Moral progress in history lies not so much in the improvement of the moral code as in the enlargement of the area within which it is applied. The morals of modern man are not unquestionably superior to those of primitive man, though the two groups of codes may differ considerably in content, practice and profession; but modern morals are, in normal times, extended – though with decreasing intensity – to a greater number of people than before. As tribes were gathered up into those larger units called states, morality overflowed its tribal bounds; and as communication – or a common danger – united and assimilated states, morals seeped through frontiers, and some men began to apply their commandments to all Europeans, to all whites, at last to all men. Perhaps there have always been idealists who wished to love all men as their neighbors, and perhaps in every generation they have been futile voices crying in a wilderness of nationalism and war. But probably the number – even the relative number – of such men has increased. There are no morals in diplomacy, and la politique n’a pas d’entrailles; but there are morals in international trade, merely because such trade cannot go on without some degree of restraint, regulation, and confidence. Trade began in piracy; it culminates in morality.

- Will Durant, Our Oriental Heritage