Positivism, with its principle that 'a law is a law', has in fact rendered the German legal profession defenceless against statutes that are arbitrary and criminal. Positivism is, moreover, in and of itself wholly incapable of establishing the validity of statutes. It claims to have proved the validity of a statute simply by showing that the statute had sufficient power behind it to prevail. But while power may indeed serve as a basis for the 'must' of compulsion, it never serves as a basis for the 'ought' of obligation or for legal validity. Obligation and legal validity must be based, rather, on a value inherent in the statute.

"Statutory Lawlessness and Supra-Statutory Law" (1946)