This paper presents a representational theory of derived physical measurements. The theory proceeds from a formal definition of a class of similar systems. It is shown that such a class of systems possesses a natural proportionality structure. A derived measure of a class of systems is defined to be a proportionality-preserving representation whose values are n-tuples of positive real numbers. Therefore, the derived measures are measures of entire physical systems. The theory provides an interpretation of the dimensional parameters in a (...) large class of physical laws, and it accounts for the monomial dimensions of these parameters. It is also shown that a class of similar systems obeys a dimensionally invariant law, which one may safely subject to a dimensional analysis. (shrink)

The traditional role which correspondence rules, coordinating definitions, or semantical rules, have in a logical analysis of a scientific theory is questioned by providing an alternative analysis. The alternative account suggests that scientific theories are "meaningful" prior to the establishment of correspondence rules, and that correspondence rules are introduced to permit explanation and testing in the "observational" sector. The role of models is briefly assessed in connection with this prior or "antecedent theoretical meaning," and a causal sequence analysis of a (...) class of correspondence rules is presented which makes explicit the interdependence of scientific theories. (shrink)

1. Introduction. Professor Nagel's account of the “cognitive status” of scientific theories has been attacked by P. K. Feyerabend [5] and M. B. Hesse [8] in terms of his alledgedly misguided distinction between experimental laws and theories. The difficulty lies, these critics agree, in Nagel's attempt to find a stable basis for scientific theories in an observational basis of experimental laws. Both Feyerabend and Hesse note the vacillation in Nagel's account of the stability of the meaning of experimental terms and (...) in his discussion of the status of observational as opposed to theoretical terms. They find Nagel too “positivistic” and see as a first step toward a more adequate account of scientific theories the abandonment of the theoretical-observational dichotomy as having more than a pragmatic significance. Nagel's discussion of the theoretical-observational dichotomy is, I agree, inadequate in certain respects. I shall, however, suggest a quite different remedy from those of Feyerabend and Hesse, one that depends neither on a phenomenalistic reduction of theoretical entities nor on a blurring of the theoretical-observational dichotomy. (shrink)