Deontic logic is the logic that deals with actual as well as ideal behavior of systems. In this paper, we survey a number of applications of deontic logic in computer science that have arisen in the eighties, and give a systematic framework in which these applications can be classified. Many applications move in the direction of programming a computer in deontic logic to make the computer prohibit, permit or obligate people to do something. We discuss conditions under which this possibility is realistic and conditions under which it would be admissible to do so.

This article is an exercise in computational jurisprudence. It seems clear that the field of AI and Law should draw upon the insights of legal philosophers, whenever possible. But can the computational perspective offer anything in return? I will explore this question by focusing on the concept of OWNERSHIP, which has been debated in the jurisprudential literature for centuries. Although the intellectual currents here flow mostly in one direction — from legal philosophy to AI — I will show that there are also some insights to be gained from a computational analysis of the OWNERSHIP relation. In particular, the article suggests a computational explanation for the emergence of abstract property rights, divorced from concrete material objects.

this paper by the U.S. Army Research Office under contract/grant number DAAH 04 95 10628 and the U.S. National Science Foundation under grant IRI9311988. Some of the work described above was developed in collaboration with James Allen and supported by ONR/DARPA under grant number N00014-92J -1512, by ONR under research grant number N00014-90-J-1811, and by NSF under grant number IRI-9003841.

Most work in artificial intelligence and law has concentrated on modelling the type of reasoning done by trial lawyers. In fact, most lawyers' work involves planning -- for example, wills and trusts, real estate deals, and business mergers and acquisitions. Certain planning issues, such as the use of underspecified, or "open-textured" rules, are illustrated especially clearly in this domain. In this thesis, I set forth the characteristic features of planning in law, place it in the context of past artificial intelligence work in both law and planning, and describe CHIRON, a system that I have developed implementing my theory of open-textured planning in the domain of personal income tax law.

. For an agent to engage in substantive dialogues with other agents, there are several complexities which go beyond the scope of standard models of rational agency. In particular, an agent must reason about social attitudes that span more than one agent, as well as the dynamic and fallible process of plan execution. In this paper we sketch a theory of plan execution which allows the representation of failure and repair, extend the underlying agency model with social attitudes of mutual belief, obligation, and multi-agent plan execution, and describe an implemented dialogue agent which uses these notions, reacting to its environment and mental state, and deliberating and planning action only when more pressing concerns are absent. 1 Overview For autonomous agents that operate in a realm of heterogeneous agents (including human agents), an agent theory should allow many of the features of natural language dialogue. The agent communication protocols should allow flexible turn-taking and ...

Abstract not found

this paper we shall be concerned with providing a computationally oriented proof method for standard DL (SDL), i.e., normal systems of modal logic with the usual possible-worlds semantics ([Aq87], [Ch80], [Han65]). Because of the natural and easily implementable style of proof construction it uses, this method seems particularly well-suited for applications in the AI and Law field, and though in the present version it works for SDL only, it forms an appropriate basis for developing efficient proof methods for more expressive and sophisticated extensions of SDL. The content of the paper is as follows. In Section 2, we briefly introduce SDL together with the logical notation being used. In Section 3, we describe the theorem proving system KED. In Sections 4 and 5, we present KED method of proof search. In the last section, we provide a sample of the KED Prolog implementation and give an example output of the program

In this paper, we view planning as a special case of reasoning about indefinite actions. We treat actions as predicates defined over a linear temporal order. This formalism permits the representation of concurrent activity. Suppose we have a set of abstract actions defined by Horn clauses from a set of basic actions. Let us assume that an abstract action / has occurred, and ask whether a given condition OE is entailed by all the basic actions that constitute /. A countermodel to this hypothetical implication is then a plan for "doing / and avoiding OE." We propose a formalization of this problem using circumscription, and argue that this is the correct formalization if our action definitions include recursive rules. We then investigate two techniques for solving the problem: (1) a special type of inductive proof procedure, which is sound but not complete; and (2) a decision procedure that works for an interesting subclass of the general problem. Because of the use of recursive rules i...

We shall introduce a set basic legal concepts, providing a logical definition of them. This basic set will include, beside the usual deontic modalities (obligations, prohibitions and permissions), the following notions: right as protected interest (obligational right), normative conditional, different kinds of legal power, the intentional production of legal determinations (proclamation), source of the law. The presentation will be as precise as possible, while keeping the logical notions at a minimum. 1

We present a solution to the paradox of free choice permission by introducingstrong and weak permission in a deontic logic of action. It is shown how counterintuitive consequences of strong permission can be avoided by limiting the contexts in which an action can be performed. This is done by introducing the only operator, which allows us to say that only ff is performed (and nothing else), and by introducing contextual interpretation of action terms. 1 Introduction In the standard system of deontic logic [Aqv84, Wri51], it is a theorem that P (p) ! P (p q) which means that if p is permitted then p q is also permitted. As a consequence, we have that P (Talk to the president) ! P (Talk to the president shoot the president), which is counterintuitive. In the literature, this is called the paradox of free choice permission. One way to resolve this paradox is to simply define two permission operators Pw and P s , denoting weak and strong permissibility, that satisfy Pw (p q) j Pw ...