Abstract
Taking the position that scientific hypotheses explain the world and do not merely classify data, the author describes the decline of the Newtonian world picture and the development of a new, "ether-theoretical" view. The nineteenth century founders of electromagnetism—Faraday, Maxwell, Hertz, Lorentz—all tendered theories of a medium, usually called the "ether," which filled the space between any two noncontiguous bodies and transported electromagnetic actions from one to the other. After Einstein profoundly reinterpreted the concept of medium, it came to be called the "field." In giving this history, William Berkson explains what problems each scientist faced and how the process of solving them led to new discoveries. He also draws out the philosophical consequences of the history, especially for the positions of Popper, Meyerson, Agassi and Kuhn.