Religion is the set of beliefs and practices that people believe to be their source of comfort, guidance and identity. It may also provide moral values, rituals and community. Religion can also be a vehicle for social cohesion and can influence political decisions in some countries.

The word “religion” is widely used today to refer to a range of diverse practices. The fact that so many different things can be said to belong to the same taxon is a reflection of how flexible and abstract the concept really is. However, two philosophical issues arise from the fact that people use this term to sort and organize so many different kinds of human activity: whether it is possible to understand this taxon in terms of necessary and sufficient properties; and whether it would be more accurate to treat it as a family-resemblance concept rather than a pure category.

Both these issues are complicated by the fact that many of the different activities that can be described as religion are highly diverse. Some scholars have tried to resolve this problem by adopting monothetic definitions of the concept. Edward Tylor, for example, defined religion as belief in spiritual beings; Paul Tillich’s functional criterion of ultimate concern is another such monothetic approach.

Other scholars have rejected the notion of a monothetic definition, asserting that no such thing exists. They have argued that a social concept must be able to recognize and include a variety of different varieties in order to serve its purpose. This view has led to the development of polythetic definitions, which abandon the classical assumption that a concept can be accurately understood by identifying just one property that defines it as such.