I propose a way of formulating scientific laws and magnitude attributions which eliminates ontological commitment to mathematical entities. I argue that science only requires quantitative sentences as thus formulated, and hence that we ought to deny the existence of sets and numbers. I argue that my approach cannot plausibly be extended to the concrete “theoretical” entities of science.

Among the liveliest disputes in evolutionary biology today are disputes concerning the role of chance in evolution—more specifically, disputes concerning the relative evolutionary importance of natural selection vs. so-called “random drift”. The following discussion is an attempt to sort out some of the broad issues involved in those disputes. In the first half of this paper, I try to explain the differences between evolution by natural selection and evolution by random drift. On some common construals of “natural selection”, those two modes of evolution are completely indistinguishable. Even on a proper construal of “natural selection”, it is difficult to distinguish between the “improbable results of natural selection” and evolution by random drift.

In the second half of this paper, I discuss the variety of positions taken by evolutionists with respect to the evolutionary importance of random drift vs. natural selection. I will then consider the variety of issues in question in terms of a conceptual distinction often used to describe the rise of probabilistic thinking in the sciences. I will argue, in particular, that what is going on here is not, as might appear at first sight, just another dispute about the desirability of “stochastic” vs. “deterministic” theories. Modern evolutionists do not argue so much about whether evolution is stochastic, but about how stochastic it is.

Previous work has shown that the problem of measurement in quantum mechanics is not correctly seen as one of understanding some allegedly univocal process of measurement in nature which corresponds to the projection postulate. The present paper introduces a new perspective by showing that how we are to understand the nature of the change of quantum mechanical state on measurement depends very sensitively on the interpretation of the state function, and by showing how attention to this dependence can greatly sharpen the problems and relations between them. In particular, the problems take a form resembling their traditional formulation only on an inexact value interpretation, according to which the state function attributes inexact values of quantities to systems. On other interpretations we can apply (with various drawbacks) the subensemble idea, according to which a discontinuous change of quantum mechanical description results on measurement simply because we need a new state function to describe a new object.

Functionalism faces a problem in accounting for the semantic powers of beliefs and other mental states. Simple causal considerations will not solve this problem, nor will any appeal to the social utility of semantic interpretations. The correct analysis of semantic representation is a teleological one, in terms of the biological purposes of mental states: whereas functionalism focuses, so to speak, only on the structure of the cognitive mechanism, the semantic perspective requires in addition that we consider the purposes of the cognitive mechanism's parts.

Russell (1948), Reichenbach (1956), and Salmon (1975, 1979) have argued that a fundamental principle of science and common sense is that “matching” events should not be chalked up to coincidence, but should be explained by postulating a common cause. Reichenbach and Salmon provided this intuitive idea with a probabilistic formulation, which Salmon used to argue for a version of scientific realism. Van Fraassen (1980, 1982) showed that the principle, so construed, runs afoul of certain results in quantum mechanics. In this paper a new formulation of the principle is offered that emerges from its use in evolutionary theory. This characterization identifies fairly general conditions in which postulating common causes will be more explanatory than postulating separate causes.

The mutual influence of science and values in biology is exhibited in several cases from the biological literature. It is argued in a number of cases, from R. A. Fisher's argument for the optimality of a 50:50 sex ratio to A. Jensen's defense of a genetic basis for intelligence, and including work on the evolution of sexual dimorphism and muted aggression, that the credence accorded the views is disproportionate with their theoretical and empirical warrant. It is, furthermore, suggested that the proper explanation for the attraction and persistence of such views lies in their conformity with ideological norms. There is thus an important, if circumscribed, role for ideological critique in the evaluation of scientific theories; in particular, it lies in the explanation of the acceptance and persistence of scientific views, given independent grounds for questioning their justifiability.

This paper examines the relationship between modern theories of microeconomics and macroeconomics and, more generally, it evaluates the prospects of theoretically reducing macroeconomics to microeconomics. Many economists have shown strong interest in providing “microfoundations” for macroeconomics and much of their work is germane to the issue of theoretical reduction. Especially relevant is the work that has been done on what is called The Problem of Aggregation. On some accounts, The Problem of Aggregation just is the problem of reducing macroeconomics to microeconomics. I show how to separate these problems and then try to determine to what extent particular kinds of solutions to The Problem of Aggregation succeed in reducing macroeconomics to microeconomics as well. I argue that reduction is not possible by this means given the current state of microeconomics. I also describe how reduction may be possible by means of (dis)aggregation if microeconomics is supplemented in a certain way with the results of experimental research on individual economic agents.

This paper examines a recent attempt by Evan Jobe to account for the asymmetric character of many scientific explanations. It is argued that a purported counterexample to Jobe's account, from Clark Glymour, is inconclusive, but that the account faces independent objections. It is also suggested, contrary to Jobe, that the explanatory relation is not always asymmetric.

Sometimes a singular sentence C can figure in a DN derivation of another singular sentence E and E can also figure in a DN derivation of C. Yet while we are inclined to regard the first derivation as an explanation of E, we are not inclined to regard the second derivation as an explanation of C. As Sylvain Bromberger pointed out in a now classic article (1966), one can explain the period of a pendulum by reference to its length and yet, although one can give a DN derivation of the length of a pendulum by reference to its period, this derivation does not seem to represent an explanation.

Evan Jobe has recently offered an interesting account of such explanatory asymmetries and Clark Glymour has in turn proposed a counterexample which seems to show that Jobe's account is defective. The aim of this paper is twofold. I shall attempt to show that (a) Glymour's proposed counterexample can be rejected on the grounds that it violates an independently plausible restriction on the role that equalities may play in DN explanation, and that (b) although Glymour's counterexample can be avoided in this way, Jobe's account is defective in several other respects.

A precise formulation of the structure of modern evolutionary theory has proved elusive. In this paper, I introduce and develop a formal approach to the structure of population genetics, evolutionary theory's most developed sub-theory. Under the semantic approach, used as a framework in this paper, presenting a theory consists in presenting a related family of models. I offer general guidelines and examples for the classification of population genetics models; the defining features of the models are taken to be their state spaces, parameters, and laws. The suggestions regarding the various aspects of the characterization of population genetics models provide an outline for further detailed research.

Glymour's account of confirmation is seen to have paradoxical consequences when applied to the confirmation of theories containing theoretical functions. An alternative conception of instances derived from Sneed's reconstruction of physical theories is conjoined with the instance view of confirmation to produce an account of confirmation that avoids these problems. The topic of selective confirmation is discussed, and it is argued that theories containing theoretical functions are not selectively confirmable.

The purpose of this paper is to explore the semantics of metaphoric language in scientific contexts. According to the theory of metaphor advanced below, the benchmark of a metaphoric expression is the implicit transfer of semantic features across incongruous semantic fields. This transfer results in a conceptual variation of “meaning” in the receiving semantic field. Thus, the theory of metaphor rests on semantic field theory. Existing semantic approaches to metaphor are evaluated in Section 1. In Sections 2 and 3 an alternative theory is introduced through an analysis of the mechanics of the feature transfer process followed by a discussion of some methodological cues for deciphering the metaphor's “meaning.” As I explore in Section 4, this theory of metaphor explains how all metaphoric expressions are potentially literal depending on the general compliance of the community of speakers. Consequently, concept formation in scientific contexts is, in large measure, metaphoric. Finally, I argue in Section 5 that metaphoric concept formation is an essential aspect of scientific reasoning for the purpose of solving conceptual problems.

The discovery that some B vitamins are constituents of respiratory coenzymes led to the development of an interfield theory of the kind discussed by Darden and Maull (1977). In this paper it is shown that the development of a useful interfield connection was made possible by two reconceptualizations: (1) a re-conceptualization that united two then-distinct fields giving rise to the concept of vitamins as dietary substances; and (2) another reconceptualization that united two approaches to respiratory metabolism producing the idea that coenzymes are transport vehicles.

Several arguments are considered which purport to demonstrate the impossibility of theory-neutral observation. The most important of these infers the continuity of observation with theory from the presumed continuity of perception with cognition, a doctrine widely espoused in recent cognitive psychology. An alternative psychological account of the relation between cognition and perception is proposed and its epistemological consequences for the observation/theory distinction are then explored.

Although it is possible to regard a species as a set with a special internal structure, it is preferable to regard a species as an individual precisely to emphasize this internal structure. It is necessary to recognize, moreover, that two organisms that are part of a single entity with respect to one process need not be part of a single entity with respect to another process. Furthermore, choosing to regard two entities (with respect to one process) as conspecific is not to deny that there are two entities within this species. Thus, the systematist need not propose formal names for every entity he discovers, but the names he proposes ought to be as faithful to the relationship among the entities as is possible.

Some critics believe Quine's semantic indeterminacy (indeterminacy of radical translation at home as well as abroad) thesis is true, but innocent, since it is just scientific underdetermination in linguistics. The Quinean reply is that in scientific underdetermination cases there are facts of the matter making claims true or false (whether knowable or not), whereas in semantic indeterminacy cases there simply are not. The critics' rejoinder that there are such facts, studied in linguistics, is met by the final reply that linguistics either on the whole or in part is riddled with appeals to “meanings” and is, thereby, as suspect as analyticity and radical translation. I recommend “saving”(?) linguistics by holding that it is permanently entangled in epistemology. Finally, the argument the critics should have made concerns paralleling semantic indeterminacy to indeterminacies in current quantum mechanics.

In his “Discussion” (1984), Elliott Sober offers some criticisms of the view about species—pluralistic realism—advocated in my 1984. Sober's comments divide into three parts. He attempts to show that species are not sets; he responds to my critique of David Hull's thesis that species are individuals; and he offers some arguments for the claim that species are “chunks of the genealogical nexus.” I consider each of these objections in turn, arguing that each of them fails. I attempt to use Sober's insightful critique to explain and defend pluralistic realism more fully.