This paper investigates the revolutionary conceptual changes that took place when the phlogiston theory of Stahl was replaced by the oxygen theory of Lavoisier. Using techniques drawn from artificial intelligence, it represents the crucial stages in Lavoisier's conceptual development from 1772 to 1789. It then sketches a computational theory of conceptual change to account for Lavoisier's discovery of the oxygen theory and for the replacement of the phlogiston theory.

Cosmologists often use certain global properties to exclude “physically unreasonable” cosmological models from serious consideration. But, on what grounds should these properties be regarded as physically unreasonable if we cannot rule out, even with a robust type of inductive reasoning, the possibility of the properties obtaining in our own universe?

C. L. Hardin has argued that the colour opponency of the vision system leads to chromatic subjectivism: chromatic sensory states reduce to neurophysiological states. Much of the force of Hardin's argument derives from a critique of chromatic objectivism. On this view chromatic sensory states are held to reduce to an external property. While I agree with Hardin's critique of objectivism it is far from clear that the problems which beset objectivism do not apply to the subjectivist position as well. I develop a critique of subjectivism that parallels Hardin's antiobjectivist argument.

We propose an “explanation scheme” for why the Gibbs phase average technique in classical equilibrium statistical mechanics works. Our account emphasizes the importance of the Khinchin-Lanford dispersion theorems. We suggest that ergodicity does play a role, but not the one usually assigned to it.

In the course of defending both a unified model of intertheoretic relations in science and scientific realism, Paul Churchland has attempted to reinvigorate eliminative materialism. Churchland's eliminativism operates on three claims:

(1) that some intertheoretic contexts involve incommensurable theories,

(2) that such contexts invariably require the elimination of one theory or the other, and

(3) that the relation of psychology and neuroscience is just such a context.

I argue that a more detailed account of intertheoretic relations, which distinguishes between the relations that hold between successive theories at a particular level of analysis over time and those that hold between theories at different levels of analysis at the same time, offers grounds for denying Churchland's second and third claims and, therefore, undermines his eliminativism. The paper concludes by suggesting why it is, nonetheless, not unreasonable, given this more detailed model of intertheoretic relations, to expect the eventual elimination of common sense psychology.

Philosophical discussions of species have focused on multicellular, sexual animals and have often neglected to consider unicellular organisms like bacteria. This article begins to fill this gap by considering what species concepts, if any, apply neatly to the bacterial world. First, I argue that the biological species concept cannot be applied to bacteria because of the variable rates of genetic transfer between populations, depending in part on which gene type is prioritized. Second, I present a critique of phylogenetic bacterial species, arguing that phylogenetic bacterial classification requires a questionable metaphysical commitment to the existence of essential genes. I conclude by considering how microbiologists have dealt with these biological complexities by using more pragmatic and not exclusively evolutionary accounts of species. I argue that this pragmatism is not borne of laziness but rather of the substantial conceptual problems in classifying bacteria based on any evolutionary standard.

The standard adaptationist explanation of the presence of a sensory mechanism in an organism—that it detects properties useful to the organism—cannot be given for color vision. This is because colors do not exist. After arguing for this latter claim, I consider, but reject, nonadaptationist explanations. I conclude by proposing an explanation of how color vision could have adaptive value even though it does not detect properties in the environment.

It is the purpose of this paper to carry out a partial syntactical analysis of imperatives. Imperatives form a large body of linguistic expressions, appearing, e.g. in mathematical proofs (“Let f(x) be a continuous function!”), laws, moral injunctions, instruction, etc. For analytical purposes we distinguish between two forms of imperatives, the fiat and the directive. By a directive we mean an imperative which includes an indication of the agent who is to carry it out. For example, “Henry, don't forget to stop at the grocery!” is a directive. By a fiat we mean an imperative which includes no reference to an agent who is to carry it out. For example, “Let there be light!” is a fiat. This is a distinction made in terms of meaning. If, however, proper symbolic devices were introduced for the formalization of imperatives, it could be made in a syntactical manner. Thus we could distinguish between imperatives which possess a certain operator—the directive operator formed by putting a name within square brackets—as “[Henry] (Let it be the case that Henry does not forget to stop at the grocery)!”, and imperatives which do not possess this operator, e.g. “Let it be the case that Henry does not forget to stop at the grocery!” In the following we pay attention only to fiats. This, of course, involves a great limitation of subject matter and excludes topics of great interest.

The purpose of this paper is to suggest that models in scientific practice can be conceived of as epistemic artifacts. Approaching models this way accommodates many such things that working scientists themselves call models but that the semantic conception of models does not duly recognize as such. That models are epistemic artifacts implies, firstly, that they cannot be understood apart from purposeful human activity; secondly, that they are somehow materialized inhabitants of the intersubjective field of that activity; and thirdly, that they can function also as knowledge objects. We argue that models as epistemic artifacts provide knowledge in many other ways than just via direct representative links. To substantiate our view we use a language-technological artifact, a parser, as an example.

The burgeoning science of well-being makes no secret of being value laden: improvement of well-being is its explicit goal. But in order to achieve this goal its concepts and claims need to be value adequate; that is, they need, among other things, to adequately capture well-being. In this article I consider two ways of securing this adequacy—first, by relying on philosophical theory of prudential value and, second, by the psychometric approach. I argue that neither is fully adequate and explore an alternative. This alternative requires thorough changes in the way philosophers theorize about well-being.

This paper offers a refutation of P. Duhem's thesis that the falsifiability of an isolated empirical hypothesis H as an explanans is unavoidably inconclusive. Its central contentions are the following:

1. 1. No general features of the logic of falsifiability can assure, for every isolated empirical hypothesis H and independently of the domain to which it pertains, that H can always be preserved as an explanans of any empirical findings O whatever by some modification of the auxiliary assumptions A in conjunction with which H functions as an explanans. For Duhem cannot guarantee on any general logical grounds the deducibility of O from an explanans constituted by the conjunction of H and some revised non-trivial version R of A: the existence of the required set R of collateral assumptions must be demonstrated for each particular case.

2. 2. The categorical form of the Duhemian thesis is not only a non-sequitur but actually false. This is shown by adducing the testing of physical geometry as a counterexample to Duhem in the form of a rebuttal to A. Einstein's geometrical articulation of Duhem's thesis.

3. 3. The possibility of a quasi a priori choice of a physical geometry in the sense of Duhem must be clearly distinguished from the feasibility of a conventional adoption of such a geometry in the sense of H. Poincaré. And the legitimacy of the latter cannot be invoked to save the Duhemian thesis from refutation by the foregoing considerations.

Means-centered approach to science is contrasted with a problem-centered orientation. Overstress on and too exclusive concern with method, instrument, technique or procedure fosters the following mistakes:

1) Emphasis on polish and elegance rather than on vitality, significance and creativeness.

2) Giving the commanding positions in science to technicians rather than discoverers.

3) Over-valuation of quantification for its own sake.

4) Fitting problems to techniques rather than vice-versa.

5) Creation of a false and pernicious hierarchical system among the sciences.

6) Overstrong compartmentalization between the sciences.

7) Emphasis on the difference rather than the similarities between scientists and other truth-seekers (poets, novelist, artists, philosophers).

8) Creation of a scientific orthodoxy, which in turn a) tends to block the development of new methods, b) tends to exclude many problems from the jurisdiction of science and c) tends to make scientists “safe” rather than daring and unconventional.

9) Neglect of the problems of values, with a consequent blurring of the criteria for judging the worth or importance of an experiment.

The area of investigation known as general systems theory or research features the study of systems as interesting in its own right or one fruitful approach to the study of science in general. This leads to an interesting and still open problem, namely, explicating the concept of a system that seems to unify the interests of researchers in this area. Contrary to received opinion, I argue that there is a unique and interesting concept of a system that underlies the expressed interests of general systems researchers and that it can be given a satisfactory explication. The concept in question has systems as extralinguistic entities that we theorize about, namely, certain sorts of sets of re-related elements. Criteria for its explication are suggested; examples of systems, earlier analyses, and various objections are all considered in leading up to a partial formal explication of the concept and a statement of additional open problems.

Many empirically minded philosophers have used neuroscientific data to argue against the multiple realization of cognitive functions in existing biological organisms. I argue that neuroscientists themselves have proposed a biologically based concept of multiple realization as an alternative to interpreting empirical findings in terms of one-to-one structure-function mappings. I introduce this concept and its associated research framework and also how some of the main neuroscience-based arguments against multiple realization go wrong.

Entropy and information are both emerging as currencies of interdisciplinary dialogue, most recently in evolutionary theory. If this dialogue is to be fruitful, there must be general agreement about the meaning of these terms. That this is not presently the case owes principally to the supposition of many information theorists that information theory has succeeded in generalizing the entropy concept. The present paper will consider the merits of the generalization thesis, and make some suggestions for restricting both entropy and information to specific arenas of discourse.

During the past decade or two the influence of theories of language and meaning has made itself felt in almost every field of study, either because, as in the case of psychology and the social sciences, meaning phenomena were part of the subject matter, or because, as in the case of physics and philosophy, the language used in the study demanded analysis and clarification. In recent years there has been (and is being) developed, especially by H. D. Lasswell and his associates, a technique known as content analysis, which attempts to characterize the meanings in a given body of discourse in a systematic and quantitative fashion.

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.

Several feminist philosophers of science have tried to open up the possibility that feminist ethical or political commitments could play a positive role in good science by appealing to the Duhem-Quine thesis and underdetermination of theories by observation. I examine several different interpretations of the claim that feminist values could play a legitimate role in theory justification and show that none of them follow from a logical gap between theory and observation. Finally, I sketch an alternative approach for defending the possibility that feminist political commitments could play a legitimate role in science.

We use game theoretic models to take an in-depth look at the dynamics of discrimination and academic collaboration. We find that in collaboration networks, small minority groups may be more likely to end up being discriminated against while collaborating. We also find that discrimination can lead members of different social groups to mostly collaborate with in-group members, decreasing the effective diversity of the social network. Drawing on previous work, we discuss how decreases in the diversity of scientific collaborations might negatively affect the progress of epistemic communities.

This is a study of the logic of the concept of evidence. Two distinct concepts of evidence will be explicated and analyzed: confirming evidence by means of which an hypothesis is established, and supporting evidence which does not establish the hypothesis, but merely renders it more tenable. The formal characteristics of each of these concepts of evidence will be examined in detail in Part II. (Part I deals with the auxiliary notion of evidential presumption.) In Part III these considerations are used as a basis for a survey of rules of evidence in order to establish the systematic character of the evidential relationship from the standpoint of formal logic. Finally, the Conclusion appends a brief indication of the methodological bearing of the logical theory of evidence.