Breaking with the Past 225In place of natural law as the ultimate source of international law, the
positivists substituted the will of the states themselves. Th ere was room for
disagreement as to how this will was formed and expressed— and in fact it
was divergence on this point that largely distinguished the three variants of
positivism from one another. Th ere was agreement, though, on the vital
principle of the centrality of will over reason in the making of law. Interna-
tional law, in the positivist picture, was a body of law that was made by the
states themselves for their own purposes. It was not a refl ection of transcen-
dental, universal, eternal norms, as natural lawyers held. Instead, it was a
practical system, man- made in origin and for the ser vice of purely human
ends. Where natural lawyers had sought to bend the conduct of states and
rulers in the direction of a preexisting corpus of law, positivist lawyers held
that the law must turn in the direction of state practice.
A second key feature of positivism in all of its varieties was a focus on
method or pro cess as the most fundamental aspect of international law. A
clear model was off ered by the natural sciences, which were coming to be
regarded chiefl y as a methodical, dispassionate pro cess for the discovery of
knowledge— rather than as a systematic corpus of knowledge seen as a “fi n-
ished product.” In a similar vein, international law, in its new scientifi c guise,
would be seen primarily as a method for discovering what the law is, and for
the forging of new law. Th is meant that law was now seen as being in a con-
stant state of fl ux— inevitably defying the eff orts of now- discredited natural
lawyers to encapsulate it into a corpus of substantive fi xed principles. Posi-
tivism, in short, represented a triumph of method over system.
A third feature of positivism in general was its insistence on distinguish-
ing law from morality. An important early fi gure here was Kant, who had
strongly insisted on the radically diff erent character of the two. Law, he
maintained, is a realm of command and coercion. Its function is to compel
persons to behave in certain prescribed ways, and to punish them if they
stray. Morality, in sharpest contrast, is a realm of freedom. More strictly,
morality is a realm of laws or of rules— but, crucially, of laws or rules that
are freely self- made by each moral actor individually. Kant can hardly be
placed among the positivists, since his primary interest was in these self-
imposed rules of morality— but his distinction between the two classes of
rules became (and remains) a key feature of the positivist outlook. Th e con-
cern of the positivist lawyer was, of course, with law rather than ethics or
morality. More specifi cally, the task of the positivist lawyer was to know