Businesses owned by responsible and organized merchants shall eventually surpass those owned by wealthy rulers. - Ibn Khaldun

When civilization [population] increases, the available labor again increases. In turn, luxury again increases in correspondence with the increasing profit, and the customs and needs of luxury increase. Crafts are created to obtain luxury products. The value realized from them increases, and, as a result, profits are again multiplied in the town. Production there is thriving even more than before. And so it goes with the second and third increase. All the additional labor serves luxury and wealth, in contrast to the original labor that served the necessity of life.

The only people who accept slavery are the Negroes, owing to their low degree of humanity and proximity to the animal stage. Other persons who accept the status of slave do so as a means of attaining high rank, or power, or wealth, as is the case with the Mameluke Turks in the East and with those Franks and Galicians who enter the service of the state [in Spain].

Eventually, Aristotle appeared among the Greeks. He improved the methods of logic and systematized its problems and details. He assigned to logic its proper place as the first philosophical discipline and the introduction to philosophy. Therefore he is called the First Teacher.