Epistemic logic has grown from its philosophical beginnings to find diverse applications in computer science, and as a means of reasoning about the knowledge and belief of agents. This book provides a broad introduction to the subject, along with many exercises and their solutions. The authors begin by presenting the necessary apparatus from mathematics and logic, including Kripke semantics and the well-known modal logics K, T, S4 and S5. Then they turn to applications in the context of distributed systems and (...) artificial intelligence. These include the notions of common knowledge, distributed knowledge, explicit and implicit belief, the interplays between knowledge and time, and knowledge and action, as well as a graded (or numerical) variant of the epistemic operators. The authors also discuss extensively the problem of logical omniscience. They cover Halpern & Moses' theory of honest formulas, and they make a digression into the realm of nonmonotonic reasoning and preferential entailment. They discuss Moore's autoepistemic logic, together with Levesque's related logic of "all I know". Furthermore, they show how one can base default and counterfactual reasoning on epistemic logic. Graduate students in philosophy or in computer science, especially those with an interest in AI, will find this book useful. (shrink)

A useful logic in which to specify normative system behaviour, deontic logic has a broad spectrum of possible applications within the field: from legal expert systems to natural language processing, database integrity to electronic contracting and the specification of fault-tolerant software.

This paper formalizes part of a well-known psychological model of emotions. In particular, the logical structure underlying the conditions that trigger emotions are studied and then hierarchically organized. The insights gained therefrom are used to guide a formalization of emotion triggers, which proceeds in three stages. The first stage captures the conditions that trigger emotions in a semiformal way, i.e., without committing to an underlying formalism and semantics. The second stage captures the main psychological notions used in the emotion model (...) in dynamic doxastic logic. The third stage introduces a BDI-based framework (belief–desire–intention) with achievement goals, which is used to firmly ground the preceding stages. The result is a formalization of emotion triggers for BDI agents with achievement goals. The idea of proceeding in these stages is to provide different levels of commitment to formalisms, so that it remains relatively easy to extend or replace the used formalisms without having to start from scratch. Finally, we show that the formalization renders properties of emotions that are in line with the psychological model on which it is based. (shrink)

Many philosophers are convinced that rationality dictates that one’s overall set of intentions be consistent. The starting point and inspiration for our study is Bratman’s planning theory of intentions. According to this theory, one needs to appeal to the fulfilment of characteristic planning roles to justify norms that apply to our intentions. Our main objective is to demonstrate that one can be rational despite having mutually inconsistent intentions. Conversely, it is also shown that one can be irrational despite having a (...) consistent overall set of intentions. To overcome this paradox, we argue that it is essential for a successful planning system that one’s intentions are practically consistent rather than being consistent or applying an aggregation procedure. Our arguments suggest that a new type of norm is needed: whereas the consistency requirement focuses on rendering the contents of one’s intentions consistent, our new practical consistency requirement demands that one’s intentions be able to simultaneously and unconditionally guide one’s action. We observe that for intentions that conform to the ‘own-action condition’, the practical consistency requirement is equivalent to the traditional consistency requirement. This implies that the consistency requirement only needs to be amended in scenarios of choice under uncertainty. (shrink)

To adequately deal with unpredictable and dynamic environments, normative frameworks typically deployed in mechanisms for modifying the norms at runtime are crucial. We present the syntax and operational semantics of programming constructs to facilitate runtime norm modification, allowing a programmer to specify when and how the norms may be changed by external agents or by the normative mechanism. The norms take on the form of conditional obligations and prohibitions, instantiating obligations and prohibitions. We present rule-based constructs for runtime modification of (...) the norms and their instances, and a mechanism for automatically updating the instances when their underlying norms change. Moreover, we investigate a mechanism for avoiding norm conflicts. (shrink)

In social interactions, it is common for individuals to possess different amounts of knowledge about a specific transaction, and those who are more knowledgeable might perform opportunistic behavior to others in their interest, which promotes their value but demotes others’ value. Such a typical social behavior is called opportunistic behavior. In this paper, we propose a formal account of opportunism based on the situation calculus. We first propose a model of opportunism that only considers a single action between two agents, (...) and then extend it to multiple actions and incorporate social context in the model. A simple example of selling a broken cup is used to illustrate our models. Through our models, we can have a thorough understanding of opportunism. (shrink)

We present a model-theoretic approach for reasoning about security protocols, applying recent insights from dynamic epistemic logics. This enables us to describe exactly the subsequent epistemic states of the agents participating in the protocol, using Kripke models and transitions between these based on updates of the agent's beliefs associated with steps in the protocol. As a case study we will consider the SRA Three Pass protocol and discuss the Wide-Mouthed Frog protocol.

The aim of the work is to provide a language to reason about Closed Interactions, i.e. all those situations in which the outcomes of an interaction can be determined by the agents themselves and in which the environment cannot interfere with they are able to determine. We will see that two different interpretations can be given of this restriction, both stemming from Pauly Representation Theorem. We will identify such restrictions and axiomatize their logic. We will apply the formal tools to (...) reason about games and their regulation. (shrink)

In Multi Agent Systems it is often the case that individual preferences are not compatible and coalitions compete to achieve a given result. The paper presents a language to talk about the conflict between coalitional choices and it expresses deontic notions to evaluate them. We will be specifically concerned with cases where the collective perspective is at odds with the individual perspective.

We demonstrate ways to incorporate nondeterminism in a system designed to formalize the reasoning of agents concerning their abilities and the results of the actions that they may perform. We distinguish between two kinds of nondeterministic choice operators: one that expresses an internal choice, in which the agent decides what action to take, and one that expresses an external choice, which cannot be influenced by the agent. The presence of abilities in our system is the reason why the usual approaches (...) towards nondeterminism cannot be used here. The semantics that we define for nondeterministic actions is based on the idea that composite actions are unravelled in the strings of atomic actions and tests that constitute them. The main notions used in defining this semantics are finite computation sequences and finite computation runs of actions. The results that we obtain meet our intuitions regarding events and abilities in the presence of nondeterminism. (shrink)

We give a model for iterated belief change in multi-agent systems. The formal tool we use for this is a combination of modal and dynamic logic. Two core notions in our model are the expansion of the knowledge and beliefs of an agent, and the processing of new information. An expansion is defined as the change in the knowledge and beliefs of an agent when it decides to believe an incoming formula while holding on to its current propositional beliefs. To (...) prevent our agents from forming inconsistent beliefs they do not expand with every piece of information they receive. Instead, our agents remember their original beliefs and every piece of information they receive. After every receipt of information they decide which subset of the received information should be incorporated into their original beliefs. This procedure is called the processing of new information. We show that our model of belief update behaves in an intuitive way and that it is not sensitive to criticism on comparable models. (shrink)

We present an epistemic default logic, based on the metaphore of a meta-level architecture. Upward reflection is formalized by a nonmonotonic entailment relation, based on the objective facts that are either known or unknown at the object level. Then, the meta (monotonic) reasoning process generates a number of default-beliefs of object-level formulas. We extend this framework by proposing a mechanism to reflect these defaults down. Such a reflection is seen as essentially having a temporal flavour: defaults derived at the meta-level (...) are projected as facts in a next object level state. In this way, we obtain temporal models for default reasoning in meta-level formalisms which can be conceived as labeled branching trees. Thus, descending the tree corresponds to shifts in time that model downward reflection, whereas the branching of the tree corresponds to ways of combining possible defaults. All together, this yields an operational or procedural semantics of reasoning by default, which admits one to reason about it by means of branching-time temporal logic. Finally, we define sceptical and credulous entailment relations based on these temporal models and we characterize Reiter extensions in our semantics. (shrink)

We demonstrate ways to incorporate nondeterminism in a system designed to formalize the reasoning of agents concerning their abilities and the results of the actions that they may perform. We distinguish between two kinds of nondeterministic choice operators: one that expresses an internal choice, in which the agent decides what action to take, and one that expresses an external choice, which cannot be influenced by the agent. The presence of abilities in our system is the reason why the usual approaches (...) towards nondeterminism cannot be used here. The semantics that we define for nondeterministic actions is based on the idea that composite actions are unravelled in the strings of atomic actions and tests that constitute them. The main notions used in defining this semantics are finite computation sequences and finite computation runs of actions. The results that we obtain meet our intuitions regarding events and abilities in the presence of nondeterminism. (shrink)

Knowledge has been a subject of philosophical study since ancient times. This is not surprising since knowledge is crucial for humans to control their actions and the appetite for acquiring it seems innate to the human race. Philosophy, therefore, has always occupied itself with the question as to the nature of knowledge. This area of philosophy is generally referred to as epistemology from the Greek word for knowledge: episteme. Plato defined knowledge as “justified true belief,” and this definition has influenced (...) philosophers ever since; cf. Gettier and Pollock. Although sensible, this definition does not yet explain the nature of knowledge, since all of the three notions of ‘justification’, ‘truth’, and ‘belief’ are not yet clear and still subject to discussion. It would go beyond the scope of our purposes here to go into this at this moment, but it is touched on later in this chapter. (shrink)

As the expansion of the Internet and the digital formatting of all kinds of creative works move us further into the information age, intellectual property issues have become paramount. Computer programs costing thousands of research dollars are now copied in an instant. People who would recoil at the thought of stealing cars, computers, or VCRs regularly steal software or copy their favorite music from a friend's CD. Since the Web has no national boundaries, these issues are international concerns. The contributors-philosophers, (...) legal theorists, and business scholars, among others-address questions such as: Can abstract ideas be owned? How does the violation of intellectual property rights compare to the violation of physical property rights? Can computer software and other digital information be protected? And how should legal systems accommodate the ownership of intellectual property in an information age? Intellectual Property is a lively examination of these and other issues, and an invaluable resource for librarians, lawyers, businesspeople, and scholars. (shrink)

Creative Intelligence: Essays in the Pragmatic Attitude represents an attempt at intellectual cooperation. No effort has been made, however, to attain unanimity of belief nor to proffer a platform of "planks" on which there is agreement. The consensus represented lies primarily in outlook, in conviction of what is most likely to be fruitful in method of approach. As the title page suggests, the volume presents a unity in attitude rather than a uniformity in results. Consequently each writer is definitively responsible (...) only for his own essay. The reader will note that the Essays endeavor to embody the common attitude in application to specific fields of inquiry which have been historically associated with philosophy rather than as a thing by itself. Beginning with philosophy itself, subsequent contributions discuss its application to logic, to mathematics, to physical science, to psychology, to ethics, to economics, and then again to philosophy itself in conjunction with esthetics and religion. The reader will probably find that the significant points of agreement have to do with the ideas of the genuineness of the future, of intelligence as the organ for determining the quality of that future so far as it can come within human control, and of a courageously inventive individual as the bearer of a creatively employed mind. (shrink)

This book is a collection of secondary essays on America's most important philosophic thinkers—statesmen, judges, writers, educators, and activists—from the colonial period to the present. Each essay is a comprehensive introduction to the thought of a noted American on the fundamental meaning of the American regime.

Compiled in the second century B.C.E, the _Huainanzi_ clarifies a crucial period in the development of Chinese conceptions of the cosmos, human nature, and the social order. Outlining "all that a modern monarch needs to know," the text emphasizes rigorous self-cultivation and mental discipline, attributing successful rule to a balance of broad knowledge, diligent application, and penetrating wisdom. In 2010, the editors of this volume completed the first complete English-language translation of the _Huainanzi_, opening exciting new pathways in the study (...) of philosophy, Asian studies, political science, and Asian literature. This abridgement contains essential selections from each of the _Huainanzi_'s twenty-one chapters and adds a new introduction and chapter descriptions. The text represents a remarkable synthesis of Daoist classics, such as the _Laozi_ and the _Zhuangzi_; works associated with the Confucian tradition, such as the _Changes_, the _Odes_, and the _Documents_; and a range of other foundational philosophical and literary works, from the _Mozi_ to the _Hanfeizi_. The abridgement preserves the _Huainanzi_'s special rhetorical features, such as its parallel prose, verse, and unique compositional techniques. For decades, Western scholars overlooked the _Huainanzi'_s sophisticated structure, creative content, and rich historical value, yet all that changed with the translation of the full text. Designed for classroom use and general readers, _The Essential Huainanzi_ continues to increase awareness of this brilliant work and change our understanding of early Chinese history. (shrink)

Jacques Derrida offers his recent commentary on the early career of Paul de Man as an urgent intervention in a discussion he fears is going awry. The most pressing danger he sees in the recent revelations is that they have played into the hands of de Man’s antagonists, who are now ready to denounce the whole of his career and even deconstruction itself. Against such indiscriminate critiques Derrida hurls the epithet: totalitarian. He is attempting to reseize the initiative in the (...) discussion and to reset the terms of the debate. His agenda extends across historical, theoretical, and political questions.He wants to affirm that a radical, indeed absolute break separates the later from the earlier de Man. He also wants to show that the young de man, however firmly committed to fascist ideology and however much an accomplice of the Nazis occupying Belgium, at the same time regularly distanced himself from that ideology and even undermined its meanings. Moreover, Derrida boldly takes up the challenge that these revelations have cast on the intellectual movement he and de Man have shaped. Can deconstruction come to grips with the political and intellectual history of its own leading American proponent? And can deconstruction in the process make a distinctive contribution to the understanding of fascism and intellectuals’ participation in it? John Brenkman is associate professor of English at Northwestern University. He is the author of Culture and Domination . Jules David Law is assistant professor of English at Northwestern University. He is currently working on a book-length study of the metaphors of surface, depth, and reflection in eighteenth- and nineteenth-century British prose. (shrink)

Compiled by scholars at the court of Liu An, king of Huainan, in the second century B.C.E, _The Huainanzi_ is a tightly organized, sophisticated articulation of Western Han philosophy and statecraft. Outlining "all that a modern monarch needs to know," the text emphasizes rigorous self-cultivation and mental discipline, brilliantly synthesizing for readers past and present the full spectrum of early Chinese thought. _The Huainanzi_ locates the key to successful rule in a balance of broad knowledge, diligent application, and the penetrating (...) wisdom of a sage. It is a unique and creative synthesis of Daoist classics, such as the _Laozi_ and the _Zhuangzi_; works associated with the Confucian tradition, such as the _Changes_, the _Odes_, and the _Documents_; and a wide range of other foundational philosophical and literary texts from the _Mozi_ to the _Hanfeizi_. The product of twelve years of scholarship, this remarkable translation preserves _The Huainanzi_'s special rhetorical features, such as parallel prose and verse, and showcases a compositional technique that conveys the work's powerful philosophical appeal. This path-breaking volume will have a transformative impact on the field of early Chinese intellectual history and will be of great interest to scholars and students alike. (shrink)

We present a solution to the paradox of free choice permission by introducing strong 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 is performed (and nothing else), and by introducing contextual interpretation of action terms.

Cognitive Science, Volume 46, Issue 6, June 2022.

In classical and intuitionistic arithmetics, any formula implies a true equation, and a false equation implies anything. In weaker logics fewer implications hold. In this paper we rehearse known results about the relevant arithmetic R, and we show that in linear arithmetic LL by contrast false equations never imply true ones. As a result, linear arithmetic is desecsed. A formula A which entails 0 = 0 is a secondary equation; one entailed by 0 6= 0 is a secondary unequation. A (...) system of formal arithmetic is secsed if every extensional formula is either a secondary equation or a secondary unequation. We are indebted to the program MaGIC for the simple countermodel SZ7, on which 0 = 1 is not a secondary formula. This is a small but signi cant success for automated reasoning. (shrink)

This article discusses relations among the multiple levels of analysis present in macro-sociological explanation—i.e., relations of individual, structural, and institutional processes. It also criticizes the doctrinal insistence upon single-level individualistic explanation found in some prominent contemporary sociological theory. For illustrative material the article returns to intellectual uses of Weber's "Protestant Ethic thesis," showing how an artificial version has been employed as a kind of proof text for the alleged scientific necessity of individualist explanation. Our alternative exposition renders the discussion of (...) Protestantism and capitalism in an explicitly multilevel way, distinguishing possible individual-level, social-organizational, and institutional linkages. The causal processes involved are distinct ones, with the more structural and institutional forms neither captured nor attainable by individual-level thinking. We argue more generally that "methodological individualisms" confuse issues of explanation with issues about microfoundations. This persistent intellectual conflation may be rooted in the broader folk models of liberal individualism. (shrink)