Religion is a worldview that reflects human beings’ deepest concerns. It deals with questions of meaning and purpose, and it addresses such concerns as death and afterlife, good versus evil, the existence of a creator who watches over humanity, and moral conduct and behavior. It also addresses a desire for salvation, either in the sense of life after death as found in Christianity or in the more symbolic sense of finding relief from suffering and nirvana in Buddhism. It typically involves devotional practices, rituals, codes of morality, and a sacred community, places, symbols, and days. It may also involve a belief in the supernatural or in a god or gods.

How one defines religion, and how this definition changes over time, is a central issue in the study of this phenomenon. One approach is to use a substantive definition, which determines whether something is religious by its belief in a distinctive kind of reality. The other is a functional definition, which determines the status of a practice by its function in the lives of the people who engage in it.

While it is difficult to make a definitive case that any specific practice is or is not religious, the facts suggest that some form of religion is an important part of most people’s lives. Roughly eight-in-ten Jehovah’s Witnesses, Mormons, and historically black Protestants say that religion is very important in their lives, and those figures are similar for other religious traditions. In addition, there is a general agreement that the practice of religion is generally good for individuals, families, society, and the world. It improves health, learning, economic well-being, self-control, and compassion. It also reduces out-of-wedlock births, crime, and social pathologies such as anxieties, prejudices, and conflicts over property.