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.

Man is the child of customs, not the child of his ancestors.

Habits are qualities of the soul.

All the sciences came to exist in Arabic. The systematic works on them were written in Arabic writing.

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.

Geometry enlightens the intellect and sets one's mind right. All of its proofs are very clear and orderly. It is hardly possible for errors to enter into geometrical reasoning, because it is well arranged and orderly. Thus, the mind that constantly applies itself to geometry is not likely to fall into error. In this convenient way, the person who knows geometry acquires intelligence.

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