 The history of the concept religion above shows how its senses have shifted over time. A concept used for scrupulous devotion was retooled to refer to a particular type of social practice. But the question—what type?—is now convoluted. The cosmic version of the concept is broader than the polytheistic version, which is in turn broader than the theistic version, and the functional definitions shift the sense of the term into a completely different register. What is counted as religion by one definition is often not counted by others. How might this disarray be understood? Does the concept have a structure? This section distinguishes between two kinds of answer to these questions. Most of the attempts to analyze the term have been “monothetic” in that they operate with the classical view that every instance that is accurately described by a concept will share a defining property that puts them in that category. The last several decades, however, have seen the emergence of “polythetic” approaches that abandon the classical view and treat religion, instead, as having a prototype structure. For incisive explanations of the classical theory and the prototype theory of concepts, see Laurence and Margolis (1999).