 On Nature is a bold and ambitious work. It is addressed variously to the Muse, Calliope; Empedocles’ disciple, Pausanias; and perhaps also to the wider community of Acragas (Obbink 1993). The poem’s authority stems from its appeal to the divine for inspiration. Empedocles’ Muse does not, however, forestall the labor that the addressee must invest in being cognitively receptive to the message of the work (B3 = D44; B 4 = D 47). As in traditional didactic verse, Empedocles cultivates a “master-pupil” relationship and promises Pausanias a mortal intelligence to soar beyond all others (B 2 = D 42). On Nature contains an ontology of matter, barring complete destruction or generation, and a cosmogony, motivated by the aggregation and separation of Empedocles’ four basic elements through the power of Love and Strife. Following this, the poem passes to zoogony and biology, as well as reflections on cognition and perception.