A history of the logic of action is outlined, beginning with St Anselm. Five modern authors are discussed in some detail: von Wright, Fitch, Kanger, Chellas and Pratt.

Individualists claim that collective obligations are reducible to the individual obligations of the collective’s members. Collectivists deny this. We set out to discover who is right by way of a deontic logic of collective action that models collective actions, abilities, obligations, and their interrelations. On the basis of our formal analysis, we argue that when assessing the obligations of an individual agent, we need to distinguish individual obligations from member obligations. If a collective has a collective obligation to bring about (...) a particular state of affairs, then it might be that no individual in the collective has an individual obligation to bring about that state of affairs. What follows from a collective obligation is that each member of the collective has a member obligation to help ensure that the collective fulfills its collective obligation. In conclusion, we argue that our formal analysis supports collectivism. (shrink)

The first issue of Artificial Intelligence and Law journal was published in 1992. This paper provides commentaries on nine significant papers drawn from the Journal’s second decade. Four of the papers relate to reasoning with legal cases, introducing contextual considerations, predicting outcomes on the basis of natural language descriptions of the cases, comparing different ways of representing cases, and formalising precedential reasoning. One introduces a method of analysing arguments that was to become very widely used in AI and Law, namely (...) argumentation schemes. Two relate to ontologies for the representation of legal concepts and two take advantage of the increasing availability of legal corpora in this decade, to automate document summarisation and for the mining of arguments. (shrink)

Hohfeld’s analysis on the different types of rights and duties is highly influential in analytical legal theory, and it is considered as a fundamental theory in AI&Law and normative multi-agent systems. Yet a century later, the formalization of this theory remains, in various ways, unresolved. In this paper I provide a formal analysis of how the working of a system containing Hohfeldian rights and duties can be delineated. This formalization starts from using the same tools as the classical ones by (...) Kanger and Lindahl used, but instead of focusing on the algebraic features of rights and duties, it aims at providing a comprehensive analysis of what these rights and duties actually are and how they behave and at saying something substantial on Power too—maintaining all along the Hohfeldian intentions that these rights and duties are sui generis and inherently relational. (shrink)

We develop a multi-agent deontic action logic to study the logical behaviour of two types of deontic conditionals: (1) conditional obligations, having the form "If group H were to perform action aH, then, in group F's interest, group G ought to perform action aG" and (2) conditional permissions, having the form "If group H were to perform action aH, then, in group F's interest, group G may perform action aG". First, we define a formal language for multi-agent deontic action logic (...) and a class of consequentialist models to interpret the formulas of the language. Second, we define a transformation that converts any strategic game into a consequentialist model. Third, we show that an outcome a* is a Nash equilibrium of a strategic game if and only if a conjunction of certain conditional permissions is true in the consequentialist model that results from the transformation of that strategic game. (shrink)

We extend stit logic by adding a spatial dimension. This enables us to distinguish between powers and opportunities of agents. Powers are agent-specific and do not depend on an agent’s location. Opportunities do depend on locations, and are the same for every agent. The central idea is to define the real possibility to see to the truth of a condition in space and time as the combination of the power and the opportunity to do so. The focus on agent-relative powers (...) and space-relative opportunities firmly roots effectivity of an autonomous choice making agent in a space–time picture. Our space–time view will be classically Newtonian, since we will assume relativistic phenomena do not play a role in agentive effectivity. We show how our semantics naturally distinguishes between different kinds of histories; histories that reflect real possibilities and histories that reflect counterfactual possibilities. Furthermore, we discuss how the spatial picture sheds light on conceptual problems plaguing the central stit property of ‘independence of agency’. At several points in the article we will emphasise and defend the differences with Belnap’s theory of agency in relativistic branching space–times. (shrink)

In this paper we propose a method for modeling social influence within the STIT approach to action. Our proposal consists in extending the STIT language with special operators that allow us to represent the consequences of an agent’s choices over the rational choices of another agent.

Throughout this paper, we are trying to show how and why our Mathematical frame-work seems inappropriate to solve problems in Theory of Computation. More exactly, the concept of turning back in time in paradoxes causes inconsistency in modeling of the concept of Time in some semantic situations. As we see in the first chapter, by introducing a version of “Unexpected Hanging Paradox”,first we attempt to open a new explanation for some paradoxes. In the second step, by applying this paradox, it (...) is demonstrated that any formalized system for the Theory of Computation based on Classical Logic and Turing Model of Computation leads us to a contradiction. We conclude that our mathematical frame work is inappropriate for Theory of Computation. Furthermore, the result provides us a reason that many problems in Complexity Theory resist to be solved.(This work is completed in 2017 -5- 2, it is in vixra in 2017-5-14, presented in Unilog 2018, Vichy). (shrink)

Situationist deontic logic is a model of that fraction of normative discourse which refers to only one situation and one set of alternatives. As we can see from a whole series of well-known paradoxes, standard deontic logic (SDL) is seriously mistaken even at the situationist level. In this paper it is shown how a more realistic deontic logic can be based on the assumption that prescriptive predicates satisfy the property of contranegativity. A satisfactory account of situation-specific norms is a necessary (...) prerequisite for a successful treatment of more complex normative structures. (shrink)

This paper provides a computational framework, based on defeasible logic, to capture some aspects of institutional agency. Our background is Kanger-Lindahl-Pörn account of organised interaction, which describes this interaction within a multi-modal logical setting. This work focuses in particular on the notions of counts-as link and on those of attempt and of personal and direct action to realise states of affairs. We show how standard defeasible logic (DL) can be extended to represent these concepts: the resulting system preserves some basic (...) properties commonly attributed to them. In addition, the framework enjoys nice computational properties, as it turns out that the extension of any theory can be computed in time linear to the size of the theory itself. (shrink)

Belief revision from the point of view of doxastic logic. Logic Journal of the IGPL, 3(4), 535–553. Segerberg, K. (1995). Conditional action. In G. Crocco, L. Fariñas, & A. Herzig (Eds.), Conditionals: From philosophy to computer science, Studies ...

This essay contains material which will hopefully be of interest not only to philosophers, but also to those social scientists whose research concerns the analysis of communication, verbal or non-verbal. Although most of the topics taken up here are central to issues in the philosophy of language, they are, in my opinion, indistinguishable from topics in descriptive social psychology. The essay aims to provide a conceptual framework within which various key aspects of communication can be described, and it presents a (...) formal language, using techniques from modern modal logic, in which such descriptions can themselves be formulated. It is my hope that this framework, or parts of it, might also turn out to be of value in future empirical work. There are, therefore, essentially two sides to this essay: the development of a framework of concepts, and the construction of a formal language rich enough to express the elements of which that framework is composed. The first of these two takes its point of departure in the statement quoted from Lewis (1972) on the page preceding this introduction. The distinction drawn there by Lewis is accepted as a working hypothesis, and in one sense this essay may be seen as an attempt to explore some of the consequences of that hypothesis. (shrink)

Agency can be construed as both the manner in which autonomous individuals embark on particular courses of action (or inaction), and the relationship between such agents and the outcomes of the courses of action on which they embark. A promising strategy for understanding both senses of agency consists in the combination of a modal logic of agency and branching time semantics. Such is the strategy behind stit theory, the theory of agentive action developed by Nuel Belnap and others. However, stit (...) theoretic evaluations of the agentive relationship between agents and outcomes that are uncertain—due to either the presence of indeterminism, or the possible intervention of other agents—yield counterintuitive results. This paper develops a pair of alternative operators (the “act” operators) for modeling agency with respect to uncertain outcomes. Unlike the stit-theoretic model, the act-theoretic model of agency with respect to a particular state of affairs does not require that the state of affairs be realized in every possible history. If the state of affairs in fact obtains in the actual history, and its obtaining was dependent on the agent’s pursuing a particular course of action, then the agent is deemed agentive under act theory. (shrink)

Abstract.The author examines the discipline of moral rights and in particular the need to embed them in a consequential system. He argues that the widely held opinion that independence from consequential evaluation is the right way of guaranteeing individual freedom is based on an inadequate appraisal of the role of moral rights in the social context. In this perspective he examines two specific cases: (1) elementary political and civil rights, and (2) the reproductive rights of women in the context of (...) poor countries with the problem of fast population growth. He argues that a coherent goal‐rights system which accommodates rights among others goals, can overcome the non‐consequential arguments and justify the force of moral rights fully within a consequentiality perspective. (shrink)

The author examines the discipline of moral rights and in particular the need to embed them in a consequential system. He argues that the widely held opinion that independence from consequential evaluation is the right way of guaranteeing individual freedom is based on an inadequate appraisal of the role of moral rights in the social context. In this perspective he examines two specific cases: (1) elementary political and civil rights, and (2) the reproductive rights of women in the context of (...) poor countries with the problem of fast population growth. He argues that a coherent goal-rights system which accommodates rights among others goals, can overcome the non-consequential arguments and justify the force of moral rights fully within a consequentiality perspective. (shrink)

In the paper we examine the problem of logical systems that are extensions of Classical Propositional Logic with new, intensional connectives of agency: monadic and dyadic _bringing it about that_. These systems are usually studied within the neighbourhood semantics. Here we propose a different strategy. We study all of the accepted laws and rules of logic of agency and define a translation of the agency operators into connectives interpreted in relating semantics. After this translation we can make a reduction to (...) more basic semantic properties that are required by the particular groups of laws and axioms. Finally, we define proper semantic structures and prove that they are complete with respect to all possible logical systems determined by the combinations of the axioms and rules. (shrink)

This paper is divided in five sections. Section 11.1 sketches the history of the distinction between speech act with negative content and negated speech act, and gives a general dynamic interpretation for negated speech act. “Downdate semantics” for AGM contraction is introduced in Section 11.2. Relying on semantically interpreted contraction, Section 11.3 develops the dynamic semantics for constative and directive speech acts, and their external negations. The expressive completeness for the formal variants of natural language utterances, none of which is (...) a retraction, has been proved in Section 11.4. The last section gives a laconic answer to the question posed in the title of the paper. (shrink)

Basin-Matthews-Viganò approach to construction of labelled deduction systems for normal modal logics is adapted to „Fitch proof-format“, and it is applied to the language of deontic-praxeological logic. Segerberg's suggestion on how to asses the adequacy of a logic for Kanger's theory of rights is being formally explicated and it is proved that herewith proposed system of labelled deduction satisfies Segerberg's criteria of adequacy. For the purpose of building the proof a semantics is given, which connects „the simplest semantics of action“ (...) with standard semantics of deontic logic. Soundness and completeness of the proposed labelled deduction with respect to aforementioned semantics is proved. (shrink)

Laws set requirements that force organizations to assess the security and privacy of their IT systems and impose them to implement minimal precautionary security measures. Several IT solutions (e.g., Privacy Enhancing Technologies, Access Control Infrastructure, etc.) have been proposed to address security and privacy issues. However, understanding why, and when such solutions have to be adopted is often unanswered because the answer comes only from a broader perspective, accounting for legal and organizational issues. Security engineers and legal experts should analyze (...) the business goals of a company and its organizational structure and derive from there the points where security and privacy problems may arise and which solutions best fit such (legal) problems. The paper investigates the methodological support for capturing security and privacy requirements of a concrete health care provider. (shrink)

An incorrect interpretation of Goodman’s theory of counterfactuals is persistently being offered in the literature. I find that strange. Even more so since the incorrectness is rather obvious. In this paper I try to figure out why is that happening. First I try to explain what Goodman did say, which of his claims are ignored, and what he did not say but is sometimes ascribed to him. I emphasize one of the bad features of the interpretation: it gives counterfactuals some (...) formal properties that neither Goodman nor (usually) the interpreter would accept. The usual interpretation (UI), which I claim should not be ascribed to Goodman, considers a counterfactual A>C true iff A, together with natural laws and all contingent truths cotenable with it, entails C. (UI) makes valid the law of conditional excluded middle, which Goodman clearly rejected. Among possible reasons for which the interpreters might find (UI) adequate is that (UI), as I argue, smuggles in the idea of minimal change, which is otherwise attractive, natural to many, but not to be found anywhere in Goodman’s paper. At the end I stress the significance of Goodman’s theory by arguing that we still need some of his notions to test the adequacy of our modern theories. (shrink)

We propose a new formalization of legal competences, and in particular for the Hohfeldian categories of power and immunity, through a deontic reinterpretation of dynamic epistemic logic. We argue that this logic explicitly captures the norm-changing character of legal competences while providing a sophisticated reduction of the latter to static normative positions. The logic is completely axiomatizable, and we apply it to a concrete case in German contract law to illustrate that it can capture the distinction between legal ability and (...) legal permissibility. (shrink)

A complete philosophy of mathematics must address Paul Benacerraf’s dilemma. The requirements of a general semantics for the truth of mathematical theorems that coheres also with the meaning and truth conditions for non-mathematical sentences, according to Benacerraf, should ideally be coupled with an adequate epistemology for the discovery of mathematical knowledge. Standard approaches to the philosophy of mathematics are criticized against their own merits and against the background of Benacerraf’s dilemma, particularly with respect to the problem of understanding the distinction (...) between pure and applied mathematics and the effectiveness of applied mathematics in the natural sciences and engineering. The evaluation of these alternatives provides the basis for articulating a philosophically advantageous Aristotelian inherence concept of mathematical entities. An inherence account solves Benacerraf’s dilemma by interpreting mathematical entities as nominalizations of structural spatiotemporal properties inhering in existent spatiotemporal entities. (shrink)

This paper is a preliminary investigation into the application of the formal-logical theory of normative positions to the characterisation of normative-informational positions, pertaining to rules that are meant to regulate the supply of information. First, we present the proposed framework. Next, we identify the kinds of nuances and distinctions that can be articulated in such a logical framework. Finally, we show how such nuances can arise in specific regulations. Reference is made to Data Protection Law and Contract Law, among others. (...) The proposed approach is articulated around two essential steps. The first involves identifying the set of possible interpretations that can be given to a particular norm. This is done by using formal methods. The second involves picking out one of these interpretations as the most likely one. This second step can be resolved only by using further information (e.g., the context or other parts of the regulation). (shrink)

Two areas of importance for agents and multiagent systems are investigated: design of agent programming languages, and design of agent communication languages. The paper contributes in the above mentioned areas by demonstrating improved or novel applications for deontic logic and normative reasoning. Examples are taken from computer-supported cooperative work, and electronic commerce.

The paper intends to show, that W. N. Hohfeld's theory of fundamental jural relations is relevant to economic theory, and that Hohfeld's system can be reconstructed by the concepts of 'liberty space' and 'ability space', understood as an agent's Spielraum for action. The first half of the paper is devoted to an exposition of Hohfeld's system and to the question of its relation to the economic analysis of property rights. The second half concerns Spielraum theory and the reformulation of Hohfeldian (...) distinctions in terms of liberty spaces and ability spaces. It is argued that the reformulation is useful, inter alia, for describing exchange of property rights by contract. El artículo intenta mostrar: que la teoría de las relaciones jurídicas fundamentales de W. N. Hohfeld es relevante para la teoría económica y que el sistema de Hohfeld puede ser reconstruido mediante los conceptos de "espacio de libertad" y "espacio de capacidad", entendidos como el Spielraum para la acción del agente. La primera mitad del artículo está dedicada a la exposición del sistema de Hohfeld y al problema de su relación con el análisis económico de los derechos reales. La segunda mitad se refiere a la teoría del Spielraum y a la reformulación de las distinciones hohfeldianas en términos de espacio de libertad y espacio de capacidad. Se argumenta que esta reformulación es útil, inter alia, para describir el cambio de los derechos reales mediante contratos. (shrink)

Abstract.The paper offers a critical survey of two main sorts of problems hindering the possibility of conceiving deontic logic as a suitable account of the logical behaviour of (sentences expressing) legal norms. The notion of “legal norm” is viewed as the main source of the first sort of problems: (a) the typological variety of legal norms requires an account both of the differing logical behaviour of (sentences expressing) differing legal norms, and of the relations which might hold amon them; (b) (...) the ontologic, semantic, and epistemic features of legal norms shed doubt on the very attempt to figure out a logical analysis of (sentences expressing) legal norms. The notion of “systemic legal validity” is viewed as the main source of the second sort of problems: Deontic logic does not provide suitable logical tools to account for legal phenomena like enactment, derogation, and conflicts between legal norms which rely on systemic legal validity. (shrink)

The essays presented in this collection were written over a long period. The first two : "On the Classification of Verbs and Actions" and "On von Wright's Theory of Action" constitute steps in my preparation for the book Events, Actions, and Ordinary Language, Lund 1977. Much of the contents of the former paper was carried over to the book, whereas the analyses in the latter paper were more or less completely left out. These papers have not been published before. "On (...) Various Forms of Interaction" is a development of soroe ideas in Events, Actions, and Ordinary Language. This paper was previously published in Swedish in Henschen-Dahlqvist A-M ed. Filosofiska smulor, Festskrift tillägnad Kon rad Marc- Wogau på hans 75-årsdag, Uppsala 1977. "Action- Explanations Reconsidered" was wri t ten in 1981 and has not been previously published. It is a short presentation of a basic idea in my dissertation Explanation of Human Actions, Uppsala 1974, as well as a commentary on sorne criticisrns that could be directed against it. "On Not Being Able To Act", finally, is a slightly modified version of a paper previously published in Pauli T. ed, Philosophical essays dedicated to Lennart Åqvist on his fiftieth birthday, Uppsala 1982. The analysis sketched in this paper has been more fully developed in my Disabilities and Their Classification, Linköping 1983. (shrink)

Some central philosophical issues concern the use of mathematics in putatively non-mathematical endeavors. One such endeavor, of course, is philosophy, and the philosophy of mathematics is a key instance of that. The present article provides an idiosyncratic survey of the use of mathematical results to provide support or counter-support to various philosophical programs concerning the foundations of mathematics.

What is informal logic, is it ``logic" at all? Main contemporary approaches are briefly presented and critically commented. If the notion of consequence is at the heart of logic, does it make sense to speak about ``informal" consequence? A valid inference is truth preserving, if the premises are true, so is the conclusion. According to Prawitz two further conditions must also be satisfied in the case of classical logical consequence: (i) it is because of the logical form of the sentences (...) involved and not because of their specific content that the inference is truth preserving; (ii) it is necessary that if the premises are true, then so is the conclusion. According to the prevalent criteria of informal logic an argument is cogent if and only if (i) its premises are rationally Acceptable, (ii) its premises are Relevant to its conclusion and (iii) its premises constitute Grounds adequate for accepting the conclusion (the ``ARG" conditions according to Govier). The ARG criteria characterize a certain broad kind of consequence relation. We do not (in general) have truth preservence in cogent arguments but if the premises are acceptable and other criteria are met, then so is the conclusion. We can speak about form in a loose sense and finally, there is rational necessity of the grounding or support relation. So a certain broad notion of logical consequence emerges from this comparison. The norms of ARG are norms of elementary scientific methodology in which argument is seen as embodying reasoning within a process of inquiry or of belief formation in subject areas accessible to every informed intellectual. (shrink)