Using H. Whitney's algebra of physical quantities and his definition of a similarity transformation, a family of similar systems (R. L. Causey [3] and [4]) is any maximal collection of subsets of a Cartesian product of dimensions for which every pair of subsets is related by a similarity transformation. We show that such families are characterized by dimensionally invariant laws (in Whitney's sense, [10], not Causey's). Dimensional constants play a crucial role in the formulation of such laws. They are represented as a function g, known as a system measure, from the family into a certain Cartesian product of dimensions and having the property gφ = φg for every similarity φ. The dimensions involved in g are related to the family by means of certain stability groups of similarities. A one-to-one system measure is a proportional representing function, which plays an analogous role in Causey's theory, but not conversely. The present results simplify and clarify those of Causey.

The paper investigates what are the proper procedures for calculating the probability on certain evidence of a particular object e having a property, Q, e.g. of Eclipse winning the Derby. Let ‘α‘ denote the conjunction of properties known to be possessed by e, and P(Q/α) the probability of an object which is α being Q. One view is that the probability of e being Q is given by the best confirmed value of P(Q/α). This view is shown not to be generally true, but to provide a useful approximation in many cases. Then given that we have information about the observed frequencies of Q among objects having one or more of the properties whose conjunction forms α, the paper shows how to establish which value of P(Q/α) is the best confirmed one.

In this article I discuss the justification of scientific change and argue that it rests on different sorts of invariance. Against this background I consider notions of observation, meaning, and regulative standards. I sketch an account of the rationale of scientific change which preserves the merits and avoids the shortcomings of the approach of Feyerabend, Hanson, Kuhn, Toulmin, and others. Each of these writers would hold that transitions from one scientific tradition to another force radical changes in what is observed, in the meanings of the terms employed, and in the metastandards involved. They would claim that “incommensurable” replacement is what does, and should, occur during scientific “revolutions.” Such writers, however, have trouble in comparing different scientific theories. My account permits different theories to be compared in various ways. These comparisons, I argue, are possible through appeal to “first-level” and “second-level” invariance. In this connection I argue that observation, meaning, and regulative standards should be, and in fact usually are, nontrivially invariant with respect to scientific change.

In order to assess the tenacity of psychoanalysts in continuing to use a concept of psychic energy, it is advisable to consider whether, as they sometimes claim, the concepts of energy, force, and work in psychoanalysis are akin to those in the natural sciences. Strong disanalogies suggest that the psychoanalytic concepts are quite different and used equivocally even within psychoanalysis. However, they may not be subject to the objections which certain critical psychoanalysts have raised.

The conditions are examined under which one theory is said to be replaceable by another, while preserving those features of the original theory which made it serviceable for a given purpose. Among such replacements, special attention is given to ones which qualify as so-called reductions of a theory, and some theorems are proved concerning the notion of a reduction.

On the critical side it is argued that, contrary to a widespread view, the explanation of particular facts does not play a central role in pure science and hence that philosophers of science are misguided in supposing that the understanding of such explanations is one of the central tasks of the philosophy of science. It is suggested that the view being attacked may stem in part from an impression that the establishing of a general law is tantamount to the explanation of particular facts that “fall under” the law. This suggestion effects a bridge to the more positive part of the paper, which consists of an exploration of the complexities exhibited by the relation between the two activities. More specifically, I point out a number of disabilities, any one of which could prevent us from being able to explain particular facts that fall under a given law even after having established the law. Some of these have to do with the form of the law, and some have to do with our powers of detection vis-à-vis the particular facts in question. The former sort have to do with the ways in which laws may deviate from the strict-necessary-and-sufficient-condition ideal. The latter include the following points. (1) The individual explanatory factors may lie beyond our present powers of detection. (2) The complexity of such factors may be too great for us to be able to interrelate them. (3) We may be unable to apply concepts used in the law to facts in this area (although they are in fact applicable).

An attempt is made to provide a statement of the sufficient conditions for the functional equivalence of observable events in Psychology. Without a statement of those conditions, no explanation of functional equivalence in empirical situations can be achieved. A characterization of functional equivalence strictly in terms of the traditional S–R language is examined. This characterization is found to be inappropriate in that it entails vacuous mediators. A revision of S–R language is attempted in order to characterize functional equivalence. While this account does not entail vacuous mediators, it is unsatisfactory since it cannot be stated naturally in terms of the S–R language. It is argued that the degree to which the conditions for functional equivalence can be appropriately and naturally stated in theoretical languages provides a criterion for choosing among them as theoretical languages for psychology. A statement of the conditions for functional equivalence in terms of a TOTE analysis (see [5]) is then given. This is found to be more satisfactory than both the traditional and modified S–R analyses in that it does not entail vacuous mediators and in that a natural characterization of functional equivalence can be achieved.

The nature of the connection between theory and observation has been a major source of difficulty for philosophers of science. It is most vexing for those who would reduce the terms of a theory to those of an observation language, e.g. Carnap, Braithwaite, and Nagel. Carnap's work, particularly his treatment of physical theories as partially interpreted formalisms, forms the point of focus of this paper. Carnap attempted to make the connection between theory and observation through correspondence postulates. It is pointed out that such postulates depend in critical ways upon theoretical truths. This particular type of theoretical dependence produces serious trouble for Carnap's approach. For reasons given it may make it untenable. Furthermore, this problem when generalized creates difficulty for any similar reductionist program. Not only is this kind of theoretical dependence pointed out, but more important, the logical conditions which produce it are revealed. In this way light is shed upon the formal characteristics of the notion of theory dependence, especially upon the way in which observation terms depend upon theories for their meaning.

In this study of Auguste Comte's philosophy of science, an attempt is made to explicate his views on such methodological issues as explanation, prediction, induction and hypothesis. Comte's efforts to resolve the dual problems of demarcation and meaning led to the enunciation of principles of verifiability and predictability. Comte's hypothetico-deductive method is seen to permit conjectures dealing with unobservable entities.

If, as it is usually understood, incommensurable theories must be compatible then one need never choose between two such theories. But if theories were incompatible and incommensurable one would have to choose between them. What if they are incompatible only outside the domain of observation? The fact that Darwin's biology can clash with Kelvin's physics (each with their respective auxiliary assumptions) regarding the age of the earth shows how commensurable theories may yet be incompatible. But it also shows that they need not be alternatives—i.e. that one may not be able to simply and satisfactorily replace the other in our world view. But standard examples of scientific revolutions consist of the replacement of one theory by another in one's world view. These alternative theories must therefore be more than merely incompatible—what do they share if not content ? (I.e. they must be commensurable.)

James argued that time is a sensation, and the main point of this paper is to deny that claim. The concept of the specious present is explained, indicating how it clarifies the concept of “the present moment.” But neither it nor an argument used by Mach and James show time to be a sensation. The analysis presented here requires distinguishing concepts of sensation from concepts of temporal relations. James' view is really a theory that time-as-duration is sensed. But this assumes that the description of time as sensed is also a description of time as an objective property of independent events. This is nowhere established, and making it plausible is a recurrent problem for philosophies like neutral monism and radical empiricism.

Putnam and Finkelstein have proposed the abandonment of distributivity in the logic of quantum theory. This change results from defining the connectives, not truth-functionally, but in terms of a certain empirical ordering of propositions. Putnam has argued that the use of this ordering (“implication”) to govern proofs resolves certain paradoxes. But his resolutions are faulty; and in any case, the paradoxes may be resolved with no changes in logic. There is therefore no reason to regard the partially ordered set of propositions as a logic—i.e. as embodying a criterion for soundness of proofs. Its role in quantum theory ought to be understood in an entirely different way.

Philosophers of science have used various formulations of the “random mutation—natural selection” scheme to explain the development of scientific knowledge. But the uncritical acceptance of this evolutionary model has led to substantive problems concerning the relation between fact and theory. The primary difficulty lies in the fact that those who adopt this model (Popper and Kuhn, for example) are led to claim that theories arise chiefly through the processes of relatively random change. Systems theory constitutes a general criticism of this model insofar as it demonstrates the necessity of supplementing this mechanism with the non-random influences exercised by the internal organization of a system on its own development.

Inductive methods can be used to estimate the accuracies of inductive methods. Call a method immodest if it estimates that it is at least as accurate as any of its rivals. It would be unreasonable to adopt any but an immodest method. Under certain assumptions, exactly one of Carnap's lambda-methods is immodest. This may seem to solve the problem of choosing among the lambda-methods; but sometimes the immodest lambda-method is λ = 0, which it would not be reasonable to adopt. We should therefore reconsider the assumptions that led to this conclusion: for instance, the measure of accuracy.

In this paper I attempt to show that adaptational sentences (i.e. sentences containing the terms “adaptive”, “adapted”, etc.) in evolutionary biology are best interpreted as equivalent to sentences about Darwinian or genetical selection. Thus, the use of adaptational languages does not introduce final purposes or other nonempirical notions into biology. I also try to demonstrate that adaptational sentences and functional sentences are not equivalent in an evolutionary context so that an analysis of function does not dispense with the need for an analysis of adaptation. Finally, it is argued that, although some adaptational sentences might be construed as teleological explanations, given an empirical content, they do not serve as explanations. Rather, they express the outcome of selection, regarded in one way, and regarded in another, they express data for which a theory of evolution must account.

There are a standard number of replies to the riddle of induction, none of which has gained ascendency. It seems that a new approach is needed that concedes less to the Humean dialectic. Humeans, both traditional and contemporary, unwittingly play on the ambiguity of the phrase “change in the course of nature,” and that is why 'C · ~E' appears to be self-consistent, though in fact it is not. I provide an analysis of 'cause' and ‘natural necessity’ which gives inductive inference that internal warrant we assume it to have in ordinary and scientific thinking and rebut in advance contemporary Humean objections based on the erroneous assumption that ‘x is necessary’ and ‘x is a priori‘ are materially equivalent.

It is suggested that there is a strong connection between intentions and plans, and these plans are then taken to be programs of the sort suggested by Miller, Galanter, and Pribram in Plans and the Structure of Behavior. There is then a hierarchy of programs connected with intentions stretching from the macroscopic level of ordinary discourse to the neurological level. It is argued that as we proceed downwards we arrive at a threshold below which we can still describe the phenomena but below which we can no longer speak of intentions. The paper concludes with a discussion of the criteria for the identity of intentions at various levels.

Several standard conditions of adequacy for confirmation are considered and a conclusion of B. Skyrms regarding the converse-consequence condition is shown to be mistaken. Widely accepted conditions such as the entailment condition and the special consequence condition are shown to be open to counterexample, and confusion about these conditions is traced to confusion about the difference between two kinds of confirmation concepts—concepts of firmness and concepts of increase in firmness. The importance of concepts of the latter sort is stressed. Finally, some suggestions are offered relating to the notion of selective confirmation.