A short but helpful look at the role of reason in Islam, part of a larger package at MercatorNet

This took place over an argument, already begun in the seventh and eighth centuries, about the status of reason in relationship to God’s omnipotence. The outcome of this struggle decisively affected the character of the Islamic world. This struggle had its roots in a profound disagreement over who God is. There was a side in this debate that would seem very familiar to Westerners because it was as deeply influenced by Greek philosophy as was Christianity. The Mu’tazilite school, composed of the Muslim rationalist philosophers, fought for the primacy of reason in Islam. The Mu’tazilites held that God is not only power, he is reason. Man’s reason is a gift from God, who expects man to use it to come to know him. God, being reason, would not expect man to accept anything contrary to it. Through reason, man is also able to understand God as manifested in his creation. God’s laws are the laws of nature, which are also manifested in the Sharia (the divine path). Therefore, the Mu’tazilites held that the statements in the Qur’an must be in accord with reason. Unfortunately, the Mu’tazilites were suppressed during the reign of Caliph Ja’afar al-Mutawakkil (847-861), who made holding the Mu’tazilite doctrine a crime punishable by death, and the long process of dehellenization and its resulting ossification began.

It was in the "darkness" of the Middle Ages that the coup de grace was delivered by Abu Hamid al-Ghazali (1058-1111), perhaps the single most influential Muslim thinker after Mohammed. Al Ghazali vehemently rejected Greek thought: "The source of their infidelity was their hearing terrible names such as Socrates and Hippocrates, Plato and Aristotle."  In The Incoherence of the Philosophers, Al-Ghazali insisted that God is not bound by any order and that there is, therefore, no "natural" sequence of cause and effect, as in fire burning cotton or, more colourfully, as in "the purging of the bowels and the using of a purgative." Things do not act according to their own natures but only according to God’s will at the moment. There are only juxtapositions of discrete events that make it appear that the fire is burning the cotton, but God could just as well do otherwise. In other words, there is no rational order invested in the universe upon which one can rely, no continuous narrative of cause and effect tying these moments together in a comprehensible way.