 The final issue we have discussed in this article is that of (iii) whether spacetime structures are substantial entities in their own right, metaphysically speaking not grounded on facts about dynamical laws, or whether instead it is best to think of the reality of spacetime structures as dependent upon, and explained by, facts about the world’s dynamical laws, as advocates of the dynamical approach maintain. The debate here is not the same as that between classical relationism and substantivalism, although there are clear affinities between the dynamical approach and classical relationism. We explored how this issue takes quite different forms in the context of special relativistic (Lorentz covariant) physical theories and in the context of general relativistic theories.