All ideology hails or interpellates concrete individuals as concrete subjects, by the functioning of the category of the subject. ... ideology ‘acts’ or ‘functions’ in such a way that it ‘recruits’ subjects among the individuals (it recruits them all), or ‘transforms’ the individuals into subjects (it transforms them all) by that very precise operation which I have called interpellation or hailing, and which can be imagined along the lines of the most commonplace everyday police (or other) hailing: ‘Hey, you there!’
Louis Althusser, "Ideology and Ideological State Apparatuses," in
