Religion is a unified system of thoughts and feelings that binds a group together. Its beliefs and practices provide a moral framework that governs the group’s conduct, as well as its values. These values are generally defined and taught by an authoritative source. They are not openly expressed, but are implied by beliefs and practices and are often ranked in order of importance with some values carrying more weight than others.

Most religions deal with what is referred to as the supernatural, that is, forces beyond the control of humans. They also include a belief in a higher power and/or a supreme being. They usually involve a set of sacred rites and customs that are considered holy.

Many scholars have approached the study of religion through phenomenology, which is a method for studying human experience. For example, Pierre Daniel Chantepie de la Saussaye catalogued observable characteristics of religion much as a zoologist would categorize animals or an entomologist would catalog insects.

The most widely accepted definitions of religion define membership in the category by the presence of a belief in a distinctive kind of reality. However, the twentieth century has witnessed the emergence of an approach that drops this substantive element and defines religion by its function: a “functional” definition. One can see this approach in Emile Durkheim’s (1912) definition of religion as whatever system of practices unites a group into a moral community (whether or not those practices involve belief in any unusual realities). Another functional definition comes from Paul Tillich (1957). It defines religion as whatever dominant concern serves to organize a person’s values.