Chapter 68: The Ontological Layer Architecture

Every object in the τ³ physics stack lives at exactly one of three ontological layers: L0 (the math kernel), L1 (internal physics), and L2 (the SI bridge). This chapter defines the layers, classifies every key equation to its layer, introduces the readout functor R_μ that maps internal identities to measurement procedures, and establishes that the entire derivation chain requires only one empirical input—the neutron mass—plus four exact SI constants.