The papers collected in this volume exemplify some of the trends in current approaches to logic, language and computation. Written by authors with varied academic backgrounds, the contributions are intended for an interdisciplinary audience. The first part of this volume addresses issues relevant for multi-agent systems: reasoning with incomplete information, reasoning about knowledge and beliefs, and reasoning about games. Proofs as formal objects form the subject of Part II. Topics covered include: contributions on logical frameworks, linear logic, (...) and different approaches to formalized reasoning. Part III focuses on representations and formal methods in linguistic theory, addressing the areas of comparative and temporal expressions, modal subordination, and compositionality. (shrink)

The Editors express their gratitude and appreciation to the indi-viduals listed below who served as referees for Informal Logic for Volumes 31 (2011) and 32 (2012).

Classical logic, beginning with the work of Aristotle, has developed into a powerful and rigorous mathematical theory with many applications in mathematics and ...

This anthology contains revised versions of selected papers presented at the the fourth bi-annual international deontic logic conference, DEON’06. There is a substantial introduction (see separate entry), papers from all four invited speakers, David Makinson, Donald Nute, Claudio Pizzi, and Georg Von Wright. After the introduction and lead chapter "Deontic Logic - as I See It" by G.H. von Wright, there are nineteen articles grouped under six headings, "Norms and Truth", "Agency and Time", "Analysis of Normative Conflicts", "Defeasibility (...) and Norm Conflicts", Computer System Applications", and "Combinations of Logics". The collection contains a number of influential articles and a large array of key authors in deontic logic contribute. (shrink)

This anthology contains revised versions of selected papers presented at the fourth bi-annual international deontic logic conference, DEON’98. This volume includes our substantial introduction, and an article from me as a contributor. The volume includes papers from all four distinguished invited speakers, David Makinson, Donald Nute, Claudio Pizzi, and the founder of deontic logic, Georg Von Wright. Other notables among the authors are Dov Gabbay (co-editor of the Handbook on Philosophical Logic vols.1-4, and editor of a number (...) of logic book series); Lars Lindahl (author of Position and Change: A Study in Law and Logic); Andrew Jones (past editor of the Norwegian Journal of Philosophical Logic, and the co-author of the entry “Deontic Logic and Contrary-to-Duties” in the 2nd edition of Handbook on Philosophical Logic); and Marek Sergot (a leading researcher at the interface of deontic logic and computer science.). (shrink)

The logic of information flow has applications in both computer science and natural language processing and is a growing area within mathematical and philosophical logic.

Ecology and sustainability are current narratives about the behavior of humans toward themselves and the environment. Ecology is defined as a science, and a philosophy of ecology has become a recognized domain of the philosophy of science. For some, sustainability is an accepted, important moral goal. In 2013, a Special Issue of the journal Sustainability dealt with many of the relevant issues. Unfortunately, the economic, ideological, and psychological barriers to ethical behavior and corresponding social action remain great as well as (...) obvious. In this paper, I propose that a new, non-standard and non-propositional logic of real processes, Logic in Reality grounded in physics applies to the science and philosophy of these narratives and helps to explicate them. Given the ecological role of organizations and institutions, reference is often made to organizational or institutional logics as guides to ecological practice. This paper suggests that these logics are either too abstract or too informal to have an impact in a conflictual world. Recognition of the suggested new, transdisciplinary logical dimension of ecological processes may provide credibility and support to new initiatives in ecology and its philosophy. (shrink)

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)

(See also the separate entry for the volume itself.) This introduction has three parts. The first providing an overview of some main lines of research in deontic logic: the emergence of SDL, Chisholm's paradox and the development of dyadic deontic logics, various other puzzles/challenges and areas of development, along with philosophical applications. The second part focus on some actual and potential fruitful interactions between deontic logic, computer science and artificial intelligence. These include applications of deontic logic to (...) AI knowledge representation in legal systems, to modelling computer systems where it is expected that sub-ideal states will emerge and require countermeasures, to norm-governed human interactions with computer systems, and to the representation of some features of multi-agent systems where different agent-like computer systems interact with one another. The third and final part briefly groups and previews the papers in the anthology. (shrink)

Information is a notion of wide use and great intuitive appeal, and hence, not surprisingly, different formal paradigms claim part of it, from Shannon channel theory to Kolmogorov complexity. Information is also a widely used term in logic, but a similar diversity repeats itself: there are several competing logical accounts of this notion, ranging from semantic to syntactic. In this chapter, we will discuss three major logical accounts of information.

"This volume comprises the proceedings of the First All-Berlin Workshop on Nonclassical Logics and Information Processing, held at the Free University of Berlin, November 9-10, 1990. The scope of the ten papers in the volume is broad, covering various different subfields of logic - particularly nonclassical logic - and its applications in artificial intelligence. The papers are grouped according to the four major topics that emerged at the meeting: modal systems, logic programming, nonmonotonic logics, and proof (...) theory. The classification is only a rough guide since the four areas overlap considerably."--PUBLISHER'S WEBSITE. (shrink)

This book illustrates the program of Logical-Informational Dynamics. Rational agents exploit the information available in the world in delicate ways, adopt a wide range of epistemic attitudes, and in that process, constantly change the world itself. Logical-Informational Dynamics is about logical systems putting such activities at center stage, focusing on the events by which we acquire information and change attitudes. Its contributions show many current logics of information and change at work, often in multi-agent settings where social (...) behavior is essential, and often stressing Johan van Benthem's pioneering work in establishing this program. However, this is not a Festschrift, but a rich tapestry for a field with a wealth of strands of its own. The reader will see the state of the art in such topics as information update, belief change, preference, learning over time, and strategic interaction in games. Moreover, no tight boundary has been enforced, and some chapters add more general mathematical or philosophical foundations or links to current trends in computer science. The theme of this book lies at the interface of many disciplines. Logic is the main methodology, but the various chapters cross easily between mathematics, computer science, philosophy, linguistics, cognitive and social sciences, while also ranging from pure theory to empirical work. Accordingly, the authors of this book represent a wide variety of original thinkers from different research communities. And their interconnected themes challenge at the same time how we think of logic, philosophy and computation. Thus, very much in line with van Benthem's work over many decades, the volume shows how all these disciplines form a natural unity in the perspective of dynamic logicians (broadly conceived) exploring their new themes today. And at the same time, in doing so, it offers a broader conception of logic with a certain grandeur, moving its horizons beyond the traditional study of consequence relations. (shrink)

Edited in collaboration with FoLLI, the Association of Logic, Language and Information this book constitutes the refereed proceedings of the of the 29th International Workshop on Logic, Language, Information, and Computation, WoLLIC 2023, held in Halifax, NS, Canada, during July 11–14, 2023. The 24 full papers (21 contributed, 3 invited) included in this book were carefully reviewed and selected from 46 submissions. The book also contains the abstracts for the 7 invited talks and 4 tutorials presented (...) at WoLLIC 2023. The WoLLIC conference series aims at fostering interdisciplinary research in pure and applied logic. (shrink)

This book examines the logical foundations of visual information: information presented in the form of diagrams, graphs, charts, tables, and maps. The importance of visual information is clear from its frequent presence in everyday reasoning and communication, and also in compution. Chapters of the book develop the logics of familiar systems of diagrams such as Venn diagrams and Euler circles. Other chapters develop the logic of higraphs, Pierce diagrams, and a system having both diagrams and sentences (...) among its well-formed representations. Syntax, semantics, rules of inference and soundness and completeness results are provided for each of the systems. In addition to developing the logic of diagrams, key questions about the status of visual information Hammer discusses, such as the relationship between the language and visually-presented information. (shrink)

I take 'informal logic' to be the (descriptive and normative) study of 'real arguments'-arguments which are or have been used with the aim of convincing others of a point of view. I argue that the informal logic tradition thus conceived (i) lends strong support to something like Quine's view that our beliefs really support one another like the filaments in a spider's web--and thus that the traditional view that implication is an asymmetric relation is false; (ii) suggests that (...) the classic division of arguments into deductive and inductive has distorted our thinking about the evaluation of real arguments; and (iii) implies that naturalised epistemology is on the right track. (shrink)

This paper provides an interpretation of the Routley-Meyer semantics for a weak negation-free relevant logic using Israel and Perry's theory of information. In particular, Routley and Meyer's ternary accessibility relation is given an interpretation in information-theoretic terms.

In order to predict and explain behavior, one cannot specify the mental state of an agent merely by saying what information she possesses. Instead one must specify what information is available to an agent relative to various purposes. Specifying mental states in this way allows us to accommodate cases of imperfect recall, cognitive accomplishments involved in logical deduction, the mental states of confused or fragmented subjects, and the difference between propositional knowledge and know-how .

We discuss how issues of information and computation interact with logic today, and what might be a natural extended agenda of investigation.

Edited in collaboration with FoLLI, the Association of Logic, Language and Information this book constitutes the refereed proceedings of the 22nd Workshop on Logic, Language, Information and Computation, WoLLIC 2015, held in the campus of Indiana University, Bloomington, IN, USA in July 2015. The 14 contributed papers, presented together with 8 invited lectures and 4 tutorials, were carefully reviewed and selected from 44 submissions. The focus of the workshop was on interdisciplinary research involving formal logic, (...) computing and programming theory, and natural language and reasoning. (shrink)

Many have adopted the view that informal logic is importantly dependent on epistemology . Finocchiaro has raised this issue in the context argumentation theory, as perhaps distinguished from informal logic A recent pair of issues of Informal Logic , guest edited by Christoph Lumer, was devoted to epistemological approaches to argumentation. On the other hand, both Johnson and Blair and Johnson have expressed reservations. In this paper I want to take another look at the relationship between informal (...) logic and epistemology. I will argue that there are reasons for skepticism regarding the Received View that have not been taken into consideration and fully appreciated by those who advocate some form of this view. (shrink)

Quantum information is discussed as the universal substance of the world. It is interpreted as that generalization of classical information, which includes both finite and transfinite ordinal numbers. On the other hand, any wave function and thus any state of any quantum system is just one value of quantum information. Information and its generalization as quantum information are considered as quantities of elementary choices. Their units are correspondingly a bit and a qubit. The course of (...) time is what generates choices by itself, thus quantum information and any item in the world in final analysis. The course of time generates necessarily choices so: The future is absolutely unorderable in principle while the past is always well-ordered and thus unchangeable. The present as the mediation between them needs the well-ordered theorem equivalent to the axiom of choice. The latter guarantees the choice even among the elements of an infinite set, which is the case of quantum information. The concrete and abstract objects share information as their common base, which is quantum as to the formers and classical as to the latters. The general quantities of matter in physics, mass and energy can be considered as particular cases of quantum information. The link between choice and abstraction in set theory allows of “Hume’s principle” to be interpreted in terms of quantum mechanics as equivalence of “many” and “much” underlying quantum information. Quantum information as the universal substance of the world calls for the unity of physics and mathematics rather than that of the concrete and abstract objects and thus for a form of quantum neo-Pythagoreanism in final analysis. (shrink)

One the most interesting debates in moral philosophy revolves around the significance of empirical moral psychology for moral philosophy. Genealogical arguments that rely on empirical findings about the origins of moral beliefs, so-called debunking arguments, take center stage in this debate. Looking at debunking arguments based on evidence from evolutionary moral psychology, experimental ethics and neuroscience, this book explores what ethicists can learn from the science of morality, and what they cannot. Among other things, the book offers a new take (...) on the deontology/utilitarianism debate, discusses the usefulness of experiments in ethics, investigates whether morality should be thought of as a problem-solving device, shows how debunking arguments can tell us something about the structure of philosophical debate, and argues that debunking arguments lead to both moral and prudential skepticism. Presenting a new picture of the relationship between empirical moral psychology and moral philosophy, this book is essential reading for moral philosophers and moral psychologists alike. (shrink)

I LOGIC IN PHILOSOPHY— PHILOSOPHY OF LOGIC i. On the relation of logic to philosophy I n this book, the consequences of certain logical insights for ...

I follow Giordani in distinguishing between a situational and informational conception of subject-matter and consider some of the different ways in which it might be explained within both an intensional and an hyperintensional account of propositional identity.

In this paper we present a modal logic framework to reason about the expertise of information sources. A source is considered an expert on a proposition φ\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\varphi $$\end{document} if they are able to correctly refute φ\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\varphi $$\end{document} in any possible world where φ\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\varphi $$\end{document} is false. Closely connected with expertise is a (...) notion of soundness of information: φ\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\varphi $$\end{document} is said to be “sound” if it is true up to lack of expertise of the source. That is, any statement logically weaker than φ\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\varphi $$\end{document} on which the source has expertise must in fact be true. This is relevant for modelling situations in which sources make claims beyond their domain of expertise. Particular attention is paid to the connection between expertise and knowledge: we show that expertise and soundness admit precise interpretations in terms of S4 and S5 epistemic logic, under certain conditions. We go on to extend the framework to multiple sources, defining two notions of collective expertise. These also have epistemic interpretations via distributed and common knowledge from multi-agent epistemic logic. On the technical side, we give several sound and complete axiomatisations of various classes of expertise models. (shrink)

Informal logic offers a radical new perspective on the evaluation of arguments. But little work has been done on how deep concepts in the logical foundations of argument need to be modified in light of such efforts. This paper offers an indication of what might be done by sketching a new approach to the theory of entailment, truth and relevance.

Informal logic offers a radical new perspective on the evaluation of arguments. But little work has been done on how deep concepts in the logical foundations of argument need to be modified in light of such efforts. This paper offers an indication of what might be done by sketching a new approach to the theory of entailment, truth and relevance.

The Aristotelian square of oppositions is a well-known diagram in logic and linguistics. In recent years, several extensions of the square have been discovered. However, these extensions have failed to become as widely known as the square. In this paper we argue that there is indeed a fundamental difference between the square and its extensions, viz., a difference in informativity. To do this, we distinguish between concrete Aristotelian diagrams and, on a more abstract level, the Aristotelian geometry. We then (...) introduce two new logical geometries, and develop a formal, well-motivated account of their informativity. This enables us to show that the square is strictly more informative than many of the more complex diagrams. (shrink)

Theoretical physics is a deductive discipline which presupposes the validity and applicability of certain other disciplines. Among these are logic, algebra, analysis, and geometry. Before relativity, Euclidean geometry was the only one thought to be important for physical space. These disciplines correlate well with experience, and, in the course of time, a priori validity came to be ascribed to them. To Kant, for example, the universe could not possibly be based on any geometry other than Euclid's. The discovery of (...) non-Euclidean geometries by Bolyai and Lobatchevsky, its systematic extension by Riemann, and the critical scrutiny of foundations by Mach and Poincaré shook the “self-evident truth” of Euclidean geometry as applied to the world of physics. The death knell of the a priori truth of any geometry was supplied by Einstein. He showed that a wider body of experience was coordinated by a Riemannian geometry than by Euclidean. He traced the success of Euclidian geometry back to the existence of so-called rigid bodies, in terms of which operations can be associated with numbers which correlate well with numbers associated in a purely mathematical way with mathematical constructs put in correspondence with these bodies. For the physicist, then, the geometry of the real world is now a physical theory whose “truth” like that of all physical theory, is measured by its degree of success in coordinating experience. (shrink)