Countless commentators have announced the advent of the post-truth era, but while everyone seems to be talking about it, there is little agreement about what it really means. This article argues that anthropology can make an important and distinctive contribution to understanding post-truth by treating it ethnographically. Commonly proposed explanations for post-truth include changes in political culture, in the structure of information in the digital age and universal cognitive weaknesses that limit people's capacity for critical thought. While all these are likely important factors, they do not account for the role of culture in creating and sustaining post-truth. In fact, it is likely that culture, especially in the form of metacognition...