But it is not wonderful that, dealing with such materials and contradictions, they developed a tendency to mysticism. There were many things which they felt compelled to hold which could only be defended and rationalized in that cloudy air and slanting light. Especially, no one but a mystic could bring together the emanations of Plotinus, the ideas of Plato, the spheres of Aristotle and the seven-storied heaven of Muhammad. With this matter of mysticism we shall have to deal immediately. Of al-Farabi it is enough to say that he was one of the most patient of the laborers at that impossible problem. It seems never to have occurred to him, or to any of the others, that the first and great imperative was to verify his references and sources. The oriental, like the mediæval scholastic, tests minutely the form of his syllogism, but takes little thought whether his premises state facts or not. With a scrupulous scepticism in deduction, he combines a childlike acceptance on tradition or on the narrowest of inductions. [Sidenote: AL-FARABI] But there are other and more ominous signs in al-Farabi of the scholastic decline. There appears first in him that tendency toward the writing of encyclopædic compends, which always means superficiality and the commonplace. Al-Farabi himself could not be accused of either, but that he thus claimed all knowledge for his portion showed the risk of the premature circle and the small gain. Another is mysticism. He is a neo-Platonist, more exactly a Plotinian; although he himself would not have recognized this title. He held, as we have seen, that he was simply retelling the doctrines of Plato and Aristotle. But he was also a devout Muslim. He seems to have taken in earnest all the bizarre details of Muslim cosmography and eschatology; the Pen, the Tablet, the Throne, the Angels in all their ranks and functions mingle picturesquely with the system of Plotinus, his ἕν, his ψυχή, his νοῦς, his receptive and active intellects. But to make tenable this position he had to take the great leap of the mystic. Unto us these things are impossible; with God, i.e., on another plane of existence, they are the simplest realities. If the veil were taken from our eyes we would see them. This has always been the refuge of the devout Muslim who has tampered with science. We shall look for it more in detail when we come to al-Ghazzali, who has put it into classical form.