In a research community, the use of the concept of category and categorization is widespread, generally helpful, but sometimes overly constraining. Despite the wealth of studies that propose new categories, a somewhat static view of categories pervades many disciplines. As we demonstrate on the analysis of a seminal framework by Gregor (2006), a given set of categories can be criticized and challenged in light of potentially valid alternatives. In contrast, we suggest for researchers to adopt the assumption of fluidity of categories, which leads to a different approach to demonstrating the contribution of research that deals with categories.