No stage/actor split

Book IV refuses the usual picture in which passive spacetime hosts active particles and forces. At E_1, the carrier is the only available physical substrate, so particles, forces, mass, energy, charge, entropy, chemistry, and matter must be read as organized regimes of the carrier itself. This is not a metaphor: it is the construction rule for the microcosm. Nothing may enter as a primitive actor on a background stage; every physical kind must be an invariant readout of carrier structure.