Genetic differences can lead to phenotypic differences either directly or indirectly (via causing differences in external environments, which then affect phenotype). This possibility of genetic effects being mediated by environmental influences is often used by scientists and philosophers to argue that heritability is not a very helpful causal or explanatory notion. In this paper it is shown that these criticisms are based on serious misconceptions about methods of behavior genetics.

We discuss the intertwined topics of Fulling non-uniqueness and the Unruh effect. The Fulling quantization, which is in some sense the natural one for an observer uniformly accelerated through Minkowski spacetime to adopt, is often heralded as a quantization of the Klein-Gordon field which is both physically relevant and unitarily inequivalent to the standard Minkowski quantization. We argue that the Fulling and Minkowski quantizations do not constitute a satisfactory example of physically relevant, unitarily inequivalent quantizations, and indicate what it would take to settle the open question of whether a satisfactory example exists. A popular gloss on the Unruh effect has it that an observer uniformly accelerated through the Minkowski vacuum experiences a thermal flux of Rindler quanta. Taking the Unruh effect, so glossed, to establish that the notion of particle must be relativized to a reference frame, some would use it to demote the particle concept from fundamental status. We explain why technical results do not support the popular gloss and why the attempted demotion of the particle concept is both unsuccessful and unnecessary. Fulling non-uniqueness and the Unruh effect merit attention despite these negative verdicts because they provide excellent vehicles for illustrating key concepts of quantum field theory and for probing foundational issues of considerable philosophical interest.

In much recent work, invariance under intervention has become a hallmark of the correctness of a causal-law claim. Despite its importance this thesis generally is either simply assumed or is supported by very general arguments with heavy reliance on examples, and crucial notions involved are characterized only loosely. Yet for both philosophical analysis and practicing science, it is important to get clear about whether invariance under intervention is or is not necessary or sufficient for which kinds of causal claims. Furthermore, we need to know what counts as an intervention and what invariance is. In this paper I offer explicit definitions of two different kinds for the notions intervention, invariance, and causal correctness. Then, given some natural and relatively uncontroversial assumptions, I prove two distinct sets of theorems showing that invariance is indeed a mark of causality when the concepts are appropriately interpreted.

In this paper I examine a dispositional property that has been receiving increased attention in biology, evolvability. First, I identify three compatible but distinct investigative approaches, distinguish two interpretations of evolvability, and treat the difference between dispositions of individuals versus populations. Second, I explore the relevance of philosophical distinctions about dispositions for evolvability, isolating the assumption that dispositions are intrinsically located. I conclude that some instances of evolvability cannot be understood as purely intrinsic to populations and suggest alternative strategies for resolving this difficulty.

Lawrence Sklar in his book, Physics and Chance (1993), proposes a sophisticated account of reduction of thermodynamics (TD) by statistical mechanics (SM). I argue that Sklar's analysis of the alleged reduction of TD by SM is problematic in several respects. I consider a few counterexamples to show that none of what Sklar takes to be the central features of successful reduction in science (unification and identification) holds in the case of TD and SM. I suggest the broader conclusion that a more useful way of understanding the relationship between TD and SM is as collaboration and competition among alternative methodologies rather than reduction of one theory to another.

This is a review essay about David Corfield and Jon Williamson's anthology Foundations of Bayesianism. Taken together, the fifteen essays assembled in the book assess the state of the art in Bayesianism. Such an assessment is timely, because decision theory and formal epistemology have become disciplines that are no longer taught on a routine basis in good philosophy departments. Thus we need to ask: Quo vadis, Bayesianism? The subjects of the articles include Bayesian group decision theory, approaches to the concept of probability, Bayesian approaches in the philosophy of mathematics, reflections on the relationship between causation and probability, the Independence axiom, and a range of criticisms of Bayesianism, among other subjects. While critical of some of the arguments presented in the articles, this review recommends Corfield and Williamson's volume to anyone who is trying to stay abreast of Bayesian research.

Classical mechanics is empirically successful because the probabilistic mean values of quantum mechanical observables follow the classical equations of motion to a good approximation (Messiah 1970, 215). We examine this claim for the one-dimensional motion of a particle in a box, and extend the idea by deriving a special case of the ideal gas law in terms of the mean value of a generalized force used to define “pressure.” The examples illustrate the importance of probabilistic averaging as a method of abstracting away from the messy details of microphenomena, not only in physics, but in other sciences as well.