A "therefore" must cross a recognized bridge.

Fabricated citations have a source of truth: a database can say whether a case exists. Inferential errors do not. A synthesis can cite only real cases, characterize each accurately, and still connect them by reasoning no court has recognized, for example by grouping holdings under different constitutional provisions into a principle none of them announced. The "therefore" floats free.

Legal reasoning is constrained, not creative. Authority does not transfer from a decided case to a new one by itself. It travels by a small set of recognized moves: a holding applied to facts inside it, an established multi-case test adopted by a controlling court, a rationale extended by acknowledged analogy, an a fortiori step, the surviving portion of a partially overruled case, a canon of construction, a doctrinal lineage developed case by case. Each move has conditions. The Twelve Bridges framework catalogs the legitimate mechanisms in four groups, authority-based, reasoning-based, evolution-based and policy-based, together with the recurring fault patterns that characterize inferential hallucination.

A catalog of this kind works as a whitelist. The audit question for any inference is whether the authority satisfies the conditions of the bridge claimed for it. Often it does not: the quoted language is dicta, the case binds a different court, the rule was announced in a different posture. Sometimes no bridge is claimed at all, as when three cases are grouped by theme with no shared holding, or a dissent is quoted as law. Then the other side is entitled to say that the "therefore" is argument, not law.

A shared catalog is what lets reasoning be audited rather than trusted, by a lawyer at midnight or by a system checking every inference in parallel.