Minimal Measurement Set (MMS): The Observational Floor for Phase-State Diagnosis

This paper introduces the Minimal Measurement Set (MMS), a diagnostic framework that specifies the minimal observational conditions required to meaningfully diagnose phase-state health in complex systems. Contrary to the common framing of systemic collapse as unpredictable, this work argues that collapse is often unmeasured rather than unforeseeable. Performance metrics, while useful for optimization, systematically fail to capture structural vulnerability, irreversibility, and latent degradation. MMS addresses this gap by fixing the observational floor—the smallest set of variables without which phase-state diagnosis becomes structurally incomplete. MMS consists of six orthogonal variables:resonance magnitude (|PLV|), distance to irreversibility (D), intervention window (IW), Buffer–Path–Rollback structure (BPR), hysteresis delay (τ), and dark phase magnitude (Φ_Dark).Together, these variables define a measurement geometry that locates systems within phase-state space according to present intensity, accumulated historical constraint, and remaining recoverability. Importantly, MMS is not a predictive, prescriptive, or normative framework. It does not define optimal states, forecast collapse timing, or recommend interventions. Instead, it specifies what can be known structurally before any claim about action, responsibility, or ethics can be meaningfully made. The paper further demonstrates that higher-order structures—such as Hourglass collapse dynamics and Joint Alignment Memory (JAM)—become diagnostically observable only when MMS-level measurements are available. Without MMS, such models collapse into retrospective narratives; with MMS, they become real-time structural diagnoses. By fixing the observational floor within the IPCSALT–UPF research program, this work establishes a coherent diagnostic baseline upon which phase-safe intervention, ethical boundary analysis, and domain-specific applications can be systematically built.