Language As Interface: Underconstraint, Genealogy, and Moral Incommensurability

Persistent moral and institutional disagreement is often treated as a problem of language: a consequence of ambiguity, vagueness, or insufficient conceptual precision. This assumption presupposes that language plays a cognitively foundational role in abstract reasoning, such that greater linguistic clarity should, in principle, secure convergence. This paper argues that this expectation is historically contingent and empirically underconstrained. Drawing on contemporary cognitive-neuroscientific evidence indicating a functional dissociation between language-selective systems and domain-general reasoning and evaluation, the paper reframes language as a specialised communicative interface rather than the medium of abstract thought. On this view, language enables coordination and articulation but does not supply the non-linguistic evaluative structures that generate moral judgment. The central claim is genealogical and diagnostic rather than refutational. Cognitively foundational conceptions of language emerged under conditions of empirical opacity and hardened into orthodoxy, licensing the expectation that semantic refinement should resolve abstract disagreement. When this expectation fails, disagreement is misdiagnosed as a communicative defect rather than a reflection of deeper ontological divergence. The paper argues that many moral disagreements track incompatible, largely tacit models of agency, motivation, and human nature. In such cases, moral terms function as coordination labels over divergent evaluative frameworks rather than as carriers of shared semantic content. Ontological plurality does not entail relativism or moral equivalence, but it does undermine the assumption that language provides a neutral adjudicative standpoint. The persistence of disagreement, therefore, is not anomalous but structurally predictable given the functional limits of language.