To this day the Arab influence is evident in southern Italy, northern Africa and, above all, in Spain.

It is not easy to tear any event out of the context of the universe in which it occurred without detaching from it some factor that influenced it.

The process by which civilization, as an abstract entity distinct from the societies in which it is embodied, dies or is reborn is a very significant one.

After years of work in both areas of study, I concluded that the social sciences were different, in many important ways, from the natural sciences, but that the same scientific methods were applicable in both areas, and, indeed, that no very useful work could be done in either area except by scientific methods.

Thus, the use of fiat money is more justifiable in financing a depression than in financing a war.

When profits are pursued by geographic interchange of goods, so that commerce for profit becomes the central mechanism of the system, we usually call it "commercial capitalism." In such a system goods are conveyed from ares where they are more common (and therefore cheaper) to areas where they are less common (and therefore less cheap). This process leads to regional specialization and to division of labor, both in agricultural production and in handicrafts.

The instrument of expansion of Classical civilization was a social organization, slavery.