The concept of Religion has evolved over time. What once referred to scrupulous devotion now encompasses a wide range of social practices. Some take the word to mean a taxon of social formations that share some defining characteristics—either a unified moral community or belief in unusual forms of reality. Others rely on functional definitions of religion, which drop the notion that forms of life have to include belief and define membership in terms of the distinctive role they play in people’s lives. Emile Durkheim, for example, defined religion as whatever systems of practices unite a group of people into one moral community.
A functional approach may be a useful way to analyze religion, but it has limits. Inevitably, a researcher will need to identify the characteristics that distinguish different types of religious practice. But stipulating that these features must appear in order for something to be called a religion creates a rigid classification system that can limit the study of new and unexpected phenomena.
In addition, there is a danger that functional definitions of religion become the dominant form of analysis, overshadowing other approaches. When the category of religion becomes a lens through which to view a culture, it can be easy to overlook other important issues such as power relations, gender roles, and economic and ecological concerns.