A being, then, whose life should be a life of pure and complete knowledge, would embody the goal toward which all Nature strives. When we ponder duly the short phrases in which Aristotle propounds his conception of God we find that he has called up before us the noblest possible object of human thought, the presentiment of that thought's perfect fulfilment. There is no alloy of naturalism in this conception, and at the same time no suspicion of irrelevancy. This God is not a mere title of honour for the psycho-physical universe, confusedly conceived and lumped together; he is an ultra-mundane ideal, to be an inviolate standard and goal for all moving reality. Yet he is not irrelevant to the facts and forces of the world, not the dream of an abstracted poet. He is an idea which reality everywhere evokes in evoking its own deepest craving and need. Nothing is so pertinent and momentous in life as the object we are trying to attain by thought or action, since that object is the source of our inspiration and the standard of our success. Thus Aristotle's God is not superfluous, not invented. This theology is a true idealism, I mean an idealism itself purely ideal, which establishes the authority of human demands, ethical, and logical, without impugning the existence or efficacy of that material universe which it endows with a meaning and a standard. Yet this rational conception, the natural out-growth of the Socratic philosophy, establishes a dualism between the actual and the ideal against which the human mind easily rebels. Aristotle himself was hardly faithful to it. He tried to prove the existence of his God, and existence is something quite irrelevant to an ideal. This confusion is very excusable, especially in an age when the strictly mechanical view of Nature still seemed hopelessly inadequate. Aristotle consequently tried to understand the natural world by viewing it systematically from the point of view of moral science, as Plato had done less coherently in his myths; and hence came what we must regard as the great error of Aristotle's philosophy, the belief in the efficacy of final causes and in the preëxistence of entelechies. But, apart from this unhappy question of existence, which is, as we have said, irrelevant to an ideal, Aristotle's conception of God remains, perhaps, the most philosophical that has yet been constructed. Without any concessions to sentiment or superstition, it presents us with a sublime vision of the essentially human, of a nature as free from an unworthy anthropomorphism as from an inhuman abstractness. It is made both human and superhuman by the same principle of idealization. It is the final cause of Nature and man, the realization of their imminent upward effort, the essence that would contain all their values and escape all their imperfections.