How do we explain that people believe in apparently bizarre things as in Evans-Prichards’s study of the Azande beliefs in witches? It is argued that radically nativist theories on the one hand and radically culturalist explanations on the other are inadequate. Rather, a more detailed account needs to be worked out. Taking the example of religious ontologies to which Azandes witches belong, it is argued that religious ontologies consist of a relatively limited catalogue of counter-intuitive concepts on a worldwide basis. The problem is then how to explain why only some of these concepts are present in one culture and others in another culture. Also it is a problem how to explain why these religious ontologies are relatively stable within one...