People have always been interested in numbers, in particular the natural numbers. Of course, we all have an intuitive notion of what these numbers are. In the late 19th century mathematicians, such as Grassmann, Frege and Dedekind, gave definitions for these familiar objects. Since then the development of axiomatic schemes for arithmetic have played a fundamental role in a logical understanding of mathematics. There has been a need for some time for a monograph on the metamathematics of first-order arithmetic. The (...) aim of the book by Hajek and Pudlak is to cover some of the most important results in the study of a first order theory of the natural numbers, called Peano arithmetic and its fragments (subtheories). The field is quite active, but only a small part of the results has been covered in monographs. This book is divided into three parts. In Part A, the authors develop parts of mathematics and logic in various fragments. Part B is devoted to incompleteness. Part C studies systems that have the induction schema restricted to bounded formulas (Bounded Arithmetic). One highlight of this section is the relation of provability to computational complexity. The study of formal systems for arithmetic is a prerequisite for understanding results such as Gödel's theorems. This book is intended for those who want to learn more about such systems and who want to follow current research in the field. The book contains a bibliography of approximately 1000 items. (shrink)

About twenty-five years ago, Charles Parsons published a paper that began by asking why we still discuss the Liar Paradox. Today, the question seems all the more apt. In the ensuing years we have seen not only Parsons’ work (1974), but seminal work of Saul Kripke (1975), and a huge number of other important papers. Too many to list. Surely, one of them must have solved it! In a way, most of them have. Most papers on the Liar Paradox offer (...) some explanation of the behavior of paradoxical sentences, and most also offer some extension for the predicate ‘true’ that they think is adequate, at least in some restricted setting. But if this is a solution, then the problem we face is far from a lack of solutions; rather, we have an overabundance of conflicting ones. Kripke’s work alone provides us with uncountably many different extensions for the truth predicate. Even if it so happens that one of these is a conclusive solution, we do not seem to know which one, or why. We should also ask, given that we are faced with many technically elegant but contradictory views, if they are really all addressing the same problem. What we lack is not solutions, but a way to compare and evaluate the many ones we have. (shrink)

I define T-schema deflationism as the thesis that a theory of truth for our language can simply take the form of certain instances of Tarski's schema (T). I show that any effective enumeration of these instances will yield as a dividend an effective enumeration of all truths of our language. But that contradicts Gödel's First Incompleteness Theorem. So the instances of (T) constituting the T-Schema deflationist's theory of truth are not effectively enumerable, which casts doubt on the idea that the (...) T-schema deflationist in any sense has a theory of truth. (The argument in section 2 of "Semantics for Deflationists" supercedes this paper.). (shrink)

In a number of influential articles published since 1972, Dorothy Grover has developed the prosentential theory of truth. Brought together and published with a new introduction, these essays are even more impressive as a group than they were as single contributions to philosophy and linguistics. Denying that truth has an explanatory role, the prosentential theory does not address traditional truth issues like belief, meaning, and justification. Instead, it focuses on the grammatical role of the truth predicate and asserts that “it (...) is true” is a prosentence, functioning much as a pronoun does. Grover defends the theory by indicating how it can handle notorious paradoxes like the Liar, as well as by analyzing some English truth-usages. The introduction to the volume surveys traditional theories of truth, including correspondence, pragmatic, and coherence theories. It discusses the essays to come and, finally, considers the implications of the prosentential theory for other theories. Despite the fact that the prosentential theory dismisses the “nature of truth” as a red herring, Grover shows that there are important aspects of traditional truth theories that prosentential theorists have the option of endorsing. (shrink)