 An additional function of music, according to Aristotle, is catharsis. Music may help individuals who are in states of extreme enthusiasm, pity, or fear return to a more balanced state (Politics, 1342a). The details of this process are hard to reconstruct, because they are tied to the debated concept of catharsis, introduced by Aristotle in his definition of tragedy (Poetics, 1449b). It seems clear that Aristotle thought of the cathartic process as requiring music expressive of emotions akin to the ones to be purged. For example, a state of uncontrolled religious frenzy could be subdued by means of frenzied music.