What is not often noted about Bas van Fraassen's distinctive approach to the scientific realism issue is that constructive empiricism, as he defines it, seems to involve a distinctively realist stance in regard to large parts of natural science. This apparent defection from the ranks of his more uncompromisingly anti-realist colleagues raises many questions. Is he really leaning to realism here? If he is, why is this not more widely noted? And, more important, if he is, is he entitled to this shyly realist concession? Does his many-pronged attack on what he sees as the main arguments in support of realism leave him with the wherewithal?

Constructive empiricism is indeed set squarely within a common sense realism that was foreign to much of the empiricist tradition. But I do not see this common sense realism, which I take myself to share with many scientific realists, as harboring or leading to scientific realism. That is in part because of the way I separate the opposition between empiricist and realist understanding of science from other issues that divide us in epistemology. This discussion brought to light our quite different conceptions of what is at issue between empiricists and realists in this area. After a response to McMullin's critique, however, I will be especially concerned to respond to his challenging proposal for a shift in the debate over realism concerning the sciences.

The idea that the use of instruments in science is theory-dependent seems to threaten the extent to which the output of those instruments can act as an independent arbiter of theory. This issue is explored by studying an early use of the electron microscope to observe dislocations in crystals. It is shown that this usage did indeed involve the theory of the electron microscope but that, nevertheless, it was possible to argue strongly for the experimental results, the theory of dislocations being tested, and the theory of the instrument, all at the same time.

Advocates of the conserved quantity (CQ) theory of causation have their own peculiar problem with conservation laws. Since they analyze causal process and interaction in terms of conserved quantities that are in turn defined as physical quantities governed by conservation laws, they must formulate conservation laws in a way that does not invoke causation, or else circularity threatens. In this paper I will propose an adequate formulation of a conservation law that serves CQ theorists’ purpose.

This paper distinguishes and critiques several forms of pluralism about the levels of selection, and introduces a novel way of thinking about the biological properties and processes typically conceptualized in terms of distinct levels. In particular, “levels” should be thought of as being entwined or fused. Since the pluralism discussed is held by divergent theorists, the argument has implications for many positions in the debate over the units of selection. And since the key points on which the paper turns apply beyond this specific issue, the paper may prove of general interest in thinking about the metaphysics of science

I elaborate and defend an interpretation of Leibniz on which he is committed to a stronger space-time structure than so-called Leibnizian space-time, with absolute speeds grounded in his concept of force rather than in substantival space and time. I argue that this interpretation is well-motivated by Leibniz's mature writings, that it renders his views on space, time, motion, and force consistent with his metaphysics, and that it makes better sense of his replies to Clarke than does the standard interpretation. Further, it illuminates the way in which Leibniz took his physics to be grounded in his metaphysics.

In this paper I consider two objections raised by Nick Smith (1997) to an argument against the probability of time travel given by Paul Horwich (1995, 1987). Horwich argues that time travel leads to inexplicable and improbable coincidences. I argue that one of Smith's objections fails, but that another is correct. I also consider an instructive way to defend Horwich's argument against the second of Smith's objections, but show that it too fails. I conclude that unless there is something faulty in the conception of explanation implicit in Horwich's argument, time travel presents us with nothing that is inexplicable.

This essay explores the nature of spontaneous symmetry breaking (SSB) in connection with a cluster of interrelated concepts such as Curie's symmetry principle, ergodicity, and chance and stability in classical systems. First, a clarification of the two existing senses of SSB is provided and an argument developed for a proposal for SSB, in which not only the possibilities but also the actual breakings are referred to. Second, a detailed analysis is given of classical SSB that answers the questions: (i) how we are justified in regarding it as a matter of chance, and (ii) why the breakings in it are equally probable. The answer provides some support to the applicability of ergodicity in special systems (such as ours).

At the center of quantum chaos research is a particular family of models known as quantum maps. These maps illustrate an important “horizontal” dimension to model construction that has been overlooked in the literature on models. Three ways in which quantum maps are being used to clarify the relationship between classical and quantum mechanics are examined. This study suggests that horizontal models may provide a new and fruitful framework for exploring intertheoretic relations.