Models of the world, data-models and the practice of science : the semantics of quantum theory
The most important problems in the philosophy of quantum mechanics are the problem of measurement and the problem of the 'acausal' EPR correlations. It is commonly thought that these problems call for a new interpretation of the quantum theory. I argue that it is possible to construe both problems rather differently, as resulting from a mistaken understanding of scientific theory-application. It then becomes possible to tackle both problems independently of questions of interpretation, by attending carefully to what constitutes a successful application of a scientific theory, and of the quantum theory in particular. In the first part of the Thesis, I argue against a standard conception of scientific theory-application. This standard conception, which is often presupposed in the philosophical discussions of quantum mechanics, takes the applications of a scientific theory to constitute its domain of empirical adequacy. I argue that, on the contrary, a scientific theory can be applied to phenomena that it does not subsume. I present a case study in the history of superconductivity to illustrate and to motivate this claim. In the second part, I argue that the problem of measurement can be construed as the impossibility of applying the quantum theory to measurement interactions. I then argue that Arthur Fine's proposed solution to the measurement problem implicitly abandons the standard conception of application. Finally I look at quantum correlation phenomena. Bas Van Fraassen has claimed that the EPR correlations fit no causal model. The correctness of this claim depends on what probabilistic constraints a causal model is taken to have to satisfy. I argue, following Nancy Cartwright, that Van Fraassen's constraints on common-cause models are too strong; and I describe a direct-cause model that, I urge, constitutes a successful application of the quantum theory to the EPR correlations.