Timaeus

Wherefore one ought to distinguish two kinds of causes, the necessary and the divine, and in all things to seek after the divine for the sake of gaining a life of blessedness, so far as our nature admits thereof, and to seek the necessary for the sake of the divine, reckoning that without the former it is impossible to discern by themselves alone the divine objects after which we strive, or to apprehend them or in any way partake thereof. Seeing, then, that we have now lying before us and thoroughly sifted—like wood ready for the joiner, —the various kinds of causes, out of which the rest of our account must be woven together, let us once more for a moment revert to our starting-point, and thence proceed rapidly to the point from which we arrived hither. In this way we shall endeavor now to supplement our story with a conclusion and a crown in harmony with what has gone before. As we stated at the commencement, all these things were in a state of disorder, when God implanted in them proportions both severally in relation to themselves and in their relations to one another, so far as it was in any way possible for them to be in harmony and proportion. For at that time nothing partook thereof, save by accident, nor was it possible to name anything worth mentioning which bore the names we now give them, such as fire and water, or any of the other elements; but He, in the first place, set all these in order, and then out of these He constructed this present Universe, one single Living Creature containing within itself all living creatures both mortal and immortal. And He Himself acts as the Constructor of things divine, but the structure of the mortal things He commanded His own engendered sons to execute. And they, imitating Him, on receiving the immortal principle of soul, framed around it a mortal body, and gave it all the body to be its vehicle, and housed therein besides another form of soul, even the mortal form, which has within it passions both fearful and unavoidable—firstly, pleasure, a most mighty lure to evil; next, pains, which put good to rout; and besides these, rashness and fear, foolish counsellors both and anger, hard to dissuade; and hope, ready to seduce. And blending these with irrational sensation and with all-daring lust, they thus compounded in necessary fashion the mortal kind of soul. Wherefore, since they scrupled to pollute the divine, unless through absolute necessity, they planted the mortal kind apart therefrom in another chamber of the body, building an isthmus and boundary for the head and chest by setting between them the neck, to the end that they might remain apart. And within the chest—or thorax, as it is called—they fastened the mortal kind of soul.