide insight into the underlying decision models and techniques. Thus, users can understand, trust and validate the system, and experts can verify that the system works as intended. At the Dutch National Police several app...

In this paper, we discuss necessary and sufficient explanations – the question whether and why a certain argument or claim can be accepted (or not) – for abstract and structured argumentation. Given a framework with which explanations for argumentation-based conclusions can be derived, we study necessity and sufficiency: what (sets of) arguments ar...

Enforcement, adjusting an argumentation framework such that a certain set of arguments becomes acceptable, is an important research topic within the study of dynamic argumentation, but one that has been little studied for structured argumentation. In this paper we study enforcement in a general structured argumentation setting. In particular, we st...

In this paper we discuss contrastive explanations for formal argumentation - the question why a certain argument (the fact) can be accepted, whilst another argument (the foil) cannot be accepted under various extension-based semantics. The recent work on explanations for argumentation-based conclusions has mostly focused on providing minimal explan...

In this paper, we present the information graph (IG) formalism, which provides a precise account of the interplay between deductive and abductive inference and causal and evidential information, where ‘deduction’ is used for defeasible ‘forward’ inference. IGs formalise analyses performed by domain experts in the informal reasoning tools they are f...

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...

We propose an agent architecture for transparent human-in-the-loop classification. By combining dynamic argumentation with legal case-based reasoning, we create an agent that is able to explain its decisions at various levels of detail and adapts to new situations. It keeps the human analyst in the loop by presenting suggestions for corrections tha...

Goal-oriented requirements modeling approaches aim to capture the intentions of the stakeholders involved in the development of an information system as goals and tasks. The process of constructing such goal models usually involves discussions between a requirements engineer and a group of stakeholders. Not all the arguments in such discussions can...

Decisions concerning proof of facts in criminal law must be rational because of what is at stake, but the decision-making process must also be cognitively feasible because of cognitive limitations, and it must obey the relevant legal-procedural constraints. In this topic three approaches to rational reasoning about evidence in criminal law are comp...

Doug Walton, who died in January 2020, was a prolific author whose work in informal logic and argumentation had a profound influence on Artificial Intelligence, including Artificial Intelligence and Law. He was also very interested in interdisciplinary work, and a frequent and generous collaborator. In this paper seven leading researchers in AI and...

In this paper we describe a method for efficient argument-based inquiry. In this method, an agent creates arguments for and against a particular topic by matching argumentation rules with observations gathered by querying the environment. To avoid making superfluous queries, the agent needs to determine if the acceptability status of the topic can...

Bayesian networks (BNs) are powerful tools that are well-suited for reasoning about the uncertain consequences that can be inferred from evidence. Domain experts, however, typically do not have the expertise to construct BNs and instead resort to using other tools such as argument diagrams and mind maps. Recently, we proposed a structured approach...

Bayesian networks (BNs) are powerful tools that are well-suited for reasoning about the uncertain consequences that can be inferred from evidence. Domain experts, however, typically do not have the expertise to construct BNs and instead resort to using other tools such as argument diagrams and mind maps. Recently, we proposed a struc-tured approach...

Bayesian networks (BNs) are powerful tools that are increasingly being used by forensic and legal experts to reason about the uncertain conclusions that can be inferred from the evidence in a case. Although in BN construction it is good practice to document the model itself, the importance of documenting design decisions has received little attenti...

Relation extraction from text is a well-known and extensively studied topic in Natural Language Processing research. However, the implementation of relation extraction approaches in real-world application scenarios raises various methodological considerations which are often left implicit in existing research. This paper explores these consideratio...

In this paper, we propose a structured approach for transforming legal arguments to a Bayesian network (BN) graph. Our approach automatically constructs a fully specified BN graph by exploiting causality information present in legal arguments. Moreover, we demonstrate that causality information in addition provides for constraining some of the prob...

We present a computational argumentation approach that models legal reasoning with evidence and proof as dialectical rather than probabilistic. This hybrid approach of stories and arguments models the process of proof in a way that is compatible with Allen and Pardo’s theory of relative plausibility by adding arguments that can be used to show how...

A new system is currently being developed to assist the Dutch National Police in the assessment of crime reports submitted by civilians. This system uses Natural Language Processing techniques to extract observations from text. These observations are used in a formal reasoning system to construct arguments supporting conclusions based on the extrac...

Software designers have been known to think naturalistically. This means that there may be inadequate rational thinking during software design. In the past two decades, many research works suggested that designers need to produce design rationale. However, design rationale can be produced to retrofit naturalistic decisions, which means that design...

Recently, a heuristic was proposed for constructing Bayesian networks (BNs) from structured arguments. This heuristic helps domain experts who are accustomed to argumentation to transform their reasoning into a BN and subsequently weigh their case evidence in a probabilistic manner. While the underlying undirected graph of the BN is automatically c...

Recently, a heuristic was proposed for constructing Bayesian networks (BNs) from structured arguments. This heuristic helps domain experts who are accustomed to argumentation to transform their reasoning into a BN and subsequently weigh their case evidence in a probabilis-tic manner. While the underlying undirected graph of the BN is automatically...

Dialogue systems attempt to capture aspects of multi-agent communication with the aim of understanding, improving, and automatically recreating such communication. Though there is ample research into the formal aspects of dialogue games for argumentation, actual software and development tools that allow for the deployment of open, multi-agent dialo...

Research in chatbots is already more than fifty years old, starting with the famous Eliza example. Although current chatbots might perform better, overall, than Eliza the basic principles used have not evolved that much. Recent advances are made through the use of massive learning on huge amounts of resources available through Internet dialogues. H...

This paper explores how machine learning techniques can be used to support handling of skewed online trade fraud complaints, by predicting whether a complaint will be withdrawn or not. To optimize the performance of each classifier, the influence of resampling, word weighting, and word normalization on the classification performance is assessed. It...

The possibility for citizens to submit crime reports and criminal complaints online is becoming ever more common, especially for cyber-and internet-related crimes such as phishing and online trade fraud. Such user-submitted crime reports contain references to entities of interest, such as the complainant, counterparty, items being traded, and locat...

In this paper, we propose a generic specification framework for argumentation dialogue protocols in an open multi-agent system. The specification framework is based on reusable elements – dialogue templates – which are realized as an open-source implementation. We provide operational semantics and show formally how templates can be used to determin...

Stories can be powerful argumentative vehicles, and they are often used to present arguments from analogy, most notably as parables, fables or allegories where the story invites the hearer to infer an important claim of the argument. Case Based Reasoning in Law has many similar features: the current case is compared to previously decided cases, and...

Software design is a complicated process, and novice designers have seldom been taught how to reason with a design. They use a naturalistic approach to work their way through software design. In order to impart the use of design techniques, a card game was developed to help design reasoning. This game was tested on groups of students and resulted i...

Goal modeling languages, such as i* and the Goal-oriented Requirements Language (GRL), capture and analyze high-level goals and their relationships with lower level goals and tasks. However, in such models, the rationalization behind these goals and tasks and the selection of alternatives are usually left implicit. To better integrate goal models a...

In this article, we aim to analyse whether a systematic method for reasoning with evidence in legal cases - the hybrid theory of stories and arguments - can be applied to a novel legal domain, namely European asylum law. This analysis serves as a case study for testing the applicability of the hybrid theory outside of the context of criminal law. F...

Due to the uses of DNA profiling in criminal investigation and decision-making, it is ever more common that probabilistic information is discussed in courts. The people involved have varied backgrounds, as factfinders and lawyers are more trained in the use of non-probabilistic information, while forensic experts handle probabilistic information on...

In the process of proof alternative stories that explain 'what happened' in a case are tested using arguments based on evidence. Building on the author's earlier hybrid theory, this paper presents a formal theory that combines causal stories and evidential arguments, further integrating the different types of reasoning in a framework for structured...

We often try to teach people through stories and narratives instead of giving them explicit facts and rules. But how do these stories influence us, how do they persuade us to change our attitudes? In this paper, we aim to answer these questions by providing a computational model that offers an internal perspective on character motives in stories. T...

In this paper, we present a software tool for ‘ArguBlogging’, which allows users to construct debate and discussions across blogs, linking existing and new online resources to form distributed, structured conversations. Arguments and counterarguments can be posed by giving opinions on one’s own blog and replying to other bloggers’ posts. The result...

In this paper, we discuss how Value-based Argumentation can be used as a tool in human and computer story understanding, especially where understanding the story requires understanding of the motives of its characters. It is shown how arguments about motives can be extracted from stories, and how dialogues about these arguments can aid in story und...

In this paper, we present the Dialogue Game Execution Platform (DGEP), which is able to process and execute any dialogue game specified in a general description language and build arguments and dialogue histories in the language of the AIF ontology. Thus, DGEP allows us to generalise techniques for generation and investigation of dialogues and, thr...

The process of proof is one of inference to the best explanation, in which alternative scenarios are supported and attacked by arguments. This combination of scenarios and arguments was previously presented as a formal hybrid theory. In this paper, the aim is to further integrate scenarios and arguments by defining a notion of attack between altern...

In this paper, we show two important connections between computational models of narrative and computational models of argumentation. First, we show how argumentation techniques can be applied to enrich story understanding, especially where an understanding the story requires understanding of the motives of its characters. This also helps to explai...

Improve online public discourse by connecting opinions across blogs, editorials, and social media.

In this paper, we continue our research on a hybrid narrative-argumentative approach to evidential reasoning in the law by showing the interaction between factual reasoning (providing a proof for ‘what happened’ in a case) and legal reasoning (making a decision based on the proof). First we extend the hybrid theory by making the connection with rea...

We discuss the value of argumentation in reaching agreements, based on its capability for dealing with conflicts and uncertainty. Logic-based models of argumentation have recently emerged as a key topic within Artificial Intelligence. Key reasons for the success of these models is that they are akin to human models of reasoning and debate, and thei...

Whilst computational argumentation and explanation have both been studied intensively in AI, models that incorporate both types of reasoning are few and far between. The two forms of reasoning need to be clearly distinguished, as they may influence dialogue protocol and strategy. Using the language of the Argument Interchange Format, we show that t...

In this article, we provide a formal logical model of evidential reasoning with proof standards and burdens of proof, which enables us to evaluate evidential reasoning by comparing stories on either side of a case. It is based on a hybrid inference model that combines argumentation and explanation, using inference to the best explanation as the cen...

The Argument Interchange Format (AIF) has been devised in order to support the interchange of ideas and data between different projects and applications in the area of computational argumentation. In order to support such interchange, an abstract ontology for argumentation is presented, which serves as an interlingua between various more concrete a...

We provide a retrospective of 25 years of the International Conference on AI and Law, which was first held in 1987. Fifty papers have been selected from the thirteen conferences and each of them is described in a short subsection individually written by one of the 24 authors. These subsections attempt to place the paper discussed in the context of...

In this paper, we look at reasoning with evidence and facts in criminal cases. We show how this reasoning may be analysed in a dialectical way by means of critical questions that point to typical sources of doubt. We discuss critical questions about the evidential arguments adduced, about the narrative accounts of the facts considered, and about th...

This paper introduces AIFdb, a database solution for the Argument Web. AIFdb offers an array of web service interfaces allowing a wide range of software to interact with the same argument data.

In this paper, we present ArguBlogging, a simple tool that allows blog users to directly respond to text on a web page, publishing the response to their blog while simultaneously capturing the argumentative structure in the Argument Web.

Dialogue systems attempt to capture structured communication with the aim of understanding, improving, and automatically recreating su communication. This paper discusses dialogue templates: blueprints that can be instantiated and combined to form argumentative dialogues. These templates provide a generic way of representing individual dialogue sys...

Whilst computational argumentation and computational explanation have both been studied intensively in AI, models that in-corporate both types of reasoning are only just starting to emerge. The two forms of reasoning need to be clearly distinguished, as they may influence dialogue protocol and strategy. We show that this dis-tinction can be made by...

We have implemented a translator that translates Carneades Argument Graphs as specified in the LKIF files of the Carneades editor to a database specification of the Argument Interchange Format and vice versa. In this paper the algorithms for this translation are presented.

The two types of reasoning that represent the main trends in the research on reasoning with criminal evidence. The first is argumentative reasoning, where the parties argue for and against the facts-at-issue using arguments based on evidence. The second type of reasoning is story-based or narrative reasoning, where the parties each provide alternat...

The general subject of the book, namely reasoning with evidence to establish the facts in criminal cases. It discusses the background of the research, which is a combination of legal theory, argumentation theory, artificial intelligence and legal psychology, and it introduces the idea of sense-making, structuring complex masses of information so th...

In this paper, we continue our research on a hybrid narrative-argumentative approach to evidential reasoning in the law by showing the interaction between factual reasoning and legal reasoning. We therefore emphasize the role of legal story schemes (as opposed to factual story schemes that formed the heart of our previous proposal). Legal story sch...

When reasoning about the facts of a case, we typically use stories to link the known events into coherent wholes. One way to establish coherence is to appeal to past examples, real or fictitious. These examples can be chosen and critiqued using the case-based reasoning (CBR) techniques from the AI and Law literature. In this paper, we apply these t...

Argumentation demands that various non-deductive patterns of reasoning are accounted for from a strong theoretical foundation. The theory of argumentation schemes has provided such a theoretical foundation, and has led to a significant programme of research not only in epistemological and metaphysical philosophy but also in knowledge representation...

The pragma-dialectical ideal model of a critical discussion takes a normative approach to argumentative discourse. The model defines the four stages of a critical discussion, conditions on speech acts and their distribution over the stages, and a set of 15 procedural rules regimenting the moves discussants may make. These problem-valid rules are in...

An actual case that made headlines in the Netherlands some time ago: the “Anjumer pensionmoorden” (murders in a boarding house in Anjum, a town in the Netherlands). In this chapter, the case is modelled in the hybrid theory and the various positions in the case (e.g. the Court’s opinion, the defence’s opinion) are analysed using the criteria propos...

A logical account of the hybrid theory. This logical theory combines abductive, model-based reasoning (as is often used in diagnostical knowledge systems) with a formal framework for defeasible argumentation. A formal dialogue game, detailing a protocol for a rational discussion about the facts, is also defined.

Abstract The process of proof, reasoning with evidence and commonsense knowledge in order to establish the facts of the case. Some general concepts that are important in this process are clarified and some general subjects (e.g. types of evidence) are discussed in detail. The chapter also discusses the types of reasoning that play an important role...