The paper is inspired by the arguments raised recently by Grünbaum criticizing the current approaches of many cosmologists to the problem of spacetime singularity, matter creation and the origin of the universe. While agreeing with him that the currently favored cosmological ideas do not indicate the biblical notion of divine creation ex nihilo, I present my viewpoint on the same issues, which differs considerably from Grünbaum's. First I show that the symmetry principle which leads to the conservation law of energy is violated when the time axis is terminated at t = 0. Next I discuss why this epoch (t = 0) is more a mathematical artifact whose supposed significance may disappear when one goes beyond the classical relativistic cosmology. This is illustrated by the example of quantum cosmology.

This paper studies the extent to which probability functions are recursively definable. It proves, in particular, that the (absolute) probability of a statement A is recursively definable from a certain point on, to wit: from the (absolute) probabilities of certain atomic components and conjunctions of atomic components of A on, but to no further extent. And it proves that, generally, the probability of a statement A relative to a statement B is recursively definable from a certain point on, to wit: from the probabilities relative to that very B of certain atomic components and conjunctions of atomic components of A, but again to no further extent. These and other results are extended to the less studied case where A and B are compounded from atomic statements by means of “∀” as well as “~” and “&”. The absolute probability functions considered are those of Kolmogorov and Carnap, and the relative ones are those of Kolmogorov, Carnap, Rényi, and Popper.

Von Mises defined a “physical” probability as a strict limit of the relative frequency of occurrence of an event in repeated trials. As a result of a number of criticisms of von Mises's approach, the more favored approach became the “propensity” interpretation. It is argued here that this interpretation is not compelling and that the only problem in von Mises's approach is the assumption that the relative frequency converges in a strict sense. This problem is then remedied by deducing the axioms of probability theory from the assumption that the relative frequency converges only in the sense of the weak law of large numbers.

In trying to characterize the relationship between psychology and neuroscience, the trend has been to argue that reductionism does not work without suggesting a suitable substitute. I offer explanatory extension as a good model for elucidating the complex relationship among disciplines which are obviously connected but which do not share pragmatic explanatory features. Explanatory extension rests on the idea that one field can “illuminate” issues that were incompletely treated in another. In this paper, I explain how this “illumination” would work between psychology and neuroscience.

The goal of evolutionary theory is to (a) specify the general causal structure of evolving systems and (b) analyze evolutionary consequences that are expected to result from the proposed structure of the model systems. Biologists frequently emphasize the hypothetico-deductive method in evolutionary theory. I will show that this method primarily provides a tactical device for (b), while evolutionary synthesis requires a foundation of a unifying conceptual model for (a). Therefore, any successful strategy for a new synthesis requires both a new conceptual insight of evolving systems, and tactical devices for analyzing new specific aspects of the evolutionary process.

The work of Tversky, Kahneman and others suggests that people often make use of cognitive heuristics such as availability, salience and representativeness in their reasoning and decision making. Through use of a historical example—the recent plate tectonics revolution in geology—I argue that such heuristics play a crucial role in scientific decision making also. I suggest how these heuristics are to be considered, along with noncognitive factors (such as motivation and social structures) when drawing historical and epistemological conclusions. The normative perspective is community-wide, contextual, and instrumental.

Naturalism implies unity of method—an application of the methods of science to the methodology of science itself and to value theory. Epistemological naturalists have tried to find a privileged discipline to be the methodological model of philosophy of science and epistemology. However, since science itself is not unitary, the use of one science as a model amounts to a reduction and distorts the philosophy of science just as badly as traditional philosophy of science distorted science, despite the fact that the central theme of naturalized philosophy of science is that methodology should be true to science as practiced. I argue that naturalized philosophy of science must apply a plurality of methods to epistemological issues.

Various claims have been made, recently, that Darwin's argumentation in the Origin instantiates and so supports some general philosophical proposal about scientific theorizing, for example, the “semantic view”. But these claims are grounded in various incorrect analyses of that argumentation. A summary is given here of an analysis defended at greater length in several papers by the present author. The historical and philosophical advantages of this analysis are explained briefly. Darwin's argument comprises three distinct evidential cases on behalf of natural selection, cases, that is, for its existence, its adequacy and its responsibility. Theorizing, today, about evolution by natural selection involves a similar structure of evidential and explanatory concerns.

Kincaid argues that molecular biology provides little support for the reductionist program, that biochemistry does not reveal common mechanisms, indeed that biochemical theory obstructs discovery. These assertions clash with biologists' stated advocacy of reductionist programs and their claims about the consequent unity of experimental biology. This striking disagreement goes beyond differences in meaning granted to the terms. More significant is Kincaid's misunderstanding of what biochemists do, for a closer look at scientific practice— and one of Kincaid's examples—reveals substantial progress toward explaining biological function with biochemical models. With the molecular detail emerge unifying generalizations as well as further aspects of the functional processes.

The unanimity theory is an account of property-level causation requiring that causes raise the probability of their effects in specified test situations. Richard Otte (1981) and others have presented counterexamples in which one property is probabilistically sufficient for at least one other property. Given the continuing discussion (e.g., Cartwright 1989; Cartwright and Dupré 1988; Eells 1988a,b), many apparently think that these problems are minor. By considering the impact of Otte's cases on recent versions of the theory, by raising several new examples, and by criticizing natural replies, I argue that the problems for the unanimity theory are severe.

While discussing the work of Kuhn and Hanson, John Greenwood (1990) misidentifies the nature of the relationship between the incommensurability of theories and the theory-ladenness of observation. After pointing out this error, I move on to consider Greenwood's main argument that the Quine-Duhem thesis suffers from a form of epistemological self-defeat if it is interpreted to mean that any recalcitrant observation can always be accommodated to any theory. Greenwood finds this interpretation implausible because some adjustments to auxiliary hypotheses undermine too much of the prior observational evidence for the test theory. I argue that Greenwood mistakes the logico-metaphysical Quine-Duhem thesis for an epistemological one. All the argument he takes to undercut it actually illustrates how well the thesis works on a practical level. This is illustrated with an example from contemporary immunology.

According to a certain type of instrumentalist, we may have good reasons for accepting scientific theories, but never for believing more than their empirical consequences. Horwich (1991) considers several attempts to capture a difference between acceptance and belief, and claims that none of them succeed. He concludes that instrumentalism has not been shown to be a coherent position. However, in the course of his discussion, Horwich himself deploys a conceptual apparatus which is sufficient for formulating the instrumentalist doctrine in a coherent manner. The worst accusation that can be laid against instrumentalists is that they have violated common linguistic usage.

This discussion adjudicates a dispute between Larry Laudan and Gerald Doppelt over the nature of methodological rules. Laudan holds that all methodological rules are hypothetical imperatives, while Doppelt argues that a subset of those rules, basic methodological standards, are not hypothetical imperatives. I argue that neither writer offers a satisfactory account of methodological rules and that their reliance on the hypothetical/nonhypothetical distinction does not advance our understanding of methodological rules. I propose that we dispense with this dubious distinction and develop an alternative account of scientific norms.

I explain why the New Theory of Reference of Marcus, Kripke, Kaplan, Putnam and others does not entail absolute time and space, contrary to what Quentin Smith has recently claimed.