Note 77 — Chapter III · OTHER KINDS OF LAW.

“The sole source of (international) law,” says Dr. Walker in his History of International Law, vol. i. p. 21, “is actual observance.” This law, he adds, p. 31, is “the embodiment of state practice.” It is not easy to make a list of the genuine adherents of this opinion, because so many writers introduce vagueness and uncertainty into their exposition by speaking of international consent as well as of international practice as a source of law; and they fail to make it clear whether such practice is operative per se, or only as evidence of underlying consent. Moreover, the word consent is itself used ambiguously and vaguely, and it is often difficult to know whether it means international agreement, or international opinion, or the harmonious practice of states.