Biological species have been treated traditionally as spatiotemporally unrestricted classes. If they are to perform the function which they do in the evolutionary process, they must be spatiotemporally localized individuals, historical entities. Reinterpreting biological species as historical entities solves several important anomalies in biology, in philosophy of biology, and within philosophy itself. It also has important implications for any attempt to present an “evolutionary” analysis of science and for sciences such as anthropology which are devoted to the study of single species.

Bayesian decision theory can be viewed as the core of psychological theory for idealized agents. To get a complete psychological theory for such agents, you have to supplement it with input and output laws. On a Bayesian theory that employs strict conditionalization, the input laws are easy to give. On a Bayesian theory that employs Jeffrey conditionalization, there appears to be a considerable problem with giving the input laws. However, Jeffrey conditionalization can be reformulated so that the problem disappears, and in fact the reformulated version is more natural and easier to work with on independent grounds.

In this paper the concept of supervenience is employed to explain the relationship between fitness as employed in the theory of natural selection and population biology and the physical, behavioral and ecological properties of organisms that are the subjects of lower level theories in the life sciences. The aim of this analysis is to account simultaneously for the fact that the theory of natural selection is a synthetic body of empirical claims, and for the fact that it continues to be misconstrued, even by biologists, for a tautological system. The notion of supervenience is then employed to provide a new statement of the relation of Mendelian predicates to molecular ones in order to provide for the commensurability and potential reducibility of Mendelian to molecular genetics in a way that circumvents the theoretical complications which appear to stand in the way of such a reduction.

Past criticisms to the contrary, methodological individualism in the social sciences is neither trivial nor obviously false. In the style of Weber's sociology, it restricts the ultimate explanatory repertoire of social science to agents' reasons for action. Although this restriction is not obviously false, it ought not to be accepted, at present, as a regulative principle. It excludes, as too far-fetched to merit investigation, certain hypotheses concerning the influence of objective interests on large-scale social phenomena. And these hypotheses, in fact, merit empirical consideration. The attractiveness of methodological individualism as a regulative principle depends on two independent confusions, the conflation of an agent's reasons for action with the beliefs, needs, desires, or goals which are the reasons why he acted as he did, and the identification of explaining a phenomenon and describing its causes.

1. Confirmation Theory One, which we shall construct, when applied to the Raven Hypothesis yields the following results:

1. (1.1) Any black raven confirms the Raven Hypothesis.

2. (1.2) Any black non-raven confirms the Raven Hypothesis.

3. (2) Any non-black raven disconfirms the Raven Hypothesis.

4. (3) Any non-black non-raven is neutral to the Raven Hypothesis.

Theory One consists of two parts: (A) six basic concepts from confirmation theory proper, and (B) the underlying logic.

The correspondence theory of truth is one of the most venerable philosophical theses. Yet it was known almost from the beginning to entail the antinomy of the liar. This antinomy affects any use of the word “true,” not only the use which the correspondence theorist intends. A definition of truth for formalized languages which avoids the antinomy was not formulated before 1931. Tarski's proposal of that year uses an ingenious device. His definition concerns the truth or falsity of the sentences of one language, the object language, but it is given in a different language, the metalanguage. Adapting this definition to natural languages poses some problems, but let us assume they do not exist. Then we may freely apply the word “true” even to sentences of natural languages. We need have no fear of getting involved in antinomies. The use of the word “true” has been rehabilitated. But what about the correspondence theory? Has it too been rehabilitated? Many philosophers claim it has, in particular Karl Popper and his followers. But whether this is so depends of course on what exactly the correspondence theory asserts.

In a recent article [4], Fred I. Dretske has proposed a new analysis of natural laws. Dretske rejects the more or less standard view which says that laws are universal truths with a special function or status in science. As an alternative account, he suggests that laws are expressed by singular statements describing the relationship between universal properties and magnitudes: the statement

(1) It is a law that F's are G's3.

is to be analysed as

(2) F-ness ↦ G-ness.

I shall argue, however, that Dretske's reasons for rejecting the standard account are not conclusive. Moreover, his own proposal seems to be either inadequate or reducible to that version of the standard account which takes laws to be nomically necessary generalizations.

In “Laws of Nature” [1] I argued that natural laws are not universal truths. Laws have properties that enable them to function in a special way. Since universal truths do not have these properties, they cannot be promoted to the status of laws by assigning them this function, by using them in the way laws are typically used. To suppose that we could effect this transformation by the way we used a generalization is like supposing that we could make thumb tacks into garden hoses by using them to water flowers. It will not work. Thumb tacks lack the requisite structure. Hence, they cannot be used in the way garden hoses are normally used. And universal truths lack the properties that would enable them to function, and thereby qualify, as laws of nature.

In The Structure of Scientific Inference ([2]), Mary Hesse has argued for a realist interpretation of science. Her realism, however, is not to be understood in the context of the traditional realist/instrumentalist debate within the philosophy of science. That debate focused on the question of whether or not science did anything other than systematize the empirical data given in our experience. The traditional realist answered “yes” and most frequently described the theoretical statements of science, not only as true, but also as providing descriptions of the world. The instrumentalist on the other hand answered “no” and ascribed no descriptive force to the theoretical statements of science. However, according to Hesse, neither party in the contemporary realism debate assumes the notion of an empirical given. Consequently, the present dispute must be understood as taking place on a level which is logically prior to its predecessor.

In recent years there has been a rebirth of interest in the philosophy of Pierre Duhem. Although I applaud the spirit of this movement, one finds the critics of Duhem frequently lacking in a basic understanding of Duhem's tenets, sometimes to the extent that one doubts a familiarity with the Duhemian text. One of the few papers which is designed to remedy this state of affairs is that of Philip Quinn entitled “What Duhem Really Meant.” Quinn is to be applauded for his meticulous and rigorous exegetical work on the Duhemian text. Unfortunately, Quinn's characterization of the logical relations of two of the central Duhemian theses is erroneous. I shall endeavor to correct these errors in this paper.

Consider the two Duhemian theses S, according to which no single or individual theoretical hypothesis by itself has any observational consequences, and F, which states that no single theoretical hypothesis can be conclusively falsified by any observations.

Does the truth of F follow from the truth of S? I had conjectured that Duhem may have thought so, but I argued that it does not [1]. Nancy Tuana contends that my argument misses the mark, and she goes on to argue that it does [2]. It seems to me that her arguments are decisive on this point, and so I welcome the correction.

Alberto Cortes, in [1], attempts to show (a) that Leibniz's Principle of The Identity of Indiscernibles (L) is a principle restricted to individuals (as distinct from a class of entities Cortes takes to be non-individuals), and (b) that photons (light quanta) appear to violate L (since they don't obey Pauli's Exclusion Principle). L is stated by Leibniz as “no two substances are completely similar, or differ solo numero.” In second-order quantification theory with identity L becomes:

Aaron Snyder and Fred Dretske present an argument for the proposition that singular causal sequences, such as S caused b, need not be related to a general regularity, that an event of type S is always followed by an event of type b. Therefore, they assert that a claim of causal relation does not require a regular observation of effect following cause or cause preceeding effect. To reinforce their assertion, they present the following case:

In Fact, Fiction, and Forecast ([1]) and numerous publications in its wake Nelson Goodman has tried to define projectibility on the basis of a notion of entrenchment. While he and his associates have been able to defend the theory ingeniously against repeated and varied attacks, there seems to be one obstacle to the applicability of that theory which has not been widely discussed and to which we can only hope that Goodman will turn his attention.

One recent problem in philosophy of science is, “Ought a methodology be construed, not merely as an instrument of appraisal, but also as a source of advice to the practising scientist(s)?” Imre Lakatos ([7], p. 174 and 178) and John Worrall ([11], p. 163), among others, have answered the question in the negative. Alan Musgrave disagrees. In a section entitled, “Appraisals and Advice,” in [9], Musgrave attempts to give us a deductive argument in support of his claim that methodologies should be construed as giving advice. After briefly explaining the plausibility of the claim, I shall present Musgrave's argument in full, and then examine each of his premises. I will try to show that his attempt to answer the above question in the affirmative raises some interesting questions, and which must be answered if his venture is to succeed. I should add, that if my objections are successful against Musgrave's attempt, it would be a Pyrrhic victory: I am neither an inductivist nor do I think that the answer to the question should be in the negative.

In a recent paper, T. R. Girill ([2]) claims to have found some difficulties with an earlier paper of mine ([5]) in which I argued, against A. M. Paul ([6]), that in principle, micro-entities are unpicturable. Paul had argued that N. R. Hanson's view, frequently repeated in Patterns of Discovery, to the effect that