| Van Fraassen, in The Scientific Image, uses Reichenbach's Principle of Common Cause to state the realist's position on scientific research strategies. Van Fraassen then claims, on the basis of his version of Bell's argument, that quantum mechanics is a couterexample to the doctrine of realism. This construal of realism is not adequate, and a more adequate formulation is developed in the first chapter of this thesis. The essential strategy of science, it is argued, is to aim for a greater unification of its concepts. An attempt is made in chapter 1 to capture this notion using the formal ideas of the so-called semantic view of theories as developed by Sneed and others. The result is that unification should be construed as the achievement of simple connections across theory applications (formally construed by Sneed as constraints of classes of models). Less formally the idea is developed as "cross-situational invariance" or "robustness" or "resiliency".;Finally, van Fraassen's original charge that quantum mechanics is a counterexample to realism is confronted in chapter 5, after formulating some of the conceptual difficulties with quantum statistics in a general way in chapter 4. The realist must give up the principle of locality, but it is argued that this need not be a high price for the realist. For it is possible to represent the quantum phenomena in terms of a model of two-way causation that achieves the "cross-situational invariance" desired by the realist without violating the relativistic taboo on causal action along space-like paths.;Two crucial difficulties with probabilistic causality are identified in chapter 2. One is the old problem of capturing the temporal asymmetry of "cause", while the other is a problem of definability when conditional probabilities are 0 or 1. A better theory of causality is developed in chapter 3 under the guidance of the realist principles as explicated in chapter 1. This theory follows the basic ideas of von Wright's "manipulability account of causality", or the intervention account (after H. Simon). The method of path analysis is thereby re-interpreted. |
