Religion is a socially complex category. It is difficult to define, which may be one of the reasons it has been so controversial. It is often assumed to refer to a set of belief systems, such as Judaism, Christianity, Islam and Hinduism. However, it can also be seen as a way of life. It can be defined as a system of symbols that establishes powerful, pervasive and long-lasting moods and motivations in men by formulating conceptions of a general order of existence and clothing them with such an aura of factuality that the moods and motivations seem uniquely realistic. This definition was crafted by the American anthropologist Clifford Geertz (1926-2006). It is more complex and holistic than those that focus on belief in a particular type of object.
Most attempts to analyze religion have been “monothetic” in that they operate on the classical view that every instance accurately described by a concept will share a defining property. An example is Emile Durkheim’s definition, which defines religion as whatever dominant concern organizes a person’s values (whether those concerns involve beliefs in unusual realities or not).
More recently, there has been an emergence of “polythetic” approaches that abandon the classical view and treat the concept of religion as a prototype. Such an approach may be found in the work of Rodney Needham, who uses a computer program to sort 1500 different kinds of bacteria according to their characteristics, then tries to understand them by looking for patterns that occur across the class. The resulting insights are sometimes striking and offer the potential to develop explanatory theories.