Jeffrey has devised a probability revision method that increases the probability of hypothesis H when it is discovered that H implies previously known evidence E. A natural extension of Jeffrey's method likewise increases the probability of H when E has been established with sufficiently high probability and it is then discovered, quite apart from this, that H confers sufficiently higher probability on E than does its logical negation H̄.

Preface. Almost fifty years ago, in 1948, when I was an undergraduate at Queens College in New York and a student of Carl G. Hempel's, I received from his hands an offprint of his now-classic but then just-published paper “Studies in the Logic of Explanation”, written in collaboration with Paul Oppenheim and then just published in Philosophy of Science (15[1948], pp. 135–75).1 This paper greatly impressed me—and I was not alone. We have here one of those unusual publications that sets the agenda for a whole generation of investigators. It set in train an enormous body of discussions and publications which shaped the course of deliberations about scientific explanation over the next decades—an effort to which my own work also made some contributions. (This literature and its inherent dialectic has been examined and analyzed in close and interesting detail in Wesley Salmon's fine survey of Four Decades of Scientific Explanation.2) However my present aim is not to consider what came out of the Hempel-Oppenheim paper but what went into it. I want, in sum, to consider the prehistory of that era of scientific explanation studies—and to look more closely at the background ramifications of this paper that launched a thousand others.

Motor imagery typically involves an experience as of moving a body part. Recent studies reveal close parallels between the constraints on motor imagery and those on actual motor performance. How are these parallels to be explained? We advance a simulative theory of motor imagery, modeled on the idea that we predict and explain the decisions of others by simulating their decision-making processes. By proposing that motor imagery is essentially off-line motor action, we explain the tendency of motor imagery to mimic motor performance. We close by arguing that a simulative theory of motor imagery gives (modest) support to and illumination of the simulative theory of decision-prediction.

Based on the historical case of galvanic experimentation in Germany, I identify five types of experimentation which explored and shaped the new phenomenon rather than tested theoretical predictions. Verification evaluated initial reports of Galvani's phenomenon. Simplification reduced the experimental protocol to the fewest and most basic steps. Optimization found experimental conditions that magnified the observed effect. Exploration tested a wide variety of metals, animals or configurations. Application modified the experiment to address unresolved related problems. Attempts to derive laws of the phenomenon or establish its underlying causes were unsuccessful primarily due to the great variability of the experimental results.

Thomas S. Kuhn's singular voice was stilled by cancer on June 17, 1996, some 49 years after his initial encounters with past science had drawn him into a career in the history and philosophy of science. One of the most widely-read and influential academics of the 20th century, Kuhn was educated at Harvard University, where he received an S.B. (summa cum laude) in Physics in 1943 and a Ph.D. in the subject in 1949. He remained there until 1956, first as a Junior Fellow in the Society of Fellows from 1948 to 1951, when he in effect retrained himself as a historian of science, and then as an Assistant Professor of General Education and History of Science. He joined the faculty of the University of California, Berkeley, in 1956, becoming Professor of History of Science in 1961. From 1964 to 1979 he was on the faculty of the History of Science Program of Princeton University, and from 1972 to 1979 also a member of the Institute for Advanced Study. He moved to the Department of Linguistics and Philosophy of Massachusetts Institute of Technology in 1979, where he became Professor Emeritus in 1991. He was President of the History of Science Society in 1968—70 and of the Philosophy of Science Association in 1988–90. He received the George Sarton Medal of the History of Science Society in 1982 and the John Desmond Bernal Award of the Society for the Social Studies of Science in 1983.

The method of positron emission tomography (PET imaging) illustrates the circular logic popular in subtractive neuroimaging and linear reductive cognitive psychology. Both require that strictly feed-forward, modular, cognitive components exist, before the fact, to justify the inference of particular components from images (or other observables) after the fact. Also, both require a “true” componential theory of cognition and laboratory tasks, before the fact, to guarantee reliable choices for subtractive contrasts. None of these possibilities are likely. Consequently, linear reductive analysis has failed to yield general, reliable, componential accounts.

Peter Railton (1978) has introduced the influential deductive-nomological-probabilistic (DNP) model of explanation which is the culmination of a tradition of formal, non-pragmatic accounts of scientific explanation. The other models in this tradition have been shown to be susceptible to a class of counterexamples involving intervening causes which speak against their sufficiency. This treatment has never been extended to the DNP model; we contend that the usual form of these counterexamples is ineffective in this case. However, we develop below a new version which overcomes these difficulties. Thus we claim that all of the models in this tradition, DNP included, have an equal status with respect to sufficiency.

Kenneth Schaffner has argued that evolutionary theory, strictly understood, cannot support the functional ascriptions used in adaptational functional explanations. Although the causal ascription clause in these ascriptions is supported, the goal-ascription clause cannot be, since it imports anthropocentric features deriving from a vulgar understanding of evolutionary theory. I argue that an etiological interpretation of selectional explanations sanctions both the causal and goal-ascription clauses of functional ascriptions and provides a way to understand teleological explanation within evolutionary biology.

New research tools such as PET can produce dramatic results. But they can also produce dramatic artifacts. Why is PET to be trusted? We examine both the rationale that justifies interpreting PET as measuring brain activity and the strategies for interpreting PET results functionally. We show that functional ascriptions with PET make important assumptions and depend critically on relating PET results to those secured through other research techniques.

The relationship between economics and the philosophy of natural science has changed substantially during the last few years. What was once exclusively a one-way relationship from philosophy to economics now seems to be much closer to bilateral exchange. The purpose of this paper is to examine this new relationship. First, I document the change. Second, I examine the situation within contemporary philosophy of science in order to explain why economics might have its current appeal. Third, I consider some of the issues that might jeopardize the success of this philosophical project.