According to the Relational Event Theory, sounds are events which involve both the source and the surrounding medium. They are relational rather than “monadic” events. (The distinction between monadic and relational events is not to be taken as cast in iron, since the latter can be reduced to the former by making the mereological sum of sources and surrounding medium the subject of sounds.) O’Callaghan (2002, 2007) has developed such a view at some length. He notes that the wave conception of so