In his Preface Wheaton quoted one of the two or three passages from Austin's Jurisprudence which have been often plunged deep into the controversy whether International Law is really 'law' at all. It has been 'very justly observed', he says, that (quoting Austin) 'international law is founded only on the opinions generally received among civilized nations, and its duties are enforced only by moral sanctions: by fear on the part of nations, or by fear on the part of sovereigns, of provoking general hostility and incurring its probable evils, in case they should violate maxims generally received and respected'. But Wheaton adds that these motives do really afford, even in the worst of times, 'a considerable security for the observance of those rules of justice between states which are dictated by international morality, although they are deficient in-that more perfect sanction annexed by the lawgiver to the observance of a positive code proceeding from the command of a superiour'. His task was to show how the history of the progress of the science of international jurisprudence has been influenced by special compacts that have modified the general rules founded on reason and usage, and adapted them to the various exigencies of human society. Accordingly, he traced the progress of the sense of international right as it is marked not only in the writings of public jurists and in judicial decisions but also in 'the history of wars and negotiations, in the debates of legislative assemblies, and in the texts of treaties, from the earliest times of classic antiquity'. He believed that the general result of the survey was to show 'a considerable advance, both in the theory of international morality, and in the practical observance of the rules of justice among states, although this advance may not entirely correspond with the rapid progress of civilization in other respects'. This field of knowledge, he urged, deserves cultivation, for it is important to 'the jurist, the statesman, and the philanthropist'.
