Dreams Born and Shattered 369laid down by Kelsen. In the pro cess, he off ered a rival candidate for the basic
norm: the principle of pacta sunt servanda. In a way, this change of position
on Anzilotti’s part did not mark any real surrender of his common-will theory.
But it did involve placing it onto a somewhat diff erent foundation. His previous
position had been that the principle of pacta sunt servanda was itself the prod-
uct of agreement between states— with the brute fact of agreement therefore
functioning as a kind of primordial juridical force in its own right.
Th e principal signifi cance of Anzilotti’s change of position lies in the light
that it sheds on the nature of Kelsen’s normative approach to international
law. Th at approach enabled a unifi cation to be achieved between the empiri-
cal and the common- will versions of positivism. Th e two variants could now
be regarded as identical in their formal structure, because both saw interna-
tional law as being rooted in a basic norm. Th ey diff ered only on what the
norm was: the empiricists (including Kelsen) thinking that it was a rule that
made customary practices of states legally binding, and the common-will
adherents (such as Anzilotti) thinking that it was the principle of pacta sunt
servanda.
In terms of its overall fl avor, the outstanding feature of Kelsen’s system
was its austerely intellectual, rigorously logical character. As a “formal”
theory of law, it focused chiefl y on the nature of law rather than its content.
Moreover, the system was entirely self- contained. It was rigorously purged
of any input from other sciences such as economics, history, or sociology.
For that reason, Kelsen referred to it as the “pure theory of law.” In its gen-
eral contours, it is strikingly reminiscent of the rationalist stream of natural-
law thought, and of Wolff in par tic u lar. And it is no accident that Kelsen had
a high regard for Wolff. It is therefore more than a little odd to fi nd Kelsen
being— or at least purporting to be— so unremittingly hostile to natural law.
Th e explanation is that, where the old natural- law systems dealt with the
substantive contents of laws, Kelsen’s concentrated on forms (i.e., on the
means for making law). His system was therefore a sort of formalist- cum-
positivist mirror image of rationalist natural law.
Th e Vienna School approach was compatible with a number of elements of
mainstream positivism. For example, Kelsen accepted the principle of state
freedom, as endorsed by the World Court in the Lotus case. In addition, he
shared the insistence of his empirical positivist ancestors on the importance
of a sanction for the viability of a legal system.