Interpellation is a concept introduced to Marxist theory by Louis Althusser as the mechanism through which pre-existing social structures "constitute" individual human organisms as subjects. Althusser asked how people come voluntarily to live within class, gender, racial or other identities, and argued that this happens through "state apparatuses" continually telling individuals what they are from infancy. In this way, apparatuses maintain the social order. In Althusser's view, apparatuses call us by labels, and we learn to respond to those labels. In this structuralist philosophy, social structures constitute subjects rather than individuals constituting their own subjectivity for themselves.