(1) Eternal realities seen by reason, and God’s models in creation.—The nature of Idea, in its fundamental sense, and its importance in the making of the world, seems to have been first considered by Plato. In his Timaeus he gives a more or less symbolical and tentative description of creation, in which Idea assumes a new meaning and importance. There is, he thinks, a personal constructor of the world whom he calls the demiurgus or artificer. The demiurgus saw before his mind’s eye the Idea of a world which, if realised, would be perfectly real, beautiful and good. The Idea was not of his own making. Plato saw that what is absolutely real and good must have self-existence in itself as Idea from all eternity, above time and space, and above all will and caprice; and that it can be discerned as an eternal reality by the eye of reason. Still it contained no self-realising energy within itself. It was merely a passive copy or model (paradigma). To become real, it had to be copied in some material foreign to itself. This required another self-existent something. This was called not-being, because it was nothing in particular, but only material out of which things could be made. But idea and matter could not come together of themselves, being both inert, having no energy of their own. But here the demiurgus came forward, and moulded self-existent matter into conformity with the self-existent Idea, and produced the world. But the world was imperfect, because matter, though called not-being, had, it seems, a nature of its own which could not be brought into harmony with that of idea or supreme Good. Hence the imperfection of the world. Here then, Plato claimed absolute reality for idea, but not active self-realising power. But they may be conceived as both—
(2) Eternal realities and principles of self-realising energy.—The Timaeus seems to have been only a symbolical or provisional working-hypothesis. Plato saw that he could not attain a clear conception of the world by assuming three separate realities without any essential connection between them, viz.
