had begun to break out afresh, and now, curiously enough, they were of a marked religious character. They were an expression of religious sects, Buddhistic, Zoroastrian, Manichaean, and parties with prophetic leaders of their own; all are swept together by Muslim writers as Zindiqs, probably literally. " initiates," originally Manichaeans, thereafter, practically non-Muslims concealing their unbelief. For when not in open revolt they must needs profess Islam. In 167, we find al-Mahdi, who was also, it is true, much more strict than his father, al-Mansur, appointing a grand inquisitor to deal with such heretics. Al-Mansur, however, had contented himself with crushing actual rebellion; and Christian, Jew, Zoroastrian, and heathen of Harran were tolerated so long as they brought to him the fruits of Greek science and philosophy.

That they did willingly, and so, through three intermediaries, science came to the Arabs. There was a heathen Syrian source with its centre at Harran, of which we know comparatively little. There was a Christian Syrian source working from the multitudinous monasteries scattered over the country. There was a Persian source by which natural science, and medicine especially, were passed on. Already in the fifth century A.D. an academy of medicine and philosophy had been founded at Gondeshapur in Khuzistan. One of the directors of this institution was summoned, in 148, to prescribe for al-Mansur, and from that time on it furnished court physicians to the Abbasids. On these three paths, then, Aristotle and Plato, Euclid and Ptolemy, Galen and Hippocrates reached the Muslim peoples.

The first hundred years of the Abbasid Khalifate was the golden age of Muslim science, the period of growth and development for the People of Muhammad fairly as a whole. Intellectual life did not cease with the close of that period, but the Khalifate ceased to aid in carrying the torch. Thereafter, learning was protected and fostered by individual rulers here and there, and individual investigators and scholars still went on their own quiet paths. But free intellectual life among the people was checked, and such learning as still generally flourished fell more and more between fixed bounds. Scholasticism, with its formal methods and systems, its subtle deductions and endless ramifications of proof and counter-proof, drew away attention from the facts of nature. The oriental brain studied itself and its own workings to the point of dizziness, and then turned and clung fast to the certainties of revelation. Under this spell heresy and orthodoxy proved alike sterile.

We return, now, to the beginnings of the Mu'tazilites. These served themselves heirs upon the Qadarites and denied that God predestined the actions of men. Death and life, sickness, health, and external vicissitudes came, they admitted, by God's qadar, but it was unthinkable that man should be punished for actions not in his control. The freedom of the will is an a priori certainty, and man possesses qadar over his own actions. This was the position of Wasil ibn Ata, of whom we have already heard. But to it he added a second doctrine, the origin of which is obscure, although suggestive of discussions with Greek theologians. The Qur'an describes God as