A case study of the development of quantum field theory and of S-matrix theory, from their inceptions to the present, is presented. The descriptions of science given by Kuhn and by Lakatos are compared and contrasted as they apply to this case study. The episodes of the developments of these theories are then considered as candidates for competing research programs in Lakatos' methodology of scientific research programs. Lakatos' scheme provides a reasonable overall description and a plausible assessment of the relative (...) value of these two programs in terms of progressive and degenerating problem shifts. Also discussed are the roles of various types of models as they have been used in these areas of theoretical high-energy physics. (shrink)

In this paper I first describe some simple, but interesting string theory. Then I discuss string field theory and suggest that even though we do not have a complete mathematical formulation, we can get an idea of some of its ontological implications. Next, the significance of supersymmetry and superspace in string theory is briefly considered. Lastly, I consider the question of whether there is, in fact, (good) reason to think string theory may (or will) emerge to replace quantum field theory.

The assumption that a classical gravitational field interacts with a quantum system is shown to lead to violations of either momentum conservation or the uncertainty principle, or to result in transmission of signals faster thanc. A similar argument holds for the electromagnetic field.

Introduction: The Winding Road to Quantum Gravity Abhay Ashtekar Traveler, there are no paths; Paths are made by walking. ...

Department of Physics. String theory is, at present, the only quantum mechanical theory of gravity interacting with matter which is not known to be inconsistent. While the theory is still rather far from making testable predictions, it does offer the prospect of realistic model-building in the not-too-distant future. Perhaps more importantly, it can serve as a theoretical testing ground for developing our ideas about what concepts like locality and general covariance mean in a quantum mechanical framework.