2. The chief philosophical expression of Dualism was Platonism. Plato followed Anaxagoras in believing that mind is separate from matter and acts upon it: he went beyond him in founding upon this separation a universal distinction between the real and the phenomenal, and between God and the world. God was regarded as being outside the world. The world was in its origin only potential being (τὸ μὴ ὄν). The action of God upon it was that of a craftsman upon his material, shaping it as a carpenter shapes wood, or moulding it as a statuary moulds clay. In so acting, He acted with reason, following out thoughts in His mind. Sometimes His reason, or His mind, is spoken of as being itself the fashioner of the world.[317] Each thought shows itself in a group of material objects. Such objects, so far as they admit of being grouped, may be viewed as imitations or embodiments of a form or pattern, existing either as a thought in the mind of the Divine Workman, or as a force proceeding from His mind and acting outside it. As the conception of these forms was developed more and more, they tended to be regarded in the latter light rather than in the former. They were cosmic forces which had the power of impressing themselves upon matter. They were less types than causes. They came midway between God and the rude material of the universe, so that its changing phenomena were united with an unchanging element. They were themselves grouped in a vast gradation, reaching its highest point in the Form of Perfection, which was higher than the Form of Being. The highest and most perfect of types is conceived as the most powerful and most active of forces. In the elaborate cosmology of the _Timæus_, it is further conceived as a person. The creative energy of God is spoken of as the _Demiurgus_, who himself made an ideal world, and employed subordinate agents in the construction of the actual world. The matter upon which the Demiurgus or his agents work is sometimes conceived as potential being,[318] the bare capacity of receiving qualities and forms, and sometimes as chaotic substance which was reduced to order.[319] The agents were gods who, having been themselves created, were bidden to create living beings, capable of growth and decay.[320] The distinction between the two spheres of creation, that of a world in which nothing was imperfect since it was the work of a Perfect Being, and that of a world which was full of imperfections as being the work of created beings, came, as we shall see, to be of importance in some phases of Christian thought. * * * * *