Error theory is usually presented as a negative doctrine: a discourse purports to represent some domain of fact, but the relevant facts, properties, powers, or objects are absent. The accompanying explaining-away argument then explains why the discourse nevertheless seems compelling. We argue that the mature form of that package has a transcendental structure: a practice or discourse requires certain appearances in order to function, while those appearances do not disclose the entities or properties they seem to disclose. The resulting macro is a deflationary transcendental argument. Given a public practice and a family of invariants—practical authority, accountability, public stability, motivational grip, or interpersonal intelligibility—the error theorist identifies an appearance as minimally required to reconstruct the practice, but blocks the stronger inference from the required appearance to the apparent object. Error theory plus explaining away is weak transcendental deduction of appearance without strong constitutive entitlement. Moral error theory supplies the central case; free-will illusionism and deflationary accounts of selfhood are treated as adjacent cases. We then diagnose the major failure modes: mere genealogy, covert dependence on the target facts, selectivity, self-defeat, companions-in-guilt pressure, and unresolved conservation.
Lorand Bruhacs (2026) studied this question.