Modernity and postmodernism are terms used to describe different eras in the development of human societies. It is different from most sociological perspectives in that it has no over arching theory. Some think that western societies have moved from an era of modernity to post modernity, but others do not agree. The debate between modernity and postmodernism tends to be about to what extent society has changed, and so which theoretical approach is the most appropriate. Modernism began as a way of describing the ideas that emerged during the decline of medieval society.