Patronised by the early Caliphs of the House of ‘Abbās, Rationalism continued to flourish in the intellectual centres of the Islamic world; until, in the first half of the 9th century, it met the powerful orthodox reaction which found a very energetic leader in Al-As̱ẖ‘arī (b, 873 A.D.) who studied under Rationalist teachers only to demolish, by their own methods, the edifice they had so laboriously built. He was a pupil of Al-Jubbā’ī[65:2]--the representative of the younger school of Mu‘tazilaism in Baṣra--with whom he had many controversies[65:3] which eventually terminated their friendly relations, and led the pupil to bid farewell to the Mu‘tazila camp. "The fact", says Spitta, "that Al-As̱ẖ‘arī was so thoroughly a child of his time with the successive currents of which he let himself go, makes him, in another relation, an important figure to us. In him, as in any other, are clearly reflected the various tendencies of this politically as well as religiously interesting period; and we seldom find ourselves in a position to weigh the power of the orthodox confession and the Mu‘tazilite speculation, the child-like helpless manner of the one, the immaturity and imperfection of the other, so completely as in the life of this man who was orthodox as a boy and a Mu‘tazila as a young man"[66:1]. The Mu‘tazila speculation (e.g. Al-Jāḥiz) tended to be absolutely unfettered, and in some cases led to a merely negative attitude of thought. The movement initiated by Al-As̱ẖ‘arī was an attempt not only to purge Islām of all non-Islamic elements which had quietly crept into it, but also to harmonize the religious consciousness with the religious thought of Islam. Rationalism was an attempt to measure reality by reason alone; it implied the identity of the spheres of religion and philosophy, and strove to express faith in the form of concepts or terms of pure thought. It ignored the facts of human nature, and tended to disintegrate the solidarity of the Islamic Church. Hence the reaction. [65:2] Extracts from Ibn ‘Asākir (Mehren)--Travaux de la troisième session du Congrès International des Orientalistes--p. 261. [65:3] Spitta: Zur Geschichte Abul-Ḥasan Al-As̱ẖ‘arī, pp. 42, 43. See also Ibn Ḵẖallikān (Gottingen 1839)--Al-Jubbā’ī, where the story of their controversy is given. [66:1] Spitta: Vorwort, p. VII.