Even Though He Be the Great King

The last dialogue considered in John Sallis's Being and Logos is The Sophist, which earlier in the month I read through for the first time in years. Some parts of it I had quite forgotten, including the binary search after the sophist that leads it off. Others were familiar, for example the section beginning at 229C

STR. I at any rate think I do see one large and grievous kind of ignorance, separate from the rest, and as weighty as all the other parts put together.
TH. What is it?
STR. Thinking that one knows a thing when one does not know it. Through this, I believe, all the mistakes of the mind are caused in all of us.

And the section beginning at 230B in which the stranger explains the method of removing this ignorance:

STR.  They question a man about the things about which he thinks he is talking sense when he is talking nonsense; then they easily discover that his opinions are like those of men who wander, and their discussions they collect those opinions and compare them with one another, and by the comparison they show that they contradict one another about the same things. But those who see this grow angry with themselves and gentle toward others, and this is the way in which they are freed from their high and obstinate opinions about themselves. The process of freeing them, moreover, affords the greatest pleasure to the listeners and the most lasting benefit to him who is subjected to it....

 For all these reasons, Theatetus, we must assert that cross-questioning is the greatest and most efficacious of all purifications, and that he who is not cross-questioned, even though he be the Great King, has not been purified of the greatest taints, and is therefore uneducated and deformed in those things in which he who is to be truly happy ought to be most pure and beautiful.

To judge by Socrates's account in The Apology, cross-questioning did not invariably make the patients gentle toward others, at least not toward Socrates. The pleasure given to the listeners, though, he does speak of.

(Quoted from the Loeb Classical Library, translation by H.N. Fowler.)