Critical theory is the reflective assessment and critique of society and culture by applying knowledge from the social sciences and the humanities to reveal and challenge power structures. It argues that social problems are influenced and created more by societal structures and cultural assumptions than by individual and psychological factors. Critical theory has origins in sociology and also in literary criticism. The sociologist Max Horkheimer described a theory as critical insofar as it seeks "to liberate human beings from the circumstances that enslave them".
In sociology and political philosophy, the term "Critical Theory" describes the Western Marxist philosophy of the Frankfurt School, which was developed in Germany in the 1930s. This use of the term requires proper noun capitalization, whereas "a critical theory" or "a critical social theory" may have similar elements of thought, but does not stress the intellectual lineage specific to the Frankfurt School. Frankfurt School critical theorists drew on the critical methods of Karl Marx and Sigmund Freud. Critical theory maintains that ideology is the principal obstacle to human liberation. Critical theory was established as a school of thought primarily by the Frankfurt School theoreticians Herbert Marcuse, Theodor Adorno, Max Horkheimer, Walter Benjamin, and Erich Fromm. Modern critical theory has additionally been influenced by György Lukács and Antonio Gramsci, as well as the second generation Frankfurt School scholars, notably Jürgen Habermas. In Habermas's work, critical theory transcended its theoretical roots in German idealism and progressed closer to American pragmatism. Concern for social "base and superstructure" is one of the remaining Marxist philosophical concepts in much of contemporary critical theory.
Postmodern critical theory analyzes the fragmentation of cultural identities in order to challenge modernist era constructs such as metanarratives, rationality and universal truths, while politicizing social problems "by situating them in historical and cultural contexts, to implicate themselves in the process of collecting and analyzing data, and to relativize their findings".
Critical theory (German: Kritische Theorie) was first defined by Max Horkheimer of the Frankfurt School of sociology in his 1937 essay Traditional and Critical Theory: Critical theory is a social theory oriented toward critiquing and changing society as a whole, in contrast to traditional theory oriented only to understanding or explaining it. Horkheimer wanted to distinguish critical theory as a radical, emancipatory form of Marxian theory, critiquing both the model of science put forward by logical positivism and what he and his colleagues saw as the covert positivism and authoritarianism of orthodox Marxism and Communism. He described a theory as critical insofar as it seeks "to liberate human beings from the circumstances that enslave them". Critical theory involves a normative dimension, either through criticizing society from some general theory of values, norms, or "oughts", or through criticizing it in terms of its own espoused values.
This version of "critical" theory derives from Kant's (18th-century) and Marx's (19th-century) use of the term "critique", as in Kant's Critique of Pure Reason and Marx's concept that his work Das Kapital (Capital) forms a "critique of political economy". For Kant's transcendental idealism, "critique" means examining and establishing the limits of the validity of a faculty, type, or body of knowledge, especially through accounting for the limitations imposed by the fundamental, irreducible concepts in use in that knowledge system.
Kant's notion of critique has been associated with the overturning of false, unprovable, or dogmatic philosophical, social, and political beliefs, because Kant's critique of reason involved the critique of dogmatic theological and metaphysical ideas and was intertwined with the enhancement of ethical autonomy and the Enlightenment critique of superstition and irrational authority. Ignored by many in "critical realist" circles, however, is that Kant's immediate impetus for writing his "Critique of Pure Reason" was to address problems raised by David Hume's skeptical empiricism which, in attacking metaphysics, employed reason and logic to argue against the knowability of the world and common notions of causation. Kant, by contrast, pushed the employment of a priori metaphysical claims as requisite, for if anything is to be said to be knowable, it would have to be established upon abstractions distinct from perceivable phenomena.
Marx explicitly developed the notion of critique into the critique of ideology and linked it with the practice of social revolution, as stated in the famous 11th of his Theses on Feuerbach: "The philosophers have only interpreted the world, in various ways; the point is to change it."
One of the distinguishing characteristics of critical theory, as Adorno and Horkheimer elaborated in their Dialectic of Enlightenment (1947), is a certain ambivalence concerning the ultimate source or foundation of social domination, an ambivalence which gave rise to the "pessimism" of the new critical theory over the possibility of human emancipation and freedom. This ambivalence was rooted, of course, in the historical circumstances in which the work was originally produced, in particular, the rise of National Socialism, state capitalism, and culture industry as entirely new forms of social domination that could not be adequately explained within the terms of traditional Marxist sociology.
For Adorno and Horkheimer, state intervention in economy had effectively abolished the tension between the "relations of production" and "material productive forces of society", a tension which, according to traditional critical theory,[clarification needed] constituted the primary contradiction within capitalism. The market (as an "unconscious" mechanism for the distribution of goods) had been replaced by centralized planning.
Yet, contrary to Marx's famous prediction in the Preface to a Contribution to the Critique of Political Economy, this shift did not lead to "an era of social revolution", but rather to fascism and totalitarianism. As such, critical theory was left, in Jürgen Habermas' words, without "anything in reserve to which it might appeal, and when the forces of production enter into a baneful symbiosis with the relations of production that they were supposed to blow wide open, there is no longer any dynamism upon which critique could base its hope". For Adorno and Horkheimer, this posed the problem of how to account for the apparent persistence of domination in the absence of the very contradiction that, according to traditional critical theory, was the source of domination itself.
In the 1960s, Jürgen Habermas, a proponent of critical social theory, raised the epistemological discussion to a new level in his Knowledge and Human Interests, by identifying critical knowledge as based on principles that differentiated it either from the natural sciences or the humanities, through its orientation to self-reflection and emancipation. Although unsatisfied with Adorno and Horkeimer's thought presented in Dialectic of Enlightenment, Habermas shares the view that, in the form of instrumental rationality, the era of modernity marks a move away from the liberation of enlightenment and toward a new form of enslavement. In Habermas's work, critical theory transcended its theoretical roots in German idealism, and progressed closer to American pragmatism.
Habermas is now influencing the philosophy of law in many countries—for example the creation of the social philosophy of law in Brazil, and his theory also has the potential to make the discourse of law one important institution of the modern world as a heritage of the Enlightenment.
His ideas regarding the relationship between modernity and rationalization are in this sense strongly influenced by Max Weber. Habermas dissolved further the elements of critical theory derived from Hegelian German Idealism, although his thought remains broadly Marxist in its epistemological approach. Perhaps his two most influential ideas are the concepts of the public sphere and communicative action; the latter arriving partly as a reaction to new post-structural or so-called "postmodern" challenges to the discourse of modernity. Habermas engaged in regular correspondence with Richard Rorty and a strong sense of philosophical pragmatism may be felt in his theory; thought which frequently traverses the boundaries between sociology and philosophy.
While modernist critical theory (as described above) concerns itself with "forms of authority and injustice that accompanied the evolution of industrial and corporate capitalism as a political-economic system," postmodern critical theory politicizes social problems "by situating them in historical and cultural contexts, to implicate themselves in the process of collecting and analyzing data, and to relativize their findings." Meaning itself is seen as unstable due to the rapid transformation in social structures. As a result, the focus of research is centered on local manifestations, rather than broad generalizations.
Postmodern critical research is also characterized by the crisis of representation, which rejects the idea that a researcher's work is an "objective depiction of a stable other". Instead, many postmodern scholars have adopted "alternatives that encourage reflection about the 'politics and poetics' of their work. In these accounts, the embodied, collaborative, dialogic, and improvisational aspects of qualitative research are clarified".
The term "critical theory" is often appropriated when an author works within sociological terms, yet attacks the social or human sciences (thus attempting to remain "outside" those frames of inquiry). Michel Foucault is one of these authors.
Jean Baudrillard has also been described as a critical theorist to the extent that he was an unconventional and critical sociologist; this appropriation is similarly casual, holding little or no relation to the Frankfurt School.
Critical theory is focused on language, symbolism, communication, and social construction. Critical theory has been applied within the social sciences as a critique of social construction and postmodern society. 
From the 1960s and 1970s onward, language, symbolism, text, and meaning came to be seen as the theoretical foundation for the humanities, through the influence of Ludwig Wittgenstein, Ferdinand de Saussure, George Herbert Mead, Noam Chomsky, Hans-Georg Gadamer, Roland Barthes, Jacques Derrida and other thinkers in linguistic and analytic philosophy, structural linguistics, symbolic interactionism, hermeneutics, semiology, linguistically oriented psychoanalysis (Jacques Lacan, Alfred Lorenzer), and deconstruction.
When, in the 1970s and 1980s, Jürgen Habermas redefined critical social theory as a study of communication, i.e. communicative competence and communicative rationality on the one hand, distorted communication on the other, the two versions of critical theory began to overlap to a much greater degree than before.
Critical theorists have widely credited Paulo Freire for the first applications of critical theory towards education/pedagogy. They consider his best-known work, Pedagogy of the Oppressed, a seminal text in what is now known as the philosophy and social movement of critical pedagogy. For a history of the emergence of critical theory in the field of education, see Isaac Gottesman (2016), (New York: Routledge).The Critical Turn in Education: From Marxist Critique to Postructuralist Feminism to Critical Theories of Race
While critical theorists have been frequently defined as Marxist intellectuals, their tendency to denounce some Marxist concepts and to combine Marxian analysis with other sociological and philosophical traditions has resulted in accusations of revisionism by classical, orthodox, and analytical Marxists, and by Marxist–Leninist philosophers. Martin Jay has stated that the first generation of critical theory is best understood as not promoting a specific philosophical agenda or a specific ideology, but as "a gadfly of other systems".
Critical theory has been criticized for not offering any clear road map to political action (praxis) following critique, often explicitly repudiating any solutions (such as with Herbert Marcuse's concept of "the Great Refusal", which promoted abstaining from engaging in active political change).