In order to understand what postmodernism is about it is essential to understand what modernity means for the social sciences and this is linked to what is deemed to be the enlightenment project. Modernity or the enlightenment project is reflected in positivism, the importance of the scientific method.
The age of enlightenment ushered in human rationality as the source of knowledge, thus encouraging the rejection of previous authorities such as the church or custom.
Advances in science encouraged people to believe that there could be a rational explanation for everything and that could lead to the solving of all of the problems faced by human beings.
This lead to the belief that the social sciences would extend this enlightenment project into explanations of the collective activities and relationships of human beings.
These beliefs shape social sciences by giving science a privileged position in the pursuit of truth, encouraging the search for sets of concepts to provide a framework for understanding social life regardless of particular social situations or time and the acceptance of metanarratives as superior to other narrative accounts about society.
Enlightenment project is apparent in some of the works of Karl Marx. Marxian theory is a large metanarrative about the historical development of western societies such that it includes all stories about society and because of its claim to be based on scientific observation and its use of a conceptual framework (modes of production, relations of production) it claims a privileged position and a universal nature.
Further, it is claimed that by using the metanarrative the consciousness of workers can be enhanced and an age of liberation will follow.