Existing “no hidden variable proofs” for quantum mechanics deal exclusively with observables with discrete spectra. This note shows that similar results hold for observables with continuous spectra.

It may seem trivial to state that one of the major trends in biological investigation consists in an attempt to explain the structural and functional aspects of living matter in chemical terms, in an effort to obtain insight into the equivalent of macroscopic phenomena on the molecular level. I am sure you are aware of, and this meeting of the Association has brought ample additional evidence, in how many fields this tendency has become apparent. It can be recognized in genetics with the molecular analysis of chromosomes and the enzymatic or metabolic interpretation of hereditary properties like the eyecolor of Drosophila. In a purely morphological branch like histology we do not ask merely for a differentiation of stained cell structure but we ask for the nature of the staining reaction; in nerve physiology we try to interpret conduction as alterations of protein lipoid layers; or in pathology where the age old syndrome of inflammation is explored with biochemical methods. I should mention molecular models of membranes and cell surfaces, the molecular interpretation of secretion and of the macroscopic phenomena of metabolism. Yet insofar as this yield of data could be designated as a trend, it would rather seem to be the natural outcome to be expected from the application of the analytic method of science. In one instance, however, this approach has been carried farther than in all the other fields, and it would seem to be worthwhile to pause for one moment to ask whether this case is important merely because of its technical implications or whether it is meaningful in a wider sense.

Calibrating a simulation is a crucial step for certain kinds of simulation modeling, and it results in a simulation that is epistemically different from its pre- or uncalibrated counterpart. This article discusses how simulation model builders mitigate uncertainty about model parameters that are necessary for modeling through calibration and argues that the simulation outcomes after calibration are physically meaningful and relevant. When evaluating the epistemic status of computer simulations, comparisons between computer simulations and traditional experiments need to consider this important methodological step.

I argue that Carl Hempel’s pioneering work on scientific explanation introduced an assumption that Hempel never motivated, namely, that explanation is an aim of science. Ever since, it has remained largely unquestioned in analytic philosophy of science. By expanding the historical scope of the debate on explanation to philosophers from the first half of the twentieth century, I show that the debate should include a critical reflection on Hempel’s assumption. This reflection includes two problems: how to motivate one’s position on the aims of scientific knowledge and how to decide which examples count as expressions of those aims.

The possibility of a sub-quantum mechanical realm has been investigated in recent years by DeBroglie, Bohm, Vigier, and others. It is felt that what is needed in this investigation is some simple and direct resolution of the problem as to whether sub-quantum entities exist or not. By restricting attention to quanta of light energy there is presented a theoretical expression for a sub-quantum or micro-photon which has proven to be testable. It is possible by this development to bridge the particle-wave duality wherein these two conceptions become arithmetically commensurate with one another. The theoretical expression derived for the micro-photon also leads to a different interpretative approach to Planck's constant as well as the appearance of a new unit or element of mass.

The charge that the limit-frequency theory of probability is inconsistent due to incompatibility between the required features of randomness and limit convergence is inapplicable when probability sequences are taken to be empirically (i.e., extensionally) generated, as they must be on a strictly empirical conception of probability.

All past attempts to meet this charge by formulating constructive definitions of randomness that would still allow for a demonstrable limit-convergence have, in their exclusive concern with logically (i.e., intensionally) prescribed sequences, left the logic of extensional classes essentially untouched. In the light of a strict differentiation between intensional and extensional classes a generalized approach is possible under which several closely connected senses of randomness, i.e., the formal, material, restricted and unrestricted senses may be easily distinguished and related to the notion of relevance.

Dirac's classical electrodynamics countenances “preaccelerations” of charged particles at a time t as mathematical functions of external forces applied after the time t. These preaccelerations have been interpreted as evidence for physical retrocausation upon assuming that, in electrodynamics no less than in Newton's second law, external forces sustain an asymmetric causal relation to accelerations. And this retrocausal interpretation has just been defended against the critiques in (Grünbaum 1976), (Grünbaum and Janis, 1977 and 1978) by appeal to the formal assimilation of the electrodynamic laws of motion to Newton's second law. It is argued below that this latest defense of the retrocausal interpretation is even more ill-founded than the prior ones in the literature.

In this paper I assess Gopnik and Meltzoff's developmental psychology of science as a contribution to the understanding of scientific development. I focus on two specific aspects of Gopnik and Meltzoff's approach: the relation between their views and recapitulationist views of ontogeny and phylogeny in biology, and their overall conception of cognition as a set of veridical processes. First, I discuss several issues that arise from their appeal to evolutionary biology, focusing specifically on the role of distinctions between ontogeny and phylogeny when appealing to biology for theoretical support. Second, I argue that to presuppose that cognition is veridical or “truth-tropic” can compromise attempts to understand scientific cognition both throughout history and in the present. Finally, I briefly sketch an evolutionary approach to understanding scientific development that contrasts with Gopnik and Meltzoff's.

In our discussion of rigidity, we agreed to set external differential forces equal to zero, or to correct our instruments for the effects of such forces. Let us suppose that we were in the presence of an electrostatically charged gravitational body. That is, the gravitational body (e.g. the sun) would have some electrostatic charge (as is probably the case for the sun). If we corrected our rods and clocks for the effect if any of this differential force (which would certainly be negligible in any case, so far as spatial geometry is concerned), we might then expect that the geometry of the field would be the same as when the gravitational body is uncharged. But is this the case? Not at all! And the explanation is not far to seek: the charge contributes energy to the field; but energy, by relativity theory, is equivalent to mass, and mass always modifies the gravitational potential. Hence, the geometry of the charged gravitational field (which depends on the potential) must be different from the uncharged.

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.