Aristotle found it necessary to complete his metaphysics by the introduction of a Prime Mover—God. This, for two reasons, is an important fact in the history of metaphysics. In the first place if we are to accord to anyone the position of the greatest metaphysician, having regard to genius of insight, to general equipment in knowledge, and to the stimulus of his metaphysical ancestry, we must choose Aristotle. Secondly, in his consideration of this metaphysical question he was entirely dispassionate; and he is the last European metaphysician of first rate importance for whom this claim can be made. After Aristotle, ethical and religious interests began to influence metaphysical conclusions. The Jews dispersed, first willingly and then forcibly, and the Judaic-Alexandrian school arose. Then Christianity closely followed by Mahometanism, intervened. The Greek gods who surrounded Aristotle were subordinate metaphysical entities, well within nature. Accordingly on the subject of his Prime Mover, he would have no motive, except to follow his metaphysical train of thought whithersoever it led him. It did not lead him very far towards the production of a God available for religious purposes. It may be doubted whether any properly general metaphysics can ever, without the illicit introduction of other considerations, get much further than Aristotle. But his conclusion does represent a first step without which no evidence on a narrower experiential basis can be of much avail in shaping the conception. For nothing, within any limited type of experience, can give intelligence to shape our ideas of any entity at the base of all actual things, unless the general character of things requires that there be such an entity. The phrase, Prime Mover, warns us that Aristotle’s thought was enmeshed in the details of an erroneous physics and an erroneous cosmology. In Aristotle’s physics special causes were required to sustain the motions of material things. These could easily be fitted into his system, provided that the general cosmic motions could be sustained. For then in relation to the general working system, each thing could be provided with its true end. Hence the necessity for a Prime Mover who sustains the motions of the spheres on which depend the adjustment of things. To-day we repudiate the Aristotelian physics and the Aristotelian cosmology, so that the exact form of the above argument manifestly fails. But if our general metaphysics is in any way similar to that outlined in the previous chapter, an analogous metaphysical problem arises which can be solved only in an analogous fashion. In the place of Aristotle’s God as Prime Mover, we require God as the Principle of Concretion. This position can be substantiated only by the discussion of the general implication of the course of actual occasions,—that is to say, of the process of realisation.