Religions are social institutions, involving beliefs, practices, and community. They provide people with meaning and purpose in life, reinforce social unity, stability, and control, promote psychological and physical well-being, and may motivate people to work for positive social change. However, scientific and philosophical criticisms of religion often lead to a lack of respect for the two-thirds of Americans who practice some form of faith. In fact, completely secular approaches to public policy, psychotherapy, and education can miss the important contributions that regular religious practice makes to the preservation of American society.
Like all social institutions, religions develop within and across cultures. They are influenced by both the surrounding environment and the human need to connect with the transcendent. This makes them more resistant to rapid social change than other social institutions, and they often maintain older features while adding new ones.
A common method for studying religion is a functional approach, which attempts to understand its effects on the social, individual, and cultural contexts in which it exists. One of the earliest sociological functionalists was Emile Durkheim, who defined religion as a system of beliefs and practices that unite individuals into a moral community. His successors have tended to use more broad, sociologically-oriented definitions of religion.
Another approach to studying religion is a polythetic, or taxonomic, approach. This is based on the idea that all religions are different, but that they can be classified as part of the same class if they share certain characteristics. Using this method, scholars look for the co-appearance of these traits and attempt to construct a theoretical framework that can explain why they appear together.