Fairness in Plato’s Republic
In Book IX of The Republic, Socrates deliberates with Glaucon on the virtues of man and State. After both agree that the rule of the king is “the very best” and the rule of the tyrant is “the very worst,” Socrates adds
“There can be no mistake, I said, as to which is which, and therefore I will at once enquire whether you would arrive at a similar decision about their relative happiness and misery. And here we must not allow ourselves to be panic-stricken at the apparition of the tyrant, who is only a unit and may perhaps have a few retainers about him; but let us go as we ought into every corner of the city and look all about, and then we will give our opinion.”
Glaucon responds
“A fair invitation, he replied; and I see, as every one must, that a tyranny is the wretchedest form of government, and the rule of a king the happiest.”
In this passage, fairness is measured by the degree to which both reach agreement. Which, in this case, is absolute. The virtue of a city is considered here within the context of extremes: tyranny = wretchedness and rule of king = happiness. Perhaps had there been a third person present who saw things another way, the invitation may not have been considered equally as fair. But, this is not the case. Therefore, fairness is measured by the fact that all parties involved see the invitation as legitimate.
Socrates continues
“And in estimating the men too, may I not fairly make a like request, that I should have a judge whose mind can enter into and see through human nature? He must not be like a child who looks at the outside and is dazzled at the pompous aspect which the tyrannical nature assumes to the beholder, but let him be one who has a clear insight. May I suppose that the judgment is given in the hearing of us all by one who is able to judge, and has dwelt in the same place with him, and been present at his dally life and known him in his family relations, where he may be seen stripped of his tragedy attire, and again in the hour of public danger –he shall tell us about the happiness and misery of the tyrant when compared with other men?”
Glaucon
“That again, he said, is a very fair proposal.”
Why does Glaucon believe that Socrates’ proposal is fair? At the very basic level, we know it’s fair because Glaucon says it is. He agrees with Socrates and does not offer any further response. What would make Glaucon believe that Socrates’ proposal was unfair? Perhaps, (1) Socrates might have presented his narrative another way, (2) Glaucon might have seen things differently, or (3) other people may have been present during the conversation offering an alternative, leading to further debate before reaching agreement on the fairness of Socrates’ proposal.
Therefore, we can understand the meaning of fairness, in this passage of The Republic, by the extent to which Socrates and Glaucon - all parties involved - reach agreement on the legitimacy of the issues discussed above.

