When philosophy has got thus far, and has constructed its eternal God, certain difficulties confront it. God, as the great first cause, has to be made perfect, for if he were imperfect thought would have to ascend higher to find a cause of his imperfection. But as the creator of all things, God at one time must have existed alone, an absolute being simply self-contemplative. When he began to create, he ceased to be absolute, and became a relative being contemplative of his own creation. If as an absolute being he was perfect, how did he remain perfect when he became a relative being? The study of this problem has generally driven philosophy into pantheism, but where it has maintained its hold on theism, it has been forced to suppose that a change occurred in God at the time of creation, by which he remained absolute in regard to himself, though he became relative in regard to that which he created. Two Gods had thus to be imagined, one absolute and eternal, the other relative and existing from the beginning of created things. But these two had to be one, or else the first or absolute God would have been relative to the second, and so the old difficulty would have been revived. Hence there was need of a mystery; God was one and yet two, two persons and one substance. The first was God as he was through all eternity, the second was God as he was manifested in creation, his representative with everything but himself. Thus the second was a mediator between the first and the world. While for purely philosophical reasons philosophy was thus compelled to dualise God, other reasons also impelled it to this conclusion. Holding him to be pure mind, it had to explain his action on matter. Here, too, it was necessary to suppose, a mediator between the material world and God. And in proportion as philosophy advanced in its theism, it extended the attributes of God and raised him to a loftier height above created things; and hence, to connect him with what was so far inferior, a mediator again was needed. But in all cases this mediator had to be a part of God himself, or no difficulty was met; and thus in every way philosophy tended towards a divine dualism in mystery. All Greek philosophy, except where it drifted into pantheism or pure materialism, was more or less influenced by this tendency. In Platonism especially it is clearly marked. The ideal world of Plato fills the place of the second or relative God, and acts as a mediator between God the absolute and the material world. God, according to Plato, is not the creator of matter, which, so far as it is recognized in his system, is given an eternal existence. The action of God is confined to the ideal world, of which material phenomena are a distorted reflection. At the time of the beginning of Christianity these features of Platonism were strongly developed in the theology of an Alexandrian Jew.