In this paper we investigate Accardi's claim that the “quantum paradoxes” have their roots in probability theory and that, in particular, they can be evaded by giving up Bayes' rule, concerning the relation between composite and conditional probabilities. We reach the conclusion that, although it may be possible to give up Bayes' rule and define conditional probabilities differently, this contributes nothing to solving the philosophical problems which surround quantum mechanics.

In his paper, “Explanations of Irrelevance” (1983), Paul Horwich proposes an amended version of hypothetico-deductivism, (H-D*). In this discussion note it is shown that (H-D*) has the consequence that “A is a non-black raven” confirms “All ravens are black” relative to any tautology! It is noted that Horwich's (H-D*) bears a strong resemblance to Hempel's prediction criterion of confirmation and that the prediction criterion faces the same obstacle. A related problem for hypothetico-deductivism in its simplest form—that is, E confirms H iff E is an (observational) consequence of H—is displayed. The discussion concludes with a suggestion about how (H-D*) and simple hypothetico-deductivism might be amended in order to avoid these results.

Suppose my utilities are representable by a set of utility assignments, each defined for atomic sentences; suppose my beliefs are representable by a set of probability assignments. Then each of my utility assignments together with each of my probability assignments will determine a utility assignment to non-atomic sentences, in a familiar way. This paper is concerned with the question, whether I am committed to all the utility assignments so constructible. Richard Jeffrey (1984) says (in effect) “no”, Isaac Levi (1974) says “yes”. I argue for “no”, and raise in passing a problem for Levi.

Previous articles on Russell's hypothesis and on criteria for scientific explanations are used as a springboard for analyzing some modern trends in science. Specifically, recent suggestions of the concept of “creation from nothing” in Big-Bang cosmology are compared to Russell's hypothesis, in light of James Woodward's criteria for an explanation purporting to be scientific. The discussion is then extended to the broader question of the direction of scientific theorizing, through examples showing that one generation's science may not build conformably upon the mindset of the previous generation.

Historians of relativity theory have puzzled over the fact that, while Einstein regarded Ernst Mach as his chief philosophical mentor, Mach himself publicly rejected relativity in the preface to Die Prinzipien der physikalischen Optik. This work was first published by Mach's son Ludwig in 1921, five years after Mach's death, but the preface is dated “July 1913”, when Einstein was working on general relativity and believing not only that he had Mach's “friendly interest” and support, but also that his project was the working-out of some of Mach's suggestions. To Einstein, whose sympathy for Mach's overall philosophy of science had already begun to wane by 1921, the posthumous appearance of the preface seemed to underscore the inconsistency between Machian positivism and his own program to construct an abstract and geometrical physics; this interpretation appears in important modern analyses like Blackmore (1972), Holton (1988), and Zahar (1989), and it has frequently served the purposes of the philosophical reaction against logical positivism in general. Now Gereon Wolters' book (translation: Mach I, Mach II, Einstein, and the Theory of Relativity. A Forgery and its Consequences) challenges the usual interpretation with a startling claim: that Ernst Mach never wrote the preface, which in fact is a forgery by his son Ludwig. The words “A Forgery and its Consequences” suggest the sweeping consequences that the preface has had for our understanding of the relation between Mach and Einstein; the point of the book is not only to document the dramatic story of the forgery, but also to defend an equally sweeping reconsideration, indeed a rehabilitation, of Mach's philosophy and its role in the history of relativity.