Constitutive Mediation: When the Reception Apparatus Is the Substrate (v1.1)

EA-DC-COG-01. A standalone development of the cognitive extension to the Diversity Contraction framework. The paper distinguishes three orders of mediation — channel (§2.1 of the parent paper: the floor cannot transmit), reception (§2.3: the floor transmits but cannot be received as legible), and constitutive (this paper: the receiver's categorial vocabulary itself was formed by the substrate the work analyzes). The third order is the terminal case of the Mediation Ratchet: the regime in which the §2.4 phenomenological-seeding response is itself constrained because the categorial slots the seeding would fill have been pre-empted by substrate-shaped categories. The dating-app structural analog is developed at the constitutive layer. An app does not need to mediate every encounter to alter the field of all encounters; nor does it need to govern how every encountered person interprets that encounter; it needs to have shaped the categories through which the encountering person learned what counts as an encounter in the first place. The cognitive case is structurally identical: a reader who has been exposed since adolescence to mode-pulling mediation has acquired a categorial vocabulary that was shaped by that mediation. The substrate has migrated into the receiver's apparatus. The paper's central practical claim: under constitutive mediation, the classroom is the most powerful exogenous floor available to a person with limited reach. Formation precedes mediation and can therefore shape mediation rather than be shaped by it. The framework's deposit work supplies the vocabulary; the classroom and its analogs (small-group reading, embodied practice, correspondence, ritual-keeping) supply the formation conditions under which the vocabulary can install. Together they constitute a response that does not break the Mediation Ratchet but operates at the layer where the ratchet's effect is least determined. The paper closes by identifying the operative population for response work under the regime: parents, teachers, mentors, small-group reading hosts, embodied-practice instructors, ritual-keepers. They are not the population the field's reproduction loop reaches; they are the population that reaches the people the field's reproduction loop will later receive.