“The More, the Merrier”: Three Ways of Case Universe Extension—Reflections on Bringing Shia into Islamism Studies

One of the fundamental questions of social science concerns the subject of scope conditions. A field of study can grow around a set of empirical puzzles, making generalized assertions without reflecting on whether the field covers all possible instances. This becomes particularly acute when sociopolitical changes have led to a diversification of cases. This paper takes the case of Islamism studies, which has suffered from a major blind spot: a (mostly) unacknowledged Sunni-centrism in the way broader claims about Islamism are often drawn from a (narrow) Sunni case universe. Although calls for bringing in the "other Islamists"have increased, so far there has been limited discussion of why and how an inclusion of Shia can enrich our overall understanding of Islamism and politico-religious actors more broadly. Drawing on experiences from other fields that have witnessed an expansion of their case universe, such as democratization, social movement, and international studies, the paper shows how an agreement in principle to expand the case universe does not necessarily translate into a consensus on why and how case expansion can strengthen and expand the field. Based on a novel typology for the rationales, methods, and outcomes for case extension, the paper proposes three different ideal-typical ways inclusion of Shia Islamists can enrich the field of Islamism studies, with important implications for how we think about case extension and knowledge production more broadly. In addition to case extension offering new case material to test classic hypotheses about Islamism (theory-testing), the paper shows that broadening the case universe and greater dialogue between the research communities - in this case around Sunni and Shia Islamism - can generate novel research puzzles (theory-development) or give rise to more fundamental (self-)reflections on the study of the subject - here Islamism - as such (meta-theorizing).