Religion is an idea that people have about what they believe in and value. Religious beliefs influence the lives of people around the world and within our diverse communities, schools, and neighborhoods. Studying different religions helps students gain an understanding of global complexity and prepares them to engage in a pluralistic democracy. The National Council for the Social Studies continues to lead the call to include the study of religion in the classroom in ways that are constitutionally sound and academically rigorous.

Scholars have long debated what it means for a belief system to be labeled as a religion. One common approach is to define religion as a social genus, a taxon that includes many types of beliefs and practices with some shared characteristics. Such a definition defines religion as a collection of social forms that can be organized into a moral community, whether or not the members believe in an unusual kind of reality.

A critique of this taxon is common in some disciplines, particularly in fields that have been influenced by Foucauldian or post-colonial theory. These scholars argue that the concept of religion was largely created during the modern period, and its use was part of a larger project of European colonialism. The critique of religion is not an attack on the beliefs and practices of self-described religious individuals or groups, but an attempt to understand how the idea of religion has shaped our interpretations of history.

As the concept of religion has become more widely accepted, the debate about its nature and meaning has moved on to other issues. Two of these are the philosophical problems that arise for this abstract taxon, similar to the questions about other social kinds such as literature or democracy.

The first problem is the question of whether or not religion has an essence. Many people have argued that it is impossible to understand religion without its essential properties, such as beliefs in disembodied spirits or cosmological orders. However, it is not clear that these properties are necessary to the definition of religion, since there have been cultures in the past and present that have no views on afterlife or supernatural beings.

Other critics have gone even further, arguing that it is impossible to make sense of any definition of religion that requires a belief in an unusual kind of reality. These scholars have argued that a more reasonable alternative is to define religion by its distinctive role in society, rather than as a specific set of beliefs or practices. Such a functional definition is more closely aligned with the way that social scientists have used the term in other disciplines. It also provides a more accurate view of the diversity of religions in the world today. However, this approach has its own limitations in describing the phenomenon. In addition, it undermines the claim that some forms of religion are more important or valuable than others. A third approach is to try to find a way to combine these two approaches.