From the Nous, as second emanation, proceeds the world-soul. This is, in Erdmann's phrase, a sort of faded-out copy of the Nous, and it is outside time, incorporeal, and indivisible. It works rationally, but yet is not conscious. It has a two-fold aspect, inclining upwards to the Nous on the one hand, and downwards to the world of nature on the other. It produces out of itself the individual souls which inhabit the world. The idea of emanation is essentially a poetical metaphor, and not a rational concept. It is conceived poetically by Plotinus as resembling light which radiates from a bright centre, and grows dimmer as it passes outwards, till it shades off at last into total darkness. This total darkness is matter. Matter, as negation of light, as the limit of being, is in itself not-being. Thus the crucial difficulty of all Greek philosophy, the problem of the whence of matter, the dualism of matter and thought, which we have seen Plato and Aristotle struggling in vain to subjugate, is loosely and lightly slurred over by Plotinus with poetic metaphors and roseate phrases. Matter Plotinus considers to be the ground of plurality and the cause of all evil. Hence the object of life can {376} only be, as with Plato, to escape from the material world of the senses. The first step in this process of liberation is _"katharsis,"_ purification, the freeing of oneself from the dominion of the body and the senses. This includes all the ordinary ethical virtues. The second step is thought, reason, and philosophy. In the third stage the soul rises above thought to an intuition of the Nous. But all these are merely preparatory for the supreme and final stage of exaltation into the Absolute One, by means of trance, rapture, ecstasy. Here all thought is transcended, and the soul passes into a state of unconscious swoon, during which it is mystically united with God. It is not a thought of God, it is not even that the soul sees God, for all such conscious activities involve the separation of the subject from its object. In the ecstasy all such disunion and separation are annihilated. The soul does not look upon God from the outside. It becomes one with God. It is God. Such mystical raptures can, in the nature of the case, only be momentary, and the soul sinks back exhausted to the levels of ordinary consciousness. Plotinus claimed to have been exalted in this divine ecstasy several times during his life. After Plotinus Neo-Platonism continues with modifications in his successors, Porphyry, Iamblicus, Syrianus, Proclus, and others.