The Autological Structure of Truth

A theory of truth makes a truth-claim. That truth-claim must satisfy whatever the theory says truth is. A theory that cannot meet its own criterion is not merely incomplete — it is self-eliminating. This essay formalizes this demand as the autological criterion (AC): a theory of truth is autological if and only if it satisfies its own definition of truth; heterological otherwise. Ten historically dominant theories are submitted to the AC. Correspondence fails by infinite regress (the correspondence relation must itself correspond to a fact). Coherence fails by requiring an independence-condition it was designed to deny. Pragmatism fails by circularity (the criterion of warranted assertibility cannot itself be warranted by inquiry). Consensus fails by performative self-refutation (asserting the theory does not depend on consensus). Deflationism fails by making a substantive claim while denying that truth is substantive. Tarski's semantic conception fails by structural self-exclusion (the theory cannot apply its own truth predicate to itself). The divine command theory fails on both horns of the Euthyphro dilemma at the truth-theoretic level. Constructivism, relativism, and truthmaker theory are shown to be structurally subsumed under the preceding types and inherit their failures. One theory survives: the identity theory — truth is not a relational property propositions acquire by corresponding to reality; truth is reality. The identity is numerical, not qualitative: truth and reality are one entity reached by two routes. The identity theory is autological because its truth-claim exists as a propositional reality whose existence is its truth, requiring no external verification. The essay addresses the triviality objection (the identity is substantive, not synonymous), the problem of false propositions (falsehood as incomplete propositional self-identity), and the self-application of the AC itself. The meta-level collapses: truth applied to the identity theory yields the identity theory, not a level above it. Three falsification conditions are stated.