Edward MacKinnon

Rom Harré's proposed Copernican Revolution in the philosophy of science is a very ambitious undertaking. It challenges established views, proposes a radically new model for scientific explanation, and forces a rethinking of the foundations of the field. In his treatment of the natural sciences, Harré rejects all deductivist accounts of scientific explanation basically on the grounds that such accounts seriously distort the methods of explanation actually operative in science. In the social sciences Harré, in collaboration with Secord, rejects mechanistic, positivistic, and behavioristic accounts of human behavior [5]. In place of these discarded interpretations he substitutes a new realism which stresses the role that models play in supplying accounts of observed patterns of phenomena in terms of the things and processes whose interactions are responsible for the manifest phenomena. This revolution, if successfully carried out, would indeed be a valuable contribution to the philosophy of science.

There are two opposing traditions in contemporary quantum field theory (QFT). Mainstream Lagrangian QFT led to and supports the standard model of particle interactions. Algebraic QFT seeks to provide a rigorous consistent mathematical foundation for field theory, but cannot accommodate the local gauge interactions of the standard model. Interested philosophers face a choice. They can accept algebraic QFT on the grounds of mathematical consistency and general accord with the semantic conception of theory interpretation. This suggests a rejection of particle ontology. Or they can accept the standard model on the grounds of its established success. This alternative, which I defend, suggests revising philosophical accounts of scientific theory and finding some way of accommodating particles.

In place of earlier instrumentalist and phenomenalist interpretations of science both Quine and Sellars have developed highly influential realist positions centering around the doctrine that accepting a theory as explanatory and irreducible rationally entails accepting the entities posited by the theory. A growing reaction against this realism is partially based on perceived inadequacies in the doctrines of Quine and Sellars, but even more on reconstructions of scientific explanations which do not involve such ontic commitments. Three types of anti-realistic positions are considered and criticized. Hesse's neo-Duhemian position couples a statistical theory of inference to a downgrading of purely theoretical statements. Sneed uses the method of axiomatrization through set-theoretic predicates to supply a reconstruction of Kuhn's account of scientific development. Here Ramsey-reduction sentences serve to eliminate purely theoretical terms. The longest section deals with van Fraassen's semantic model based on a state-space representation of scientific theories and the use of this model in interpreting quantum mechanics. It is argued that the model is valuable, but that the anti-realist interpretation accorded it is not justified and entails serious inconsistencies