  Before we can consider Socrates’ answer to the question of the  Republic, we must have reason to accept that those who have  harmonious souls do what is required by justice. Otherwise, we cannot be sure that psychological harmony is justice. Unfortunately,  Socrates does not give any explicit attention to this worry at the  end of Book Four or in the argument of Books Eight and Nine. But  there are other places to look for a solution to this worry. First,  we might look to Books Five through Seven. Second, we might look to  Books Two and Three.