The practical man, however, for whom morals is mere theory, even
while admitting that what ought to be can be, bases his dreary
verdict against our well-meant hopes really on this: he pretends
that he can foresee from his observation of human nature, that men
will never be willing to do what is required in order to bring
about the wished-for results leading to perpetual peace. It is
true that the will of all individual men to live under a legal
constitution according to the principles of liberty—that is to
say, the distributive unity of the wills of all—is not sufficient
to attain this end. We must have the collective unity of their
united will: all as a body must determine these new conditions. The
solution of this difficult problem is required in order that civil
society should be a whole. To all this diversity of individual wills
there must come a uniting cause, in order to produce a common will
which no distributive will is able to give. Hence, in the practical
realisation of that idea, no other beginning of a law-governed
society can be counted upon than one that is brought about by force:
upon this force, too, public law afterwards rests. This state of
things certainly prepares us to meet considerable deviation in actual
experience from the theoretical idea of perpetual peace, since we
cannot take into account the moral character and disposition of a
law-giver in this connection, or expect that, after he has united a
wild multitude into one people, he will leave it to them to bring
about a legal constitution by their common will.
It amounts to this. Any ruler who has once got the power in his
hands will not let the people dictate laws for him. A state which
enjoys an independence of the control of external law will not
submit to the judgment of the tribunals of other states, when it
has to consider how to obtain its rights against them. And even a
continent, when it feels its superiority to another, whether this be
in its way or not, will not fail to take advantage of an opportunity
offered of strengthening its power by the spoliation or even conquest
of this territory. Hence all theoretical schemes, connected with
constitutional, international or cosmopolitan law, crumble away into
empty impracticable ideals. While, on the other hand, a practical
science, based on the empirical principles of human nature, which
does not disdain to model its maxims on an observation of actual
life, can alone hope to find a sure foundation on which to build up a
system of national policy.