  Weyl lists two reasons in support for his agens theory of matter.  First, the agens theory of matter is the only theory which coheres  with the basic experiences of life and physics: matter generates the  field and all our actions ultimately involve matter. For example,  only through matter can we change the field. Secondly, in order to  understand the fact of the existence of charged material particles,  we have two possibilities: either we follow Mie and adopt a pure  field theory of matter, or we elevate the ontological status of  matter and regard it as a real singularity of the field and  not merely as a high concentration of field energy in a tiny region  of spacetime. Since Mie’s approach is necessarily limited to the  framework of the theory of special relativity, and since there is no  room in the general theory of relativity for a generalization and  modification of the classical field laws, as envisaged by Mie in the  context of the special theory of relativity, Weyl adopted the second  possibility. He was motivated to do so by his recognition that the  field equation of an electron at rest contains a finite mass term  \(m\) that appears to have nothing to do with the energy of the  associated field. Weyl’s subsequent analysis of mass in terms of  electromagnetic field energy provided a definition of mass and a  derivation of the basic equations of mechanics, and led Weyl to the  invention of the topological idea of wormholes in spacetime. Weyl did not use the term ‘wormholes’; it was John  Wheeler who later coined the term ‘wormhole’ in 1957.  Weyl spoke of one-dimensional tubes instead.  “Inside” these tubes no space exists, and their  boundaries are, analogous to infinite distance, inaccessible; they do not belong to the field. In a chapter entitled “Hermann Weyl  and the Unity of Knowledge” Wheeler (1994) says, 