The easiest method of acquiring the habit of scholarship is through acquiring the ability to express oneself clearly in discussing and disputing scholarly problems. This is what clarifies their import and makes them understandable. Some students spend most of their lives attending scholarly sessions. Still, one finds them silent. They do not talk and do not discuss matters. More than is necessary, they are concerned with memorizing. Thus, they do not obtain much of a habit in the practice of scholarship and scholarly instruction.
Ibn KhaldunAt 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.
Ibn KhaldunAll the sciences came to exist in Arabic. The systematic works on them were written in Arabic writing.
Ibn KhaldunTherefore, the Negro nation are, as a rule, submissive to slavery, because [Negroes] have little [that is essentially] human and have attributes that are quite similar to those of dumb animals, as we have stated.
Ibn Khaldun