Abstract

Comparing action-at-a-distance electrodynamics in the tradition of Coulomb and Ampère with electromagnetic field theory of Faraday and Maxwell provides an example for a relation between theories, that are on a par in many respects. They have a broadly overlapping domain of applicability, and both were widely successful in explanation and prediction. The relation can be understood as an inhomogeneous reduction without a clear distinction between reducing and reduced theory. It is argued in general, when a clear hierarchy between competing theories cannot be determined, the plurality of standpoints should be preserved and the bridge laws carefully developed.