Gustav Radbruch Quote

Because a judgement on the truth or error of the differing convictions in law is impossible, and because on the other hand a uniform law for all citizens is necessary, the law-giver faces the task of cleaving with a stroke of the sword the Gordian knot which jurisprudence cannot untangle. Since it is impossible to ascertain what is just, it must be decided what is lawful. In lieu of an act of truth (which is impossible) an act of authority is required. Relativism leads to positivism.

Der Relativismus in der Rechtsphilosophie (1934)