STRANGER: They cross-examine a man's words, when he thinks that he is saying something and is really saying nothing, and easily convict him of inconsistencies in his opinions; these they then collect by the dialectical process, and placing them side by side, show that they contradict one another about the same things, in relation to the same things, and in the same respect. He, seeing this, is angry with himself, and grows gentle towards others, and thus is entirely delivered from great prejudices and harsh notions, in a way which is most amusing to the hearer, and produces the most lasting good effect on the person who is the subject of the operation. For as the physician considers that the body will receive no benefit from taking food until the internal obstacles have been removed, so the purifier of the soul is conscious that his patient will receive no benefit from the application of knowledge until he is refuted, and from refutation learns modesty; he must be purged of his prejudices first and made to think that he knows only what he knows, and no more. THEAETETUS: That is certainly the best and wisest state of mind. STRANGER: For all these reasons, Theaetetus, we must admit that refutation is the greatest and chiefest of purifications, and he who has not been refuted, though he be the Great King himself, is in an awful state of impurity; he is uninstructed and deformed in those things in which he who would be truly blessed ought to be fairest and purest. THEAETETUS: Very true. STRANGER: And who are the ministers of this art? I am afraid to say the Sophists. THEAETETUS: Why? STRANGER: Lest we should assign to them too high a prerogative. THEAETETUS: Yet the Sophist has a certain likeness to our minister of purification. STRANGER: Yes, the same sort of likeness which a wolf, who is the fiercest of animals, has to a dog, who is the gentlest. But he who would not be found tripping, ought to be very careful in this matter of comparisons, for they are most slippery things. Nevertheless, let us assume that the Sophists are the men. I say this provisionally, for I think that the line which divides them will be marked enough if proper care is taken. THEAETETUS: Likely enough. STRANGER: Let us grant, then, that from the discerning art comes purification, and from purification let there be separated off a part which is concerned with the soul; of this mental purification instruction is a portion, and of instruction education, and of education, that refutation of vain conceit which has been discovered in the present argument; and let this be called by you and me the nobly-descended art of Sophistry. THEAETETUS: Very well; and yet, considering the number of forms in which he has presented himself, I begin to doubt how I can with any truth or confidence describe the real nature of the Sophist.