STRANGER: There is the purification of living bodies in their inward and in their outward parts, of which the former is duly effected by medicine and gymnastic, the latter by the not very dignified art of the bath-man; and there is the purification of inanimate substances—to this the arts of fulling and of furbishing in general attend in a number of minute particulars, having a variety of names which are thought ridiculous.
THEAETETUS: Very true.
STRANGER: There can be no doubt that they are thought ridiculous, Theaetetus; but then the dialectical art never considers whether the benefit to be derived from the purge is greater or less than that to be derived from the sponge, and has not more interest in the one than in the other; her endeavour is to know what is and is not kindred in all arts, with a view to the acquisition of intelligence; and having this in view, she honours them all alike, and when she makes comparisons, she counts one of them not a whit more ridiculous than another; nor does she esteem him who adduces as his example of hunting, the general's art, at all more decorous than another who cites that of the vermin-destroyer, but only as the greater pretender of the two. And as to your question concerning the name which was to comprehend all these arts of purification, whether of animate or inanimate bodies, the art of dialectic is in no wise particular about fine words, if she may be only allowed to have a general name for all other purifications, binding them up together and separating them off from the purification of the soul or intellect. For this is the purification at which she wants to arrive, and this we should understand to be her aim.
THEAETETUS: Yes, I understand; and I agree that there are two sorts of purification, and that one of them is concerned with the soul, and that there is another which is concerned with the body.
STRANGER: Excellent; and now listen to what I am going to say, and try to divide further the first of the two.
THEAETETUS: Whatever line of division you suggest, I will endeavour to assist you.
STRANGER: Do we admit that virtue is distinct from vice in the soul?
THEAETETUS: Certainly.
STRANGER: And purification was to leave the good and to cast out whatever is bad?
THEAETETUS: True.