The idea of ‘apparatus’ reintroduces pessimistic functionalism: it’s an ‘infernal engine’, programmed to bring about certain ends. The educational system, the State, the Church, the parties, are not apparatuses, but fields. However, in certain conditions, they may start functioning as apparatuses. Those conditions need [to] be examined.
In a field, agents and institutions are engaged in struggle, with unequal strengths, and in accordance with the rules constituting that field of play, to appropriate the specific profits at stake in that game. Those who dominate the field have the means to make it function to their advantage; but they have to reckon with the resistance of the dominated agents. A field becomes an apparatus when the dominant agents have the means to nullify the resistance and the reactions of the dominated - in other words, when the lower clergy, or the grass-roots activists, or the working classes, etc., can only suffer domination; when all movement runs downwards and the effects of domination are such that the struggle and dialectic that are constitutive of the field come to an end. There is history so long as there are people who revolt, who make trouble. The ‘total’ or totalitarian institution, the asylum, prison or concentration camp as described by Goffman, or the totalitarian state, attempts to institute the end of history.
Pierre Bourdieu, Sociology in question, p.88 (via socio-logic)