Kripke and Putnam have proposed that terms may be introduced to refer to theoretical entities by means of causal descriptions such as 'whatever causes observable effects O'. It is argued that such a reference-fixing definition is ill-formed and that theoretical beliefs must be involved in fixing the reference of a theoretical term. Some examples of reference-fixing are discussed e.g., the term 'electricity'. The Kripke-Putnam theory can not give an account of how terms may be introduced into science and then subsequently be discovered to be non-referring. A modified account of reference-fixing is suggested in which terms such as Gilbert's ‘electric effluvia’ and ‘phlogiston’ can be introduced into science and then be found to lack a reference.

The prevalence of optimality models in the literature of evolutionary biology is testimony to their popularity and importance. Evolutionary biologist R. C. Lewontin, whose criticisms of optimality models are considered here, reflects that “optimality arguments have become extremely popular in the last fifteen years, and at present represent the dominant mode of thought.”

Although optimality models have received little attention in the philosophical literature, these models are very interesting from a philosophical point of view. As will be argued, optimality models are central to evolutionary thought, yet they are not readily accomodated by the traditional view of scientific theories. According to the traditional view, we would expect optimality models to employ general, empirical laws of nature, but they do not. Fortunately, the semantic view of scientific theories, a recent alternative to the traditional view, more readily accomodates optimality models. As we would expect on the semantic view, optimality models can be construed as specifications of ideal systems. These specifications may be used to describe empirical systems—that is, the specifications may have empirical instances. But the specifications are not empirical claims, much less general, empirical laws.

Although philosophers have yet to discuss the general features and uses of optimality models, these topics have stimulated much recent discussion among evolutionary biologists. Their discussions raise a number of precautions concerning the proper use of optimality models. Moreover, many of their caveats can be interpreted as general reminders that 1) optimality models specify ideal systems whose empirical instantiations may be quite restricted, and that 2) optimality models should not be construed as general, empirical laws. As G. F. Oster and E. O. Wilson caution, “the prudent course is to regard optimality models as provisional guides to further empirical research and not necessarily as the key to deeper laws of nature.” It seems, then, that the semantic view of theories is more sensitive to the nature and limitations of optimality models than is the more traditional view of theories.

A new problem about mathematical expectation: there exists a state of affairs S and options H and T such that in every element of one partition of S, the expectation of H exceeds that of T, while in every element of a different partition of S, the expectation of T exceeds that of H. This problem may be connected with questions about inference in the short and long run, and with questions about confidence intervals and fiducial probability.

This paper defends the relevance of Taylor's (1964) critique of S-R behaviorism to Skinner's model of operant conditioning. In particular, it is argued against Ringen (1976) that the model of operant conditioning is a nonteleological variety of explanation. Operant conditioning is shown unable, on this account, to provide a parsimonious and predictive explanation of the behavior of higher level organisms. Finally, it is shown that the principle of operant conditioning implicitly assumes a teleological capacity, the admission of which renders the principle of operant conditioning superfluous.

Dutch Book arguments have been presented for static belief systems and for belief change by conditionalization. An argument is given here that a rule for belief change which under certain conditions violates probability kinematics will leave the agent open to a Dutch Book.

In this paper I want to cast doubt on the claim that there is a legitimate process of reasoning to the best explanation which can serve as an alternative to either straightforward inductive reasoning or a combination of inductive and deductive reasoning. I shall argue a) that paradigmatic cases of acceptable arguments to the best explanation must be considered enthymemes and b) that when the suppressed premises are made explicit we have all of the premises we need to present either a straightforward inductive argument or an argument employing both induction and deduction.

In a recent book, Laudan has put forward a new and provocative theory of scientific progress. In this discussion we shall show that some of the claims which Laudan presents as new, are (or at least can be made into) parts of more “traditional” wisdom. In particular (in Section 1) we shall criticize his claim to have uncovered a new class of non-refuting anomalies for theories. We shall also (in section 2) criticize Laudan's view that a theory may have an anomaly because of conflict with non-scientific theories—as long as those theories are perceived of as rational. Laudan's view of theory-assessment—via the assessment of “research traditions”—is also examined in this section. It is found to be a significant departure from both traditional, and more radical (Lakatosian, Kuhnian, Feyerabendian) alternatives. Finally, (in Section 3), we examine Laudan's claim that theories may have anomalies because of conflict with methodological theories.

I am grateful to Brendan Minogue (1978) for his careful and detailed discussion of the concept of “intensional reference” (IR) as it appears in my book The Structure of Scientific Inference (1974). He concludes that my account contains some important inconsistencies that vitiate my attempt to reconcile the idea of cumulative acquisition of scientific knowledge with radically changing theories. He rightly sees that this attempt depends crucially on the account of translatability between theories, and this in turn upon the notion of “identity of intensional reference.” This means that the attempt fails if there are inconsistencies in the concept of IR. Since Minogue's careful analysis nevertheless contains some misunderstandings, I must plead guilty to a number of unclarities, but I do not believe there are basic inconsistencies. Let me try again.

In (Cupples 1977), it was argued that Professor David Kaplan's model of S-explanation could be formulated so as to provide a unified framework for three types of explanation, viz., potential, rationally acceptable, and true. In this note I correct an error in the statement of the conditions for a potential direct S-explanans, show that the corrected version leads to a further simplification in the conditions of the model, and propose a fourth type of explanation which the framework of S-explanation can accommodate.

In (Nelson 1976b) I used Turing machine arguments to show that computers can recognize humanly recognizable patterns in principle. In 1978 James D. Heffernan has expressed some doubts about such arguments. He does not question the propositions that I defend in the paper, nor the specific arguments in their support. What he does criticize are certain background assumptions.

Shames' article (1979) ingeniously attempts to impeach arguments which support the view that a psychologist's experimental results are significantly influenced by the experimenter expectancy effect. This attack is a powerful one in which Shames unveils his “expectancy paradox”: the scientist investigating the influence of the expectancy effect in psychology remains himself subject to any such expectancy effect. Therefore, he argues, “The more substantial is the evidence for the veridicality of experimenter expectancy ... the more suspect it becomes ...” (1979, p. 384). Shames maintains that this paradox is inescapable only if the experimenter expectancy effect is inexorable in any particular research program and is pervasive through the broad spectrum of psychological research. A review of the literature leads him to hold that this effect is neither inexorable nor unquestionably pervasive. “Thus,” Shames concludes, “the expectancy paradox is less pernicious than may have been feared; however, since it is so intimately tied to the experimenter expectancy effect, the spectre of doubt as to the compass of this effect is cast” (1979, p. 387).

In a recent note, Horwich (1978) challenges the foundations of Hempel's classic paradox of confirmation by a clever example purporting to show that under Nicod's Criterion, data can be made to confirm a hypothesis with which they are logically incompatible. Specifically, Horwich observes that 'Pb' (i.e., 'object b has property P') is formally equivalent to '(x)(∼Px · ∼Pb ⊃ x ≠ b)'. The latter has form '(x)(ψx ⊃ ϕx)' with '∼P___ · ∼Pb' for 'Ψ' and '___ ≠ b' for 'ϕ', while the observation that distinct objects a and b both lack P, i.e. that —Pa · ∼Pb · a ≠ b, can be expressed as 'Ψa · ϕa' for these same instantiations of the predicate markers. Accordingly, if an uncertain generality '(x)(Ψx ⊃ Ψx)' were always to be confirmed by an observation of form 'Ψa · ϕa', as Nicod's Criterion has long been presumed to say, then we could confirm that b has P by observing that b and some other object both lack P—a flagrant absurdity.

In the theory of explanation it is imperative that self-explanation be excluded; we cannot allow an explanandum to explain itself. This applies to the explanation of events and to the explanation of laws. In Nagel's account the following three features of a valid explanation of a universal law serve as a prophylaxis against self-explanation: “... all the premises are universal statements, there is more than one premise, each of which is essential in the derivation, and the premises, taken singly or conjointly, do not follow logically from the explicandum”).

In their article, “Relative Simultaneity in the Special Theory of Relativity,” Jackson and Pargetter (1977) have offered a method to determine distant simultaneity which they claim to be independent of any assumptions concerning one-way velocities and thus a basis for denying the conventionality of distant simultaneity within the framework of the Special Theory. In what follows, I shall argue that the case they make to support the claim to independence is mistaken.