  After sketching these four virtues in Book Four, Socrates is ready to move from considering what justice is in a person to why a person  should be just (444e). But this is premature. Socrates is moving to  show that it is always better to have a just soul, but he was asked  to show that it is always better to be the person who does just  actions. We might doubt that an answer concerning psychological  justice is relevant to the question concerning practical justice (Sachs 1963).