Four philosophical problems—predication, speech acts, rules, and innate ideas— are discussed in the light of their implications for psychological and linguistic research. The discussion of predication concerns both form and use. With respect to form, it is argued that our lexical memory is organized according to a predicate-argument formula that underlies the subject-predicate form of our sentences. With respect to use, it is argued that the illocutionary force of the sentence as a speech act must be taken into account. Both the formation and the use of such verbal constructions are normally characterized by systems of rules, but there is no clear account of what a rule is or how it might operate to control behavior, and this problem is especially difficult when, as in language, the person's knowledge of the rules is implicit. The innate basis for our human ability to acquire linguistic rules is considered and the problem of innateness is redefined around the conjecture that there are innate, language-specific mechanisms unique to human beings. The problem of investigating such language-specific mechanisms psychologically, however, is quite difficult at the present time.

Intentionality is characteristic of many psychological phenomena. It is commonly held by philosophers that intentionality cannot be ascribed to purely physical systems. This view does not merely deny that psychological language can be reduced to physiological language. It also claims that the appropriateness of some psychological explanation excludes the possibility of any underlying physiological or causal account adequate to explain intentional behavior. This is a thesis which I do not accept. I shall argue that physical systems of a specific sort will show the characteristic features of intentionality. Psychological subjects are, under an alternative description, purely physical systems of a certain sort. The intentional description and the physical description are logically distinct, and are not intertranslatable. Nevertheless, the features of intentionality may be explained by a purely causal account, in the sense that they may be shown to be totally dependent upon physical processes.

Suppose that entities composed of two distinct components can be qualitatively ordered in two ways, such that each ordering relation satisfies the axioms of conjoint measurement. Without further assumptions nothing can be said about the relation between the pair of numerical scales constructed for each component. Axioms are stated that relate the two measurement theories, and that are sufficient to establish that the two conjoint scales on each component are linearly related.

The Reichenbach-Grünbaum thesis of the conventionality of simultaneity is clarified and defended by developing the consequences of the Special Theory when assumptions are not made concerning the one-way speed of light. It is first shown that the conventionality of simultaneity leads immediately to the conventionality of all relative speeds. From this result, the general-length-contraction and time-dilation relations are then derived. Next, the place of time-dilation and length-contraction effects within the Special Theory is examined in the light of the conventionality thesis. The slow-transport method of synchrony is then examined in the light of these results and is shown not to provide an adequate method of uniquely determining the one-way speed of light. Finally, the general ∊-Lorentz transformations for events along the x-axis are derived from three principles : the round-trip light principle, the principle of equal passage times, and the linearity principle. These principles are shown to be independent of one-way velocity assumptions, and thus may form the basis of a Special Theory of Relativity without simultaneity assumptions.

Roughly speaking all economists can be divided into two groups—those who agree with Milton Friedman and those who do not. Both groups, however, espouse the view that science is a series of approximations to a demonstrated accord with reality. Methodological controversy in economics is now merely a Conventionalist argument over which comes first—simplicity or generality. Furthermore, this controversy in its current form is not compatible with one important new and up and coming economic (welfare) theory called “the theory of the Second Best.” In this paper I offer a Second Best meta-theory that says that (1) any compromise between simplicity and generality must yield a theory which is “third best” by these Conventionalist criteria; and (2) there exists a better way than a compromise.

The relationship between a class of structural forms and a single reduced form econometric model is discussed. These are shown to be empirically equivalent. It is made clear that choice of a particular structural form for estimation, rather than another of the same class, rests on a priori heuristic and computational considerations, not on empirical or logical grounds.

Alternative scientific strategies are discussed briefly.

If the problem of induction were soluble, it should be solved inductively: by observing how scientists observe, etc. The fact is that scientific research is successful, and the real question is, will it be so in future? If there is a formula of induction by which success is achieved, then by this formula we can say, as long as it will be used science will succeed. If there is no formula it looks as if future success in scientific research is most doubtful. Hence, a transcendental argument for induction goes, there is an inductive formula. Since, however, such a view of induction is rejected even by inductivists as naive, the argument collapses. Hence the question is, on what basis do we project the future success of science? My answer is that this future success is built into our social institutions and is partially institutionally safeguarded.

The meaning and justification of the requirement of total evidence are examined. It is argued that there are several significantly different interpretations of the requirement, but each interpretation makes the requirement highly suspect. For any of the usual interpretations of the requirement, it would be quite unreasonable to conduct inquiry in such a way as to fulfill it. It is then suggested that the rational inquirer should seek the optimal amount of evidence, rather than all the evidence. This raises the problems surrounding the idea of scientific or epistemic utility.

The main argument of this paper is that an evaluation of the overall explanatory power of a theory is less problematic and more relevant as an assessment of the state of knowledge than evaluation of statistical explanations of single occurrences in terms of likelihoods that are assigned to explananda.