Abstract

What precisely does it mean to unify fields like the electric and magnetic field to only one field? Are there different kinds of unification? Is there only ‘unified’ and ‘not unified’, or could a unififcation of fields also be partially succesful? I will argue that what is normally referred to as the project of a unified field theory is actually a bundle of three research programmes that are logically independent of each other. The sub-programmes are those of a unified field theory, a complete field theory, and a geometrised field theory. Here I will focus on the programme of a unified field theory in a narrow sense. In particular, I will make use of an almost unknown debate between Einstein and Pauli about which criteria a unification of fields should fulfil, in order to distinguish between different degrees of unification in field theories