Religion is a word that describes many different things, from ancient pagan beliefs in disembodied spirits to modern Western ideas about tolerance, faith, authority and the meaning of life. The fact that there are so many different religions, and that people in so many cultures believe in them, makes it difficult to agree on a definition of what religion is.
This is because religions are, in the end, about much more than just believing in some gods or spirits. They are, rather, systems for protecting and transmitting the information that has been tested and winnowed over time. This information is of immense importance to human beings, because it enables them to make their way through the worlds in which they live. It is information about how the world works, about the history of the universe and the development of humanity. It is also the means by which they deal with the ultimate concerns that lie across the project of their lives, whether these are proximate (a wiser and more fruitful way of living, or some form of salvation) or ultimate (the fate of this or any other person after death).
A number of scholars have therefore developed functional definitions of religion. These have ranged from Durkheim’s focus on the social function of solidarity, to the anthropological approach to culture taken by Clifford Geertz and the theologian Paul Tillich. The defining characteristics of religion, according to these approaches, are its intensity and comprehensiveness.
The problem with these approaches is that they tend to treat religion as something that is universal, and that all cultures have a version of it. This is a mistake, as the great philosopher William James noted: “To be real is to be a process, and not an outcome.” To be religious is to be part of a system of values that is a process of valuation. There are many other processes of valuation, and religions differ from one another in the specifics of their values and how they are expressed.
The term “religion” is so important and so fundamental to the human experience that it can not simply be dismissed as a mere idea or belief. It is, in the end, a human phenomenon that is a vitally important part of all cultures. That is why it is so difficult to define: definitions that treat it as a social genus or a functional concept do not really get the job done.