This chapter first considers the most important of Kelsen's own express statements of a connection between his legal theory and the philosophy of Cohen. It then argues that Cohen's interpretations of Kant as well as his own ‘System of Philosophy’ actually differ profoundly from the historical Kant, thus showing the key theorem of Cohen's system to be not Kantian in origin but Platonic. Finally, the chapter considers the centrepiece of Kelsen's theory, the doctrine of the basic norm. It shows that (...) Kelsen's solution to the problem of establishing legal validity by appeal to the basic norm represents a direct application of the key theorem of Cohen's system, and that this theorem offers one plausible possibility — albeit not the only one — for the problem of validity on the basis of a concept of law that refers neither to natural law nor to any metajuridical source. (shrink)