POPULATION [Sidenote: Unity of civilized world] Political history is that of the state; economic and intellectual history that of a different group.

In modern times this group includes all civilized nations.

Even in political history there are many striking parallels, but in social development and in culture the recent evolution of civilized peoples has been nearly identical.

This fundamental unity of the nations has grown stronger with the centuries on account of improving methods of transport and communication.
Formally it might seem that in the Middle Ages the white nations were more closely bound together than they are now.

They had one church, a nearly identical jurisprudence, one great literature and one language for the educated classes; they even inherited from Rome the ideal of a single world-state.