Rational speculative theology (kalam) in early Islam was represented most distinctly by the theological school of the Mu'tazila. Founded in Basra in the early 8th century, the school soon became predominant in theological scholarship and discourse and remained so until the early 11th century. The Mu'tazila held that the basic truths of theology, such as the existence of God and the nature of His attributes and justice, are entirely subject to rational proof without the benefit of scriptural revelation. Only after these basic truths have been established can the veracity of scripture be proved...