"While al-'aql is in one sense stable,

it is also open to change and evolution, as its actual substance is not dictated by revelation but is negotiated in real space and time. Such change, however, occurs slowly, organically, within the recognized rules of the game, and - as with the rules of any sport - for the purpose of improving rather than destroying the game itself. In its actual operation, al-'aql has a certain dialectical relationship with al-naql. For while al-naql is in one sense fixed (the canon of revelation being closed), in another sense, Unanimous Consensus (or simple vertical longevity or horizontal predominance) can confer upon rational/intellectual methods and arguments an authority approaching that of the transmitted canon. Through the aegis of al-'aql, in other words, a doctrine can move from the periphery to the center, where its "Islamicity" comes to be assumed rather than argued." [24]

-Sherman A. Jackson, Islam and the Problem of Black Suffering, p. 10