 The attraction of Avicenna’s position is evident in the work of Siger of Brabant. In some of his writings, Siger teaches that God as the first being creates only one being immediately, the first immaterial substance, from which emanate the other intelligences, the celestial spheres and finally the sublunar world, in an eternal and necessary process. The necessity is not universal, however, but finds its limits in the contingency and in the free will which exists in the sublunar world (De necessitate et contingentia causarum; Van Steenberghen 1991, 346). Duns Scotus, in contrast, is very critical of Avicenna’s theory of necessary causation through the first cause. He advances several reasons against it, the most important being that there can only be contingency in the world if the first cause does not act by necessity (Ordinatio I d. 8 p. 2 q. un).