This book provides a detailed exposition of one of the most practical and popular methods of proving theorems in logic, called Natural Deduction. It is presented both historically and systematically. Also some combinations with other known proof methods are explored. The initial part of the book deals with Classical Logic, whereas the rest is concerned with systems for several forms of Modal Logics, one of the most important branches of modern logic, which has wide applicability.

This book is a companion to logical thought and logical thinking in China with a comparative and interdisciplinary perspective. It introduces the basic ideas and theories of Chinese thought in a comprehensive and analytical way. It covers thoughts in ancient, pre-modern and modern China from a historical point of view. It deals with topics in logical (including logico-philosophical) concepts and theories rooted in China, Indian and Western Logic transplanted to China, and the development of logical studies in contemporary China and other Chinese communities. The term "philosophy of logic" or "logico-philosophical thought" is used in this book to represent "logical thought" in a broad sense which includes thinking on logical concepts, modes of reasoning, and linguistic ideas related to logic and philosophical logic. Unique in its approach, the book uses Western logical theories and philosophy of language, Chinese philology, and history of ideas to deal with the basic ideas and major problems in logical thought and logical thinking in China. In doing so, it advances the understanding of the lost tradition in Chinese philosophical studies.

Philosophical logic has been, and continues to be, a driving force behind much progress and development in philosophy more broadly. This collection by up-and-coming philosophical logicians deals with a broad range of topics, including, for example, proof-theory, probability, context-sensitivity, dialetheism and dynamic semantics.

In this volume, the author investigates and argues for, a particular answer to the question: What is the right way to logically analyze modalities from natural language within formal languages? The answer is: by formalizing modal expressions in terms of predicates. But, as in the case of truth, the most intuitive modal principles lead to paradox once the modal notions are conceived as predicates. The book discusses the philosophical interpretation of these modal paradoxes and argues that any satisfactory approach to modality will have to face the paradoxes independently of the grammatical category of the modal notion. By systematizing modal principles with respect to their joint consistency and inconsistency, Stern provides an overview of the options and limitations of the predicate approach to modality that may serve as a useful starting point for future work on predicate approaches to modality. Stern also develops a general strategy for constructing philosophically attractive theories of modal notions conceived as predicates. The idea is to characterize the modal predicate by appeal to its interaction with the truth predicate. This strategy is put to use by developing the modal theories Modal Friedman-Sheard and Modal Kripke-Feferman.

A new approach to reading Frege's notations that adheres to the modern view that terms and well-formed formulas are any disjoint syntactic categories. On this new approach, we can at last read Frege's notations in their original form revealing striking new solutions to many of the outstanding problems of interpreting his philosophy.

Penetrating and practical, Logic Made Easy is filled with anecdotal histories detailing the often muddy relationship between language and logic. Complete with puzzles you can try yourself and questions you can use to raise your test scores, Logic Made Easy invites readers to identify and ultimately remedy logical slips in everyday life. Even experienced logicians will be surprised by Deborah Bennett's ability to identify the illogical in everything from maddening street signs to tax forms that make April the cruelest month. Designed with dozens of visual examples, the book guides readers through those hair-raising times when logic is at odds with common sense. Logic Made Easy is indeed one of those rare books that will actually make you a more logical human being.

In the last two decades modal logic has undergone an explosive growth, to thepointthatacompletebibliographyofthisbranchoflogic, supposingthat someone were capable to compile it, would ?ll itself a ponderous volume. What is impressive in the growth of modal logic has not been so much the quick accumulation of results but the richness of its thematic dev- opments. In the 1960s, when Kripke semantics gave new credibility to the logic of modalities? which was already known and appreciated in the Ancient and Medieval times? no one could have foreseen that in a short time modal logic would become a lively source of ideas and methods for analytical philosophers, historians of philosophy, linguists, epistemologists and computer scientists. The aim which oriented the composition of this book was not to write a new manual of modal logic (there are a lot of excellent textbooks on the market, and the expert reader will realize how much we bene?ted from manyofthem)buttoo?ertoeveryreader, evenwithnospeci?cbackground in logic, a conceptually linear path in the labyrinth of the current panorama of modal logic. The notion which in our opinion looked suitable to work as a compass in this enterprise was the notion of multimodality, or, more speci?cally, the basic idea of grounding systems on languages admitting more than one primitive modal opera

The present collection represents an attempt to bring together several contributions to the ongoing debate pertaining to supervenience of the normative in law and morals and strives to be the first work that addresses the topic comprehensively. It addresses the controversies surrounding the idea of normative supervenience and the philosophical conceptions they generated, deserve a recapitulation, as well as a new impulse for further development. Recently, there has been renewed interest in the concepts of normativity and supervenience. The research on normativity - a term introduced to the philosophical jargon by Edmund Husserl almost one hundred years ago - gained impetus in the 1990s through the works of such philosophers as Robert Audi, Christine Korsgaard, Robert Brandom, Paul Boghossian or Joseph Raz. The problem of the nature and sources of normativity has been investigated not only in morals and in relation to language, but also in other domains, e.g. in law or in the c ontext of the theories of rationality. Supervenience, understood as a special kind of relation between properties and weaker than entailment, has become analytic philosophers' favorite formal tool since 1980s. It features in the theories pertaining to mental properties, but also in aesthetics or the law. In recent years, the 'marriage' of normativity and supervenience has become an object of many philosophical theories as well as heated debates. It seems that the conceptual apparatus of the supervenience theory makes it possible to state precisely some claims pertaining to normativity, as well as illuminate the problems surrounding it.

We do not perceive the present as it is and in totality, nor do we infer the future from the present with any high degree of dependability, nor yet do we accurately know the consequences of our own actions. In addition, there is a fourth source of error to be taken into account, for we do not execute actions in the precise form in which they are imaged and willed. Frank H. Knight [R4.34, p. 202] The "degree" of certainty of confidence felt in the conclusion after it is reached cannot be ignored, for it is of the greatest practical signi- cance. The action which follows upon an opinion depends as much upon the amount of confidence in that opinion as it does upon fav- ableness of the opinion itself. The ultimate logic, or psychology, of these deliberations is obscure, a part of the scientifically unfathomable mystery of life and mind. Frank H. Knight [R4.34, p. 226-227] With some inaccuracy, description of uncertain consequences can be classified into two categories, those which use exclusively the language of probability distributions and those which call for some other principle, either to replace or supplement.

Arguing that our attachment to Aristotelian modes of discourse makes a revision of their conceptual foundations long overdue, the author proposes the consideration of unacknowledged factors that play a central role in argument itself. These are in particular the subjective imprint and the dynamics of argumentation. Their inclusion in a four-dimensional framework (subjective-objective, structural-procedural) and the focus on thesis validity allow for a more realistic view of our discourse practice. Exhaustive analyses of fascinating historical and contemporary arguments are provided. These range from Columbus s advocacy of the Western Passage to India, over the trial of King Louis XVI during the French Revolution, to today s highly charged controversies surrounding euthanasia and embryo research.

Excavating foundational issues such as the purpose of argument itself (assent of an audience or critical examination of validity claims) and the contested role of argument as a generator of knowledge, the book culminates in a discussion of the relationship between rationality and reasonableness and criticizes the restrictions of rational argument relying on fixed logical, economic or cultural criteria that in reality are mutable. Here, a true, open argument requires the infusion of Paul Lorenzen s principle of transsubjectivity, which recognizes but transcends the partiality of the individual and which can be seen in the pragmatic and expanding consensus that humanity can control itself to safeguard the future of a fragile, damaged world."

The rise of scientific (analytic) philosophy since the turn of the twentieth century is linked to the philosophical interaction between, on the one hand, Ernst Mach, the Vienna Circle around Moritz Schlick and Otto Neurath, the Berlin Group (Hans Reichenbach, Carl G. Hempel), and the Prague Group (Rudolf Carnap, Philipp Frank), and, on the other, philosophers and scientists in Denmark (Niels Bohr, Joergen Joergensen), Finland (Eino Kaila, Georg Henrik von Wright and their disciples), Norway (Arne Naess and his students), and Sweden (Ake Petzall, the journal Theoria and a younger generation of philosophers in Uppsala). In addition, the pure theory of law of Hans Kelsen achieved wide dissemination in the Nordic countries (through, for example, Alf Ross). One of the key events in the relations between the Central European philosophers and those of the Nordic countries was the Second International Congress for the Unity of Science which was arranged in Copenhagen in 1936.

Besides considering the interactions of these groups, the book also pays special attention to their interactions, in the context of the Cold War period following the Second World War, with the so-called Third Vienna Circle and with the Forum Alpbach/Austrian College around Viktor Kraft and Bela Juhos (along with Ludwig Wittgenstein and Paul Feyerabend), where the issues of (philosophical and scientific) realism and "psychologism"-the relationship between psychology and philosophy-were matters of controversy.

By comparison with the more extensively investigated and better known transatlantic transfer and transformation of "positivism" and logical empiricism, the developments outlined above remain

neglected and marginalized topics in historiography. The symposium aims to reveal the remarkable continuity of the philosophical enlightened "Nordic Connection." We intend to shed light on this forgotten communication and to reconstruct these hidden scholarly networks from an historical and logical point of view, thereby evaluating their significance for today's research."

Foundational questions in logic, mathematics, computer science and physics are constant sources of epistemological debate in contemporary philosophy. To what extent is the transfinite part of mathematics completely trustworthy? Why is there a general 'malaise' concerning the logical approach to the foundations of mathematics? What is the role of symmetry in physics? Is it possible to build a coherent worldview compatible with a macroobjectivistic position and based on the quantum picture of the world? What account can be given of opinion change in the light of new evidence? These are some of the questions discussed in this volume, which collects 14 lectures on the foundation of science given at the School of Philosophy of Science, Trieste, October 1989. The volume will be of particular interest to any student or scholar engaged in interdisciplinary research into the foundations of science in the context of contemporary debates.

This book, provides a critical approach to all major logical paradoxes: from ancient to contemporary ones. There are four key aims of the book: 1. Providing systematic and historical survey of different approaches - solutions of the most prominent paradoxes discussed in the logical and philosophical literature. 2. Introducing original solutions of major paradoxes like: Liar paradox, Protagoras paradox, an unexpected examination paradox, stone paradox, crocodile, Newcomb paradox. 3. Explaining the far-reaching significance of paradoxes of vagueness and change for philosophy and ontology. 4. Proposing a novel, well justified and, as it seems, natural classification of paradoxes. "

Church's Thesis (CT) was first published by Alonzo Church in 1935. CT is a proposition that identifies two notions: an intuitive notion of a effectively computable function defined in natural numbers with the notion of a recursive function. Despite of the many efforts of prominent scientists, Church's Thesis has never been falsified. There exists a vast literature concerning the thesis. The aim of the book is to provide one volume summary of the state of research on Church's Thesis. These include the following: different formulations of CT, CT and intuitionism, CT and intensional mathematics, CT and physics, the epistemic status of CT, CT and philosophy of mind, provability of CT and CT and functional programming.

This volume is dedicated to Leo Esakia's contributions to the theory of modal and intuitionistic systems. Consisting of 10 chapters, written by leading experts, this volume discusses Esakia s original contributions and consequent developments that have helped to shape duality theory for modal and intuitionistic logics and to utilize it to obtain some major results in the area.

Beginning with a chapter which explores Esakia duality for S4-algebras, the volume goes on to explore Esakia duality for Heyting algebras and its generalizations to weak Heyting algebras and implicative semilattices. The book also dives into the Blok-Esakia theorem and provides an outline of the intuitionistic modal logic KM which is closely related to the Godel-Lob provability logic GL. One chapter scrutinizes Esakia s work interpreting modal diamond as the derivative of a topological space within the setting of point-free topology. The final chapter in the volume is dedicated to the derivational semantics of modal logic and other related issues."

Over the past few years, the tree model of time has been widely employed to deal with issues concerning the semantics of tensed discourse. The thought that has motivated its adoption is that the most plausible way to make sense of indeterminism is to conceive of future possibilities as branches that depart from a common trunk, constituted by the past and the present. However, the thought still needs to be further articulated and defended, and several important questions remain open, such as the question of how actuality can be understood and formally represented in a branching framework. The present volume is intended to be a 360 degree reflection on the tree model. The contributions is gathers concern the model and its alternatives, both from a semantic and from a metaphysical point of view. "

How can we advance knowledge? Which methods do we need in order to make new discoveries? How can we rationally evaluate, reconstruct and offer discoveries as a means of improving the 'method' of discovery itself? And how can we use findings about scientific discovery to boost funding policies, thus fostering a deeper impact of scientific discovery itself? The respective chapters in this book provide readers with answers to these questions. They focus on a set of issues that are essential to the development of types of reasoning for advancing knowledge, such as models for both revolutionary findings and paradigm shifts; ways of rationally addressing scientific disagreement, e.g. when a revolutionary discovery sparks considerable disagreement inside the scientific community; frameworks for both discovery and inference methods; and heuristics for economics and the social sciences.

This book offers a detailed study of the truth-bearers problem, that is, the question of which category of items the predicates a ~truea (TM) and a ~falsea (TM) are predicated. The book has two dimensions: historical and systematic. Both focus around Tarskia (TM)s semantic theory of truth. The author locates Tarskia (TM)s ideas in a broad context of Austrian philosophy, in particular, Brentanoa (TM)s tradition. However, Bolzano and phenomenology (Husserl and Reinach) are also taken into account. The historical perspective is completed by showing how Tarski was rooted in Polish philosophical tradition originated with Twardowski and his version of Brentanism. The historical considerations are the basis for showing how the idea of truth-bearers as acts of judging was transformed into the theory of truth-bearers as sentences. In particular, the author analyses the way to nominalism in Polish philosophy, culminating in Lesniewski, Kotarbinski and Tarski. This book is indispensable for everybody interested in the evolution of Austrian philosophy from descriptive psychology to semantics. It is also a fundamental contribution toward a deeper understanding of the philosophical background of Tarskia (TM)s theory of truth.

Aristotle's Prior Analytics marks the beginning of formal logic. For Aristotle himself, this meant the discovery of a general theory of valid deductive argument, a project that he had described as either impossible or impracticable, probably not very long before he actually came up with syllogistic reasoning. A syllogism is the inferring of one proposition from two others of a particular form, and it is the subject of the Prior Analytics. The first book, to which this volume is devoted, offers a fairly coherent presentation of Aristotle's logic as a general theory of deductive argument.

This volume is a collation of original contributions from the key actors of a new trend in the contemporary theory of knowledge and belief, that we call "dynamic epistemology." It brings the works of these researchers under a single umbrella by highlighting the coherence of their current themes, and by establishing connections between topics that, up until now, have been investigated independently. It also illustrates how the new analytical toolbox unveils questions about the theory of knowledge, belief, preference, action, and rationality, in a number of central axes in dynamic epistemology: temporal, social, probabilistic and even deontic dynamics.

This book reconstructs the theory of signification implicit in Aristotle's De Interpretatione and its psychological background in his writing De Anima, a project often envisioned by scholars but never systematically undertaken. I begin by explaining what sort of phonetic material, according to Aristotle, can be a significans and a phone. To that end, I provide a physiological account of which animal sounds count as phone, as well as a psychological evaluation of the cognitive content of the phonai under consideration in De Interpretatione: names, verbs, and assertive sentences. I then turn to noemata, which, for Aristotle, are the psychological reference and significata of names, verbs and assertive sentences. I explain what, for Aristotle, are the logical properties a significatum must have in order to be signified by the phonetic material of a name, verb or assertive sentence, and why noemata can fulfil those logical conditions. Finally, I elucidate the significans-significatum relation without making use of the modern semantic triangle. This approach is consonant with Aristotle's methodology and breaks new ground by exploring the connection between the linguistic and psychological aspects of Aristotle's theory of signification.

This volume presents different conceptions of logic and mathematics and discuss their philosophical foundations and consequences. This concerns first of all topics of Wittgenstein's ideas on logic and mathematics; questions about the structural complexity of propositions; the more recent debate about Neo-Logicism and Neo-Fregeanism; the comparison and translatability of different logics; the foundations of mathematics: intuitionism, mathematical realism, and formalism. The contributing authors are Matthias Baaz, Francesco Berto, Jean-Yves Beziau, Elena Dragalina-Chernya, Gunther Eder, Susan Edwards-McKie, Oliver Feldmann, Juliet Floyd, Norbert Gratzl, Richard Heinrich, Janusz Kaczmarek, Wolfgang Kienzler, Timm Lampert, Itala Maria Loffredo D'Ottaviano, Paolo Mancosu, Matthieu Marion, Felix Muhlhoelzer, Charles Parsons, Edi Pavlovic, Christoph Pfisterer, Michael Potter, Richard Raatzsch, Esther Ramharter, Stefan Riegelnik, Gabriel Sandu, Georg Schiemer, Gerhard Schurz, Dana Scott, Stewart Shapiro, Karl Sigmund, William W. Tait, Mark van Atten, Maria van der Schaar, Vladimir Vasyukov, Jan von Plato, Jan Wolenski and Richard Zach.

Hegelian philosophy is now enjoying an enormous renaissance in the English-speaking world. At the very centre of his work is the monumental "Science of Logic." Hegel's theory of subjectivity, which comprises the final third of the "Science of Logic," has been comparatively neglected. This volume collects 15 essays on various aspects of Hegel's theory of subjectivity. For Hegel, "substance is subject." Anyone aspiring to understand Hegel's philosophy cannot afford to neglect this central topic.