In place of earlier instrumentalist and phenomenalist interpretations of science both Quine and Sellars have developed highly influential realist positions centering around the doctrine that accepting a theory as explanatory and irreducible rationally entails accepting the entities posited by the theory. A growing reaction against this realism is partially based on perceived inadequacies in the doctrines of Quine and Sellars, but even more on reconstructions of scientific explanations which do not involve such ontic commitments. Three types of anti-realistic positions are considered and criticized. Hesse's neo-Duhemian position couples a statistical theory of inference to a downgrading of purely theoretical statements. Sneed uses the method of axiomatization through set-theoretic predicates to supply a reconstruction of Kuhn's account of scientific development. Here Ramsey-reduction sentences serve to eliminate purely theoretical terms. The longest section deals with van Fraassen's semantic model based on a state-space representation of scientific theories and the use of this model in interpreting quantum mechanics. It is argued that the model is valuable, but that the anti-realist interpretation accorded it is not justified and entails serious inconsistencies.

Sometimes a theory is interpreted realistically—i.e., as literally true—whereas sometimes a theory is interpreted instrumentalistically—i.e., as merely a convenient device for summarizing, systematizing, deducing, etc., a given body of observable facts. This paper is part of a program aimed at determining the basis on which scientists decide on which of these interpretations to accept a theory. I proceed by examining one case: the nineteenth-century debates about the existence of atoms. I argue that there was a gradual transition from an instrumentalist to a realistic acceptance of the atomic theory, because of gradual increases in its predictive power, the “testedness” of its hypotheses, the “determinateness” of its quantities, and because of resolutions of doubts about the acceptability of its basic explanatory concepts.

Efforts to bare the psychonomic nature of the semantic reference (representation) relation have been remarkably scanty; in fact, the only contemporary account developed with any care is the one proposed by Osgood. However, not even Osgood has looked deeply at the difficulties that beset any attempt to analyze reference in terms of common effects appropriately shared by a symbol and its significate.

A series of explanatory hypotheses are examined under the assumption that the logical structure of function attributions is dependent on the methodological constraints which these hypotheses conform to. Two theses are argued for: (1) Given these methodological constraints, if something has the function of doing Y, then normally it is the only kind of thing that can do Y in that kind of system. (2) What distinguishes function attributions from causal attribution is not that function attributions explain the etiology Of the causally efficacious object, as Wright has suggested. The distinction lies rather in that the object's having the effect, which is attributed to it as its function, must figure in the explanation of why it does what it does to achieve that effect.

We summarize the evidence and arguments usually employed against the use of the profit maximization assumption in microeconomic theory, and then pass directly to the methodological arguments. Two arguments are considered. The first summarizes positions which have been taken by various defenders of the “people who think a theory should be given up just because it is false are naive and confused” view. To rebut this view, we develop a scheme for classifying theoretical assumptions and show that the specious plausibility of the argument in question derives from ignoring the distinctions we have drawn. The second argument attempts to show that a better theory is more likely to be attained by continuing the development of the orthodox theory. We show that this view is mistaken and then discuss steps which have been taken to develop a better theory.

It is here argued that functionalist constraints on psychology do not preclude the applicability of classic forms of reduction and, therefore, do not support claims to a principled, or de jure, autonomy of psychology. In Part I, after isolating one minimal restriction any functionalist theory must impose on its categories, it is shown that any functionalism imposing an additional constraint of de facto autonomy must also be committed to a pure functionalist—that is, a computationalist—model for psychology. Using an extended parallel to the reduction of Mendelian to molecular genetics, it is shown in Parts II and III that, contrary to the claims of Hilary Putnam and Jerry Fodor, there is no inconsistency between computational models and classical reductionism: neither plurality of physical realization nor plurality of function are inconsistent with reductionism as defended by Ernest Nagel. Employing the results of Part I, the conclusions of Parts II and III are generalized in Part IV to cover any version of functionalism whatsoever; thus, functionalism and reductionism are shown to be consistent. It is urged in conclusion that although a de facto form of autonomy is defensible, there are sound methodological grounds for unconditionally rejecting any principled version of the autonomy of psychology.

Wesley Salmon has recently proposed a new theory of scientific explanation based on a model which he calls the statistical-relevance model. It is intended primarily as an account of the structure of explanations of particular events—explanations which, according to Salmon, are very often motivated largely by practical concerns. Two important features of this account are the concepts of homogeneity and screening off. In this paper we argue that the employment of these two concepts (which, in fact, are intimately connected) is fundamentally at odds with the desire to capture everyday explanations of the practical sort, and that it leads instead to an account in which the only satisfactory explanations are those expressed in the very deepest physical terms.

The subject of this essay is the dependence of evidential relations on background beliefs and assumptions. In Part I, two ways in which the relation between evidence and hypothesis is dependent on such assumptions are discussed and it is shown how in the context of appropriately differing background beliefs what is identifiable as the same state of affairs can be taken as evidence for conflicting hypotheses. The dependence of evidential relations on background beliefs is illustrated by discussions of the Michelson-Morley experiment and the discovery of oxygen. In Part II, Hempel's analysis of confirmation and the contrasting model of theory acceptance provided by philosophers such as Kuhn and Feyerabend are discussed. It is argued that both are inadequate (on different grounds) and the problems addressed by each are shown to be more satisfactorily approached by means of the analysis developed in Part I. In Part III, it is argued that if there are objective criteria for deciding between competing theories, these cannot be simply that one theory has greater evidential support than another. Finally, some further methodological questions arising from the analysis are mentioned.

I characterize a notion of causal agency that is the causitive component of many transitive verbs. The agency of what I call substantial causes relates objects physically to systems with which they interact. Such agent causation does not reduce to conditionship relations, nor does it cease to play a role in scientific discourse. I argue, contrary to regularity theories, that causal claims do not in general depend for their sense on generalities nor do they entail the existence of laws. Clarification of the relationships among substantial causes, causal processes, and explanatory conditions separates the analysis of causal connection from that of nomological connection. This clarification is then applied to a variety of issues in the analysis of causality.

Many philosophers, both past and present, object to materialism not from any romantic anti-scientific bent, but from sheer inability to understand the thesis. It seems utterly inconceivable to some that qualia should exist in a world which is entirely material. This paper investigates the grain objection, a much neglected argument which purports to prove that sensations could not be brain events. Three versions are examined in great detail. The plausibility of the first version is shown to depend crucially on whether one holds a direct or non-direct theory of perception. Only on the latter is this version plausible. An analysis of the second “semantic” version concludes that a materialist description and explanation of the world should not be expected to transparently convey all that would be of interest or importance to human beings. The final version explicitly makes use of Grover Maxwell's non-direct perceptual theory of structural realism. Although a confusion is charged to Maxwell between phenomenal and objective properties, the critical difficulty for the grain objection is its failure to characterize “structure” from a non-percipient point of view. As the grain objection is ultimately found wanting, the real difficulty for materialism crystallizes as its irreconciliability with the mere existence of sentience, which seems to force some sort of emergence upon us.

Probability measures can be constructed using the measure-theoretic techniques of Caratheodory and Hausdorff. Under these constructions one obtains first an outer measure over “events” or “propositions.” Then, if one restricts this outer measure to the measurable propositions, one finally obtains a classical probability theory. What I argue is that outer measures can also be used to yield the structures of probability theories in quantum mechanics, provided we permit them to range over at least some unmeasurable propositions. I thereby show that nonclassical probability theories can be seen to arise naturally within the framework of possible worlds semantics.

When an experimenter uses the experimental method to investigate the effects of the experimenter's expectancy it may be that this research, too, is affected by his expectancy and thus there is an expectancy paradox. To the extent that the experimenter expectancy effect accounts for the variation in the dependent variable and is general, that is to say, universal in psychological research, the expectancy paradox is ineluctable. However, an analysis of the research reviews extant in this area yields the conclusion that expectancy effects are neither inexorable nor highly general in psychological research and this provides the basis for its extrication from the expectancy paradox.

Richard Rorty's eliminative materialism is an attack on dualism that has frequently been misrepresented and incorrectly criticized. By taking account of the mistakes that philosophers have made concerning eliminative materialism, a proper definition of the doctrine and a clarification of its relation to traditional materialism will emerge, as well as an understanding of its true strengths and weaknesses. The discussion centers around the original manner in which Rorty defended eliminative materialism by means of analogies to the elimination of talk about demons and talk about macroscopic physical objects.

The theory of general relativity has produced some great insights into the nature of space and time. Unfortunately, its relevance to the problem of the direction of time has been overestimated. This paper points out that the problem of the direction of time can be formulated in purely local ways, and that in this kind of formulation considerations of general relativity are of little or no importance. On the basis of this, positions which assume that relativistic considerations are always relevant are criticised.

Following an account of the incommensurability argument, an objection, based on assumptions concerning rival theories, is examined and rejected. This rejection leads to an alternative direction of criticism of incommensurability, a direction that involves the articulation of comparative standards of theory evaluation that are independent of meaning invariance.

The applicability of Nagel's concept of theory reduction, and related concepts of reduction, to the reduction of genetics to molecular biology is examined using the lactose operon in Escherichia coli as an example. Geneticists have produced the complete nucleotide sequence of two of the genes which compose this operon. If any example of reduction in genetics should fit Nagel's analysis, the lactose operon should. Nevertheless, Nagel's formal conditions of theory reduction are inapplicable in this case. Instead, it is argued that genetics has been partially reduced to molecular biology in the sense of token-token reduction.

It is argued that Hempel's original rejection of the prediction criterion of confirmation in [8] (on the grounds that it leads to a circular definition of confirmation) was ill-conceived, and that his own approach exhibits undesirable consequences to the degree that it deviates from this criterion. A version of the prediction criterion is formulated which, in addition to being-non circular, escapes the criticisms advanced against Hempel's satisfaction criterion, offers certain clear advantages over alternative approaches, and may serve as the basis for a theory of qualitative confirmation. The definition of confirmation developed here violates two of Hempel's three criteria of adequacy, and in showing why it should do so some light is shed on various issues in the debate concerning the acceptability of these criteria.

I argue against the currently popular view that a radical change in theory affects the meaning of theoretical terms, and hence render pre- and post-shift theories incomparable. I first show how to pose the meaning-change issue without appeal to meanings reified. I contend that arguments against theory-neutral observation languages are faulty, but that even if they were sound, there are semantic devices that allow a theory to refer to the factual basis of a competitor. This suggests a picture of science as the accumulation of truths, with each successive stage being more stable.

The concept of “fitness” is a notion of central importance to evolutionary theory. Yet the interpretation of this concept and its role in explanations of evolutionary phenomena have remained obscure. We provide a propensity interpretation of fitness, which we argue captures the intended reference of this term as it is used by evolutionary theorists. Using the propensity interpretation of fitness, we provide a Hempelian reconstruction of explanations of evolutionary phenomena, and we show why charges of circularity which have been levelled against explanations in evolutionary theory are mistaken. Finally, we provide a definition of natural selection which follows from the propensity interpretation of fitness, and which handles all the types of selection discussed by biologists, thus improving on extant definitions.

The fact that the names of biological species refer independently of identifying descriptions does not support the view of Ghiselin and Hull that species are individuals. Species may be regarded as natural kinds whose members share an essence which distinguishes them from the members of other species and accounts for the fact that they are reproductively isolated from the members of other species. Because evolutionary theory requires that species be spatiotemporally localized their names cannot occur in scientific laws. If natural kind status is denied to species on this ground, it must also be denied to most classes of concrete entities which are now accorded such status.