There is a certain force,[209:2] less primary than Being but more primary than the Soul, which draws its existence from Being and completes the Soul as the Sun completes the eyes. Of Souls some are rational and immortal, some irrational and mortal. The former are derived from the first Gods, the latter from the secondary. First, we must consider what soul is. It is, then, that by which the animate differs from the inanimate. The difference lies in motion, sensation, imagination, intelligence. Soul, therefore, when irrational, is the life of sense and imagination; when rational, it is the life which controls sense and imagination and uses reason. The irrational soul depends on the affections of the body; it feels desire and anger irrationally. The rational soul both, with the help of reason, despises the body, and, fighting against the irrational soul, produces either virtue or vice, according as it is victorious or defeated. It must be immortal, both because it knows the gods (and nothing mortal knows[210:1] what is immortal), it looks down upon human affairs as though it stood outside them, and, like an unbodied thing, it is affected in the opposite way to the body. For while the body is young and fine, the soul blunders, but as the body grows old it attains its highest power. Again, every good soul uses mind; but no body can produce mind: for how should that which is without mind produce mind? Again, while Soul uses the body as an instrument, it is not in it; just as the engineer is not in his engines (although many engines move without being touched by any one). And if the Soul is often made to err by the body, that is not surprising. For the arts cannot perform their work when their instruments are spoilt. IX. _On Providence, Fate, and Fortune._ This is enough to show the Providence of the Gods. For whence comes the ordering of the world, if there is no ordering power? And whence comes the fact that all things are for a purpose: e. g. irrational soul that there may be sensation, and rational that the earth may be set in order? But one can deduce the same result from the evidences of Providence in nature: e. g. the eyes have been made transparent with a view to seeing; the nostrils are above the mouth to distinguish bad-smelling foods; the front teeth are sharp to cut food, the back teeth broad to grind it. And we find every part of every object arranged on a similar principle. It is impossible that there should be so much providence in the last details, and none in the first principles. Then the arts of prophecy and of healing, which are part of the Cosmos, come of the good providence of the Gods.