The history of contemporary modal logic dates back to the writings of C. S. Lewis in the early part of this century. Since then, a growing body of literature has attested to professional interest in the area, and in a number of related issues in philosophical logic which have received wide attention. The recent development of powerful formal techniques for modal system building, together with an increasing interest in modal logic as a tool for philosophical analysis, have created a need (...) for an up-to-date text to introduce students to this material. Snyder's book attempts to answer this need. Assuming an understanding of elementary propositional logic, Snyder introduces a reductive technique called cancellation for detecting the theorems of a system of logic. This technique, analogous to the construction of Smullyan trees but more compact, is extended to modal and quantified contexts. Cancellation versions of the systems M and Mn of G. H. von Wright, and S4 and S5 of Lewis are developed. Snyder uses a Hintikka type of semantics, showing how the various formal systems are differentiated at the semantic level by differing conditions which must be imposed on the model systems used as interpretations for them. These model systems, and the conditions imposed upon them, are in turn described by means of a metalanguage which is essentially first-order quantificational logic. The power of this technique stems from the fact that for every object language formula of a system, there is a corresponding formula in the metalanguage which describes the conditions an interpretation must meet in order to satisfy the original formula. The conditions that the interpretations of a given system of logic must meet are reflected in this metalanguage as "antecedent assumptions," and these in turn correspond to cancellation rules for the object language. This correspondence is constructed in such a way that the metalinguistic counterpart of each theorem of the system will be a theorem of first-order logic. Snyder's primary interest is in showing how modal logic can be used, with the help of these techniques, to build a large variety of formal systems and to "tailor" such systems to meet a variety of analytical tasks. Simple modal systems are developed for the articulation of a number of modal concepts, in addition to the classic alethic ones. Examples are taken from temporal, deontic, and epistemic logic to show how specific interpretations of the meanings of the relevant operators lead to the incorporation of appropriate conditions in the formal systems used to articulate them. An entire chapter is devoted to a discussion of the paradoxes of material and strict implication, and to an attempt to articulate the notion of entailment through the development of formal systems which include a dyadic modal operator that is free of these paradoxes. The final chapter discusses such classical issues as proper names, reference, fictional entities, definite descriptions, and existence presuppositions. Appendices deal with such matters as the equivalence of the cancellation systems to more classical axiomatic-deduction systems, and the sketch of a proof of soundness and completeness for all the modal systems presented. While designed as a text, this volume should be of interest to both logicians and those working in metaphysics and language analysis, since the primary concern of the author is to develop techniques that will facilitate the usefulness of modal logic as a tool for philosophical analysis. The instructor's manual contains many suggestions derived from the author's experience in teaching this non-standard treatment of the subject.--K. T. (shrink)

Prior apparently left a substantially completed manuscript dealing with the objects of thought when he died in 1969. Geach and Kenny have edited this material, supplementing it with both published and unpublished other writings, including an appendix on names in lieu of Prior's intended final chapter. The result is an interesting, often non-standard, discussion of many issues central to philosophical logic. There are two major concerns treated--what is it that we think?, and what is it that we think about?. These (...) are the two principle ways in which 'thinking of' can occur as a relation for Prior. An examination of the first sense results in a defense of the view that propositions, as language-independent logical constructions, are the objects of thought. In doing so, a large number of related issues are discussed to include criticisms of extentionalist [[sic]] theses, a sympathetic version of the assertive redundancy theory of truth, and an account of non-assertoric logic. Prior also devotes chapters to paradoxes such as that of the liar, and to Tarskian and alternative semantics. Perhaps the most interesting section of the book is that devoted to discussing what sentences are about, especially when their ostensible subjects are non-existent, e.g., "The King of France is bald." It is not clear just what his positive views are, but Prior has a number of criticisms directed against current intentionalistic views of names as well as against Russellian names. His chief worry seems to concern oratio obliqua constructions in which a reporter does not believe in the existence of that of which/whom a reportee speaks. Although critical of writers influenced by either the early Brentano or the later Russell, Prior appears to be sympathetic to both schools in that he seems to view non-demonstrative sentences as never being directly about their subjects. Thus, neither "Gustavus is bald" nor "The King of Sweden is bald" would be about the King of Sweden, i.e., Gustavus. However, since Gustavus is the King of Sweden, the sentences are indirectly about him. Presumably, such a move precludes a reporter's being committed to the reportee's ontology, thereby avoiding the difficulty. An interesting but undeveloped aspect of his view is the role of background stories in our use of names. While some use is made of formal logic in the Polish notation, unfamiliarity with either is not a bar to following the text as English translations and keys are provided. It is unfortunate that we cannot look forward to further elucidation of Prior's views.--K. T. (shrink)

Despite the title, some of the essays are devoted to matters which are not strictly epistemological. Both Malcolm and Stoutland are concerned with accounting for the connection between intention and the object of intention. Malcolm reviews Wittgenstein's thoughts on the subject while Stoutland gives an account of intentions in terms of teleology. With an eye toward the free will and skepticism controversies, White attempts an account of "What Might Have Been," distinguishing between existential and problematic possibilities. The remaining essays delve (...) into the topics of traditional epistemology. Oliver gives "A Sober Look at Solipsism" focussing attention on its 'causal' and 'privacy' postulates. Taking up the challenge of skepticism, Unger argues that "Our Knowledge of the Material World" not only is a reality, but is a function of our immediate experience. We can't help but believe such experiences, just as dogs must. The attempt is made by Pollock to map out "The Structure of Epistemic Justification" and he eschews a deductive model of explanation in favor of showing that logical reasons are but one kind of good reason--good reasons being the stuff of justification. Knox argues that "Do Appearances Exist?" deserves an affirmative answer as a consequence of the fact that we perceive objects, given his treatment of appearances as events. This is an interesting collection of essays, albeit for the non-subscriber, an expensive one.--K. T. (shrink)

The double issue of Synthese devoted to essays on the work of W. V. Quine has been re-issued under hard cover with an additional paper by Grice on "Vacuous Names" and a 13-page bibliography of Quine's writings. With the exception of Berry's "Logic with Platonism" and Jensen's "On The Consistency of a Slight. Modification of Quine's New Foundation," the papers are concerned with the key issues of Word and Object. Quine's responses to each of the contributors are not as helpful (...) as they might be, but are at times quite illuminating. He dispels Stenius's view in "Beginning with Ordinary Things" that Quine holds a Russellian epistemology, for example, and clarifies somewhat his account of ontic commitment in replying to Hintikka's "Behavioral Criteria of Radical Translation." Hintikka argues that "to be is to be a value of a bound variable" presupposes the principle, "to be is to be an object of search." Quine rejects this view, identifying his ontology with the range of the variables as opposed to the class of all things to which a theory is ontically committed. The introduction to chapter two of Word and Object by Harman is quite helpful, suggesting among other things that Quine's use of 'propositional attitude' is a misnomer to be better replaced by 'sentential attitude'. An interesting and provocative paper by Kaplan offers a Fregean alternative to Quine's general mode of handling referentially opaque contexts, allowing "Quantifying In" with the variable ranging over expressions. Interestingly enough, Quine's remarks are rather laudatory and sympathetic. Davidson's "On Saying That" suggests a roughly similar account of oratio obliqua discourse. Føllesdal and Sellars discuss "Quine on Modality" and "Some Problems about Belief." There is a discussion of "Quine's Philosophy of Science" by Smart, tracing a shift from instrumentalism to realism on the part of Quine. Also included are papers by Chomsky, Stroud, and Geach, as well as Strawson's familiar "Singular Terms and Predication." In spite of the imposing price and the uneven quality of the essays, the book is a desirable piece of Quineana.--K. T. (shrink)