The contradiction is escaped by the unmeaning evasion: for though his real and apparent interests may differ, what the ruler thinks to be his interest will always remain what he thinks to be his interest.
Of course this was not the original assertion, nor is the new interpretation accepted by Thrasymachus himself.

But Socrates is not disposed to quarrel about words, if, as he significantly insinuates, his adversary has changed his mind.

In what follows Thrasymachus does in fact withdraw his admission that the ruler may make a mistake, for he affirms that the ruler as a ruler is infallible.

Socrates is quite ready to accept the new position, which he equally turns against Thrasymachus by the help of the analogy of the arts.

Every art or science has an interest, but this interest is to be distinguished from the accidental interest of the artist, and is only concerned with the good of the things or persons which come under the art.