‘Ein Bleibender Kern’ — An Enduring Core

Abstract

The creation of the theory of relativity in the first two decades of this century drastically changed the inherited physical concepts of space and time. The vision of a unified theory of matter first appeared in the work of Mie, Hilbert, Weyl and Kaluza. But, at the same time, another revision of classical theory had begun which also affected the understanding of the notions of space and time; it led in the middle twenties to a consistent theory of the microscopic processes. Oskar Klein’s early attempts to unite the two lines of development failed, and we are not much closer now to a unified theory of matter. In the late nineteen-twenties already, certainly since Dirac’s theory of the electron, it became clear that electromagnetism was not the only force which had to be united with gravitation. In quick succession new forces and fields were discovered, and the existence of a massive particle with no charge at all destroyed the hopes of ever achieving an electromagnetic theory of matter.