 The need for a professionally trained army leads to the discussion of education and moral psychology, because the preservation of internal peace and external security presupposes the combination of two different character-traits among the ‘guardians’ (‘the philosophical watchdogs’, 375d–376c): friendliness towards their fellow-citizens and fierceness towards their enemies. The injunctions concerning their appropriate education are very detailed, because it must combine the right kind of ‘muses’ (poetry, music, and other fine arts) with the appropriate physical training to develop the right temperament and attitude in the soldiers (376d–403d). The ‘muses’ come in for protracted criticism, both in content and form. All stories that undermine respect towards the gods are to be banned, along with tales that instill fear of death in the guardians. The imitation of bad persons is forbidden, as are depictions of varieties of character, quite generally. Analogous injunctions apply, mutandis mutatis, to the modes and rhythms in music and to painting. Physical exercise must suit the harmonious soul and therefore must not exceed what is healthy and necessary (403e–412b). Because the educational scheme is geared to secure a harmonious and yet spirited class of soldiers, Plato bans from his city most of the cultural achievements that were his contemporaries’ pride and joy. There must be nothing to disturb the citizens’ willingness to fulfill their tasks. The supervision of education is the function of the third class, the rulers of the city (412b–417b). They are to be selected through tests of intelligence and character from among the soldiers, to identify individuals who are unshakable in their conviction that their own well-being is intimately tied to that of the city. To ensure that members of the ruling and military classes retain their right attitude towards their civic duties, members of both classes must lead a communal life, without private homes, families, or property. His interlocutor’s objection that such a life is not apt to make these citizens happy (419a) is the first approach to the topic of happiness, but it is quickly brushed aside at this point on the grounds that the political order is designed to make the entire city happy, rather than any particular group.