In his book, The Scientific Image, Bas van Fraassen argues for an anti-realist view of science according to which the sole epistemological aim of science is to “save the phenomena”. As originally conceived, his constructive empiricism is strongly extensional, but in his account of the empirical adequacy of probabilistic theories, van Fraassen reluctantly abandons this extensional position, arguing that modal (intensional) notions are unavoidable in interpreting probability. I argue in this paper that van Fraassen has not presented the strongest possible case for a fully extensional account of empirical adequacy. On the present account, a probabilistic theory is empirically adequate just in case there is no theory that has a higher likelihood relative to all the phenomena in the actual world. I prove that a theory is empirically adequate if and only if the probability attributed to each observable event that occurs in the actual world is its limiting relative frequency. Thus, in so far as one is concerned with the empirical adequacy (rather than with the literal truth) of probabilistic theories, strict relative frequencies provide an adequate basis for “interpreting probability”.

Probabilistic theories are treated in a genuine measurement context. In this connection I distinguish between worlds that are “strongly infinite” and worlds that are only “weakly infinite”. It is characteristic of the former worlds that there is no limit to the precision of actual measurements. I show by example that in some “strongly infinite” worlds, theories will be empirically adequate only if observables are represented by continuous (rather than discrete) random variables. The range of such examples is clarified by a theorem which states necessary and sufficient conditions under which the “phenomena can be saved” without recourse to continuous random variables and real numbers.

After clarifying the probabilistic conception of causality suggested by Good (1961–2), Suppes (1970), Cartwright (1979), and Skyrms (1980), we prove a sufficient condition for transitivity of causal chains. The bearing of these considerations on the units of selection problem in evolutionary theory and on the Newcomb paradox in decision theory is then discussed.

This paper makes explicit and takes issue with the bizarre view, which is unfortunately prevalent among social scientists, that causal relations are features of models only. There are some good reasons to represent causal factors with independent variables. But the association between causes and independent variables is only a desideratum in model construction. It is not a criterion for judging which things are causes and which are effects.

The conditional probability of h given e is commonly claimed to be equal to the probability that h would have if e were learned. Here I contend that this general claim about conditional probabilities is false. I present a counter-example that involves probabilities of probabilities, a second that involves probabilities of possible future actions, and a third that involves probabilities of indicative conditionals. In addition, I briefly defend these counter-examples against charges that the probabilities they involve are illegitimate.

The background hypothesis of this essay is that psychological phenomena are typically explained, not by subsuming them under psychological laws, but by functional analysis. Causal subsumption is an appropriate strategy for explaining changes of state, but not for explaining capacities, and it is capacities that are the central explananda of psychology. The contrast between functional analysis and causal subsumption is illustrated, and the background hypothesis supported, by a critical reassessment of the motivational psychology of Clark Hull. I argue that Hull's work makes little sense construed along the subsumptivist lines he advocated himself, but emerges as both interersting and methodologically sound when construed as an exercise in the sort of functional analysis featured in contemporary cognitive science.

When natural selection theory was presented, much active philosophical debate, in which Darwin himself participated, centered on its hypothetical nature, its explanatory power, and Darwin's methodology. Upon first examination, Darwin's support of his theory seems to consist of a set of claims pertaining to various aspects of explanatory success. I analyze the support of his method and theory given in the Origin of Species and private correspondence, and conclude that an interpretation focusing on the explanatory strengths of natural selection theory accurately reflects neither Darwin's own self-consciously held views, nor the nature of his support. Darwin's methodological and philosophical arguments were at once consistently empiricist and more sophisticated than such interpretations credit to him.

This paper discusses “Russell's hypothesis” that the world sprang into existence five minutes ago. The three most widely accepted “solutions” to the Russell's hypothesis problem are shown to be unsatisfactory.

Two main points of interest are involved in the paper's discussion. First, I show all the widely accepted “solutions” to be unacceptable by using the same device—alternatives to Russell's hypothesis. The device, which has never previously been applied to this problem, is a familiar one in discussions of the problem of induction. (Parallels between these two problems are sketched at the paper's end.) Second, the discussion introduces the new concept of crucial consequences for hypotheses that are otherwise different in only trivial linguistic ways.

Larry Wright's analysis of teleological description of goal-directed behavior, though ingenious and insightful, errs in the following ways: it incorrectly claims that intentional human action exhibits consequence-etiology, making it impossible, contrary to his claim, for reference to consequence-etiology to be metaphorically transmitted to teleological descriptions of nonhuman behavior; it does not remove the threat of reverse causation for nonhuman behavior; it assumes in the face of contrary evidence that reference to purpose drops out in metaphorical extension; and it cannot account for unrequired behavior directed toward impossible goals.