This article takes the form of a debate between the two authors on the social ontology of propositional culture. Archer applies the morphogenetic approach, analysing culture as a cycle of interaction between the Cultural System and Socio-Cultural Interaction. In this model, the Cultural System is comprised of the objective content of intelligibilia, as theorized by Karl Popper with his concept of objective World 3 knowledge. Elder-Vass agrees that culture works through an interplay between subjective belief and an external objective moment, but argues that the external moment cannot take the form of 'objective knowledge' as this is understood by Popper. Instead, the external moment of culture takes the form of normative pressures exerted by groups of people: norm circles. Ultimately both authors share a commitment to a similar critical realist ontological framework, while offering alternative accounts of the nature of culture within that framework.