Religion is a form of life that involves beliefs, practices, and communities. It also involves a sense of meaning and value in the world. It serves as a source of faith and hope in humans and a primary method of transmitting values from one generation to the next. It also offers answers to questions that science cannot answer, including the afterlife and the nature of the universe.

Most people around the world participate in a religion. Its definition varies from case to case, but most include belief in god or spirits, a sense of purpose in the world, and a community of believers. It often includes a moral code, sacred books, rituals, and symbols, a leader or clergy, and places and events that are holy to the religion. It may even have a philosophy of life that is considered important to the people that practice it.

Some scholars reject substantive definitions of religion, arguing that they have a Protestant bias and should instead focus attention on institutions and disciplinary practices. Others counter that this shift of focus from mental states to visible structures misses the point and merely obscures the fact that what counts as religion is not universal.

A third way of understanding religion is to drop the idea that it is a distinct kind of reality and simply define it as whatever social phenomenon generates solidarity among its participants. This approach, which Emile Durkheim and Paul Tillich developed in the twentieth century, is often called a functional definition.