 So, here’s the detail of the objection. Lorentz’s theory was born of Newtonian mechanics and Maxwellian electrodynamics (Janssen 2002: 423): the latter incorporated electric and magnetic fields, but made no pronouncements at all concerning other forms of matter. Thus, although we can extend the Lorentzian theory to all laws governing matter, we have no reason to do so. It just happens to turn out that the laws governing matter all instantiate this property. Craig Callender (2008) makes the point clearly, as follows: