Religion is a very large category, covering a wide variety of beliefs and ritual practices. It is a key part of many peoples’ lives and is the subject of extensive research. Its influence is complex and multifaceted, and recent studies suggest that it may play a role in health and well-being.
The simplest definition of religion is the belief in spiritual beings. This covers a wide range of ideas and practices, from the animism of primitive peoples (where animals, plants, rocks, weather systems, and human handiwork are seen as alive) to the monotheism of the Abrahamic faiths and Hinduism. But this is a problematic approach, since it tends to exclude religious developments that are not monotheistic.
It also misses the fact that, for most peoples, religion is a system of evaluation that takes account of the many clashing forces in their lives and the vast unknown future, about which they know extremely little. The ancient Greek philosophers Thales (6th century bce) and Heracleitus (flourished c. 500 bce) both held that water and fire were the primary substances from which all other things are made.
Religions help people to recognize the many limitations that stand across their projects and to learn how to deal with them. They also provide maps of time and space: they may be coherently organized and hierarchical, as in Roman Catholicism with its clear centre at the Vatican and hierarchy of Pope, cardinals, bishops, priests, laity, and so on, or they may be loosely structured, with a wide range of subsystems such as cults, gurus, temples, holy places, and so on.