Postmodernism is a broad term used to describe movements in a wide range of disciplines, including art, philosophy, critical theory, and music. Many view it as a response to the preceding modernist movement, but where modernism simply reacts against classical concepts, particularly in the arts and literature, things that are postmodern take this reaction to its extreme conclusion. Indeed, some see it not as a separate movement, but simply as a continuation of the modernist struggle.
The word itself has been used so widely as to strip it of much of its meaning. There is hardly a discipline of the arts or social sciences that has not spawned numerous movements given this label, and the aims of many of these movements seem to be contrary to one another. Nonetheless, most of the time when the term is applied, it indicates one of a smaller handful of meanings.
In a pejorative sense, postmodernism implies an almost nihilistic outlook, stripping whatever the targeted sphere of any innate meaning. Views seen as being very relativist are often given this label in an effort to disparage them.
In the creative disciplines, such as painting, literature, music, and sculpture, postmodernism tends to lean heavily on using forms not traditionally perceived as artistic. Heavy use of kitsch or overly simplistic styles are two examples of this mode. Many artists appropriate earlier modernist and classical works and combine or alter them to create a new, ironic piece. In literature particularly, but also in much theater, traditional barriers between audience and narrator are broken down. A self-awareness of a character's role as a character in a novel is a prime example of this mode. Many would argue that the presence of a self-aware irony is a necessary cornerstone of any work claiming to be part of this movement.
In critical theory and philosophy, postmodernism serves as a striking counterpoint to classical foundations of philosophy. While earlier philosophers and theorists were devoted to the ongoing exploration of a universal system, postmodernists focus on the role of that search in creating what is known as truth itself. To most of these theorists, it is the discourse itself that gives rise to any sort of perceived universality.
Architecture that falls under this category — exemplified by the school known as deconstructivist architecture — tends to invert traditional elements, such as placing interior elements on the exterior, and visa versa. It might also place symbolic elements in highly visible and thought-provoking locations, and emphasize jarring and discordant aesthetics.
Fundamentally, postmodernism may best be viewed as any form of thought and action that places an emphasis on a strongly ironic self-consciousness, intentional discontinuity with other elements of a work, or knee-jerk responses without self-censoring. It is based on preconceived notions of what is proper but done with a spirit of liveliness and joyousness, verses modernism's rather dismal view of this subjectivity.