The unity of God
The debate over the created Qur’ān relates to the other important element of Mu’tazilī thought, the concept of the unity of God, tawhid. Polemic with Christianity and Manichaeism appears to have been part of the reason for the emphasis within Mu’tazilī thought on the doctrine, and the use of the Greek mode of reasoning by protagonists from these other two religions may well account for the introduction of rationalism into Islam as well, occurring initially within the polemical framework. Al-Khayyāt’s work paints the portrait of a real threat posed by the radical dualism of the Manicheans, although it is likely that the Christian Trinity was a far more important topic of discussion. The position adopted by the most of the Mu’tazila was that God can only be described in negatives. Any attempt to ascribe positive attributes to God was seen as impinging upon His unity, for such would suggest that He could be divided into a series of eternal aspects. The closest that one may come to saying something positive about God would be to say that God is “knowing,” but this “knowing” occurs not by an attribute of God, but rather by and through God Himself in His essence. Once again, the parallels in these arguments to Christian discussions over the nature of Jesus in his relationship to the Father cannot be overlooked.
An implication of this position on the unity of God was the emphasis on de-anthropormorphization of the divinity especially as He is described in the Qur’ān. Any suggestion that God might have a “face” (Qur’ān 2/272, 6/52, etc.) or be “sitting upon a throne” (Qur’ān 2/255, etc. in reality was to be rejected and taken as a metaphorical statement; no reference to the human form could be applied to God in its usual meaning. God’s “face” was to be understood as His “essence,” according to al-Khayyāt, for example. Thus the discussion conducted during the mihna over the status of the Qur’ān was not limited only to the matter of free will. For the Mu’tazila at least, both major aspects of their doctrine, unity and justice were encapsulated in the idea of a created Qur’ān; an eternal Qur’ān would suggest an attribute of God (speech) which existed separately (in the concept of the “heavenly tablet”) alongside God, impinging thereby on His unity, as well as suggesting the predestination of events. (Andrew Rippin, Muslims: Their Religious Beliefs and Practices [3d ed.; New York: Routledge, 2005], 82-83, emphasis added)