Thrasymachus Is Like Chesterton

So that explains why the argument gets derailed in Republic I!

Can you identify the source?

The fact is that Thrasymachus, like Mr. Shaw and Mr. Chesterton, has the journalist's trick of facile expression. He is too good a journalist to be an esprit juste, and the consequence is that he lands himself in a dilemma. If his 'sovereign', who has a view only to the interests of 'number one', is meant to be an actual person or body of persons, it is obvious, as Socrates says, that he is not infallible....But if you assume that the sovereign is always alive to his own interests and always embodies them in his regulations, your sovereign is a creature of theory, an 'ideal', and you lay yourself open at once to the line of argument adopted by Socrates to show that his worth depends on fulfilling a social function, independently of the question of whether he gets any private advantage from his position or not.

I also ask: Has this person correctly captured why it is that Thrasymachus gets refuted? The question might be put in this way. Thrasymachus of course needs to say that justice is what works to the benefit of the stronger, but he gets into trouble only because he also says that justice is a matter of following the law (hence something set down in law may not after all work out to the advantage of the stronger, that is, the lawgiver--and the same action may be both just and unjust). But why should he grant that?