The only real struggle in the history of the world...is between the vested interest and social justice.

Athens reacted to the population problem in a different way again. She specialized her agricultural production for export, started manufactures also for export and then developed her political institutions so as to give a fair share of political power to the new classes which had been called into being by these economic innovations. In other words, Athenian statesmen averted a social revolution by successfully carrying through an economic and political revolution; and, discovering this solution of the common problem in so far as it affected themselves, they incidentally opened up a new avenue of advance for the whole of the Hellenic Society.

On a stationary military frontier between a civilization and a barbarism, time always works in the barbarians' favour; and, besides this, the barbarians' advantages increases in geometrical progression at each arithmetical addition to the length of the line which the defenders of the civilization have to hold