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 explanations for the (non-)acceptance of arguments. What is still lacking, however, is a proper argumentation-based interpretation of contrastive explanations. We show under which conditions contrastive explanations in abstract and structured argumentation are meaningful, and how argumentation allows us to make implicit foils explicit.

Over the last few years there has been rapid research growth into eXplainable Artificial Intelligence (XAI) and the closely aligned Interpretable Machine Learning (IML). Drivers for this growth include recent legislative changes and increased investments by industry and governments, along with increased concern from the general public. People are affected by autonomous decisions every day and the public need to understand the decision-making process to accept the outcomes. However, the vast majority of the applications of XAI/IML are focused on providing low-level `narrow' explanations of how an individual decision was reached based on a particular datum. While important, these explanations rarely provide insights into an agent's: beliefs and motivations; hypotheses of other (human, animal or AI) agents' intentions; interpretation of external cultural expectations; or, processes used to generate its own explanation. Yet all of these factors, we propose, are essential to providing the explanatory depth that people require to accept and trust the AI's decision-making. This paper aims to define levels of explanation and describe how they can be integrated to create a human-aligned conversational explanation system. In so doing, this paper will survey current approaches and discuss the integration of different technologies to achieve these levels with Broad eXplainable Artificial Intelligence (Broad-XAI), and thereby move towards high-level `strong' explanations.

Even as the search continues over a week later for signs of life in the mangled debris of the fallen Champlain Towers South, the process of seeking answers about why it happened and who is to blame is already underway in Florida's legal system. Authorities have opened criminal and civil investigations into the collapse of the oceanfront condominium building, which left at least 28 confirmed dead and more than 117 unaccounted for. Miami-Dade State Attorney Katherine Fernandez Rundle pledged to bring the matter soon before grand jurors, who could recommend criminal charges or simply investigate the cause to suggest reforms. And at least five lawsuits have been filed on behalf of residents who survived or are feared dead. One lawyer involved in the litigation said the collapse raises widespread concerns about infrastructure issues and the trust we put in those responsible for them.

Methods to find counterfactual explanations have predominantly focused on one step decision making processes. In this work, we initiate the development of methods to find counterfactual explanations for decision making processes in which multiple, dependent actions are taken sequentially over time. We start by formally characterizing a sequence of actions and states using finite horizon Markov decision processes and the Gumbel-Max structural causal model. Building upon this characterization, we formally state the problem of finding counterfactual explanations for sequential decision making processes. In our problem formulation, the counterfactual explanation specifies an alternative sequence of actions differing in at most k actions from the observed sequence that could have led the observed process realization to a better outcome. Then, we introduce a polynomial time algorithm based on dynamic programming to build a counterfactual policy that is guaranteed to always provide the optimal counterfactual explanation on every possible realization of the counterfactual environment dynamics. We validate our algorithm using both synthetic and real data from cognitive behavioral therapy and show that the counterfactual explanations our algorithm finds can provide valuable insights to enhance sequential decision making under uncertainty.

The implementation of Artificial Intelligence (AI) systems in the manufacturing domain enables higher production efficiency, outstanding performance, and safer operations, leveraging powerful tools such as deep learning and reinforcement learning techniques. Despite the high accuracy of these models, they are mostly considered black boxes: they are unintelligible to the human. Opaqueness affects trust in the system, a factor that is critical in the context of decision-making. We present an overview of Explainable Artificial Intelligence (XAI) techniques as a means of boosting the transparency of models. We analyze different metrics to evaluate these techniques and describe several application scenarios in the manufacturing domain.

ABSTRACT Typical state of the art flow cytometry data samples consists of measures of more than 100.000 cells in 10 or more features. AI systems are able to diagnose such data with almost the same accuracy as human experts. However, there is one central challenge in such systems: their decisions have far-reaching consequences for the health and life of people, and therefore, the decisions of AI systems need to be understandable and justifiable by humans. In this work, we present a novel explainable AI method, called ALPODS, which is able to classify (diagnose) cases based on clusters, i.e., subpopulations, in the high-dimensional data. ALPODS is able to explain its decisions in a form that is understandable for human experts. For the identified subpopulations, fuzzy reasoning rules expressed in the typical language of domain experts are generated. A visualization method based on these rules allows human experts to understand the reasoning used by the AI system. A comparison to a selection of state of the art explainable AI systems shows that ALPODS operates efficiently on known benchmark data and also on everyday routine case data. KEYWORDS: Explainable AI, Expert System, Symbolic System, Biomedical Data 1. INTRODUCTION State of the art machine learning (ML) artificial intelligence (AI) algorithms are effectively and efficiently able to diagnose (classify) high-dimensional data sets in modern medicine, e.g., for multiparameter flow cytometry data [Hu et al., 2019; Zhao et al., 2020]. These are systems that, after a training (learning) phase using learning data, perform well on data that are not part of the training data, i.e., the test data. This is called supervised learning [Murphy, 2012].

This paper applies t-SNE, a visualisation technique familiar from Deep Neural Network research to argumentation graphs by applying it to the output of graph embeddings generated using several different methods. It shows that such a visualisation approach can work for argumentation and show interesting structural properties of argumentation graphs, opening up paths for further research in the area.

In the field of Artificial Intelligence, the trade-off between accuracy and interpretability is a crucial aspect when developing a machine learning pipeline. Accuracy refers to the correctness degree of model predictions, while interpretability specifies how easy is the human understanding of the results. The balance between the two is related to the final business needs. When we try to explain the output of our ML pipeline we should consider a crucial aspect. Interpretability may not result in explainability.

The increasingly widespread application of AI models motivates increased demand for explanations from a variety of stakeholders. However, this demand is ambiguous because there are many types of 'explanation' with different evaluative criteria. In the spirit of pluralism, I chart a taxonomy of types of explanation and the associated XAI methods that can address them. When we look to expose the inner mechanisms of AI models, we develop Diagnostic-explanations. When we seek to render model output understandable, we produce Explication-explanations. When we wish to form stable generalizations of our models, we produce Expectation-explanations. Finally, when we want to justify the usage of a model, we produce Role-explanations that situate models within their social context. The motivation for such a pluralistic view stems from a consideration of causes as manipulable relationships and the different types of explanations as identifying the relevant points in AI systems we can intervene upon to affect our desired changes. This paper reduces the ambiguity in use of the word 'explanation' in the field of XAI, allowing practitioners and stakeholders a useful template for avoiding equivocation and evaluating XAI methods and putative explanations.

Explainable machine learning models primarily justify predicted labels using either extractive rationales (i.e., subsets of input features) or free-text natural language explanations (NLEs) as abstractive justifications. While NLEs can be more comprehensive than extractive rationales, machine-generated NLEs have been shown to sometimes lack commonsense knowledge. Here, we show that commonsense knowledge can act as a bridge between extractive rationales and NLEs, rendering both types of explanations better. More precisely, we introduce a unified framework, called RExC (Rationale-Inspired Explanations with Commonsense), that (1) extracts rationales as a set of features responsible for machine predictions, (2) expands the extractive rationales using available commonsense resources, and (3) uses the expanded knowledge to generate natural language explanations. Our framework surpasses by a large margin the previous state-of-the-art in generating NLEs across five tasks in both natural language processing and vision-language understanding, with human annotators consistently rating the explanations generated by RExC to be more comprehensive, grounded in commonsense, and overall preferred compared to previous state-of-the-art models. Moreover, our work shows that commonsense-grounded explanations can enhance both task performance and rationales extraction capabilities.