178 Reason and Its Rivals (ca. 1550– 1815)
“is positive [i.e., man- made] only in the manner of applying it, and is natural
as to its subject matter: it is the law of nature applied by positive consent to
the artifi cial persons of civil societies.” A “constant and uninterrupted
practice” of states cannot become legally mandatory by its mere existence.
Only a command by a sovereign could make it so— and there is no sovereign
in international aff airs.
Th e conceptual line between the Grotians and the naturalists was, in sum, of
the utmost sharpness— and was clearly perceived to be so by contemporaries.
But it was not actually the most important division among international law-
yers in the century and a half that followed Grotius. Rival approaches would
emerge within the Grotian camp that would prove, in the longer run, more
important for the evolution of international law.