Selective scientific realists disagree on which theoretical posits should be regarded as essential to the empirical success of a scientific theory. A satisfactory account of essentialness will show that the (approximate) truth of the selected posits adequately explains the success of the theory. Therefore, (a) the essential elements must be discernible prospectively; (b) there cannot be a priori criteria regarding which type of posit is essential; and (c) the overall success of a theory, or ‘cluster’ of propositions, not only individual (...) derivations, should be explicable. Given these desiderata, I propose a “unification criterion” for identifying essential elements. (shrink)

Structural realism is an attempt to balance the competing demands of the No Miracles Argument and the Pessimistic Meta-Induction. In this paper I trace the development of the structuralist idea through the work of one of its leading advocates, John Worrall. I suggest that properly thought through what the structuralist is offering or should be offering is not an account of how to divide up a theory into two parts—structure and ontology—but (perhaps surprisingly) a certain kind of theory of meaning—semantic (...) holism. I explain how a version of structural realism can be developed using Davidson’s theory of meaning and some advantages this has over the Ramsey-sentence version of structuralism. (shrink)