What spacetime does: ideal observers and (Earman's) symmetry principles

The interpretation and justification of Earman's symmetry principles (stating that any spacetime symmetry should be a dynamical symmetry and vice-versa) are controversial. This is directly connected to the question of how certain structures in physical theories acquire a spatiotemporal char-acter. In this paper I address these issues from a perspective (arguably functionalist) that relates the clas-sical discussion about the measurement and geometrical determination of space with a characterization of the notion of dynamical symmetry in which its application to subsystems that act as measuring devices plays an essential role. I argue that in order to reformulate and justify Earman's principles, and to provide a general account of the chronogeometrical character of some structures, the existence of a coordination between two notions of congruence, one mathematical and one dynamical, must be assumed for the in-terpretation of physical theories. This coordination provides the basis on which we can understand space-time in physical theories as the codification (representation) of certain features of the access ideal observ-ers have to experience.