Social science studies often explain the emergence of collective beliefs by reference to factors that are supposed to be part of the social context. How do these macro-factors shape the beliefs of individuals? How can structural factors provide evidence supporting a given belief? In answering these questions, I propose a link connecting macro-factors and beliefs by introducing the notion of "evidential categorization." I expect to show that our structural explanations of beliefs often contain an analysis of the socially diffused systems of reasons—an important part of what we call the "epistemic context of belief-formation"—for they partially determine our evidential categorizations. Finally, I will show by an example, how structural explanations work if they include these components.