Consciousness as a Boundary Phenomenon: A Process-Ontological Framework for the Quantum-Classical Transition and Testable Predictions

What physical process underlies the transition between unconscious and conscious brain states? Indicators such as the Perturbational Complexity Index (PCI) can track consciousness level with clinical reliability, yet the mechanism that generates conscious experience remains unspecified. We develop a framework—the Boundary Process Hypothesis (BPH)—built on a single empirically risky identification: we propose that consciousness be identified with the quantum-to-classical decoherence transition as experienced from the inside. On this view, what we call 'experience' is the dynamical process through which quantum coherence is irreversibly lost and effective classicality takes hold—the decoherence/einselection process described by Zurek (2003). The hard problem of consciousness and the measurement problem of quantum mechanics, on this reading, turn out to be external and internal descriptions of one and the same physical event. We position BPH relative to Integrated Information Theory, Orchestrated Objective Reduction, and recent work on quantum-classical hybrid agency, then derive three falsifiable predictions: (P1) decoherence-related proxy signatures (spectral entropy and excess noise ratio from NV-diamond magnetometry) should covary with PCI scores under pharmacological modulation; (P2) experienced meditators should show detectable proxy differences versus controls; (P3) graded anesthetic depth should map onto monotonically changing decoherence complexity profiles. We sketch protocols for each, including a near-term in vitro pilot. Falsification is explicit: if the decoherence-proxy model fails to improve consciousness-level prediction over a classical-only baseline by at least ΔR² ≥ 0.05 across two independent datasets, the empirical core of BPH is disconfirmed.