Foundational Problems in and Methodological Lessons from Quantum Field Theory

Abstract

Abstract One can consider the developments in quantum field theory from the point of view of foundational problems posed about physical reality at both the epistemological and ontological levels, or as a ‘laboratory’ to study the actual methodology of the scientific enterprise. I shall address both of these issues in this paper. My contention is that at the foundational level there is essentially nothing new in quantum field theory that is not already present in non-relativistic quantum mechanics. This is quite different in emphasis from the view expressed by Redhead (1983a). Even in quantum mechanics most of the difficulties which arise are generated by the realist’s inclination to take the formalism too literally as representing physical reality, often in a modified or distorted classical view. More serious consideration of Bohr’s philosophical framework of complementarity may prove fruitful for coping with this problem, which is not new to quantum field theory, being already the central interpretative problem of quantum mechanics. On the other hand, as a source to illustrate how theories arc constructed and established in actual scientific practice, quantum field theory does provide a wide range of useful examples. Here too, although there are many technically fascinating topics (such as renormalization), quantum field theory is pretty much (meth odological) business as usual. Much more interesting, essentially new, methodological departures are seriously proposed (with varying degrees of credibility) by some rival or alternative developments in modern theoretical physics, such as the S-matrix programme, with its bootstrap conjecture, or cosmology, with various forms of the anthropic principle (Gale 1983) and with the inflationary universe scenario (Guth 1981 ).