Abstract

The quantum vacuum is a zero-temperature, maximally entangled state whose virtual processes rigorously refuse on-shell propagation and classical localisation (Peskin & Schroeder 1995; Weinberg 1995). The observable classical world therefore emerges through near-total erasure of ∼10⁹³ bits m⁻³ of vacuum entanglement density (’t Hooft 1993; Susskind 1995; Bousso 2002). Living human cortex is the only known macroscopic system that systematically sustains a small but reproducible deviations from perfect classical pointer-state purity. Near-critical dynamics (Beggs & Plenz 2003; Shriki et al. 2013) combined with an unusually low-loss intracerebral electromagnetic cavity below ∼100 Hz (Kucewicz MT, et al., 2024) allow residual quantum correlations to persist on perceptual timescales (tens to hundreds of milliseconds). Current upper bounds on the entropy of these residuals, derived from long- range temporal correlations, avalanche criticality, and participation-ratio analyses during waking consciousness, lie in the range 40–150 bits per ∼50 ms frame (Luppi et al. 2019; Luppi & Mediano 2024). We hypothesise that phenomenal consciousness — the brute fact that experience feels like something — is physically identical to this faint, topologically non-trivial deviation: the largest and most persistent residual quantum entropy deficit that thermodynamics permits in a warm, wet, macroscopic system. The unity, privacy, finite capacity, and precise fragility of the conscious present under general anaesthesia (Demertzi et al. 2019; Tagliazucchi 2017) then follow from standard open-quantum-system physics (Zurek 2003, 2018) applied to a near-critical network with unusually slow environmental decoherence. No objective collapse, no microtubule quantum computation, and no new fundamental fields or forces are required. The hard problem is thereby bounded, not solved: it reduces to explaining why the residual quantum memory permitted by physics is so extraordinarily small (≲ 150 bits) and why it is shaped exactly as human phenomenology reports.