Beyond representations: from active inference to active interference.

Active inference describes the system-environment boundary through statistical constructs such as the Markov blanket, a substrate-independent formalism that specifies a boundary's functional role without committing to the physical structure realizing it. We ask what structure can perform that role, and propose Active Interference as a complementary, biophysically grounded layer beneath the statistical description. We argue that biological boundaries are physically instantiated, resonant interfaces-lipid membranes coupled to vicinal water and endogenous electromagnetic fields-capable of wave superposition and history-dependent feedback. We present a minimal formalism for interference-based write/read cycles in which the substrate does not carry a representation but constitutes it. Inference is thereby grounded in interference, yielding an ontology of biological autonomy with phase-specific, falsifiable predictions.