d the establishment of
international courts are the business of the Hague Peace Conferences;
but to work out the new enactments and to turn them to good account and
to prepare for their practical application, this is the business of the
science of international law. Science obtains thereby a share in the
future of the law of nations, and quite new tasks are allotted to it. As
mentioned earlier, the law of nations was, until the first of the Peace
Conferences, essentially a book-law. Treatises depicted the law such as
it was growing, in the form of custom, out of the practice of states in
international intercourse. There were only a few international
enactments, and there was no international court practice. But that
state of things has now been altered once and for all. International
enactments appear in greater number. Decisions of international courts
will follow, just as we already possess a number of awards of the
Permanent Court of Arbitration. If science is to be equal to its tasks,
it must take good heed to itself, it must become wholly positive and
impartial, it must free itself from the domination of phrases, and it
must become international.

[Sidenote: The science of international law must become positive.]

68. It is indispensably requisite that this science should be positive
in character. What natural law and natural law methods have done for the
law of nations in the past stands high above all doubt, but they have
lost their value and importance for present and future times. Now and
onwards the task is, in the first place, to ascertain and to give
precision to the rules which have grown up in custom, and in the second
place to formulate the enacted rules in their full content and in their
full bearing. In doing so it will come to light that there are many gaps
not yet regulated by law. Many of these gaps may be successfully filled
up by a discreet employment of analogy, but many others will remain
which can only be remedied by international legislation or by the
development of customary law in the practice of the courts or otherwise.
What science can do here is to make proposals _de lege ferenda_ of a
politico-jural character, but it cannot and may not fill up the gaps.
Science may also test and criticize, from the politico-jural standpoint,
the existing rules of customary or enacted law, but, on the other hand,
it may not contest their operation and applicability, even if convinced
of their worthlessn