An analysis understood in terms of interdependent levels and practices helps us to conceive of how society is organised, but also allows us to comprehend social change and thus provides a theory of history. Althusser explains the reproduction of the relations of production by reference to aspects of ideological and political practice; conversely, the emergence of new production relations can be explained by the failure of these mechanisms. Marx's theory seems to posit a system in which an imbalance in two parts could lead to compensatory adjustments at other levels, or sometimes to a major reorganisation of the whole. To develop this idea, Althusser relies on the concepts of contradiction and non-contradiction, which he claims are illuminated by their relation to a complex structured whole. Practices are contradictory when they "grate" on one another and non-contradictory when they support one another. Althusser elaborates on these concepts by reference to Lenin's analysis of the Russian Revolution of 1917.[44]
Lenin posited that in spite of widespread discontent throughout Europe in the early 20th century, Russia was the country in which revolution occurred because it contained all the contradictions possible within a single state at the time.[45] It was, in his words, the "weakest link in a chain of imperialist states".[46] He explained the revolution in relation to two groups of circumstances: firstly, the existence within Russia of large-scale exploitation in cities, mining districts, etc., a disparity between urban industrialisation and medieval conditions in the countryside, and a lack of unity amongst the ruling class; secondly, a foreign policy which played into the hands of revolutionaries, such as the elites who had been exiled by the Tsar and had become sophisticated socialists.[47]
For Althusser, this example reinforces his claim that Marx's explanation of social change is more complex than the result of a single contradiction between the forces and the relations of production.[48] The differences between events in Russia and Western Europe highlight that a contradiction between forces and relations of production may be necessary, but not sufficient, to bring about revolution.[49] The circumstances that produced revolution in Russia, mentioned above, were heterogeneous, and cannot be seen to be aspects of one large contradiction.[50] Each was a contradiction within a particular social totality, at a different structural level of social practice. From this, Althusser concludes that Marx's concept of contradiction is inseparable from the concept of a complex structured social whole. To emphasise that changes in social structures relate to numerous contradictions, Althusser describes these changes as "overdetermined", using a term taken from Sigmund Freud.[51] This interpretation allows us to account for the way in which many different circumstances may play a part in the course of events, and how these circumstances may combine to produce unexpected social changes or "ruptures".[50]
However, Althusser does not mean to say that the events that determine social changes all have the same causal status. While a part of a complex whole,economic practice is a "structure in dominance": it plays a major part in determining the relations between other spheres, and has more effect on them than they have on it. The most prominent aspect of society (the religious aspect in feudal formations and the economic aspect in capitalist ones) is called the "dominant instance", and is in turn determined "in the last instance" by the economy. For Althusser, the economic practice of a society determines which other aspect of that society dominates the society as a whole.
Althusser's arguably more complex and materialist (than other Marxisms) understanding of contradiction in terms of the dialectic attempts to rid Marxism of the influence and vestiges of Hegelian (idealist) dialectics, and is a component part of his general anti-humanist position.
