The Situationist International (SI) was an international organization of social revolutionaries made up of avant-garde artists, intellectuals, and political theorists. It was prominent in Europe from its formation in 1957 to its dissolution in 1972.
The intellectual foundations of the Situationist International were derived primarily from Libertarian Marxism and the avant-garde art movements of the early 20th century, particularly Dada and Surrealism. Overall, situationist theory represented an attempt to synthesize this diverse field of theoretical disciplines into a modern and comprehensive critique of mid-20th century advanced capitalism. The situationists recognized that capitalism had changed since Karl Marx's formative writings, but maintained that his analysis of the capitalist mode of production remained fundamentally correct; they rearticulated and expanded upon several classical Marxist concepts, such as his theory of alienation. In their expanded interpretation of Marxist theory, the situationists asserted that the misery of social alienation and commodity fetishism were no longer limited to the fundamental components of capitalist society, but had now in advanced capitalism spread themselves to every aspect of life and culture. They rejected the idea that advanced capitalism's apparent successes—such as technological advancement, increased income, and increased leisure—could ever outweigh the social dysfunction and degradation of everyday life that it simultaneously inflicted.
Essential to situationist theory was the concept of the spectacle, a unified critique of advanced capitalism of which a primary concern was the progressively increasing tendency towards the expression and mediation of social relations through objects. The situationists believed that the shift from individual expression through directly lived experiences, or the first-hand fulfillment of authentic desires, to individual expression by proxy through the exchange or consumption of commodities, or passive second-hand alienation, inflicted significant and far-reaching damage to the quality of human life for both individuals and society. Another important concept of situationist theory was the primary means of counteracting the spectacle; the construction of situations, moments of life deliberately constructed for the purpose of reawakening and pursuing authentic desires, experiencing the feeling of life and adventure, and the liberation of everyday life.
When the Situationist International was first formed, it had a predominantly artistic focus; emphasis was placed on concepts like unitary urbanism and psychogeography. Gradually, however, that focus shifted more towards revolutionary and political theory. The Situationist International reached the apex of its creative output and influence in 1967 and 1968, with the former marking the publication of the two most significant texts of the situationist movement, The Society of the Spectacle by Guy Debord and The Revolution of Everyday Life by Raoul Vaneigem. The expressed writing and political theory of the two aforementioned texts, along with other situationist publications, proved greatly influential in shaping the ideas behind the May 1968 insurrections in France; quotes, phrases, and slogans from situationist texts and publications were ubiquitous on posters and graffiti throughout France during the uprisings.