Wilhelm von Humboldt s legal philosophy is much less familiar than his philosophy of language or even his role as an educational reformer. For this purpose the author examines Humboldt s Ideas on an attempt to determine the limits of the effectiveness of the state . This early work, which is central for political liberalism, was created in an exchange of ideas with Friedrich Schiller and had a substantial effect on John Stuart Mill's essay On Liberty . The author attempts a legal-philosophical examination of Humboldt s ideas that is linked with a critical tracing of the Anglo-American origins and reception (together with Mill, above all Adam Smith, Rawls, Nozick and Buchanan).