The article discusses Friedman's classic claim that economics can be based on irrealistic assumptions. It exploits Samuelson's distinction between two "F-twists" (that is, "it is an advantage for an economic theory to use irrealistic assumptions" vs "the more irrealistic the assumptions, the better the economic theory"), as well as Nagel's distinction between three philosophy-of-science construals of the basic claim. On examination, only one of Nagel's construals seems promising enough. It involves the neo-positivistic distinction between theoretical and non-theoretical ("observable") terms; so (...) Friedman would in some sense argue for the major role of theoretical terms in economics. The paper uses a model-theoretic apparatus to refine the selected construal and check whether it can be made to support the claim. This inquiry leads to essentially negative results for both F-twists, and the final conclusion is that they are left unsupported. (shrink)

The sheer multitude of criteria of empirical significance has been taken as evidence that the pre-analytic notion being explicated is too vague to be useful. I show instead that a significant number of these criteria—by Ayer, Popper, Przełęcki, Suppes, and David Lewis, among others—not only form a coherent whole, but also connect directly to the theory of definition, the notion of empirical content as explicated by Ramsey sentences, and the theory of measurement; two criteria by Carnap and Sober are trivial, (...) but can be saved and connected to the other criteria by slight modifications. A corollary is that the ordinary language defense of Lewis, the conceptual arguments by Ayer and Popper, the theoretical considerations by Przełęcki, and the practical considerations by Suppes all apply to the same criterion or closely related criteria. Furthermore, the equivalence of some criteria allows for their individual justifications to be taken cumulatively and, together with the entailment relations between nonequivalent criteria, suggest criteria for general auxiliary assumptions, comparative criteria, and more liberal conceptions of observation. (shrink)

This dissertation consists of three parts. Part I is a defense of an artificial language methodology in philosophy and a historical and systematic defense of the logical empiricists' application of an artificial language methodology to scientific theories. These defenses provide a justification for the presumptions of a host of criteria of empirical significance, which I analyze, compare, and develop in part II. On the basis of this analysis, in part III I use a variety of criteria to evaluate the scientific (...) status of intelligent design, and further discuss confirmation, reduction, and concept formation. (shrink)