416 Between Yesterday and Tomorrow (1914– )of Roberto Ago, its hallmark is “a scientifi cally objective examination of
empirical reality.” Th e primary focus remained, now as then, on custom-
ary law. Ian Brownlie, a professor at Oxford and experienced practitioner
before international tribunals, frankly pronounced customary law to be “for
all practical purposes identical” to general international law. Also evident
was the empiricist’s bluff disdain for theory, which, in Brownlie’s opinion,
“provides no real benefi ts and frequently obscures the more interesting
questions.” To discern what the law is, he maintained, the surest guide is
an “examination of the vast array of evidence” of state practice.
Perhaps the most forthright spokesman for the empirical viewpoint was
Schwarzenberger, in a 1965 book entitled (fi ttingly enough) Th e Inductive
Approach to International Law. In it, he expressed the strong hostility of the
empiricist to rationalistic, à priori methods in international law, insisting
instead that international law must be regarded as “an empirical device” and
not as “an exercise in logic.” Hypothetico- deductive approaches to inter-
national law were dismissed as “a beautiful spiral in the air, coming from
nowhere and disappearing in the clouds.” For “[s]peculation, intuition and
other brainwaves,” he had only scorn.
State practice, contended Schwarzenberger, is the sole source of legal
rules. International law, in his view, comprises “the sum total of the rules
actually considered law by the subjects of international law.” He forth-
rightly rejected any attempt to propound broad principles “abstracted from
such rules.” Such searches for general principles underlying specifi c rules
amount to lawmaking by courts and commentators, to which he was reso-
lutely opposed. He bluntly denounced the use of “legal conceptualism (Beg-
riff sjurisprudenz)” as a basis for “surreptitious law- making.” Deduction
from principles was acceptable, in his opinion, only as a teaching device or
as a classifi cation tool. He compared principles to labels on bottles in a
chemist’s shop, insisting on a sharp distinction between the labels on the
bottles and the contents (i.e., the actual rules of law). Supposed principles
are in fact merely con ve nient labels, he argued, not themselves legally bind-
ing. Consequently, they must not be employed as devices for the creation of
new rules of law in the absence of actual consent by states. Th e urgent need
in international legal scholarship, Schwarzenberger held, is for systematic
study of state practice, with the goal of obtaining a substantial body of solid
evidence as to what rules have actually been accepted by states, as evidenced
by their practice.