Al-Ghazali

Ghazali, throughout his life, identified himself with the Asharite kalam. This is evidenced in his 11th century book "The Incoherence of the Philosophers" which marks a major turn in Islamic epistemology, as Ghazali effectively discovered philosophical skepticism that would not be commonly seen in the west until George Berkeley and David Hume in the 18th century. The encounter with skepticism led Ghazali to embrace a form of theological occasionalism, or the belief that all causal events and interactions are not the product of material conjunctions but rather the immediate and present will of Allah, the Islamic divine being. The logical consequence of this belief in practice, and an outcome that has developed in part from it over the subsequent centuries, is a turn towards fundamentalism in many Islamic societies.

The Incoherence also marked a turning point in Islamic philosophy in its vehement rejections of Aristotle and Plato. The book took aim at the falasifa, a loosely defined group of Islamic philosophers from the 8th through the 11th centuries (most notable among them Ibn Sina (Avicenna) who drew intellectually upon the Ancient Greeks. Ghazali bitterly denounced Plato, Socrates and other Greek writers as mushrikuwn ('polytheist') and labelled those who employed their methods and ideas as corrupters of the Islamic faith.

Though Ghazali was an Asharite and avowedly anti-philosophical it is notable--as pointed out by Ibn Rushd (Averroes), in his bitterly entitled Incoherence of the Incoherence)--that he refutes the falasifa on their own terms, by employing philosophical models of his own.In contrast to the Mutazilite school of Greek-inspired philosophers, the Asharite view was that comprehension of unique nature and characteristics of God were beyond human capability. And that, while man had free will, he had no power to create anything. It was an ignorance-based view which did not assume that human reason could discern morality.

Despite being named for Ashari, the most influential work of this school's thought was "The Incoherence of the Philosophers", by the Muslim polymath Al-Ghazali (d. 1111). He laid the groundwork to "shut the door of ijtihad" centuries later in the Ottoman Empire. This is one of the most influential works ever produced. Ibn Rushd, a rationalist, famously responded that "to say that philosophers are incoherent is itself to make an incoherent statement." and even wrote a book "The Incoherence of the Incoherence" to refute Al-Ghazali's views, though the work was not well received in the Muslim community. wikipedia