Just as a body which has a leg too long, or which is unsymmetrical in some other respect, is an unpleasant sight, and also, when doing its share of work, is much distressed and makes convulsive efforts, and often stumbles through awkwardness, and is the cause of infinite evil to its own self-in like manner we should conceive of the double nature which we call the living being; and when in this compound there is an impassioned soul more powerful than the body, that soul, I say, convulses and fills with disorders the whole inner nature of man; and when eager in the pursuit of some sort of learning or study, causes wasting; or again, when teaching or disputing in private or in public, and strifes and controversies arise, inflames and dissolves the composite frame of man and introduces rheums; and the nature of this phenomenon is not understood by most professors of medicine, who ascribe it to the opposite of the real cause.
And once more, when body large and too strong for the soul is united to a small and weak intelligence, then inasmuch as there are two desires natural to man,-one of food for the sake of the body, and one of wisdom for the sake of the diviner part of us-then, I say, the motions of the stronger, getting the better and increasing their own power, but making the soul dull, and stupid, and forgetful, engender ignorance, which is the greatest of diseases.
There is one protection against both kinds of disproportion:-that we should not move the body without the soul or the soul without the body, and thus they will be on their guard against each other, and be healthy and well balanced.
And therefore the mathematician or any one else whose thoughts are much absorbed in some intellectual pursuit, must allow his body also to have due exercise, and practise gymnastic; and he who is careful to fashion the body, should in turn impart to the soul its proper motions, and should cultivate music and all philosophy, if he would deserve to be called truly fair and truly good.
And the separate parts should be treated in the same manner, in imitation of the pattern of the universe; for as the body is heated and also cooled within by the elements which enter into it, and is again dried up and moistened by external things, and experiences these and the like affections from both kinds of motions, the result is that the body if given up to motion when in a state of quiescence is overmastered and perishes; but if any one, in imitation of that which we call the foster-mother and nurse of the universe, will not allow the body ever to be inactive, but is always producing motions and agitations through its whole extent, which form the natural defence against other motions both internal and external, and by moderate exercise reduces to order according to their affinities the particles and affections which are wandering about the body, as we have already said when speaking of the universe, he will not allow enemy placed by the side of enemy to stir up wars and disorders in the body, but he will place friend by the side of friend, so as to create health.
Now of all motions that is the best which is produced in a thing by itself, for it is most akin to the motion of thought and of the universe; but that motion which is caused by others is not so good, and worst of all is that which moves the body, when at rest, in parts only and by some external agency.
The Stoic and Plotinian doctrine that all parts of the cosmos are bound by hidden affinities, so that a movement in one part resonates through the whole; the metaphysical basis for astrology, magic, and divination.
The passage states that motions in one part of the body affect the whole composite frame similarly to the universe.
Augustinian and Plotinian doctrine that evil has no positive being of its own but is a lack, distortion, or absence of the good — denying ontological dualism while preserving moral seriousness.
Disorders are described as resulting from the imbalance of powers rather than positive evil forces.