This collection of essays was compiled for the occasion of Nuel Belnap's 60th birthday.

"This book is valuable as expounding in full a theory of meaning that has its roots in the work of Frege and has been of the widest influence.

In spite of a powerful tradition, more than two thousand years old, that in a valid argument the premises must be relevant to the conclusion, twentieth-century logicians neglected the concept of relevance until the publication of Volume I of this monumental work. Since that time relevance logic has achieved an important place in the field of philosophy: Volume II of Entailment brings to a conclusion a powerful and authoritative presentation of the subject by most of the top people working in (...) the area. Originally the aim of Volume II was simply to cover certain topics not treated in the first volume--quantification, for example--or to extend the coverage of certain topics, such as semantics. However, because of the technical progress that has occurred since the publication of the first volume, Volume II now includes other material. The book contains the work of Alasdair Urquhart, who has shown that the principal sentential systems of relevance logic are undecidable, and of Kit Fine, who has demonstrated that, although the first-order systems are incomplete with respect to the conjectured constant domain semantics, they are still complete with respect to a semantics based on "arbitrary objects." Also presented is important work by the other contributing authors, who are Daniel Cohen, Steven Giambrone, Dorothy L. Grover, Anil Gupta, Glen Helman, Errol P. Martin, Michael A. McRobbie, and Stuart Shapiro. Robert G. Wolf's bibliography of 3000 items is a valuable addition to the volume. (shrink)

We critically investigate and refine Dunn's relevant predication, his formalisation of the notion of a real property. We argue that Dunn's original dialectical moves presuppose some interpretation of relevant identity, though none is given. We then re-motivate the proposal in a broader context, considering the prospects for a classical formalisation of real properties, particularly of Geach's implicit distinction between real and ''Cambridge'' properties. After arguing against these prospects, we turn to relevance logic, re-motivating relevant predication with Geach's distinction in mind. (...) Finally we draw out some consequences of Dunn's proposal for the theory of identity in relevance logic. (shrink)

Models are constructed for a variety of systems of quantified relevance logic with identity. Models are given for systems with different principles governing the transitivity of identity and substitution, and the relative merits of these principles are discussed. The models in this paper are all extensions of the semantics of Fine's Semantics for Quantified Relevance Logic (Journal of Philosophical Logic 17 (1988)).

This paper reformulates and decides a certain conjecture in Dunn's 'Relevant Predication 1: The Formal Theory' (Journal of Philosophical Logic 16, 347-381, 1987). This conjecture of Dunn's relates his object-language characterisation of a property's being relevant in a variable x to certain grammatical characterisations of relevance, analogous to some given by Helman, in 'Relevant Implication and Relevant Functions' (to appear in Entailment: The Logic of Relevance and Necessity, vol. 2, by Alan Ross Anderson, Nuel Belnap, and J. Michael Dunn et (...) al.) In the course of the investigation this paper also investigates Kit Fine's semantics for quantified relevance logics, which appears in his appropriately titled 'Semantics for Quantified Relevance Logics'. (shrink)

There is an intuition, notoriously difficult to formalise, that only some predicates express real properties. J. M. Dunn formalises this intuition with relevance logic, proposing a notion of relevant predication. For each first order formula Ax, Dunn specifies another formula that is intuitively interpreted as "Ax expresses a real property". Chapter I calls such an approach an object language approach, since the claim that Ax expresses a real property is rendered as a formula in the object language. On a metalanguage (...) approach, on the other hand, the claim that Ax expresses a real property would be metalinguistic, mentioning but not using the formula Ax. ;Our Introduction begins by investigating Dunn's motivation for relevant predication, and argues that it implicitly presupposes some interpretation of identity. Indeed, part of the dissertation's work is to use relevant predication as a key to a coherent account of relevant identity. ;Chapter I re-motivates relevant predication. We consider P. Geach's distinction between real and "Cambridge" change, and suggest that there is an underlying distinction between real and Cambridge predicates. We further argue that no classical object language approach can formalise this distinction. So we turn to relevance logic, remotivating relevant predication, with Geach's distinction in mind. ;In light of this new motivation, we argue that relevant prediction relies on a logically weak notion of identity, according to which "x = y" means "x and y share all relevant properties". Identity is taken up in a more technical setting in Chapters IV and V. ;Subsequent chapters investigate technical issues that flow from Chapter I. Chapter II investigates metalinguistic grammatical characterisations of relevant predication. Chapter III concerns the semantics of first order relevance logic. Chapter IV investigates the identity in R and its relationship to relevant predication. In particular, Chapter IV argues against introducing the axiom, $\to$ Ay), in relevance logic, since the resulting systems are unstable, in a sense motivated by the notion of relevant identity underlying Dunn's notion of relevant predication. Finally Chapter V investigates the possibility of a coherent theory of identity in R's modal relatives ${\bf R}\sp\square$ and E. (shrink)

This collection of nine papers brings together Many of Geach's thoughts on such wide topics as resurrection, deductive proof of the existence of God, God's role in ethics, materialism, and the relation of time and prayer. The first three papers are concerned with the survival of death and what form such a survival might take. This includes Geach's argument against materialism in "What Do We Think With?" Two further papers are concerned with arguments about existence, and the remaining papers concern (...) natural theology. (shrink)