Tried by this test, several of the Platonic Dialogues, according to our modern ideas, appear to be defective, but the deficiency is no proof that they were composed at different times or by different hands.

And the supposition that the Republic was written uninterruptedly and by a continuous effort is in some degree confirmed by the numerous references from one part of the work to another.
The second title, 'Concerning Justice,' is not the one by which the Republic is quoted, either by Aristotle or generally in antiquity, and, like the other second titles of the Platonic Dialogues, may therefore be assumed to be of later date.

Morgenstern and others have asked whether the definition of justice, which is the professed aim, or the construction of the State is the principal argument of the work.

The answer is, that the two blend in one, and are two faces of the same truth; for justice is the order of the State, and the State is the visible embodiment of justice under the conditions of human society.

The one is the soul and the other is the body, and the Greek ideal of the State, as of the individual, is a fair mind in a fair body.