Antithesis in the form of the unity of opposites appears to a limited extent in the early mythic cosmogonies. However, this theme emerges much more strongly in subsequent presocratic thought. This phenomenon was analysed closely by Geoffrey Lloyd without being explained; here, presocratic speculation on the cosmos is explained as ‘cosmisation’, that is, interpretation shaped by a combination of political and economic factors alongside mystery cult. Anaximander’s idea of the universe as apeiron (‘unlimited’) is interpreted as a projection of the qualities of money, reflecting the emerging process of monetisation. Anaximander’s characterisation of the interchange of different elements within the unlimited in terms of ‘order’ and ‘retribution’ reflects both monetisation and emerging political structures. Similar factors underlie Herakleitos’ sustained focus on antithesis in the sense of the unity of opposites. Herakleitos’ universe is one of continuity within constant change, unity within interchange, expressed as fire or logos (‘reason’ or ‘calculation’). This worldview reflects the expanding influence of commercial exchange that underpins the emergence of a unified polis. It also reflects the paradoxical combination of unity and opposites within mystery cult, which is formulated in ritual language and gestures couched as antithetical dyads.