Enriching Deontic Logic

Deontic considerations are usually conducted in one of the following contexts: (i) general norms expressed in: legal documents, regulations or implicitly present in society in the form of moral or social rules; (ii) specific norms, i.e., duties of particular agents in particular situations. Norms of the two kinds refer to obligatory, permitted and forbidden actions or states. In the paper we start from presenting a simple deontic logic of actions and a simple deontic logic of states. Then we combine them to provide a unified logic of general norms. Finally, we discuss the way in which specific norms can be introduced into the system.

Normative Multi-agent …, 2007

The paper discusses ten philosophical problems in deontic logic: how to formally represent norms, when a set of norms may be termed 'coherent', how to deal with normative conflicts, how contraryto-duty obligations can be appropriately modeled, how dyadic deontic operators may be redefined to relate to sets of norms instead of preference relations between possible worlds, how various concepts of permission can be accommodated, how meaning postulates and counts-as conditionals can be taken into account, and how sets of norms may be revised and merged. The problems are discussed from the viewpoint of input/output logic as developed by van der Torre & Makinson. We argue that norms, not ideality, should take the central position in deontic semantics, and that a semantics that represents norms, as input/output logic does, provides helpful tools for analyzing, clarifying and solving the problems of deontic logic.

Journal of Applied Logic, 2014

A. Introduction. Two key concepts and three perspectives in deontic logic. Situation, agency and agent oriented deontic theories. B. Concept of norm and its structure revisited. Norms as atomic and molecular entities. C. Two approaches to deontic logic: deterministic, focusing on alethic \ deontic regularities, and indeterministic, viewing agentive choice and alternative lines of behavior. D. Conclusion. Three faces of deontic logic pursue different perspective of normative codes' analysis, reasoning about norms and agentive behavior with preferences \ priorities accordingly.

Introduction to Formal Philosophy, 2018

Deontic logic is the logic of normative concepts such as obligation, permission, and prohibition. This non-technical overview of the area has a strong emphasis on the connections between deontic logic and problems discussed in moral philosophy. Major issues treated are the distinction between ought-to-be and oughtto-do, the various meanings of permissive expressions, the logical relations among norms, the paradoxes of deontic logic, and the nature of moral conflicts and moral dilemmas. It is concluded that deontic logic has resources for precise treatment of important issues in moral philosophy, but in order to make full use of these resources, more cooperation between logicians and moral philosophers is needed.

Studia Logica

This paper tackles the problem of inference in normative systems where norms concerning actions and states of affairs appear together. A deontic logic of actions and states is proposed as a solution. It is made up of two independent deontic logics, namely a deontic logic of action and a deontic logic of states, interlinked by bridging definitions. It is shown at a language and a model level how an agent should look for norms to follow in a concrete situation. It is pointed out that such specific norms are obtained by finding the most specific obligation and the most general prohibition. They are to be derived from all norms applicable to the situation by using the principles of the logic presented in this paper.

2008

W The Logica Yearbook, 2011

The aim of the paper is to point out the modelling choices that lead to different systems of deontic action logic. A kind of a roadmap is presented. On the one hand it can help the reader to find the deontic logic appropriate for an intended application relying on the information considering the way in which a deontic logic represents actions and how it characterises deontic properties in relation to (the representation of) actions. On the other hand it is a guideline how to build a deontic action logic which satisfies the desired properties.

We present a refinement of Anderson’s reduction of deontic logic to modal logic with only alethic modalities. The refined proposal contextualizes the Andersonian sanction constant s by replacing it with a unary sanction operator S that is dependent on the concrete normative requirement that is violated. A formula SB is then for instance interpreted as “B causes a sanction” or as “B provides a reason for (the applicability of) a sanction”. Due to its modified sanction operator, the resulting logic DSL invalidates some instances of the inheritance principle. This gives rise to new interesting features. For instance, DSL consistently allows for the presence of conflicting obligations. Moreover, it provides novel insights in various central ‘paradoxes’ in deontic logic such as the Ross paradox, the paradox of the good Samaritan, and Forrester’s ‘gentle murderer’ paradox.

Electronic Notes in Theoretical Computer Science, 2009

Deontic Logic was introduced in the first half of the last century to formalize aspects of legal reasoning. Since then a lot of effort has gone into improving the formalism(s) and widening their applicability, including in Computer Science and Software Engineering. One strand of work has focused on the use of an action based approach to deontic operators, rather than the traditional property focused operators. We propose a new version of this kind of deontic logic that has very nice meta-logical properties, avoids many of the traditional problems of deontic logics and has an appealing treatment of contrary to duty reasoning. This kind of reasoning provides a kind of conditional reasoning about having violated normative constraints and describing the resulting consequences. We show how to apply this formalism to characterize fault tolerance mechanisms and to then reason about the properties of the mechanisms.