What research on immigrant religion can teach us about religion as a social boundary in contemporary Europe

In the fields of migration and religious studies, there is an interest in how migrants’ religiosity compares to that of non-migrants and develops after arrival in societies that are often more secular and dominated by other religious traditions. From a sociological perspective, such research can shed light on the role of religion as a social boundary marker between migrants and non-migrants, or specific religious minorities and the ‘mainstream’. Drawing on several empirical studies, most of which have been conducted in the Netherlands, I will first provide supportive evidence for the argument that the boundary between Muslims and non-Muslims is the brightest in contemporary European societies. Subsequently, I will address the question to what extent this boundary is a religious one, i.e., resulting from differences in religious identities, beliefs and practices. Weaving together results from longitudinal studies of Muslims’ religious involvement (compared to religious developments among migrants of other denominations), with research on the internal diversity of Muslim communities (both in terms of their ethnic composition, and substantive diversity within demographically similar subgroups) I will argue that the brightness of this boundary is not a function of (changes in) Muslims’ level of religiosity. I will end with suggestions for future research that can may be able to provide explanations for the currently bright boundary beyond Muslims’ religious behaviour.