In agent theory, epistemic trust is used to infer beliefs, for example by filtering out the information the agent receives from untrustworthy agents. Moreover, trust itself can be inferred from other information. We introduce a simple information filtering architecture that clearly distinguishes the relation between the two kinds of inference. We provide a logical analysis of the architecture, based on a new family of input/output logics. We then explore information filtering and belief manipulation within this formal framework. Our key finding is that with this architecture, some of the widely debated logical rules for trust inference are redundant with respect to information-filtering mechanisms and some others are redundant with respect to belief manipulation.

Inspired by revealed preference in economics, we study revealed epistemic trust: an agent’s (dis)trust in an information source is typically hidden, while her accept/reject behavior leaves observable traces. We model such traces by an acceptance function that maps each reported set of formulas to the subset the agent accepts. We develop two complementary models: a white-list mode, where acceptance is supported by trusted information in the report, and a black-list mode, where acceptance avoids distrusted patterns via a cautious remainder-set/full-meet construction. For both modes, we provide postulate-based representation theorems and show how canonical "revealed" trust and distrust cores can be reconstructed from the acceptance function itself.

We present a rights-first model of contrary-to-duty (CTD) reasoning with two remedial regimes and a revision track. In the CTD-Claim regime, when a primary duty is not fulfilled and no exception applies, a remedial claim detaches automatically, without any recognition act. In the CTD-Power regime, a remedial claim arises only if the rights-holder exercises a recognition power; until then there is no recognised violation and no remedial duty. Revision-of-Duty (RoD) is an alternative discretionary power that adapts the primary duty without recognising a violation, keeping the purpose aligned and avoiding sanctions. Under CTD-Power, revision competes directly with recognition on the same case. We develop a model for agreements, give concise dynamic-logic-style specifications of guards and acts, implement an institutional rights system that executes these specifications over live Hohfeldian bundles (with per-case exclusivity, exception handling and provenance), and show how agentic AI can use reasons to choose among the admissible acts within the rights-first framework.

Abstract argumentation is an important research area in AI. It is mainly about the acceptability of arguments in an argumentation framework. The classical notion of defense has not fully reflected some useful information implicitly encoded by the interaction relation between arguments. In this paper, instead of using arguments and attacks as first citizens, a novel notion of attack-defense is adopted as a first citizen, based on which a theory of attack-defense framework and attack-defense semantics are established, where an attack-defense is a triple (x,y,z), meaning that: an argument x defends an argument z against an attacker y. Attack-defense semantics can be used not only to identify the impact of arguments in some odd cycles, and remove some “useless” defenses, but also to capture new types of equivalence that cannot be represented by the existing notions of equivalence of argumentation frameworks. In addition, it shows that an attack-defense framework and attack-defense semantics can represent some knowledge that cannot be represented in Dung-style argumentation, e.g., some context-sensitive knowledge in a dialogue.

Abstract This article provides a systematic analysis of the well-known notions of weak and strong permission in input/output (I/O) logic. We extend the account of permission initially put forward by Makinson and Van der Torre to the whole family of I/O systems developed during the last two decades. The main contribution is a series of characterization results for strong permission, based on establishing the so-called non-repetition property. We also study an input/output logic not yet covered in the literature. It supports reasoning by cases—a natural feature of human reasoning. The output is not closed under logical entailment. At the same time, it avoids excess output using a consistency check—a technique familiar from non-monotonic logic. This makes it well suited for contrary-to-duty reasoning. The axiomatic characterization is in terms of a generalized OR rule. We discuss the implications of all this for our understanding of the notion of the coherence of a normative system. Topics for future research are identified.1

This paper presents a formal model of specific reasoning patterns in conflict of laws (CoL). CoL arises when multiple countries have jurisdiction due to the diverse nationalities of the involved factors. When initiating legal action in one country, the question of which country’s substantial law to apply emerges, possibly involving the CoL regulations of other countries (in cases of transmission and renvoi). Moreover, parties contemplating legal action in a case falling under CoL often engage in a deliberation process known as forum shopping: determining which country’s CoL regulations would result in the most favorable outcome for them. Our model integrates deontic logic (specifically Input/Output logic) with proof theory and formal argumentation techniques to model both types of reasoning.

An autonomous system is constructed by a manufacturer, operates in a society subject to norms and laws, and interacts with end users. All of these actors are stakeholders affected by the behavior of the autonomous system. We address the challenge of how the ethical views of such stakeholders can be integrated in the behavior of an autonomous system. We propose an ethical recommendation component called Jiminy which uses techniques from normative systems and formal argumentation to reach moral agreements among stakeholders. A Jiminy represents the ethical views of each stakeholder by using normative systems, and has three ways of resolving moral dilemmas that involve the opinions of the stakeholders. First, the Jiminy considers how the arguments of the stakeholders relate to one another, which may already resolve the dilemma. Secondly, the Jiminy combines the normative systems of the stakeholders such that the combined expertise of the stakeholders may resolve the dilemma. Thirdly, and only if these two other methods have failed, the Jiminy uses context-sensitive rules to decide which of the stakeholders take preference over the others. At the abstract level, these three methods are characterized by adding arguments, adding attacks between arguments, and revising attacks between arguments. We show how a Jiminy can be used not only for ethical reasoning and collaborative decision-making, but also to provide explanations about ethical behavior.

In this paper, we give an overview of several recent proposals for non-admissible non-naive semantics for abstract argumentation frameworks. We highlight the similarities and differences between weak admissibility-based approaches and undecidedness-blocking approaches using examples and principles as well as a study of their computational complexity. We introduce a kind of strengthened undecidedness-blocking semantics combining some of the distinctive behaviours of weak admissibility-based semantics with the lower complexity of undecidedness-blocking approaches. We call it loop semantics, because in our new semantics, an argument can only be undecided if it is part of a loop of undecided arguments. Our paper shows how a principle-based approach and a complexity-based approach can be used in tandem to further develop the foundations of formal argumentation.

Abstract agent argumentation frameworks extend Dung’s theory with agents, and in this paper we study four types of semantics for them. First, agent defense semantics replaces Dung’s notion of defense by some kind of agent defense. Second, social agent semantics prefers arguments that belong to more agents. Third, agent reduction semantics considers the perspective of individual agents. Fourth, agent filtering semantics are inspired by a lack of knowledge. We study five existing principles and we introduce twelve new ones. In total, we provide a full analysis of fifty-two agent semantics and the seventeen principles.

peer reviewed

This paper studies explanation semantics of argumentation by using a principle-based approach. In particular, we introduce and study explanation semantics associating with each accepted argument a set of such explanation arguments. We introduce various principles for explanation semantics for abstract argumentation, and list various relations among them. Then, we introduce explanation semantics based on defence graphs, and show which principles they satisfy.

The theory of formal argumentation distinguishes and unifies various notions of attack, support and preference among arguments, and principles are used to classify the semantics of various kinds of argumentation frameworks. In this paper, we consider the case in which we know that an argument is supporting another one, but we do not know yet which kind of support it is. Most common in the literature is to classify support as deductive, necessary, or evidentiary. Alternatively, support is characterized using principles. We discuss the interpretation of support using a legal divorce action. Technical results and proofs can be found in an accompanying technical report.

This paper is concerned with the goal of maintaining legal information and compliance systems: the ‘resource consumption bottleneck’ of creating semantic technologies manually. The use of automated information extraction techniques could significantly reduce this bottleneck. The research question of this paper is: How to address the resource bottleneck problem of creating specialist knowledge management systems? In particular, how to semi-automate the extraction of norms and their elements to populate legal ontologies? This paper shows that the acquisition paradox can be addressed by combining state-of-the-art general-purpose NLP modules with pre- and post-processing using rules based on domain knowledge. It describes a Semantic Role Labeling based information extraction system to extract norms from legislation and represent them as structured norms in legal ontologies. The output is intended to help make laws more accessible, understandable, and searchable in legal document management systems such as Eunomos (Boella et al., 2016).

An autonomous system is constructed by a manufacturer, operates in a society subject to norms and laws, and is interacting with end-users. We address the challenge of how the moral values and views of all stakeholders can be integrated and reflected in the moral behavior of the autonomous system. We propose an artificial moral agent architecture that uses techniques from normative systems and formal argumentation to reach moral agreements among stakeholders. We show how our architecture can be used not only for ethical practical reasoning and collaborative decision-making, but also for the explanation of such moral behavior.

To resolve conflicts amongst norms, various non-monotonic formalisms can be used to perform prioritized normative reasoning. Meanwhile, formal argumentation provides a way to represent non-monotonic logics. In this paper we propose a representation of prioritized normative reasoning by argumentation. Using hierarchical abstract normative systems (HANS), we define three kinds of prioritized normative reasoning approaches called Greedy, Reduction and Optimization. Then, after formulating an argumentation theory for a HANS, we show that for a totally ordered HANS, Greedy and Reduction can be represented in argumentation by applying the weakest link and the last link principles, respectively, and Optimization can be represented by introducing additional defeats capturing the idea that for each argument that contains a norm not belonging to the maximal obeyable set then this argument should be rejected.

Ethics by Design concerns the methods, algorithms and tools needed to endow autonomous agents with the capability to reason about the ethical aspects of their decisions, and the methods, tools and formalisms to guarantee that an agent's behavior remains within given moral bounds. In this context some questions arise: How and to what extent can agents understand the social reality in which they operate, and the other intelligences (AI, animals and humans) with which they co-exist? What are the ethical concerns in the emerging new forms of society, and how do we ensure the human dimension is upheld in interactions and decisions by autonomous agents?. But overall, the central question is: "Can we, and should we, build ethically-aware agents?" This paper presents initial conclusions from the thematic day of the same name held at PRIMA2017, on October 2017.

Also in Volume 305: Computational Models of Argument (IOS Press)

In Dung's abstract argumentation theory, an extension can be represented by subsets of it in the sense that from each of these subsets, the extension can be obtained again by iteratively applying the characteristic function. Such so-called regular representations can be used to differentiate argumentation frameworks having the same extensions. In this paper we provide a full characterization of relations between seven different types of representation equivalence.

The aim of the present study was to assess the usefulness of QTrobot, a socially assistive robot, in interventions with children with autism spectrum disorder (ASD) by assessing children's attention, imitation, and presence of repetitive and stereotyped behaviors. Fifteen children diagnosed with ASD, aged from 4 to 14 years participated in two short interactions, one with a person and one with the robot. Statistical analyses revealed that children directed more attention towards the robot than towards the person, imitated the robot as much as the person, and engaged in fewer repetitive or stereotyped behaviors with the robot than with the person. These results support previous research demonstrating the usefulness of robots in short interactions with children with ASD and provide new evidence to the usefulness of robots in reducing repetitive and stereotyped behaviors in children with ASD, which can affect children's learning.

The ideal worlds of a possible worlds semantics may satisfy both a primary obligation and an associated secondary obligation, for example the obligation to keep a promise and the obligation to apologise for not keeping it. This is known as the pragmatic oddity introduced by Prakken and Sergot. We argue that an adequate treatment of the pragmatic oddity within a norm-based semantics can be obtained, by not allowing primary and secondary obligations to aggregate, because they are obligations of a different kind. On the basis of this conceptual analysis, we introduce two logics, depending on the stance taken on the representation of normative conflicts, and we present sound and complete proof systems for these logics. We then give a formal analysis, discuss extensions, and highlight various topics for further research.

The interpretation of a norm is often uncertain and conflicting. In this paper we propose a model for arguing about legal interpretation, which considers the problems of vagueness. After motivating our adoption of graded categories as a tool to tackle the problem of open texture in legal interpretation, we introduce a model based on fuzzy logic and argumentation. Then, we conduct a case study by using an example from medically assisted reproduction.

This paper looks at the use of recitals in the interpretation of EU legislation, and mechanisms for connecting them to normative provisions. The purposive approach to the interpretation of EU legislation taken by the European Court of Justice makes frequent references to recitals as helping to establish the purpose of normative provisions. Our research uses a cosine similarity based approach to link articles with relevant provisions to help legal professionals and lay end-users interpret the law. Such support can be used in legal knowledge-based systems.

In the last years, argumentation theory has been exploited to reason about norms, argue about enforced obligations and permissions, and establish the validity of norms seen as argumentative claims. In this paper, we start from the dynamic legal argumentation framework recently proposed by Prakken and Sartor, and we extend their ASPIC-based system by introducing deontic modalities, to include also normative concepts like factual and deontic detachment, and normative dynamics. Properties of the original and proposed legal argumentation system are presented and discussed, and related to deontic logic and logics of normative systems.

We develop a model of abduction in abstract argumentation, where changes to an argumentation framework act as hypotheses to explain the support of an observation. We present dialogical proof theories for the main decision problems (i.e., finding hypotheses that explain skeptical/credulous support) and we show that our model can be instantiated on the basis of abductive logic programs.

Michael Fisher, Leendert van der Torre, Mehdi Dastani, Guido Governatori; Preface to the Special Issue on Computational Logic in Multi-Agent Systems (CLIMA

João Leite, Paolo Torroni, Thomas Ågotnes, Guido Boella, Leendert van der Torre; Preface to the Special Issue on Computational Logic in Multi-Agent Systems (CLI

Maintaining regulatory compliance is an increasing area of concern for business. Legal Knowledge Management systems that combine repositories of legislation with legal ontologies can support the work of in-house compliance managers. But there are challenges to overcome, of interpreting legal knowledge and mapping that knowledge onto business processes, and developing systems that can adequately handle the complexity with clarity and ease. In this paper we extend the Legal Knowledge Management system Eunomos to deal with alternative interpretations of norms connecting it with Business Process Management systems. Moreover, we propose a workflow involving the different roles in a company, which takes legal interpretation into account in mapping norms and processes, using Eunomos as a support.

This paper introduces Input/Output Argumentation Frameworks, a novel approach to characterize the behavior of an argumentation framework as a sort of black box exposing a well-defined external interface. As a starting point, we define the novel notion of semantics decomposability and analyze complete, stable, grounded and preferred semantics in this respect. Then we show as a main result that, under grounded, complete, stable and credulous preferred semantics, Input/Output Argumentation Frameworks with the same behavior can be interchanged without affecting the result of semantics evaluation of other arguments interacting with them.

Dung-style abstract argumentation theory centers on argumentation frameworks and acceptance functions. The latter take as input a framework and return sets of labelings. This methodology assumes full awareness of the arguments relevant to the evaluation. There are two reasons why this is not satisfactory. Firstly, full awareness is, in general, not a realistic assumption. Second, frameworks have explanatory power, which allows us to reason abductively or counterfactually, but this is lost under the usual semantics. To recover this aspect, we generalize conventional acceptance, and we present the concept of a conditional acceptance function.

Many voting rules are based on some minimization principle. Likewise, in the field of logic-based knowledge representation and reasoning, many belief change or inconsistency handling operators also make use of minimization. Surprisingly, minimization has not played a major role in the field of judgment aggregation, in spite of its proximity to voting theory and logic-based knowledge representation and reasoning. Here we make a step in this direction and study six judgment aggregation rules; two of them, based on distances, have been previously defined; the other four are new, and all inspired both by voting theory and knowledge representation and reasoning. We study the inclusion relationships between these rules and address some of their social choice theoretic properties.

In this paper, we consider two drawbacks of Cayrol and Lagasque-Schiex's meta-argumentation theory to model bipolar argumentation frameworks. We consider first the “lost of admissibility” in Dung's sense and second, the definition of notions of attack in the context of a support relation. We show how to prevent these drawbacks by introducing support meta-arguments. Like the model of Cayrol and Lagasque-Schiex, our formalization confirms the use of meta-argumentation to reuse Dung's properties. We do not take a stance towards the usefulness of a support relation among arguments, though we show that if one would like to introduce them, it can be done without extending Dung's theory. Finally, we show how to use meta-argumentation to instantiate an argumentation framework to represent defeasible support. In this model of support, the support relation itself can be attacked.

We introduce and study higher-order coalition logic, a multi modal monadic second-order logic with operators [{x}ψ]φ expressing that the coalition of all agents satisfying ψ(x) can achieve a state in which φ holds. We use neighborhood semantics to model extensive games of perfect information with simultaneous actions and we provide a framework reasoning about agents in the same way as it is reasoning about their abilities. We illustrate higher-order coalition logic to represent and reason about coalition formation and cooperation, we show a more general and expressive way to quantify over coalitions than quantified coalition logic, we give an axiomatization and prove completeness.

peer reviewed

In this paper we introduce and discuss five guidelines for the use of normative systems in computer science. We adopt a multiagent systems perspective, because norms are used to coordinate, organize, guide, regulate or control interaction among distributed autonomous systems. They are derived from the computer science literature. From the so-called ‘normchange’ definition of the first workshop on normative multiagent systems in 2005 we derive the guidelines to motivate which definition of normative multiagent system is used, to make explicit why norms are a kind of (soft) constraints deserving special analysis, and to explain why and how norms can be changed at runtime. From the so-called ‘mechanism design’ definition of the second workshop on normative multiagent systems in 2007 we derive the guidelines to discuss the use and role of norms as a mechanism in a game-theoretic setting, and to clarify the role of norms in the multiagent system.

peer reviewed

Various tasks need to consider preferences in a dynamic way. We start by discussing several possible meanings of preference change, and then focus on the one we think is the most natural: preferences evolving after some new fact has been learned. We define a family of such preference change operators, parameterized by a revision function on epistemic states and a semantics for interpreting preferences over formulas. We list some natural properties that this kind of preference change should fulfill and give conditions on the revision function and the semantics of preference for each of these properties to hold.

Normative multiagent systems provide agents with abilities to autonomously devise societies and organizations coordinating their behavior via social norms and laws. In this paper, we study how agents negotiate new social norms and when they accept them. We introduce a negotiation model based on what we call the social delegation cycle, which explains the negotiation of new social norms from agent desires in three steps. First, individual agents or their representatives negotiate social goals, then a social goal is negotiated in a social norm, and finally the social norm is accepted by the agents when it leads to fulfillment of the desires the cycle started with. We characterize the allowed proposals during social goal negotiation as mergers of the individual agent desires, and we characterize the allowed proposals during norm negotiation as both joint plans to achieve the social goal (obligations associated with the norm) and the associated sanctions or rewards (a control system associated with the norm). The norm is accepted when the norm is stable in the sense that agents will act according to the norm, and effective in the sense that fulfillment of the norm leads to achievement of the agents' desires. We also compare norm negotiation with contract negotiation and negotiation of the distribution of obligations.

In this paper we consider the extension of non-monotonic preference logic with the distinction between controllable (or endogenous) and uncontrollable (or exogenous) variables, which can be used for example in agent decision making and deliberation. We assume that the agent is optimistic about its own controllable and pessimistic about its uncontrollable, and we study ways to merge these two distinct dimensions. We also consider complex preferences, such as optimistic preferences conditional on an uncontrollable, or optimistic preferences conditional on a pessimistic preference

Contracts are used to create new interaction possibilities among agents, and therefore play an important role in the game theoretic analysis of agent interaction. We use normative multiagent systems to model both the contracts and the interactions. In particular, we formalize contracts as systems of regulative and constitutive norms within a larger rule-governed setting and, using recursive modeling, we develop a game theory wherein agents make contracts. We show how agents can modify the behavior of normative systems by means of constitutive rules in the contract changing these systems, and we illustrate how agents use the game theory within contract negotiation in organizations

Knowledge management exploits the new opportunities of sharing knowledge among members of virtual communities in distributed computer networks, and knowledge-management systems are therefore modeled and designed as multiagent systems. In this paper, normative multiagent systems for secure knowledge management based on access-control policies are studied. It is shown how distributed access control is realized by means of local policies of access-control systems for documents of knowledge providers, and by means of global community policies regulating these local policies. Moreover, it is shown how such a virtual community of multiple knowledge providers respects the autonomy of the knowledge providers

The distinction between the notions of permission and authorization is subtle. In the Cambridge Advanced Learner's Dictionary [4] permitting is "to allow something", "to make it possible for someone to do something, or to not prevent something from happening", while authorizing means "to give someone official permission to do something". Law studies argue that the distinction goes beyond the "officiality" of authorization. E.g., the Del Giudice [5]'s dictionary of law argues that adding or removing an authorization does not change the normative status of an agent while adding or removing a permission does. Authorizations change what is obligatory or permitted for agents without adding or removing norms. However, though legal philosophers distinguish permission from authorization, the distinction between the two is ignored in many (agent) theories and systems. How can this apparent paradox be explained?

We are interested in interactive access control to Web services in virtual organizations. We discuss argument games in which the set of credentials requested by the service provider to access a service is established by means of an interaction between a client acting as a proponent and a server acting as an opponent.

In this article we discuss how cognitive attitudes like beliefs, obligations, intentions, and desires can be represented as components with input/output functionality. We study how to break down an agent specification into a specification of individual components and a specification of their coordination. A typical property discussed at the individual component specification level is whether the input is included in the output, and a typical property discussed at the coordination level is whether beliefs override desires to ensure realism. At the individual level we show how proof rules of so-called input/output logics correspond to properties of functionality descriptions, and at the coordination level we show how global constraints coordinating the components formalize coherence properties. © 2005 Wiley Periodicals, Inc. Int J Int Syst 20: 893–919, 2005.

In this paper we address the problem of defining roles in organizations like e-trade ones. The methodology we use is to model roles according to the agent metaphor: we attribute to roles mental attitudes, like beliefs, desires and goals, we relate them to the agent's required expertise and responsibilities, and we model role behavior in game theoretic terms. Analogously, the organization is modelled as an agent which acts as a normative system: it imposes obligations to roles and to the agents playing the roles.

We are interested in the design of policies for virtual communities of agents based on the grid infrastructure. In a virtual community agents can play both the role of resource consumers and the role of resource providers, and they remain in control of their resources. We argue that this requirement creates a distinction between two dimensions: global vs local and centralized and decentralized control by means of policies. The providers should be enabled to specify their local policies on their own resources, but their policies should be consistent with the global policies. At the same time, some aspects of the decentralized control should be delegated to specialized providers; this delegation requires a distinction between the authorization to access a resource and a permission to do so.

A coherent description of enterprise architecture provides insight, enables communication among stakeholders and guides complicated change processes. Unfortunately, so far no enterprise architecture description language exists that fully enables integrated enterprise modeling, because for each architectural domain, architects use their own modeling techniques and concepts, tool support, visualization techniques, etc. In this paper, we outline such an integrated language and we identify and study concepts that relate architectural domains. In our language, concepts for describing the relationships between architecture descriptions at the business, application, and technology levels play a central role, related to the ubiquitous problem of business-ICT alignment, whereas for each architectural domain we conform to existing languages or standards such as UML. In particular, usage of services offered by one layer to another plays an important role in relating the behaviour aspects of the layers. The structural aspects of the layers are linked through the interface concept, and the information aspects through realization relations.

A coherent description of architectures provides insight, enables communication among different stakeholders and guides complicated (business and ICT) change processes. Unfortunately, so far no architecture description language exists that fully enables integrated enterprise modeling. In this paper we focus on the requirements and design of such a language. This language defines generic, organization-independent concepts that can be specialized or composed to obtain more specific concepts to be used within a particular organisation. It is not our intention to re-invent the wheel for each architectural domain: wherever possible we conform to existing languages or standards such as UML. We complement them with missing concepts, focusing on concepts to model the relationships among architectural domains. The concepts should also make it possible to define links between models in other languages. The relationship between architecture descriptions at the business layer and at the application layer (business-IT alignment) plays a central role.

If a legislator introduces a new norm in a normative system, then rationality prescribes that it ensures that the norm can and will be fulfilled by agents subjected to the norm. Since agents may not follow the law, it associates sanctions with norms. But even with sanction-based obligations, some agents will look for ways to violate the norm while at the same time evading the sanction, for example by making sure that their violation will not be noticed, blocking the sanction, bribing the system, et cetera. Consequently, to reason about the creation of norms, we need a model of norm-evading agents. In [2] we argue that a model of normevading agents can be based on the attribution of mental attitudes to normative systems. In this paper we address the following two questions:1. How can the attribution of mental attitudes to normative systems be used to reason about norm creation?2. How can we formalize norm creation using the attribution of mental attitudes to normative systems?

In this paper we discuss different types of permissions and their roles in deontic logic. We study the distinction between weak and strong permissions in the context of input/output logic, combining the logic with constraints, priorities and hierarchies of normative authorities. In this setting we observe that the notion of prohibition immunity no longer applies, and we introduce a new notion of permission as exception and a new distinction between static and dynamic norms. We show that strong permissions can dynamically change a normative system by adding exceptions to obligations, provide an explicit representation of what is permitted to the subjects of the normative system and allow higher level authorities to limit the changes that lower level authorities can do to the normative system.

Here we study the rational balance between local and global policies in Web based distributed systems. We use a logical framework for multiagent systems to model obligations and permissions composing policies. In particular, a qualitative decision theory allows agents to trade off the decision of respecting a norm against the consequences of not respecting it: the possibility that they are considered violators and thus sanctioned. Global policies refer not to the existence of a local norm but to the fact that it is enforced by the local authority by recognizing and sanctioning violations.

In this paper we introduce the DIagnostic and DEcision-theoretic framework for \nDEontic\nreasoning diO(de)2. The framework diO(de)2 formalizes reasoning about \nviolations and goals.\nWe use this framework to discuss two theories of normative reasoning, diagnosis \ntheory and\n(qualitative) decision theory. A crucial distinction between the two theories \nis their perspective\non time. Diagnosis theory reasons about incomplete knowledge and only considers \nthe past. It\ndistinguishes between violations and non-violations. Qualitative decision \ntheory reasons about\ndecision variables and considers the future. It distinguishes between fulfilled \nobligations and\nunfulfilled obligations. Moreover, we discuss the relation between the two \ntheories of normative\nreasoning and deontic logic. The theories formalize reasoning with norms, and \nthey are thus\ndifferent from deontic logic, that formalizes reasoning about norms.