According to a standard account of evidence, one piece of information is stronger evidence for an hypothesis than is another iff the probability of the hypothesis on the one is greater than it is on the other. This condition, I argue, is neither necessary nor sufficient because various factors can strengthen the evidence for an hypothesis without increasing (and even decreasing) its probability. Contrary to what probabilists claim, I show that this obtains even if a probability function can take these evidential factors into account in ways they suggest and yield a unique probability value. Nor will the problem be solved by appealing to second-order probabilities.

This paper argues that when used judiciously Bayes's law has a role to play in the evaluation of scientific hypotheses. Several examples are presented in which a rational response to evidence requires a judgement whether to apply Bayes's law or whether, for example, to redistribute prior probabilities. The paper concludes that reflection on Bayes's law illustrates how an adequate account of the rational evaluation of hypotheses requires an account of judgement—a point which several philosophers have noted despite few attempts to develop an adequate theory of judgement.

In this paper we critically review the various attempts that have been made to understand quantum field theory. We focus on Teller's (1990) harmonic oscillator interpretation, and Bohm et al.'s (1987) causal interpretation. The former unabashedly aims to be a purely heuristic account, but we show that it is only interestingly applicable to the free bosonic field. Along the way we suggest alternative models. Bohm's interpretation provides an ontology for the theory—a classical field, with a quantum equation of motion. This too has problems; it is not Lorentz invariant.

“Accessibility” is a crucial concept of possible worlds semantics. The simplest approach to accessibility is the “magical theory” that construes this relation as analogous to spatial or temporal relations. In this paper I give a nonmagical structural account of the accessibility relation that can be used to give a necessitarian account of kinds and laws. Laws are characterized in a structural way as stable invariants of the world's gestalt. Finally, I point out how the structural approach can be embedded in a general representational theory of modality.

This paper examines the nomic covariationist strategy of using idealization to define representation. While the literature has focused upon the possibility of defining ideal conditions for perception, I argue that nomic covariationist appeals to idealization are pseudoscientific and contrary to a foundational and empirically well-supported methodological presupposition in cognitive science. Moreover, one major figure in this camp fails to come to grips with its role and its problems in mainstream science. Thus he forwards a false dichotomy of the sciences and treats idealization as a blank check written by scientists on an unknown bank. Finally, I consider and reject alternative formulations of the nomic covariationist's idealization strategy.

This paper proposes an explanation in terms of three kinds of freedom, first for the special efficacy of science in general and then for why such efficacy has been more impressive in the natural than the social sciences. This explanation thus complements “post-positivist” interpretations of science which argue that science's effectiveness cannot be accounted for by fundamental epistemic differences from other kinds of discourse. My explanation tries to say what is responsible for science's effectiveness, in purely nonepistemic, sociological terms. All of the three kinds of freedom have so far been denied to most other forums, including in particular nations' populations taken overall. And one of these freedoms, while now allowed to the natural sciences, is still denied to the social sciences.

In a series of important papers, A. Fine has developed and defended the view that the proper reading of scientific practice is neither realist nor antirealist. Instead, he argues that realism and antirealism both add something extra to a core position which is neither. In this discussion I reexamine his claim in the light of some criticisms. Fine's position contains an important insight, but to draw that point out requires shifting the way in which Fine poses the argument. I do so by examining an argument by H. Stein.

The general context of this paper is the locality problem in quantum theory. In a recent issue of this journal, Rédei (1991) offered a proof of the proposition that algebraic Lorentz-covariant quantum field theory is past stochastic Einstein local. We show that Rédei's proof is either spurious or circular, and that it contains two deductive fallacies. Furthermore, we prove that the mentioned theory meets the stronger condition of stochastic Haag locality.

Sober (1992) has recently evaluated Brandon's (1982, 1990; see also 1985, 1988) use of Salmon's (1971) concept of screening-off in the philosophy of biology. He critiques three particular issues, each of which will be considered in this discussion.