Tim. Their nature is made clear whenever there is some block in the respiration and a man draws in his breath forcibly; for then no accompanying smell is strained through, but the breath passes in alone by itself isolated from the smells. So for these reasons the varieties of these smells have no name, not being derived either from many or from simple forms, but are indicated by two distinctive terms only, pleasant and painful of which the one kind roughens and violently affects the whole of our bodily cavity which lies between the head and the navel, whereas the other mollifies this same region and restores it agreeably to its natural condition.

 The third organ of perception within us which we have to describe in our survey is that of hearing, and the causes whereby its affections are produced. In general, then, let us lay it down that sound is a stroke transmitted through the ears, by the action of the air upon the brain and the blood, and reaching to the soul; and that the motion caused thereby, which begins in the head and ends about the seat of the liver, is hearing ; and that every rapid motion produces a shrill sound, and every slower motion a more deep sound; and that uniform motion produces an even and smooth sound and the opposite kind of motion a harsh sound; and that large motion produces loud sound, and motion of the opposite kind soft sound. The subject of concords of sounds must necessarily be treated in a later part of our exposition. Cf. 80 A. 

 We have still remaining a fourth kind of sensation, which we must divide up seeing that it embraces numerous varieties, which, as a whole, we call colors. This consists of a flame which issues from the several bodies, and possesses particles so proportioned to the visual stream as to produce sensation; and as regards the visual stream, we have already stated Cf. 45 C ff. merely the causes which produced it. Concerning colors, then, the following explanation will be the most probable and worthy of a judicious account. Of the particles which fly off from the rest and strike into the visual stream some are smaller, some larger, and some equal to the particles of the stream itself; those, then, that are equal are imperceptible, and we term them transparent ; while the larger and smaller particles—of which the one kind contracts, the other dilates the visual stream—are akin to the particles of heat and cold which affect the flesh, and to the astringent particles which affect the tongue, and to all the heating particles which we call bitter Cf. 65 E. with these white and black are really identical affections, occurring in a separate class of sensation, although they appear different for the causes stated. Tim. These, therefore, are the names we must assign to them: that which dilates the visual stream is white and the opposite thereof black Cf. 45 C ff. ; and the more rapid motion, being that of a different species of fire, which strikes upon the visual stream and dilates it as far as to the eyes, and penetrating and dissolving the very passages of the eyes causes a volume of fire and water to pour from them, which we call tears. And this moving body, being itself fire, meets fire from the opposite direction; and as the one firestream is leaping out like a flash, and the other passing in and being quenched in the moisture, in the resultant mixture colors of all kinds are produced. This sensation we term dazzling and the object which causes it bright or brilliant. Again, when the kind of fire which is midway between these i.e., between the kinds of fire which produce blackness and brightness. reaches to the liquid of the eyes and is mingled therewith, it is not brilliant but, owing to the blending of the fire’s ray through the moisture, it gives off a sanguine color, and we give it the name of red. And bright color when blended with red and white becomes yellow. But in what proportions the colors are blended it were foolish to declare, even if one knew, seeing that in such matters one could not properly adduce any necessary ground or probable reason. Red blended with black and white makes purple ; but when these colors are mixed and more completely burned, and black is blended therewith, the result is violet. Chestnut comes from the blending of yellow and grey; and grey from white and black; and ochre from white mixed with yellow. And when white is combined with bright and is steeped in deep black it turns into a dark blue color; and dark blue mixed with white becomes light blue ; and chestnut with black becomes green. As to the rest, it is fairly clear from these examples what are the mixtures with which we ought to identify them if we would preserve probability in our account. But should any inquirer make an experimental test of these facts, he would evince his ignorance of the difference between man’s nature and Gods—how that, whereas God is sufficiently wise and powerful to blend the many into one and to dissolve again the one into many, there exists not now, nor ever will exist hereafter, a child of man sufficient for either of these tasks. 

 Such, then, being the necessary nature of all these things, the Artificer of the most fair and good took them over at that time amongst things generated when He was engendering the self-sufficing and most perfect God; and their inherent properties he used as subservient causes, but Himself designed the Good in all that was being generated. Tim. Wherefore one ought to distinguish two kinds of causes, Cf. 46 D, 48 A. 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, i.e., 47 E. 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, Cf. 30 A, 42 D ff. 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, Cf. 44 E. 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 Cf. 64 E. ; 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. Tim. And inasmuch as one part thereof is better, and one worse, they built a division within the cavity of the thorax— as if to fence off two separate chambers, for men and for women—by placing the midriff between them as a screen. That part of the soul, then, which partakes of courage and spirit, since it is a lover of victory, they planted more near to the head, between the midriff and the neck, in order that it might hearken to the reason, and, in conjunction therewith, might forcibly subdue the tribe of the desires whensoever they should utterly refuse to yield willing obedience to the word of command from the citadel of reason. And the heart, which is the junction of the veins and the fount of the blood which circulates vigorously through all the limbs, they appointed to be the chamber of the bodyguard, to the end that when the heat of the passion boils up, as soon as reason passes the word round that some unjust action is being done which affects them, either from without or possibly even from the interior desires, every organ of sense in the body might quickly perceive through all the channels both the injunctions and the threats and in all ways obey and follow them, thus allowing their best part to be the leader of them all. And as a means of relief for the leaping of the heart, in times when dangers are expected and passion is excited—since they knew that all such swelling of the passionate parts would arise from the action of fire,—they contrived and implanted the form of the lungs. This is, in the first place, soft and bloodless; and, moreover, it contains within it perforated cavities like those of a sponge, so that, when it receives the breath and the drink, it might have a cooling effect and furnish relief and comfort in the burning heat. To this end they drew the channels of the windpipe to the lungs, and placed the lungs as a kind of padding round the heart, in order that, when the passion therein should be at its height, by leaping upon a yielding substance and becoming cool, the heart might suffer less and thereby be enabled the more to be subservient to the reason in time of passion.

 And all that part of the Soul which is subject to appetites for foods and drinks, and all the other wants that are due to the nature of the body, they planted in the parts midway between the midriff and the boundary at the navel, fashioning as it were a manger in all this region for the feeding of the body; and there they tied up this part of the Soul, as though it were a creature which, though savage, they must necessarily keep joined to the rest and feed, if the mortal stock were to exist at all. Tim. In order, then, that this part, feeding thus at its manger and housed as far away as possible from the counselling part, and creating the least possible turmoil and din, should allow the Supreme part to take counsel in peace concerning what benefits all, both individually and in the mass,—for these reasons they stationed it in that position. And inasmuch as they knew that it would not understand reason, and that, even if it did have some share in the perception of reasons, it would have no natural instinct to pay heed to any of them but would be bewitched for the most part both day and night by images and phantasms,—to guard against this God devised and constructed the form of the liver and placed it in that part’s abode; and He fashioned it dense and smooth and bright and sweet, yet containing bitterness, that the power of thoughts which proceed from the mind, moving in the liver as in a mirror which receives impressions and provides visible images, should frighten this part of the soul; for when the mental power bears down upon it with stern threats, it uses a kindred portion of the liver’s bitterness i.e., gall. and makes it swiftly suffuse the whole liver, so that it exhibits bilious colors, and by contraction makes it all wrinkled and rough; moreover, as regards the lobe and passages and gates i.e., the right lobe, the viliary vesicle, and the vena porta; cf. Eurip. Electra 827 ff. of the liver, the first of these it bends back from the straight and compresses, while it blocks the others and closes them up, and thus it produces pains and nausea. On the other hand, when a breath of mildless from the intellect paints on the liver appearances of the opposite kind, and calms down its bitterness by refusing to move or touch the nature opposite to itself, and using upon the liver the sweetness inherent therein rectifies all its parts so as to make them straight and smooth and free, it causes the part of the soul planted round the liver to be cheerful and serene, so that in the night it passes its time sensibly, being occupied in its slumbers with divination, seeing that in reason and intelligence it has no share.

 For they who constructed us, remembering the injunction of their Father, when He enjoined upon them to make the mortal kind as good as they possibly could, rectified the vile part of us by thus establishing therein the organ of divination, that it might in some degree lay hold on truth. And that God gave unto man’s foolishness the gift of divination Cf. Rep . 346 B, Laws 772 D, Phaedo . 244 A ff. a sufficient token is this: no man achieves true and inspired divination when in his rational mind, but only when the power of his intelligence is fettered in sleep or when it is distraught by disease or by reason of some divine inspiration.