The result, then, is that more plentiful and better-quality goods are more easily produced if each person does one thing for which he is naturally suited, does it at the right time, and is released from having to do any of the others.

In Book 2, Socrates introduces the principle of specialization. According to Plato, political justice boils down to this guiding rule—that everyone do that to which their nature best suits them, and not meddle in any other business. Producers must produce according to their natures (e.g., the farmer farms, the carpenter builds wooden objects, the artist paints, and the doctor heals); warriors must fight; and the philosophers must rule.