Discourse is a generalization of the notion of a conversation to any form of communication. Discourse is a major topic in social theory, with work spanning fields such as sociology, anthropology, continental philosophy, and discourse analysis. Following pioneering work by Michel Foucault, these fields view discourse as a system of thought, knowledge, or communication that constructs our experience of the world. Since control of discourse amounts to control of how the world is perceived, social theory often studies discourse as a window into power. Within theoretical linguistics, discourse is understood more narrowly as linguistic information exchange and was one of the major motivations for the framework of dynamic semantics, in which expressions' denotations are equated with their ability to update a discourse context.
Social theory
In the humanities and social sciences, discourse describes a formal way of thinking that can be expressed through language. Discourse is a social boundary that defines what statements can be said about a topic. Many definitions of discourse are largely derived from the work of French philosopher Michel Foucault. In sociology, discourse is defined as "any practice (found in a wide range of forms) by which individuals imbue reality with meaning".
Political science sees discourse as closely linked to politics and policy making. Likewise, different theories among various disciplines understand discourse as linked to power and state, insofar as the control of discourses is understood as a hold on reality itself (e.g. if a state controls the media, they control the "truth"). In essence, discourse is inescapable, since any use of language will have an effect on individual perspectives. In other words, the chosen discourse provides the vocabulary, expressions, or style needed to communicate. For example, two notably distinct discourses can be used about various guerrilla movements, describing them either as "freedom fighters" or "terrorists".
In psychology, discourses are embedded in different rhetorical genres and meta-genres that constrain and enable them—language talking about language. This is exemplified in the APA's Diagnostic and Statistical Manual of Mental Disorders, which tells of the terms that have to be used in speaking about mental health, thereby mediating meanings and dictating practices of professionals in psychology and psychiatry.
Modernism
Modernist theorists were focused on achieving progress and believed in the existence of natural and social laws which could be used universally to develop knowledge and thus a better understanding of society. Such theorists would be preoccupied with obtaining the "truth" and "reality", seeking to develop theories which contained certainty and predictability. Modernist theorists therefore understood discourse to be functional. Discourse and language transformations are ascribed to progress or the need to develop new or more "accurate" words to describe new discoveries, understandings, or areas of interest. In modernist theory, language and discourse are dissociated from power and ideology and instead conceptualized as "natural" products of common sense usage or progress. Modernism further gave rise to the liberal discourses of rights, equality, freedom, and justice; however, this rhetoric masked substantive inequality and failed to account for differences, according to Regnier.
Structuralism (Saussure & Lacan) Structuralist theorists, such as Ferdinand de Saussure and Jacques Lacan, argue that all human actions and social formations are related to language and can be understood as systems of related elements. This means that the "individual elements of a system only have significance when considered in relation to the structure as a whole, and that structures are to be understood as self-contained, self-regulated, and self-transforming entities". In other words, it is the structure itself that determines the significance, meaning and function of the individual elements of a system. Structuralism has made an important contribution to our understanding of language and social systems. Saussure's theory of language highlights the decisive role of meaning and signification in structuring human life more generally.
Poststructuralism (Foucault) Following the perceived limitations of the modern era, emerged postmodern theory. Postmodern theorists rejected modernist claims that there was one theoretical approach that explained all aspects of society. Rather, postmodernist theorists were interested in examining the variety of experiences of individuals and groups and emphasized differences over similarities and common experiences.