The special relativity principle presupposes that the states of the physical
system concerned can be meaningfully characterized, at least locally, as such
in which the system is at rest or in motion with some velocity relative to an
arbitrary frame of reference. In the first part of the paper we show that
electrodynamic systems, in general, do not satisfy this condition. In the
second part of the paper we argue that exatly the same condition serves as a
necessary condition for the persistence of an extended physical object. As a
consequence, we argue, electromagnetic field strengths cannot be the
individuating properties of electromagnetic field---contrary to the standard
realistic interpretation of CED. In other words, CED is ontologically
incomplete.Comment: 14 pages, 4 figures. arXiv admin note: substantial text overlap with
arXiv:0912.438
