Religions are organized systems for monitoring, coding, protecting, transmitting, and sharing knowledge, from information about the past to the future (for example, in rites of passage such as marriage or funerals). They also organize the organization of people involved in religious life. Depending on the kind of religion, this may involve the professional skills and specialization of priests, witches, shamans, imams, rabbis, monks, or nuns, or it may be informal, with the members of a community assuming the roles of religious specialists as needed (see for instance, Mystery Religions and Missionary Religions).
It can also involve regulating behavior, establishing laws and social norms, imposing punishments for violating those rules and values, promoting morality, providing meaning in life, offering hope and guidance, and making sense of the world around us. Religions may also have a spiritual component, and they often evoke feelings of reverence and awe. In addition, they are a source of many of the most beautiful and monumental human creations, from architecture, music, and art to agriculture, cuisine, medicine, and the exploration of the cosmos that issued into what we now call natural science.
But it is important to recognize that religions are not all the same, even though they share some of the same features. In particular, there is a risk that a monothetic definition of religion will inevitably lead to intolerance, cruelty, bigotry, and social oppression.
Another concern is that substantive definitions of religion are ethnocentric, because they focus on beliefs, personal experience, and a dichotomy between the natural and supernatural, leaving out faith traditions that emphasize immanence or oneness such as Buddhism and Jainism.
In contrast, there is a growing awareness, particularly among scholars inspired by continental philosophers such as Friedrich Nietzsche and Michel Foucault (see Wittgenstein, Ludwig), that it is possible to create and sustain religions that have no belief in any gods or spirits, or in fact anything at all. These religions are sometimes called nontheistic religions, and there is an increasing interest in their value and purpose.
In the final analysis, it is probably best to take a polythetic approach to the concept of religion. This will allow us to distinguish between different forms of the same phenomenon, and it will encourage a more fruitful investigation into what it is that makes religions what they are. It is likely that, at least at some level, it will be possible to develop a scientific theory which causally explains why the various features we call “religion” tend to cluster together, and which may explain why those features are so essential to the lives of many human beings. It is also possible that this will eventually lead to an understanding of the nature of a religion, and whether or not it is a natural kind. If so, it will be a powerful and useful tool for explaining the diversity of human societies. It will not, however, be a way of reducing the threat of intolerance, cruelty, and social oppression which religions still pose to our world.