Substrate Independence as a Structural Requirement: A capacity profile for contamination-resistant evaluation

Three reservations made earlier in this series come due together: the externality conditions of the first note, the capacity relation of the second, and the recursive use channel of the third. This note distinguishes independence by governance — who holds the judgment — from independence by substrate — how the judgment is produced. Independence belongs to that production relation, not to the office alone. Three necessary conditions follow: a lineage condition on the sources from which the criterion is built; an anchor condition requiring both a reference the evaluated population cannot inhabit and task-relevant verification access to it; and a rate condition on the tempo of observation. A capacity profile places designs in a three-dimensional partial order rather than collapsing the conditions into one score. Seven candidate families occupy eight matrix rows; rotating tests split by verdict type because an executable oracle anchors correctness while leaving task coverage exposed. No candidate dominates the field, and each leaves a named residue. Governance can purchase substrate distance when it changes evidence, tooling, and access. Organizational separation by itself purchases only custody. Restricted physical-feedback domains supply local existence cases for joint satisfaction; general frontier audit remains the combination problem. The result is a design grammar: close enough to read the auditee, constituted far enough away to judge it, and fast enough to retain the difference.