Religion is a broad category and, therefore, definitions of it are difficult to construct. In the twentieth century, one saw an emergence of “functional” definitions which drop the notion of a belief in a distinctive kind of reality and define religion as whatever system of practices unite a number of people into a single moral community (whether those practices involve belief in unusual realities or not).

These functional definitions are controversial because they seem to reduce the concept of religion to mere social binds and to ignore a significant degree of nuance in the practice of religious life. But they are also able to offer a glimpse at the way that the term has been defined in the past.

A classic approach defines the true, the beautiful, and the good: the values that any given social group cherishes, the virtues of its members, and the way it organizes its structures. Some have suggested that a fourth C should be added: the material realities of its members, including their bodies, habits, physical culture, and social structures.

Religions protect and transmit the means to attain some of the most important goals imaginable. Some of these goals are proximate, having to do with making this life a better one—a wiser, more fruitful, more charitable, or more successful way of living—while others are ultimate, and have to do with the final condition of this or any other human person, or of the cosmos itself.