I outline six components of a comprehensive proposal for overhauling the foundations of deontic logic. (1) Actions and prescriptions are temporally indexed; more preciselym they attach to nodes of a tree in a branching time structure. (2) Actions are (modeled as) sets of branches and can be coarse- or fine-grained depending on whether or not they have have proper subsets which are also actions. (3) Prescriptions have satisfaction and violation sets; these are sets of branches which may -but need not- be or include actions. (4) Prescriptive propositions, which state that an action is obligatory/permitted/forbidden according to a given prescription, are defined by relationg the action with the satisfaction and violation sets of the prescription. (5) Conditional prescriptions can -but need not- be derived from unconditional or even from other conditional ones. (6) Thick prescriptions, in contrast to thin ones, prescribe or proscribe actions with varying intensities, and can have embedded subprescriptions (some of which are negative, namely “contrary-to-duty"). Most of the above components are inspired by the literature, but their combination is novel.

Keywords: deon02

This paper proposes a logic-oriented framework for organization specification, analysis and design. Within this framework organizations are seen as a society of agents with responsibilities and capabilities, and that interact with each other according to some form of “institutionalized power relations". Organizations are analyzed according to the properties of their agents' interactions, characterized by means of modal action and deontic logics of the type developed in the Philosophy area. Although rather simple, the proposed framework supports some interesting aspects of the analyses of organizations, with potential applications in the scope of organizational design, e.g. analysis of task distribution and analysis of attribution of responsibilities. This later analysis is based on Reiter's diagnosis theory. These aspects of analyisis have been automated in a workbench capable of answering queries about what can and should be done, in a given organization, to achieve particular goals. The workbench uses a tableaux theorem proving method extended with additional rules to deal with the proposed classical action and deontic modalities.

Keywords: deon02

Is it possible to create a theory of how social procedures work with a view of understanding them and designing better ones? I want to start with an illustrative example of a common difficulty.

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Input/Output logics are abstract structures designed to represent conditional obligations and goals. In this paper we use them to study conditional permission. This perspective provides a clear separation of the familiar notion of negative permission from the more elusive one of positive permission. Moreover, it helps reveal that there are at least two kinds of permission. Although indistinguishable in the unconditional case, they are quite different in conditional contexts, essentially because contraposition is not available. One of them, which we call forward positive permission, guides the citizen and law enforcement authorities in the assessment of specific actions, and it behaves like a weakened obligation. Another, which we call backward positive permission or prohibition immunity, guides the legislator. It describes the limis on what may subsequently be prohibited, and for certain codes behaves like a strenghtened negative permission. These operators are defined explicitly and their basic properties and interrelations investigated.

Keywords: deon02

At DEON'00, I employed a simple classical non-normal logic for agency integrated with a normal logic for predetermination, and then defined “ability" in terms of elements of both. In the current paper, I explore various ways of integrating that framework with a framework for obligations. However, the agential obligation operator explored here is defined in terms of non-agential yet personal obligation operator and a non-deontic agency operator. This is contrary to the main current trend, which assumes statements of personal obligation always take agential complements. Instead, we take the basic form to be an agent's being obligated to be such that p. I sketch some logics for agential obligation based on personal obligations (and derivatively, agential obligations), and then in contexts that do allow for conflicts of both sorts.

Keywords: deon02

The design of complex multi-agent systems is increasingly having to confront the possibility that agents may not behave as they are supposed to. In addition to analysing the properties that hold if protocols are followed correctly, it is also necessary to predict, test, and verify the properties that would hold if these protocols were to be violated. We illustrate how the formal machinery of deontic interpreted systems can be applied to the analysis of such problems by considering three variations of the bit transmission problem. The first, an example in which an agent may fail to do something it is supposed to do, shows how we deal with violations of protocols and specifications generally. The second, an example in which an agent may do somethiing it is not supposed to do, shows how it is possible to specify and analyze remedial or error-recovery procedures. The third combines both kinds of faults and introduces a new component to the system, a controller whose role is to enforce compliance with the protocol. In each case the formal analysis is used to test whether critical properties of the system are compromised, in this example, the reliable communication of information from one agent to the other.

Keywords: deon02

The formal analysis of normative systems as initiated by Alchourron and Bulygin can be complemented by the analysis of normative positions as pursued by Kanger, Lindahl, Sergot and Jones. The paper is a step towards integrating te two approaches within an algebraic theory of so-called Boolean quasi-orderings (Bqo's). In the general Bqo theory presented, a number of theoretical tools are introduced and elucidated by theorems, in particular those of fragment, connection, coupling and pair coupling. Condition implication structures (cis's) are models of the Bqo theory used for the representation of normative systems. A system of normative positions is introduced as a special kind of cis. The final section is devoted to an example exhibiting a legal mini-system where a cis of normative positions is joined to a descriptive cis.

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No abstract given.

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Deviating from standard possible-worlds semantics, authors belonging to what might be called the `imperative' tradition of deontic logic have proposed a semantics that directly represents norms (or imperatives). The paper examines possible definitions of deontic operators in such a semantics and some properties of the resulting logical systems.

Keywords: deon02

In this paper we present a Gentzen system for reasoning with contrary-to-duty obligations. The intuition behind the system is that a contrary-to-duty is a special kind of normative exception. The logical machinery to formalize this idea is taken from substructural logics and it is based on the definition of a new non-classical connective capturing the notion of reparational obligation. Then the system is tested against well-known contrary-to-duty paradoxes.

Keywords: deon02

A solution to the frame problem in the context of belief change has been defined in the framework of Situation Calculus. In this paper we show how this solution can be adapted to obligation change. For that purpose ideality levels are assigned to situations in the context of belief change. However, it is shown that there are deep differences between the evolution of beliefs and the evolution of obligations. This is a preliminary study and we do not consider all the aspects of obligation change. In particular obligations about the evolution of the world are ignored.

Keywords: deon02

A collective obligation is an obligation directed to a group of agents so that the group, as a whole, is obliged to achieve a given task. The problem investigated here is to study the impact of collective obligations to individual obligations, i.e. obligations directed to single agents of the group. The groups we consider do not have any particular hierarchical structure nor have an institutionalized representative agent. In this case, we claim that the derivation of individual obligations from collective obligations depends on several parameters among which the abiligy of the agents (i.e. what they can do) and their own personal commitments (i.e. what they are determined to do). As for checking if these obligations are fulfilled or not, we need to know what are the actual actions performed by the agents. This present paper addresses these questions in the rather general case when the collective obligations are conditional ones.

Keywords: deon02

This paper begins the development of new types of deontic operators, particulary ones whose semantic characterization is based on models with forward-branching time. In such models, supplemented by a choice function to model human agency, and an obligation function to introduce normative features, it is possible to develop a rich language with a variety of obligation operators, the causal consequences, and the logical consequences of actions. We approach these concepts making extensive use of the notion of a transition, as introduced in Xu [1997].

Keywords: deon02

In dynamic deontic logics, ought-to-do deontic assertions are reduced to dynamic logic assertions about violating postconditions of actions. This paper redefines the notion of action negation for dynamic logics, and uses this notion in an alternative version of the deontic-dynamic reduction. The approach provides a uniform treatment to all three central normative concepts, i.e., permission, prohibition and obligation, as applied to compound action exhibiting all relevant action cmbinators, i.e. choice, sequence, concurrency, converse, and iteration. It is shown that the resulting series of deontc dynamic logic is intuitive: they obey a set of minimal logic requirements for ought-to-do dynamic deontic logics, and they perform well on standard reasoning examples concerning choice and contrary to duty norms. Furthermore, the deontic-dynamic reduction avoids some strong interdefinabilities between deontc operators as assumed by Meyer [17].

Keywords: deon02

In this paper we argue for a treatment of obligations, permissions, and prohibitions that differs from the standard treatment of these notions in deontic logic. Firstly, in Section 2, we propose that instantiated norms be treated as individual, identified entities - that is, variables that can be quantified over - rather than simply as logical operators as in Standard Deontic Logic. This allows us to refer to specific instances of obligations, permissions, and prohibitions. We explain why we believe that norms take, as their arguments, sets of occurrences rather than simply propositions as in the standard treatment. Further, we argue that specific, identified norms themselves are brought about by occurrences. In Section 3, we provide an account of the life-cycle of norms: we explain how individual identified norm-instances are generated from general norms through functions of occurrences, and how each such instance's life may end with its fulfilment, violation, or nullification. In addition, we suggest (Section 4) that norms are situated: that they must be tagged with the context in which they were written or spoken. This is necessary for conflict specification, detection, and resolution purposes (Section 5). Finally, in Section 6, we tag our conclusions with a time, so that, without contradiction, we may non-monotonically conclude different results as cases and norms vary over time.

Keywords: deon02

There are interesting times for those interested in applications of deontic logic, or at least they ought to be. Current research and development in computer science is addressing a host of new types of applications and technologies that have deontic concepts at their core, including digital rights management, web services, personal data services and public key authorization infrastructures. The distributed nature of these applications inherently constrains what implementations are able to achieve. Tha talk will discuss the new breed of applications and the impact that distributed computing has at the level of deontic specification. In particular, it will be argued that in addition to the deontic modalities, reasoning about knowledge and probability is critical to an understanding of the precise sense in which real distributed systems implement deontic specifications.

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Despite interest in the topic since it was introduced by Aristotle, the practical side of reasoning has remained broadly speculative and informal, at least as a branch of logic. I will argue that ideas from logical AI provide ways of fundamentally improving this situation. I will illustrate the point with examples from my own work, which draws on nonmonotonic logic, planning formalisms, and qualitative theories of preferences.

Keywords: deon02

I will describe a formal framework for models of dispute resolution, and apply it to an example procedure, the Dutch civil summons procedure. A key aim of the framework is to relate (static) logical accounts of defeasible reasoning with (dynamic) models of dispute resolution. The framework is flexible in several respects. It allows for different underlying logics, alternative sets of speech acts and more or less strict rules for when they are allowed. Its formal nature supports the study of formal properties of disputational protocols, especially on how they respect the underlying logic. The example application improves earlier models of legal procedures in several respects. Most importantly, it models a realistic role of the judge instead of hardwiring it in the logic of protocols.

Keywords: deon02

Most systems of deontic logic, including standard deontic logic, give rise to blatantly implausible theorems. Attempts to accomodate these “paradoxes" have taken up much of the efforts spent in this field of logic. According to the speaker, in order to avoid the paradoxical results it is necessary to give up the traditional possible world semantics for deontic logic. Instead, we should investigate new semantic constructions on which weaker and more plausible deontic logics can be based. A construction is proposed that is based on the simple idea that whatever is better than something permitted is also permitted. Some results obtained along these lines are presented, including axiomatic characterizations.

Keywords: deon02

No abstract given.

Keywords: deon02

Keywords: deon02