Drawing on his own theory, Hans Kelsen (1881–1973) had little to say about legal sociology. Still, in the role of critic he consorted with the giants in the field, Eugen Ehrlich (1862–1922) among others. As a critic, Kelsen relentlessly followed through on the implications of his various positions, even where those implications were decidedly counterintuitive. The result is usually instructive.

There are two high points in Kelsen's criticism of the legal sociologists. Early in his career, his review article on Ehrlich's 1913 book Fundamental Principles of the Sociology of Law prompted a heated exchange with Ehrlich. Kelsen was not prepared to yield any ground whatever in favor of Ehrlich's sociological jurisprudence. Much later, in General Theory of Law and State(1945), Kelsen's attitude had softened a bit; ...