Free logic - i.e., logic free of existential presuppositions in general and with respect to singular terms in particular- began to come into its own as a field of research in the 1950s. As is the case with so many developments in Western philosophy, its roots can be traced back to ancient Greek philo sophy. It is only during the last fifty years, however, that it has become well established as a branch of modern logic. The name of Karel Lambert is most closely connected with this development: he gave it its name and its profile as a well defined field of research. After a development of fifty years, it is time to look back and take stock while at the same time scanning for new perspectives. This is the purpose of the papers collected in this volume. The first paper is written by Karel Lambert himself who also comments on all the papers of the other authors. In an introductory essay we give a survey of the present status of and new directions in free logic.

Thinking about Logic is an accessible and thought-provoking collection of classic articles in the philosophy of logic. An ideal companion to any formal logic course or textbook, this volume illuminates how logic relates to perennial philosophical issues about knowledge, meaning, rationality, and reality. The editors have selected each essay for its brevity, clarity, and impact and have included insightful introductions and discussion questions. The puzzles raised will help readers acquire a more thorough understanding of fundamental logic concepts and a firmer command of the connections between formal logic and other areas of philosophical study: epistemology, philosophy of language, philosophy of science, and metaphysics.

This edited volume collects essays on the four-valued logic known as Belnap-Dunn logic, or first-degree entailment logic (FDE). It also looks at various formal systems closely related to it. These include the strong Kleene logic and the Logic of Paradox. Inside, readers will find reprints of seminal papers written by the fathers of the field: Nuel Belnap and Michael Dunn. In addition, the collection also features a well-known but previously unpublished manuscript of Dunn, an interview with Belnap, and a new essay by Dunn. Besides the original, monumental papers, the book also includes research by leading scholars. They consider the extraordinary importance of Belnap-Dunn logic from several perspectives. They look at how, philosophically, it has served as a basic system of inconsistency-tolerant reasoning, as the core of underlying logics for theories based on dialetheism, and, more recently, for theories based on Buddhist philosophy. Coverage also explores its contributions to computer science, such as knowledge representation and information processing. This mix of seminal papers and insightful analysis by top scholars offers readers a comprehensive outlook on Belnap-Dunn logic and its related expansions, which have been agenda setting for the debate on philosophical logic as well as philosophy of logic. The book will also enhance further discussion on the philosophical issues related to nonclassical logics in general.

Questions about truth and questions about reality are intimately connected. One can ask whether numbers exist by asking "Are there numbers?" But one can also ask what arguably amounts to the same question by asking "Is the sentence 'There are numbers' true?" Such semantic ascent implies that reality can be investigated by investigating our true sentences. This line of thought was dominant in twentieth century philosophy, but is now beginning to be called into question. In From Truth to Reality, Heather Dyke brings together some of the foremost metaphysicians to examine approaches to truth, reality, and the connections between the two. This collection features new and previously unpublished material by JC Beall, Mark Colyvan, Michael Devitt, John Heil, Frank Jackson, Fred Kroon, D. H. Mellor, Luca Moretti, Alan Musgrave, Robert Nola, J. J. C. Smart, Paul Snowdon, and Daniel Stoljar.

Free logic is an important field of philosophical logic that first appeared in the 1950s. J. Karel Lambert was one of its founders and coined the term itself. The essays in this collection (written over a period of 40 years) explore the philosophical foundations of free logic and its application to areas as diverse as the philosophy of religion and computer science. Amongst the applications on offer are those to the analysis of existence statements, to definite descriptions and to partial functions. The volume contains a proof that free logics of any kind are non-extensional and then uses that proof to show that Quine's theory of predication and referential transparency must fail. The purpose of this collection is to bring an important body of work to the attention of a new generation of professional philosophers, computer scientists and mathematicians.

New Essays on Tarski and Philosophy aims to show the way to a proper understanding of the philosophical legacy of the great logician, mathematician, and philosopher Alfred Tarski (1902-1983). The contributors are an international group of scholars, some expert in the historical background and context of Tarski's work, others specializing in aspects of his philosophical development, others more interested in understanding Tarski in the light of contemporary thought. The essays can be seen as addressing Tarski's seminal treatment of four basic questions about logical consequence. (1) How are we to understand truth, one of the notions in terms of which logical consequence is explained? What is it that is preserved in valid inference, or that such inference allows us to discover new claims to have on the basis of old? (2) Among what kinds of things does the relation of logical consequence hold? (3) Given answers to the first two questions, what is involved in the consequence relationship itself? What is the preservation at work in 'truth preservation'? (4) Finally, what do truth and consequence so construed have to do with meaning?

In this exciting new collection, a distinguished international group of philosophers contribute new essays on central issues in philosophy of language and logic, in honor of Michael Dummett, one of the most influential philosophers of the late twentieth century. The essays are focused on areas particularly associated with Professor Dummett. Five are contributions to the philosophy of language, addressing in particular the nature of truth and meaning and the relation between language and thought. Two contributors discuss time, in particular the reality of the past. The last four essays focus on Frege and the philosophy of mathematics. The volume represents some of the best work in contemporary analytical philosophy.