Tim. For whenever the humors which arise from acid and saline phlegms, and all humors that are bitter and bilious wander through the body and find no external vent but are confined within, and mingle their vapor with the movement of the soul and are blended therewith, they implant diseases of the soul of all kinds, varying in intensity and in extent; and as these humors penetrate to the three regions Cf. 73 D ff. of the Soul, according to the region which they severally attack, they give rise to all varieties of bad temper and bad spirits, and they give rise to all manner of rashness and cowardice, and of forgetfulness also, as well as of stupidity. Furthermore, when, with men in such an evil condition, the political administration also is evil, and the speech in the cities, both public and private, is evil; and when, moreover, no lessons that would cure these evils are anywhere learnt from childhood,—thus it comes to pass that all of us who are wicked become wicked owing to two quite involuntary causes. And for these we must always blame the begetters more than the begotten, and the nurses more than the nurslings; yet each man must endeavor, as best he can, by means of nurture and by his pursuits and studies to flee the evil and to pursue the good. This, however, forms a separate subject of discussion. 

 Again, it is reasonable and proper to set forth in turn the subject complementary to the foregoing, namely the remedial treatment of body and mind, and the causes which conserve this. For what is good merits description more than what is evil. All that is good is fair, and the fair is not void of due measure; wherefore also the living creature that is to be fair must be symmetrical. Of symmetries we distinguish and reason about such as are small, but of the most important and the greatest we have no rational comprehension. For with respect to health and disease, virtue and vice, there is no symmetry or want of symmetry greater than that which exists between the soul itself and the body itself. But as regards these, we wholly fail to perceive or reflect that, whenever a weaker and inferior type of body is the vehicle Cf. 44 E, 69 C. of a soul that is strong and in all ways great,—or conversely, when each of these two is of the opposite kind,—then the creature as a whole is not fair, seeing that it is unsymmetrical in respect of the greatest of symmetries; whereas a creature in the opposite condition is of all sights, for him who has eyes to see, the fairest and most admirable. A body, for example, which is too long in the legs, or otherwise disproportioned owing to some excess, is not only ugly, but, when joint effort is required, it is also the source of much fatigue and many sprains and falls by reason of its clumsy motion, whereby it causes itself countless evils. Tim. So likewise we must conceive of that compound of soul and body which we call the living creature. Whenever the soul within it is stronger than the body and is in a very passionate state, it shakes up the whole body from within and fills it with maladies; and whenever the soul ardently pursues some study or investigation, it wastes the body; and again, when the soul engages, in public or in private, in teachings and battles of words carried on with controversy and contention, it makes the body inflamed and shakes it to pieces, and induces catarrhs; and thereby it deceives the majority of so-called physicians and makes them ascribe the malady to the wrong cause.

 And, on the other hand, when a large and overbearing body is united to a small and weak intellect, inasmuch as two desires naturally exist amongst men, —the desire of food for the body’s sake, and the desire of wisdom for the sake of the most divine part we have,—the motions of the stronger part prevail and augment their own power, but they make that of the soul obtuse and dull of wit and forgetful, and thereby they produce within it that greatest of diseases, ignorance.

 From both these evils the one means of salvation is this—neither to exercise the soul without the body nor the body without the soul, Cf. Laws 728 E. so that they may be evenly matched and sound of health. Thus the student of mathematics, or of any other subject, who works very hard with his intellect must also provide his body with exercise by practising gymnastics; while he who is diligent in molding his body must, in turn, provide his soul with motion by cultivating music i.e., music in the wide sense of mental culture. and philosophy in general, if either is to deserve to be called truly both fair and good.

 The various parts, likewise, must be treated in the same manner, in imitation of the form of the Universe. For as the body is inflamed or chilled within by the particles that enter it, and again is dried or moistened by those without, and suffers the affections consequent on both these motions, whenever a man delivers his body, in a state of rest, to these motions, it is overpowered and utterly perishes; whereas if a man imitates that which we have called the nurturer and nurse of the Universe, Cf. 49 A, 52 D. and never, if possible, allows the body to be at rest but keeps it moving, and by continually producing internal vibrations defends it in nature’s way against the inward and outward motions, and by means of moderate vibrations arranges the affections and particles which stray about in the body in their due reciprocal order, Cf. 33 A. according to their affinities,—as described in the previous account which we have given of the Universe—then he will not suffer foe set beside foe to breed war in the body and disease, but he will cause friend to be set beside friend so as to produce sound health. Tim. Further, as concerns the motions, the best motion of a body is that caused by itself in itself; for this is most nearly akin to the motion of intelligence and the motion of the Universe. Motion due to the agency of another is less good; and the least good motion is that which is imparted to a body lying in a state of rest and which moves it piecemeal and by means of others. Wherefore the motion that is best for purgings and renovations of the body consists in gymnastic exercises; and second-best is the motion provided by swaying vehicles, Cf. Laws 789 C. such as boats or any conveyances that produce no fatigue; while the third kind of motion, although useful for one who is absolutely driven to it, is by no means acceptable, under any other conditions, to a man of sense, it being the medical kind of purging by means of drugs. For no diseases which do not involve great danger ought to be irritated by drugging. For in its structure every disease resembles in some sort the nature of the living creature. For, in truth, the constitution of these creatures has prescribed periods of life for the species as a whole, and each individual creature likewise has a naturally predestined term of life, apart from the accidents due to necessity. For from the very beginning the triangles of each creature are constructed with a capacity for lasting until a certain time, beyond which no one could ever continue to live. With respect to the structure of diseases also the same rule holds good: whenever anyone does violence thereto by drugging, in despite of the predestined period of time, diseases many and grave, in place of few and slight, are wont to occur. Wherefore one ought to control all such diseases, so far as one has the time to spare, by means of dieting rather than irritate a fractious evil by drugging.

 Concerning both the composite living creature and the bodily part of it, how a man should both guide and be guided by himself so as to live a most rational life, let our statement stand thus. But first and with special care we must make ready the part which is to be the guide to the best of our power, so that it may be as fair and good as possible for the work of guidance. Now to expound this subject alone in accurate detail would in itself be a sufficient task. Education is the theme of Rep . vii. and Laws vii. and xii ad fin. But treating it merely as a side-issue, if we follow on the lines of our previous exposition, we may consider the matter and state our conclusions not inaptly in the following terms. Tim. We have frequently asserted Cf. 69 D, 79 D, 87 A. that there are housed within us in three regions three kinds of soul, and that each of these has its own motions; so now likewise we must repeat, as briefly as possible, that the kind which remains in idleness and stays with its own motions; in repose necessarily becomes weakest, whereas the kind which exercises itself becomes strongest; wherefore care must be taken that they have their motions relatively to one another in due proportion. And as regards the most lordly kind of our soul, we must conceive of it in this wise: we declare that God has given to each of us, as his daemon, i.e., genius or guardian-angel ; Cf. Laws 732 C, 877 A. that kind of soul which is housed in the top of our body and which raises us—seeing that we are not an earthly but a heavenly plant up from earth towards our kindred in the heaven. And herein we speak most truly; for it is by suspending our head and root from that region whence the substance of our soul first came that the Divine Power keeps upright our whole body.

 Whoso, then, indulges in lusts or in contentions and devotes himself overmuch thereto must of necessity be filled with opinions that are wholly mortal, and altogether, so far as it is possible to become mortal, fall not short of this in even a small degree, inasmuch as he has made great his mortal part. But he who has seriously devoted himself to learning and to true thoughts, and has exercised these qualities above all his others, must necessarily and inevitably think thoughts that are immortal and divine, if so be that he lays hold on truth, and in so far as it is possible for human nature to partake of immortality, Cf. Sympos . 212 A. he must fall short thereof in no degree; and inasmuch as he is for ever tending his divine part and duly magnifying that daemon who dwells along with him, he must be supremely blessed. Literally, with a good daemon (a play on δαίμων and εὐδαίμων ). And the way of tendance of every part by every man is one—namely, to supply each with its own congenial food and motion; and for the divine part within us the congenial motions are the intellections and revolutions of the Universe. Cf. 37 A ff. These each one of us should follow, rectifying the revolutions within our head, which were distorted at our birth, by learning the harmonies and revolutions of the Universe, and thereby making the part that thinks like unto the object of its thought, in accordance with its original nature, and having achieved this likeness attain finally to that goal of life which is set before men by the gods as the most good both for the present and for the time to come. 

 And now the task prescribed for us at the beginning to give a description of the Universe up to the production of mankind, would appear to be wellnigh completed. For as regards the mode in which the rest of living creatures have been produced we must make but a brief statement, seeing that there is no need to speak at length; for by such brevity we will feel ourselves to be preserving a right proportion in our handling of these subjects. Wherefore let this matter be treated as follows. Tim. According to the probable account, all those creatures generated as men who proved themselves cowardly and spent their lives in wrong-doing were transformed, at their second incarnation, Cf. 41 D ff. into women. And it was for this reason that the gods at that time contrived the love of sexual intercourse by constructing an animate creature of one kind in us men, and of another kind in women; and they made these severally in the following fashion. From the passage of egress for the drink, where it receives and joins in discharging the fluid which has come through the lungs beneath the kidneys into the bladder and has been compressed by the air, they bored a hole into the condensed marrow which comes from the head down by the neck and along the spine which marrow, in our previous account, Cf. 73 C, 86 C. we termed seed. And the marrow, inasmuch as it is animate and has been granted an outlet, has endowed the part where its outlet lies with a love for generating by implanting therein a lively desire for emission. Wherefore in men the nature of the genital organs is disobedient and self-willed, like a creature that is deaf to reason, and it attempts to dominate all because of its frenzied lusts. And in women again, owing to the same causes, whenever the matrix or womb, as it is called,—which is an indwelling creature desirous of child-bearing,—remains without fruit long beyond the due season, it is vexed and takes it ill; and by straying all ways through the body and blocking up the passages of the breath and preventing respiration it casts the body into the uttermost distress, and causes, moreover, all kinds of maladies; until the desire and love of the two sexes unite them. Then, culling as it were the fruit from trees, they sow upon the womb, as upon ploughed soil, animalcules that are invisible for smallness and unshapen; and these, again, they mold into shape and nourish to a great size within the body; after which they bring them forth into the light and thus complete the generation of the living creature.

 In this fashion, then, women and the whole female sex have come into existence.

 And the tribe of birds are derived by transformation, growing feathers in place of hair, from men who are harmless but light-minded Cf. Rep . 529 A ff. —men, too, who, being students of the worlds above, suppose in their simplicity that the most solid proofs about such matters are obtained by the sense of sight. And the wild species of animal that goes on foot is derived from those men who have paid no attention at all to philosophy nor studied at all the nature of the heavens, because they ceased to make use of the revolutions within the head and followed the lead of those parts of the soul which are in the breast. Cf. 69 E ff.