  In Book Four, Socrates defines each of the cardinal virtues in terms  of the complicated psychology he has just sketched. A person is wise  just in case her rational attitudes are functioning well, so that her rational part “has in it the knowledge of what is advantageous for  each part [of the soul] and for the whole in common of the three  parts” (442c5–8). So the unwise person has a faulty conception of  what is good for him. A person is courageous just in case her  spirited attitudes do not change in the face of pains and pleasures  but stay in agreement with what is rationally recognized as fearsome  and not (442bc). So the coward will, in the face of prospective  pains, fail to bear up to what he rationally believes is not  genuinely fearsome, and the rash person will, in the face of  prospective pleasures, rush headlong into what he rationally believes to be fearsome. A person is temperate or moderate just in case the  different parts of her soul are in agreement. So the intemperate  person has appetitive or spirited attitudes in competition with the  rational attitudes, appetitive or spirited attitudes other than those the rational attitudes deem to be good. Finally, a person is just  just in case all three parts of her soul are functioning as they  should (441d12–e2; cf. 443c9–e2). Justice, then, requires the other  virtues. So the  unjust person fails to be moderate, or fails to be wise, or fails to  be courageous.