Working with Fred on action at a distance
This paper reviews the work the author carried out with Fred Hoyle on the development of electrodynamics and gravitation as direct particle theories. In this account the author reviews how the work was started, and went through stages of increasing sophistication, e.g., extending the Wheeler-Feynman electrodynamics to curved spacetime, its consequences in different cosmologies, and the issues arising from its quantization. The resolution of ultraviolet divergences in quantum electrodynamics is also briefly discussed. The parallel development of a Machian theory of gravitation followed the lead from electrodynamics. In both theories one sees a strong link between the large scale structure of the universe and local physics, as might be expected from an action-at-a-distance framework. It is recalled why Fred considered this an important aspect of a physical theory.