The most significant aspect of Critical Theory is its assertion that the "reality" we perceive in the world is not "real" in the sense of existing outside of the meaning that we give to it - and that this meaning is created and shaped by the cultures and social institutions in which we live. Following this logic, the meaning attributed to different linguistic acts or formations is itself heavily mediated by the forms of power which structure the social formations of everyday life. This aspect of Critical Theory has been most profoundly developed b the theorists Peter Berger and Thomas Luckmann. In this PDF I explain their theories in detail and depth, citing contextual issues and influences and explaining the extensiveness of their influence.