The Frankfurt School is a school of neo-Marxist social theory, social research, and philosophy.

It started life at the Institut für Sozialforschung (Institute for Social Research) of Frankfurt am Main, West Germany, when Max Horkheimer became the institute's director in 1930. The Frankfurt School gathered together dissident Marxists, severe critics of capitalism who believed that some of Marx's alleged followers had come to parrot a narrow selection of Marx's ideas, usually in defense of orthodox Communist Parties. Influenced especially by the failure of working-class revolutions in Western Europe after World War I and by the rise of Nazism in an economically, technologically, and culturally advanced nation such as Germany, they took up the task of choosing what parts of Marx's thought might serve to clarify social conditions which Marx himself had never seen. They drew on other schools of thought to fill in perceived omissions in Marx's. Max Weber exerted a principal influence,as did Sigmund Freud (as in Herbert Marcuse's integration of Marx and Freud. Their emphasis on the "critical" component of theory was derived significantly from their attempt to overcome the limits of positivism, crude materialism, and phenomenology by returning to Kant's critical philosophy and its successors in German idealism, principally Hegel's philosophy, with its emphasis on negation and contradiction as inherent properties of reality. A key influence was also the publication in the 1930's of Marx's Economic-Philosophical Manuscripts and The German Ideology, which showed the continuity with Hegelianism that underlay Marx's thought. The intellectual influences on and theoretical focus of the first generation of Frankfurt School critical theorists are captured in the following diagram:

The major contributions of the Institute were in two areas relating to the possibility of rational human subjects, i.e. individuals who could act rationally to take charge of their own society and their own history. The first consisted of social phenomena previously considered by Marxism as part of the "superstructure" or as ideology: personality, family and authority structures (its first book publication was (Studies of Authority and the Family), and the realm of aesthetics and mass culture. The common concern here was the ability of capitalism to destroy the preconditions of critical, revolutionary consciousness. This meant arriving at a sophisticated awareness of the depth dimension in which social oppression sustains itself. It also meant the beginning of critical theory's recognition of ideology as part of the foundations of social structure. The Institute and various collaborators had a gigantic impact on (especially American) social science through their work The Authoritarian Personality, which conducted extensive empirical research, using sociological and psychoanalytic categories, in order to understand the forces that led individuals to affiliate with or support fascist movements or parties.

The second area was the nature of Marxism itself, and it was in this context that the concept of critical theory originated. Although Horkheimer's distinction between traditional and critical theory is in one sense merely a repetition of Marx's dictum that philosophers have always interpreted the world and the point is to change it, the Institute, in its critique of ideology, took on such philosophical currents as positivism, phenomenology, existentialism, and pragmatism, with an implied critique of contemporary Marxism, which had turned dialectics into an alternate science or metaphysics. The Institute attempted to reformulate dialectics as a concrete method continually aware of the specific social roots of thought and of the specific constellation of forces that affected the possibility of liberation. Accordingly, critical theory rejected the materialist metaphysics of orthodox Marxism. For Horkheimer and his associates, materialism meant the orientation of theory towards practice and towards the fulfillment of human needs, not a metaphysical statement about the nature of reality.

The second phase of Frankfurt School critical theory is sedimented principally in two works that rank as classics of twentieth-century thought: Horkheimer's and Adorno's Dialectic of Enlightenment and Adorno's Minima Moralia. Both works were written during the Institute's American exile during the Nazi period. While retaining much of the Marxian analysis, in these works critical theory has shifted its emphasis. The critique of capitalism has turned into a critique of Western civilization as a whole. Indeed, the Dialectic of Enlightenment uses the Odyssey as a paradigm for the analysis of bourgeois consciousness. Many themes that have come to dominate the social thought of recent years are already presented by Horkheimer and Adorno in these works: the domination of nature is seen as central to Western civilization long before ecology had become a catchphrase of the day.

The analysis of reason is carried one stage further. The rationality of Western civilization is seen as a fusion of domination and technological rationality, bringing all of external and internal nature under the power of the human subject. In the process, however, the subject itself is swallowed up, and no social force analogous to the proletariat can be identified that will enable the subject to emancipate itself. Hence the subtitle of Minima Moralia: "Reflections from Damaged Life". In Adorno's words,

"For since the overwhelming objectivity of historical movement in its present phase consists so far only in the dissolution of the subject, without yet giving rise to a new one, individual experience necessarily bases itself on the old subject, now historically condemned, which is still for-itself, but no longer in-itself. The subject still feels sure of its autonomy, but the nullity demonstrated to subjects by the concentration camp is already overtaking the form of subjectivity itself."

Consequently, at a time when it appears that reality itself has become ideology, the greatest contribution that critical theory can make is to explore the dialectical contradictions of individual subjective experience, on the one hand, and to preserve the truth of theory, on the other. Even the dialectic can become a means to domination: "Its truth or untruth, therefore, is not inherent in the method itself, but in its intention in the historical process." And this intention must be toward integral freedom and happiness: "the only philosophy which can be responsibly practiced in face of despair is the attempt to contemplate all things as they would present themselves from the standpoint of redemption". How far from orthodox Marxism is Adorno's conclusion: "But beside the demand thus placed on thought, the question of the reality or unreality of redemption itself hardly matters."

From these thoughts it was but a short step to the third phase of the Frankfurt School, which coincided with the postwar period, particularly from the early 1950s to the middle 1960s. With the growth of advanced industrial society under Cold War conditions, the critical theorists recognized that the structure of capitalism and history had changed decisively, that the modes of oppression operated differently, and that the industrial working class was no longer the determinate negation of capitalism. This led to the attempt to root the dialectic in an absolute method of negativity, as in Marcuse's One-Dimensional Man and Adorno's Negative Dialectics. During this period the Institute of Social Research was re-established in Frankfurt (although many of its associates remained in the United States), with the task not merely of continuing its research but of becoming a leading force in the sociological education and democratization of West Germany. This led to a certain systematization of the lnstitute's entire accumulation of empirical research and theoretical analysis.

More important, however, was the Frankfurt School's attempt to define the fate of reason in the new historical period. While Marcuse did so through analysis of structural changes in the labor process under capitalism and inherent features of the methodology of science, Horkheimer and Adorno concentrated on a re-examination of the foundation of critical theory. This effort is systematized in Adorno's Negative Dialectics, which tries to redefine dialectics for an era in which "philosophy, which once seemed obsolete, lives on because the moment to realize it was missed ". The idea of negative dialectics is the idea of critical thought so conceived that it cannot be co-opted into the apparatus of domination. its central notion, long a focal one for Horkheimer and Adorno, is that the original sin of thought is its attempt to eliminate all that is other than thought, the attempt by the subject to devour the object, the striving for identity. It is this reduction that makes thought the accomplice of domination. Negative Dialectics rescues the "preponderance of the object", not through a naive epistemological or metaphysical realism but through a thought based on differentiation, paradox, and ruse: a "logic of disintegration ". Adorno thoroughly criticizes Heidegger's fundamental ontology, which reintroduces idealistic and identity-based concepts under the guise of having overcome the philosophical tradition.

Negative Dialectics is a monument to the end of the tradition of the individual subject as the locus of criticism. Without a revolutionary working class, the Frankfurt School had no one to rely on but the individual subject. But, as the liberal capitalist social basis of the autonomous individual receded into the past, the dialectic based on it became more and more abstract. This stance helped prepare the way for the fourth, current phase of the Frankfurt School, shaped by the communication theory of Habermas.

Habermas' work takes the Frankfurt School's abiding interests in rationality, the human subject, democratic socialism, and the dialectical method and overcomes a set of contradictions that always weakened critical theory: the contradictions between the materialist and transcendental methods, between Marxian social theory and the individualist assumptions of critical rationalism between technical and social rationalization, and between cultural and psychological phenomena on the one hand and the economic structure of society on the other. The Frankfurt School avoided taking a stand on the precise relationship between the materialist and transcendental methods, which led to ambiguity in their writings and confusion among their readers. Habermas' epistemology synthesizes these two traditions by showing that phenomenological and transcendental analysis can be subsumed under a materialist theory of social evolution, while the materialist theory makes sense only as part of a quasi-transcendental theory of emancipatory knowledge that is the self-reflection of cultural evolution. The simultaneously empirical and transcendental nature of emancipatory knowledge becomes the foundation stone of critical theory.

By locating the conditions of rationality in the social structure of language use, Habermas moves the locus of rationality from the autonomous subject to subjects in interaction. Rationality is a property not of individuals per se, but rather of structures of undistorted communication. In this notion Habermas has overcome the ambiguous plight of the subject in critical theory. If capitalistic technological society weakens the autonomy and rationality of the subject, it is not through the domination of the individual by the apparatus but through technological rationality supplanting a describable rationality of communication. And, in his sketch of communicative ethics as the highest stage in the internal logic of the evolution of ethical systems, Habermas hints at the source of a new political practice that incorporates the imperatives of evolutionary rationality.

Frankfurt School critical theory has influenced some segments of Left wing and thought (particularly the New Left). Herbert Marcuse was sometimes described as the theorist or intellectual progenitor of the New Left.

Two main sorts of criticism have repeatedly been made of critical theory, captured in Gyorgy Lukacs's assertion that the members of the Frankfurt School suffered from "Grand Hotel" syndrome. The first is that the intellectual perspective of the Frankfurt School is really a romantic, elitist critique of mass culture dressed-up in neo-Marxist clothing: what really bothers the critical theorists, in this view, is not social oppression but that the masses like Ian Fleming and the Beatles instead of Samuel Beckett and Webern. The second, originating on the Left, is that critical theory is a form of bourgeois idealism that has no inherent relation to political practice and is totally isolated from any ongoing revolutionary movement.

Major Frankfurt school thinkers and scholars

Notable Frankfurt school critics