The allegory from the Dialogue Phaedrus (246a–254e), in which Plato compares the soul to a tripartite composition of the charioteer, and two unruly horses which he controls. The usual interpretation is that the charioteer represents the rational part of the soul, while the horses are, respectively, a force akin to shame or honour, and one that is simply appetite, lust, or blind emotion. In this form the image is directly opposed by Hume’s assertion that ‘reason is the slave of the passions and has no office but to serve and obey them’, or in other words that without emotion or passion the charioteer has no motive for going one way or another. For a different interpretation of the allegory, see dual process theory.