chiefly concerned with the question of whether acceptance of such theories reasonably entails acceptance of the 'theoretical entities’ posited or presupposed by these theories.
The chief examples of such deep constructive theories in physics are atomism and particle physics. While speculative atomism has a venerable history, atomism did not develop as a science until the twentieth century. Atomism, especially as developed in the Copenhagen tradition, and particle physics, especially since World War II, have been characterized by a close continual interaction between experimenters and theoreticians. Elsewhere (MacKinnon, 1982) I have attempted to trace the role this dialog, and the language in which it was conducted, played in the development of atomic theory and quantum physics. Almost any survey of the development of particle physics emphasizes an even stronger interaction. Any particular theories offered, e.g., of the anomalous Zeeman effect, of the helium atom, of weak or strong interactions, emerge from and are modified through this ongoing dialog. This requires a common language where the basic terms have meanings through their use, rather than through particular theories. This language is LCP with the inclusion of new terms that go beyond classical physics. The issue here is not the classical/quantum divide, but the conditions of the possibility of meaningful dialog.
Theories as developed by physicists reflect temporal slices in this historical process. However, one can prescind from such temporal and dialectical qualifications and make theories as such an object of philosophical analysis. As van Fraassen (1991, p. 1) put it: “Philosophy of science has focused on theories as the main products of science, more or less in the way philosophy of art has focused on works of art, and philosophy of mathematics on arithmetic, analysis, abstract algebra, set theory, and so forth.” This is an appraisal of the role to be accorded theories as such, rather than particular types of theories. The truth of scientific claims is seen as derivative from the truth of theories36.
I will not attempt an appraisal of such analyses of theories. Instead I will simply sketch a scenario that calls the objectivity of physics into question. It runs as follows. Questions such as the objectivity or realistic significance of theories are best addressed by isolating a theory from the temporal flux of scientific development and making it an object of study in its own right. An adequate analysis generally requires a critical reconstruction of a theory. Functioning theories often involve dirty math, or mathematical formulations justified on physical grounds. Since they are often tailored to fit experimental discoveries, it is often difficult to separate the consequences of the theory from the interpretative presuppositions of the theorists. This is remedied by supplying a rigorous mathematical foundation and explicit rules of inference.
Different arguments may support the same conclusion that the philosophical consequences of theories are best studied by rational reconstruction of the theories to be interpreted. This, as noted earlier, leaves no role for linguistic analysis or material inferences. There is a renewed reliance on the theoretical/observational distinction. The concession that most observation reports rely on theory-laden terms is minimized by the suggestion that it should be possible in principle to eliminate such theory-laden terms. Theories, so construed, fit into a larger perspective. Physics advances by developing new theories to replace presently accepted theories. Theories rejected as inadequate cannot be considered true. Though the substructures differ markedly, the overall structure is quite
36 For a different appraisal de-emphasizing the role of fundamental theories as grounds of truth claims see Cartwright (1983)