  To explain how the plurality of the sub-lunar world can proceed from this absolutely one God, Ibn Daud presents the theory of “intermediaries”, as he found it in the works of the Muslim philosophers. This theory holds that there are secondary substances (or: heavenly intelligences) that serve as intermediaries between God and the lower world. His first step is to prove the existence of the Active Intellect, the lowest in the series of heavenly intelligences. His proof is based on the premise that the human intellect passes from potentiality into actuality, which can only be due to an agent that possesses the end of motion (that is, knowledge) in actuality. Ibn Daud then proceeds to prove the existence of other incorporeal substances, for which he likewise bases himself on the Aristotelian theory of motion, an approach that is new to Jewish philosophy. Taking the circularity of the motions of the heavenly bodies as a point of departure, he argues that the souls of the spheres in their motions pass from potentiality into actuality just as the human soul does. This motion must be caused by the intellects of the spheres that are objects of desire for their souls. The existence of heavenly incorporeal substances thus having been established, Ibn Daud goes on to describe how the lower proceeds from the higher, according to “the philosophers”. In their view, a first intelligence emanates from the One, which is similarly incorporeal, but not simple, as it has a cause, which involves composition in this entity. In a three-fold act of cognition, this intelligence produces a triad of heavenly intellect, sphere-soul and heavenly body, and this process is repeated until the sphere of the moon to which the active intellect belongs. From the various motions of the spheres, matter and forms emanate on the sub-lunar world. The details of this process are not pertinent to our current purposes. It is more relevant to note that Ibn Daud criticizes the emanation-theory of the philosophers by claiming that there are no demonstrative proofs for it. In his view, they invented their theory to solve the problem of how many can come forth from one, yet, at the same time, it seems to raise more questions than it actually solves. As he puts it: “They escaped from one defamation but fell into others” (ER W 67; S 159b).