It is often claimed that there can be no such thing as a logic of scientific discovery, but only a logic of verification. By ‘logic of discovery’ is usually meant a normative theory of discovery processes. The claim that such a normative theory is impossible is shown to be incorrect; and two examples are provided of domains where formal processes of varying efficacy for discovering lawfulness can be constructed and compared. The analysis shows how one can treat operationally and formally phenomena that have usually been dismissed with fuzzy labels like ‘intuition’ and ‘creativity’.

The problem of the critical assessment of theories across paradigms raised by Kuhn is not resolved, it is argued, either by Scheffler's appeal to initial credibility or by Lakatos' conception of a research program. It is argued further that, in these contexts, the notion of reasonable choice by individuals makes no sense. The conclusion supports Feyerabend's position of “epistemological anarchism.”

In this paper I prove a theorem which is similar to Arrow's famous impossibility theorem. I show that no social welfare function can be both minimally majoritarian and also independent of irrelevant alternatives. My condition of minimal majoritarianism is substantially weaker than simple majority rule.

A four dimensional approach to Newtonian physics is used to distinguish between a number of different structures for Newtonian space-time and a number of different formulations of Newtonian gravitational theory. This in turn makes possible an in-depth study of the meaning and status of Newton's Law of Inertia and a detailed comparison of the Newtonian and Einsteinian versions of the Law of Inertia and the Newtonian and Einsteinian treatments of gravitational forces. Various claims about the status of Newton's Law of Inertia are critically examined including these: the Law of Inertia is not an empirical law but a definition; it is not a law simpliciter but a family of schemata; it is a convention and gravitational forces exist only by convention; it is (or is not) redundant; the concepts it embodies can be dispensed with in favor of operationally defined entities; it is unique for a given theory. More generally, the paper demonstrates the importance of space-time structure for the philosophy of space and time and provides support for a realist interpretation of space-time theories.

It is argued in this paper that the valid argument forms coming under the general heading of Demonstrative Induction have played a highly significant role in the history of theoretical physics. This situation was thoroughly appreciated by several earlier philosophers of science and deserves to be more widely known and understood.

A philosophy might take its general inspiration from (1) commonsense; (2) careful observation; (3) philosophical argumentation; (4) the sciences; (5) “higher” sources of illumination. It is argued in this paper that it is bedrock commonsense, and the sciences, which are the most reliable foundations for a philosophy. This result is applied to the discussion and defense of a materialist theory of the mind.

This paper defends a realist interpretation of theories and a modest realism concerning the existence of quantities as providing the best account both of the logic of quantity concepts and of scientific measurement practices. Various operationist analyses of measurement are shown to be inadequate accounts of measurement practices used by scientists. We argue, furthermore, that appeals to implicit definitions to provide meaning for theoretical terms over and above operational definitions fail because implicit definitions cannot generate the requisite descriptive content. The special case of establishing a temperature scale is examined to show that nonrealist accounts fail to provide insight into the theoretical connections that scientific laws postulate to hold among quantities.

The measurement of force is based on a formal law of additivity, which characterizes the effects of two or more configurations on the equilibrium of a material point. The representing vectors (resultant forces) are additive over configurations. The existence of a tight interrelation between the force vector and the geometric space, in which motion is described, depends on observations of partial (directional) equilibria; an axiomatization of this interrelation yields a proof of part two of Newton's second law of motion.

The present results (which were derived from a curious and deep isomorphism between force measurement and trichromatic color measurement) yield a kind of subunit, which needs to be incorporated into more complete axiomatizations of mechanics that would fulfill the Mach–Kirchhoff program.

We consider the mind-dependence or independence of the “now,” of “becoming,” and of “time's arrow,” by considering the various senses in which these notions might be mind-dependent or not. These matters cannot be sensibly discussed without taking a stand regarding criteria of “reality.” Proceeding from a basically phenomenalist position we conclude that merely to differentiate between appearance and reality is implicitly to assume a directed flow of time. We discuss the relationship between phenomenological and physical time and their possible asymmetries. We find that physical time acquires meaning only through phenomenological time, and that phenomenological time is fundamentally asymmetric. This still leaves room for the question: Is there anything in physical time which reflects the fact that it, to be meaningful, must be applied asymmetrically? The relevance of relativity theory to this question is discussed.

It is well known that a degree-of-belief function P is coherent if and only if it satisfies the probability calculus. In this paper, we show that the notion of coherence can be extended to higher order probabilities such as P(P(h) = p) = q, and that a higher order degree-of-belief function P is coherent if and only if it satisfies the probability calculus plus the following axiom: P(h) = p iff P(P(h) = p) = 1. Also, a number of lemmata which extend an incomplete probability function to a complete one are established.

Some philosphers of science of an empiricist and pragmatist bent have proposed models of statistical explanation, but have then become sceptical of the adequacy of these models. It is argued that general considerations concerning the purpose of function of explanation in science which are usually appealed to by such philosophers show that their scepticism is not well taken; for such considerations provide much the same rationale for the search for statistical explanations, as these philosophers have characterized them, as they do for lawlike explanations.

But, it is further argued, a significant piece of what is frequently offered as an explanation of well known phenomena in statistical mechanics, fails to meet this general “pragmatic rationale” for statistical, or indeed any kind of, explanation. The question then arises whether the physicists have misconstrued the value of this piece of physical theorizing, ergodic theory, taking it to be explanatory when it is actually not; or whether, instead, the philosopher's account of just what is genuinely explanatory is too narrow.

Within Special Relativity accelerated systems can be described as those systems in which standard clock synchronism does not hold. Therefore, the ε-generalized Lorentz equations derived by Winnie are the equations governing accelerated systems. The ε-generalized equation for time is used in analyzing two cases of the clock paradox: (1) the case in which a clock travels in a straight line, stops, and returns, and (2) the case in which a clock travels with uniform velocity in a circular path. The treatment of case (1) of the paradox within this generalization of the Special Theory is compared with Møller's treatment of it within the General Theory.

An axiom set is given which purports to formalize the notion of a “theory involving measurement.” The abstract objects satisfying these axioms are examined, and some candidates for measures of complexity are considered.

This framework allows us to discuss some forms of a degree of confirmation. Both “complexity” and “degree of confirmation” appear to be intimately bound up with geometrical aspects of these “theories” which derive from measurement considerations, suggesting that the concepts may be inapplicable to more “general theories.”

The view is taken throughout that the well known paradoxes indicate inadequacies of the linguistic apparatus and that the axiomatization here presented is an attempt to construct an adequate language for the relevant portion of the world. This position is not defended in the paper.

Many philosophers have asserted that evolutionary theory is unfalsifiable. In this paper I refute these assertions by detailing some falsifiable predictions of the theory and the evidence used to test them. I then analyze both these predictions and evidence cited to support assertions of unfalsifiability in order to show both what type of predictions are possible and why it has been so difficult to spot them. The conclusion is that the apparent logical peculiarity of evolutionary theory is not a property of evolutionary theory; it is a property of our human-sized perspective on evolutionary theory.

Some scientists believe that although evolutionary theory is explanatory, it does not have, in contrast to the theories of physics, any predictive power. This raises the question of its testability. The analysis given shows that there are good reasons to claim the unpredictability of evolutionary events; nevertheless, the evolutionary theory has potential predictive power. It is argued that the difference between biology and physics lies not in the predictive power of the theories involved, but in the different weight which is lent to the forecasting of particular events in these sciences. A second source of confusion derives from the ambiguity of the term ‘prediction’. In order to define ‘prediction’ for cases in which the term is used to refer to a part of testing procedure, the reference to the time-point “now” is quite irrelevant. Prediction of unknown observational data is sufficient for testing a hypothesis, but such prediction may or may not be identical with forecasting of future events. Different factors that may cause particular difficulties met by biologists in forecasting future events are analyzed subsequently in the second part of the paper. The conclusion is drawn that although particular cognitive situations limiting the ability of forecasting are very frequent in biological sciences, the claim about the peculiar logical status of biological theories is not thereby justified.

It has been alleged that Bayesian usage of prior probabilities allows one to obtain empirical statements on the basis of no evidence whatever. We examine this charge with reference to several examples from the literature, arguing, first, that the difference between probabilities based on weighty evidence and those based on little evidence can be drawn in terms of the variance of a distribution. Moreover, qua summaries of vague prior knowledge, prior distributions only transmit the empirical information therein contained and, therefore, their consequences for long-run frequency behavior are “a priori” in at best a Pickwickian sense.