Building Anew 417Th e voluntarist version of positivism was similarly in rude health aft er
1945, although the expression was now used rather loosely— basically to mean
the thesis that international law is based entirely on the freely given consent of
the states of the world. It remained the case, as it had in the nineteenth cen-
tury, that the two versions of positivism were allies more than foes, since both
of them agreed on the fundamental importance of state consent as the basis of
international law. Th ey diff ered chiefl y in how best to determine the presence
of that consent— whether in observation of state practice (the empiricists) or
in a fi rmer insistence on evidence of actual expressions of state will (the
voluntarists).
Th e ethos of the voluntarist version of positivism was instructively evi-
dent in the writing of the Italian writer Gaetano Arangio- Ruiz. He taught
international law at the Universities of Padua, Bologna, and Rome, as well as
serving on the International Law Commission. In the spirit of the
nineteenth- century voluntarists, he insisted on the state as “a ‘given’ person,
a real entity,” rejecting contentions that a state is merely “a secondary, artifi -
cial, person.” Th e state, in his opinion, is the primary unit and subject of
international law. His picture of the international community could have
come straight from Hobbes. Th e states of the world were asserted to be “the
private parties of the international system” existing in “a natural society.”
Th ey operate in a situation in which there are no underlying general rules
“stemming from the whole society of men.” Arangio- Ruiz therefore rejected
the idea of “an underlying collective entity or community” underpinning in-
ternational law. International law is essentially contractual in character,
without any “continuous normative texture corresponding to [a supposed]
public law of mankind.” In par tic u lar, customary law is contractual, and
not legislative, in nature. Like the nineteenth- century positivists, he insisted
that “the raison d’ être of international law” is the resolution of disputes be-
tween states, not the forging of a global great society. He endorsed the
dualist position of a strict separation of national from international law and
explicitly rejected the idea of a dédoublement fonctionnel in international
law. He believed that states were currently “more attached to voluntarism
than they have ever been in the past.” Nor did he believe that developments
since World War II had made any fundamental change in the nature of in-
ternational law.
Another outspoken champion of the voluntarist (or contractual) school
was the French lawyer Prosper Weil, who forthrightly pronounced himself