At the beginning of a dynasty, taxation yields a large revenue from small assessments. At the end of the dynasty, taxation yields a small revenue from large assessments.

He who finds a new path is a pathfinder, even if the trail has to be found again by others; and he who walks far ahead of his contemporaries is a leader, even though centuries pass before he is recognized as such.

Sedentary culture is the goal of civilization. It means the end of its lifespan and brings about its corruption.

The term of life of a dynasty does not normally exceed three generations. For in the first generation are still preserved the characteristic features of rough, uncivilized rural life, such as hard conditions of life, courage, ferocity, and partnership in authority. Therefore the strength of the 'Asabiya is maintained.

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.

At the beginning of a dynasty, taxation yields a large revenue from small assessments. At the end of the dynasty, taxation yields a small revenue from large assessments.

The sciences of only one nation, the Greeks, have come down to us, because they were translated through Al-Ma'mun's efforts. He was successful in this direction because he had many translators at his disposal and spent much money in this connection.