This major work challenges some widely held positions in epistemology - those of Peirce and Popper on the one hand and those of Quine and Kuhn on the other.

"[This book] proposes new foundations for the Bayesian principle of rational action, and goes on to develop a new logic of desirability and probabtility."—Frederic Schick, _Journal of Philosophy_.

This comprehensive discussion of the problem of rational belief develops the subject on the pattern of Bayesian decision theory. The analogy with decision theory introduces philosophical issues not usually encountered in logical studies and suggests some promising new approaches to old problems."We owe Professor Levi a debt of gratitude for producing a book of such excellence. His own approach to inductive inference is not only original and profound, it also clarifies and transforms the work of his predecessors. In short, the (...) book deserves to become a classic....There is a great deal of interest in the book besides these basic matters [forumlating rules of acceptance]. Some of the most interesting chapters are those that examine the implications of such rules. The discussions of probability, generalization, and various forms of inference are brilliant and enlightening. Indeed, the problems and methods elaborated by Professor Levi in his book serve as a new foundation for the study of inductive inference."--Keith Lehrer, Nous"Levi's book is an extremely interesting report on 'tentative and speculative first steps' toward a decision-theoretic approach to inductive inference....Professor Levi is to be congratulated on his ingenious development and application of this approach...."--Richard C. Jeffrey, The Journal of Philosophy. (shrink)

Nothing seems to follow strictly from 'X believes that p'. But if we reinterpret it to mean: 'X can consistently be described as consistently believing p'--which roughly renders, I think, Hintikka's notion of "defensibility"--we can get on with the subject, freed from the inhibitions of descriptive adequacy. But defensibility is neither necessary nor sufficient for truth: it tells us little, therefore, about the concept of belief on which it is based. It cannot, in particular, specify necessary conditions for the consistent (...) ascription of belief--as opposed to rational belief. If there are no such conditions, all belief ascriptions must be treated as atomic: which is implausible. If there are some, they must be settled on before an account of consistency can be complete. The reason is simple: it is that we have beliefs about our own beliefs. A set of first order beliefs is consistent if they can all be true together; but it is a lesson of Moore's paradox that consistency of second-order beliefs requires additional constraints. If someone both believes that p and that he does not believe that p, the propositions he believes might all be true together, yet he is inconsistent. And the characterization of second order consistency will remain incomplete, so long as nothing is said about the consistency of first order belief ascriptions. Suppose someone says and believes: "I am inconsistent: I believe both p and ~p." This is "indefensible": but is it insight, or nonsense? Breast-beating of this sort is guaranteed success: something he believes is bound to be false. But that remains diagnostically frustrating: is he inconsistent because what he said is true, or on the contrary because it is inconsistent? (shrink)

In "The Logical Structure of Linguistic Commitment I" (The Journal of Philosophical Logic 23 (1994), 369-400), we sketch a linguistic theory (inspired by Brandom's Making it Explicit) which includes an "expressivist" account of the implication connective, →: the role of → is to "make explicit" the inferential proprieties among possible commitments which proprieties determine, in part, the significances of sentences. This motivates reading (A → B) as "commitment to A is, in part, commitment to B". Our project is to study (...) the logic of →. LSLC I approximates (A → B) as "anyone committed to A is committed to B", ignoring issues of whether A is relevant to B. The present paper includes considerations of relevance, motivating systems of relevant commitment entailment related to the systems of commitment entailment of LSLC I. We also consider the relevance logics that result from a commitment reading of Fine's semantics for relevance logics, a reading that Fine suggests. (shrink)