Religions provide the framework of understanding and behaviour for two-thirds of the world’s people. They protect and transmit the means to attain some of life’s most important goals, whether proximate (a wiser, more fruitful, more charitable, or more successful way of living) or ultimate (the end of this or any other human person’s life and of the cosmos itself). The ways in which they do this are vastly varied. They may be large-scale and coherently organized and hierarchical, as in Roman Catholicism with its Pope, cardinals, bishops, priests, and a hierarchy of religious orders, both male and female; or they may be small and intimate, with strong subsystems, as among Hindus with their gurus, temples, and holy places.

Religion is an essentially positive and stabilizing force in the lives of most people, although, for many, it also provides the basis for bitter conflict, violence, and prejudice. For this reason, it is a topic that is highly politicized.

Scholars who study religion seek to understand its nature and the forces that make it work. Some scholars take a realist approach, seeking to find its essence in its historical creativity and meaningfulness for the social, cultural, and individual lives with which it is interwoven. Others, such as Ninian Smart and Catherine Albanese, take a more materialist view and divide the concept of religion into its components: beliefs, practices, and a system of social organization.

It is essential to distinguish between the two approaches. One can criticize a stipulative definition, but it is not possible to prove it wrong, since it is judged not by its accuracy but by its usefulness in the purposes for which it is intended.

In addition, a stipulative definition must be consistent with the way that a religion works in actual life. It must explain what the religion teaches, in general terms, and how its teachings are applied, in specific contexts, to actual people. It must account for the historical development of the religion, including the fact that it is not always faithful to its original doctrine or tenets and that there is often an element of adaptation in its responses to contemporary challenges and situations.

Another challenge to realist analyses is the difficulty of identifying what a religion really is, particularly when it changes and adapts over time. In the past, it was common for religions to have elements of the new and the old, with changes occurring slowly or quickly. For example, new ideas about a scientific phenomenon could change a religion’s interpretation of it, but such changes were usually gradual. In the modern era, religions are much more rapid in their changing, but the same basic elements remain: the belief in a divine power, moral rules for behavior, and the practice of ritual. It is also common for religions to have a vision of the future, eschatology, and the purpose of human existence in which the old and the new are integrated. This integration can be seen in the ways in which religions deal with issues of social change, the problems of evil and suffering, and the meaning of life.