This collection of papers, published in honour of Hector J. Levesque on the occasion of his 60th birthday, addresses a number of core areas in the field of knowledge representation and reasoning. In a broad sense, the book is about knowledge and belief, tractable reasoning, and reasoning about action and change. More specifically, the book contains contributions to Description Logics, the expressiveness of knowledge representation languages, limited forms of inference, satisfiablity (SAT), the logical foundations of BDI architectures, only-knowing, belief revision, planning, causation, the situation calculus, the action language Golog, and cognitive robotics.

This meticulous critical assessment of the ground-breaking work of philosopher Stanislaw Le niewski focuses exclusively on primary texts and explores the full range of output by one of the master logicians of the Lvov-Warsaw school. The author's nuanced survey eschews secondary commentary, analyzing Le niewski's core philosophical views and evaluating the formulations that were to have such a profound influence on the evolution of mathematical logic.

One of the undisputed leaders of the cohort of brilliant logicians that congregated in Poland in the early twentieth century, Le niewski was a guide and mentor to a generation of celebrated analytical philosophers (Alfred Tarski was his PhD student). His primary achievement was a system of foundational mathematical logic intended as an alternative to the Principia Mathematica of Alfred North Whitehead and Bertrand Russell. Its three strands-'protothetic', 'ontology', and 'mereology', are detailed in discrete sections of this volume, alongside a wealth other chapters grouped to provide the fullest possible coverage of Le niewski's academic output.

With material on his early philosophical views, his contributions to set theory and his work on nominalism and higher-order quantification, this book offers a uniquely expansive critical commentary on one of analytical philosophy's great pioneers. "

This book focuses on the problems of rules, rule-following and normativity as discussed within the areas of analytic philosophy, linguistics, logic and legal theory. Divided into four parts, the volume covers topics in general analytic philosophy, analytic legal theory, legal interpretation and argumentation, logic as well as AI& Law area of research. It discusses, inter alia, "Kripkenstein's" sceptical argument against rule-following and normativity of meaning, the role of neuroscience in explaining the phenomenon of normativity, conventionalism in philosophy of law, normativity of rules of interpretation, some formal approaches towards rules and normativity as well as the problem of defeasibility of rules. The aim of the book is to provide an interdisciplinary approach to an inquiry into the questions concerning rules, rule-following and normativity.

Logical form has always been a prime concern for philosophers belonging to the analytic tradition. For at least one century, the study of logical form has been widely adopted as a method of investigation, relying on its capacity to reveal the structure of thoughts or the constitution of facts. This book focuses on the very idea of logical form, which is directly relevant to any principled reflection on that method. Its central thesis is that there is no such thing as a correct answer to the question of what is logical form: two significantly different notions of logical form are needed to fulfill two major theoretical roles that pertain respectively to logic and to semantics. This thesis has a negative and a positive side. The negative side is that a deeply rooted presumption about logical form turns out to be overly optimistic: there is no unique notion of logical form that can play both roles. The positive side is that the distinction between two notions of logical form, once properly spelled out, sheds light on some fundamental issues concerning the relation between logic and language.

In recent years, mathematical logic has developed in many directions, the initial unity of its subject matter giving way to a myriad of seemingly unrelated areas. The articles collected here, which range from historical scholarship to recent research in geometric model theory, squarely address this development. These articles also connect to the diverse work of Vaananen, whose ecumenical approach to logic reflects the unity of the discipline."

John Horty effectively develops deontic logic (the logic of ethical concepts like obligation and permission) against the background of a formal theory of agency. He incorporates certain elements of decision theory to set out a new deontic account of what agents ought to do under various conditions over extended periods of time. Offering a conceptual rather than technical emphasis, Horty's framework allows a number of recent issues from moral theory to be set out clearly and discussed from a uniform point of view.

Terence Parsons presents a new study of the development and logical complexity of medieval logic. Basic principles of logic were used by Aristotle to prove conversion principles and reduce syllogisms. Medieval logicians expanded Aristotle's notation in several ways, such as quantifying predicate terms, as in 'No donkey is every animal', and allowing singular terms to appear in predicate position, as in 'Not every donkey is Brownie'; with the enlarged notation come additional logical principles. The resulting system of logic is able to deal with relational expressions, as in De Morgan's puzzles about heads of horses. A crucial issue is a mechanism for dealing with anaphoric pronouns, as in 'Every woman loves her mother'. Parsons illuminates the ways in which medieval logic is as rich as contemporary first-order symbolic logic, though its full potential was not envisaged at the time. Along the way, he provides a detailed exposition and examination of the theory of modes of common personal supposition, and the useful principles of logic included with it. An appendix discusses the artificial signs introduced in the fifteenth century to alter quantifier scope.

This edited volume brings together 18 state-of-the art essays on pluralism about truth and logic. Parts I and II are dedicated to respectively truth pluralism and logical pluralism, and Part III to their interconnections. Some contributors challenge pluralism, arguing that the nature of truth or logic is uniform. The majority of contributors, however, defend pluralism, articulate novel versions of the view, or contribute to fundamental debates internal to the pluralist camp. The volume will be of interest to truth theorists and philosophers of logic, as well as philosophers interested in relativism, contextualism, metaphysics, philosophy of language, semantics, paradox, epistemology, or normativity.

This monograph proposes a new way of implementing interaction in logic. It also provides an elementary introduction to Constructive Type Theory (CTT). The authors equally emphasize basic ideas and finer technical details. In addition, many worked out exercises and examples will help readers to better understand the concepts under discussion. One of the chief ideas animating this study is that the dialogical understanding of definitional equality and its execution provide both a simple and a direct way of implementing the CTT approach within a game-theoretical conception of meaning. In addition, the importance of the play level over the strategy level is stressed, binding together the matter of execution with that of equality and the finitary perspective on games constituting meaning. According to this perspective the emergence of concepts are not only games of giving and asking for reasons (games involving Why-questions), they are also games that include moves establishing how it is that the reasons brought forward accomplish their explicative task. Thus, immanent reasoning games are dialogical games of Why and How.

First published in 2000. Routledge is an imprint of Taylor & Francis, an informa company.

Tyler Burge presents a collection of his seminal essays on Gottlob Frege (1848-1925), who has a strong claim to be seen as the founder of modern analytic philosophy, and whose work remains at the centre of philosophical debate today. Truth, Thought, Reason gathers some of Burge's most influential work from the last twenty-five years, and also features important new material, including a substantial introduction and postscripts to four of the ten papers. It will be an essential resource for any historian of modern philosophy, and for anyone working on philosophy of language, epistemology, or philosophical logic.

Ordinary language and scientific language enable us to speak about, in a singular way (using demonstratives and names), what we recognize not to exist: fictions, the contents of our hallucinations, abstract objects, and various idealized but nonexistent objects that our scientific theories are often couched in terms of. Indeed, references to such nonexistent items-especially in the case of the application of mathematics to the sciences-are indispensable. We cannot avoid talking about such things. Scientific and ordinary languages thus enable us to say things about Pegasus or about hallucinated objects that are true (or false), such as "Pegasus was believed by the ancient Greeks to be a flying horse," or "That elf I'm now hallucinating over there is wearing blue shoes." Standard contemporary metaphysical views and semantic analyses of singular idioms on offer in contemporary philosophy of language have not successfully accommodated these routine practices of saying true and false things about the nonexistent while simultaneously honoring the insight that such things do not exist in any way at all (and have no properties). That is, philosophers often feel driven to claim that such objects do exist, or they claim that all our talk isn't genuine truth-apt talk, but only pretence. This book reconfigures metaphysics (and the role of metaphysics in semantics) in radical ways that allow the accommodation of our ordinary ways of speaking of what does not exist while retaining the absolutely crucial presupposition that such objects exist in no way at all, have no properties, and so are not the truth-makers for the truths and falsities that are about them.

This volume responds to and reassesses the work of Hector-Neri Castaneda (1924-1991). The essays collected here, written by his students, followers, and opponents, examine Castaneda s seminal views on deontic logic, metaethics, indedicality, praticitions, fictions, and metaphysics, utilizing the critical viewpoint afforded by time, as well as new data, to offer insights on his theories and methodology."

This book presents a constitutive approach to controversy based on a discourse analysis of news texts, focusing on the role of journalists as participants who shape public controversy for readers. Drawing data from the Reuters Corpus, the project identifies formulas that journalists use in reporting controversy and draws conclusions about how these serve professional and textual functions and how they shape public controversy as a natural, historical, and pragmatic event. While the traditions of dialectic and rhetoric have focused on the prescriptive aim of training participants to resolve controversies in philosophical dialogue or public debate settings, this orientation has tended to preempt questions about where controversy is located and how it is shaped. This project contributes to descriptive, ethnographic research about controversy, using discourse analysis to address a problem in argumentation.

This volume brings together a group of philosophically oriented logicians and logic-minded philosophers, mainly from Asia, to address a variety of logical and philosophical topics, such as modal logic and related directions (e.g. temporal logic, epistemic logic, deontic logic, logic of conditionals, and modal proof theory), theory of truth, paradoxes, intentionality, and social networks. New approaches are also proposed, such as extended modal logic with planarity of graphs, extended branching time temporal logic with conditional operators, and a relational treatment of language and logical systems, to name but a few.Given the variety of topics and issues discussed here, the book will appeal to readers from a broad range of disciplines, from mathematical/philosophical logic, computing science, cognitive science and artificial intelligence, to linguistics, game theory and beyond.

The essays in this volume concern the points of intersection between analytic philosophy and the philosophy of the exact sciences. More precisely, it concern connections between knowledge in mathematics and the exact sciences, on the one hand, and the conceptual foundations of knowledge in general. Its guiding idea is that, in contemporary philosophy of science, there are profound problems of theoretical interpretation-- problems that transcend both the methodological concerns of general philosophy of science, and the technical concerns of philosophers of particular sciences. A fruitful approach to these problems combines the study of scientific detail with the kind of conceptual analysis that is characteristic of the modern analytic tradition. Such an approach is shared by these contributors: some primarily known as analytic philosophers, some as philosophers of science, but all deeply aware that the problems of analysis and interpretation link these fields together.

This book offers a novel perspective on abduction. It starts by discussing the major theories of abduction, focusing on the hybrid nature of abduction as both inference and intuition. It reports on the Peircean theory of abduction and discusses the more recent Magnani concept of animal abduction, connecting them to the work of medieval philosophers. Building on Magnani's manipulative abduction, the accompanying classification of abduction, and the hybrid concept of abduction as both inference and intuition, the book examines the problem of visual perception together with the related concepts of misrepresentation and semantic information. It presents the author's views on caricature and the caricature model of science, and then extends the scope of discussion by introducing some standard issues in the philosophy of science. By discussing the concept of ad hoc hypothesis generation as enthymeme resolution, it demonstrates how ubiquitous the problem of abduction is in all the different individual scientific disciplines. This comprehensive text provides philosophers, logicians and cognitive scientists with a historical, unified and authoritative perspective on abduction.

This book explores the two major elements of Hintikka's model of inquiry: underlying game theoretical motivations and the central role of questioning. The chapters build on the Hintikkan tradition extending Hintikka's model and present a wide variety of approaches to the philosophy of inquiry from different directions, ranging from erotetic logic to Lakatosian philosophy, from socio-epistemologic approaches to strategic reasoning and mathematical practice. Hintikka's theory of inquiry is a well-known example of a dynamic epistemic procedure. In an interrogative inquiry, the inquirer is given a theory and a question. He then tries to answer the question based on the theory by posing questions to nature or an oracle. The initial formulation of this procedure by Hintikka is rather broad and informal. This volume introduces a carefully selected responses to the issues discussed by Hintikka. The articles in the volume were contributed by various authors associated with a research project on Hintikka's interrogative theory of inquiry conducted in the Institut d'Histoire et de Philosophie des Sciences et des Techniques (IHPST) of Paris, including those who visited to share their insight.

Legal theory, political sciences, sociology, philosophy, logic, artificial intelligence: there are many approaches to legal argumentation. Each of them provides specific insights into highly complex phenomena. Different disciplines, but also different traditions in disciplines (e.g. analytical and continental traditions in philosophy) find here a rare occasion to meet. The present book contains contributions, both historical and thematic, from leading researchers in several of the most important approaches to legal rationality. One of the main issues is the relation between logic and law: the way logic is actually used in law, but also the way logic can make law explicit. An outstanding group of philosophers, logicians and jurists try to meet this issue. The book is more than a collection of papers. However different their respective conceptual tools may be, the authors share a common conception: legal argumentation is a specific argumentation context.

The present volume has its origin in a meeting of philosophers, linguists and cognitive scientists that was held at Umea University, Sweden, September 24-26, 1993. The meeting was organized by the Department of Philosophy in co-opersation with the Department of Linguistics, and it was called UmLLI-93, the Umea Colloquium on Dynamic Approaches in Logic, Language and Information. The papers included here fall into three broad categories. In the first part of the book, Action, are collected papers that concern the formal theory of action, the logic of norms, and the theory of rational decision. The papers in the second part, Belief Change, concern the theory of belief dynamics in the tradition of Alchourron, Gardenfors and Makinson. The third part, Cognition, concerns abstract questions about knowledge and truth as well as more concrete questions about the usefulness and tractability of various graphic representations of information.

This book offers an inspiring and naive view on language and reasoning. It presents a new approach to ordinary reasoning that follows the author's former work on fuzzy logic. Starting from a pragmatic scientific view on meaning as a quantity, and the common sense reasoning from a primitive notion of inference, which is shared by both laypeople and experts, the book shows how this can evolve, through the addition of more and more suppositions, into various formal and specialized modes of precise, imprecise, and approximate reasoning. The logos are intended here as a synonym for rationality, which is usually shown by the processes of questioning, guessing, telling, and computing. Written in a discursive style and without too many technicalities, the book presents a number of reflections on the study of reasoning, together with a new perspective on fuzzy logic and Zadeh's "computing with words" grounded in both language and reasoning. It also highlights some mathematical developments supporting this view. Lastly, it addresses a series of questions aimed at fostering new discussions and future research into this topic. All in all, this book represents an inspiring read for professors and researchers in computer science, and fuzzy logic in particular, as well as for psychologists, linguists and philosophers.

Changing preferencesis a phenomenonoften invoked but rarely properlyaccounted for. Throughout the history of the social sciences, researchers have come against the possibility that their subjects' preferenceswere affected by the phenomenato be explainedor by otherfactorsnot taken into accountin the explanation.Sporadically, attempts have been made to systematically investigate these in uences, but none of these seems to have had a lasting impact. Today we are still not much further with respect to preference change than we were at the middle of the last century. This anthology hopes to provide a new impulse for research into this important subject. In particular, we have chosen two routes to amplify this impulse. First, we stress the use of modellingtechniquesfamiliar from economicsand decision theory. Instead of constructing complex, all-encompassing theories of preference change, the authors of this volume start with very simple, formal accounts of some possible and hopefully plausible mechanism of preference change. Eventually, these models may nd their way into larger, empirically adequate theories, but at this stage, we think that the most importantwork lies in building structure.Secondly, we stress the importance of interdisciplinary exchange. Only by drawing together experts from different elds can the complex empirical and theoretical issues in the modelling of preference change be adequately investigated.