 Al-Fārābī often refers to “universal rules”. But they need not be laws that can be shown to hold without exceptions. Take for example his essay [Canons], which closes (272.16) with a statement that the work has presented “universal rules” of poetry. The work consists mostly of classifications of different types of poetry, together with definitions of terms used in analyzing poetry, and a broad comparison with decorative arts. These “rules” are at best things that a person who aspires to work on the theory of poetry ought to know.