The whole Universe is one vast Organism (_Enn._ ix. 4, §§ 32, 45), and the Heart of God, the source of all life, is at the centre, in which all finite things have their being, and to which they must flow back; for there is in this Organism, so Plotinus conceives, a double circulatory movement, an eternal out-breathing and in-breathing, the way down and the way up. The way down is the out-going of the undivided "One" towards manifestation. From Him there flows out a succession of emanations. The first of these is the "Nous" or Over-Mind of the Universe, God as thought. The "Mind" in turn throws out an image, the third Principle in this Trinity, the Soul of all things. This, like the "Nous," is immaterial, but it can act on matter. It is the link between man and God, for it has a lower and a higher side. The lower side _desires_ a body and so creates it, but it is not wholly incarnate in it, for, as Plotinus says, "the soul always leaves something of itself above." From this World Soul proceed the individual souls of men, and they partake of its nature. Its nature is triple, the animal or sensual soul, closely bound to the body, the logical reasoning human soul, and the intellectual soul, which is one with the Divine Mind, from whence it comes and of which it is an image. Souls have forgotten then: divine origin because at first they were so delighted with their liberty and surroundings (like children let loose from their parents, says Plotinus), that they ran away in a direction as far as possible from their source. They thus became clogged with the joys and distractions of this lower life, which can never satisfy them, and they are ignorant of their own true nature and essence. In order to return home, the soul has to retrace the path along which she came, and the first step is to get to know herself, and so to know God. (See _Enn._ vi. 9, § 7.) Thus only can she be restored to the central unity of the universal soul. This first stage on the upward path is the purgative life, which includes all the civic and social virtues, gained through general purification, self-discipline, and balance, with, at the same time, a gradual attainment of detachment from the things of sense, and a desire for the things of the spirit.