Religion is a large and complex concept, whose definition is of central interest to disciplines as diverse as anthropology, history, philosophy, sociology, religious studies, psychology, and even cognitive science. Because of the broad and deep range of religious beliefs and practices, there is enormous variation in what gets called “religion” from place to place. As a result, scholars have been debating the question of how to define religion for a long time.
One approach is to adopt a substantive definition, which determines whether something counts as religion based on the presence of certain kinds of beliefs and practices. This approach has the advantage of being fairly inclusive, but it is often criticized for being too broad. For example, it may include belief in ghosts or in UFOs as religious phenomena. Moreover, it tends to exclude faith traditions that emphasize immanence or oneness, like some forms of Buddhism and Jainism.
Another approach is to drop the substantive element and instead define religion in terms of a distinctive role that it plays in people’s lives. This approach, which is usually called a functional definition, has received less attention than the substantive and lexical definitions. Emile Durkheim’s defining work, The Elementary Forms of the Religious Life, from 1912, exemplifies this type of definition.
A functional definition has the advantage of being fairly inclusive, but like the substantive definition, it is sometimes criticized for being too narrow. For example, it may exclude faith traditions that focus on morality and social responsibility.