Althusser begins by agreeing with Marx that a "social formation which did not reproduce the conditions of its production at the same time as it produced" (127) was doomed to die. To be precise, if the existing social relations of production within each social formation (i.e. its class structure) are to be perpetuated, that social formation must seek to reproduce the means of production, i.e. what he calls the "material conditions of production" (128) (the raw material, the machines, etc.), by reinvesting profits in fresh capital outlays; and the forces of production, i.e. what he calls the "productive forces" (130) and "labour power" (130), by paying wages that not only ensure the worker’s physical survival but also increase his productivity through skills-training and education. Althusser argues that the

reproduction of labour power requires not only a reproduction of its skills, but also, at the same time, a reproduction of its submission to the rules of the established order, i.e. a reproduction of submission to the ruling ideology for the workers, and a reproduction of the ability to manipulate the ruling ideology correctly for the agents of exploitation and repression, so that they too will provide for the domination of the ruling class ‘in words.’ (132-133)

In other words, the schooling system and other state institutions like the church do not only seek to pass on "‘know-how’" (133) but also to ensure "subjection to the ruling ideology or the mastery of its ‘practice’" (133).

This raises the question: what is ideology? To answer this question, Althusser argues that he must first "re-raise my old question: what is a society?" (134). He reminds us that his point in earlier essays such as "Contradiction and Overdetermination" was that Marx’s "conception of the ‘social whole’" (134) was "distinct from the Hegelian totality" (134):

Marx conceived the structure of every society as constituted by ‘levels’ or ‘instances’ articulated by a specific determination: the infrastructure, or economic base (the unity of the productive forces and the relations of production) and the superstructure, which itself contains two ‘levels’ or ‘instances’: the politico-legal (law and the State) and ideology (the different ideologies, religious, ethical, legal, political, etc. (134)

He reminds us that Marx offers, in so arguing, a "spatial metaphor: the metaphor of a topography" (135) whereby society is compared to an "edifice" (134) in which the "upper floors [superstructure] could not ‘stay up’ (in the air) alone, if they did not rest precisely on their base" (135). Questions arise within the Marxist tradition, he stresses, concerning the nature of the relationship linking these two levels of society: some posit the "relative autonomy" of the superstructure and others go so far as to argue that there is a "‘reciprocal action’ of the superstructure on the base" (135). Althusser states his intention to "[re]think what characterises the essential . . . existence and nature of the superstructure on the basis of reproduction" (136). In other words, his emphasis will be less on the cause (or source) of these various instances or levels than on their effect (or function). When viewed from this perspective, "many of the questions whose existence was indicated by the spatial metaphor of the edifice, but to which it could not give a conceptual answer, are immediately illuminated" (136).

Althusser then turns his attention to a critical analysis of the key social concepts which Marxists deploy (the Law, the State and Ideology) from two perspectives: "from the point of view of practice and production . . . and from that of reproduction on the other" (136). The State is defined in the Marxist tradition as a "force of repressive execution and intervention ‘in the interests of the ruling classes’ in the class struggle conducted by the bourgeoisie and its allies against the proletariat" (137). This is its basic "function" (137). It is, in that sense, an apparatus or instrument by which the ruling class cements its hold on power. A distinction must be drawn, therefore, between the "use of the State apparatus" (141) and "State power" (141) the seizure or maintenance of which is the goal of utilising the State apparatus. Arguing that this is merely a description which must be superseded by a theory per se, Althusser contends that such a definition "casts a brilliant light on all the facts observable" (139). However, he wants to "add something" (14) to this "classical definition" (140). Claiming to revert, as usual, to the "Marxist classics which treated the State as a more complex reality" (142) (he has in mind, Marx, Engels, and Lenin) than this description would seem to suggest and drawing in particular upon the suggestive comments made by Gramsci more recently concerning the role played by hegemony (as opposed to coercion) in the maintenance of State power, Althusser argues that there are in fact two kinds of State apparatuses: the Repressive State Apparatus (RSA) and the Ideological State Apparatus (ISA). The former includes the "institutions" (148) of the Government, the Administration, the Army, the Police, the Courts, the Prisons, etc. The latter includes the "religious ISA (the system of the different Churches)" (143), the "educational ISA (the system of the different public and private ‘Schools’)" (143), the "family ISA" (143), the "legal ISA" (143), the "political ISA" (143), the "trade-union ISA" (143), the "communication ISA (press, radio and television, etc.)" (143), and the "cultural ISA (Literature, the Arts, sports, etc.)" (143). The former "function massively and predominately by repression (including physical repression)" (145) while the latter "function massively and predominately by ideology" (145). Althusser’s particular interest here is in the functioning of the various ISAs which, although diverse (they are, he says, "multiple, distinct, ‘relatively autonomous’ and capable of providing an objective field to contradictions which express . . . the effects of the clashes between the capitalist class struggle and the proletarian class struggle" [149]), are unified by their common function: subtending the dominant ideology and, thus, the interests of the ruling class. The RSAs function to secure the "political conditions of the reproduction of relations of production" (149), which are "relations of exploitation" (150), via media of repression that range from "the most brutal physical force, via mere administrative commands and interdictions, to open and tacit censorship" (150). The ISAs function to secure the same goal (that is, the "reproduction of the relations of production, i.e. of capitalist relations of exploitation" [154]) behind the "‘shield’" (150) provided by the RSAs by inculcating in all members of society and naturalising the dominant ideology which is that of the ruling class. Each ISA accomplishes this function "in the way proper to it" (154): the political ISA "by subjecting individuals to the political State ideology" (154); the communications ISA "by cramming every ‘citizen’ with daily doses of nationalism, chauvinism, liberalism, moralism, etc. by means of the press, the radio and television" (155); etc. "This concert is dominated by a single score . . .: the score of the Ideology of the current ruling class which integrates into its music the great themes of the Humanism of the Great Forefathers" (154).

Where the Church was the dominant ISA in the pre-Capitalist period, Althusser, argues, the dominant ISA in "mature capitalist social formations" (152) is the educational ISA. Some might argue that the dominant apparatus is the political ISA but this is not the case, Althusser contends. Indeed, he argues that the "School-Family couple has replaced the Church-Family couple" (154) of previous epochs:

It takes children from every class at infant-school age, and then for years, the years in which the child is most ‘vulnerable,’ squeezed between the family State apparatus, it drums into them, whether it uses new or old methods, a certain amount of ‘know-how’ wrapped in the ruling ideology (French, arithmetic, natural history, the sciences, literature) or simply the ruling ideology in its pure state (ethics, civic instruction, philosophy). Somewhere around the age of sixteen, a huge mass of children are ejected ‘into production’: these are the workers or small peasants. Another portion of scholastically adapted youth carries on . . . it goes somewhat further, until it falls by the wayside and fills the posts of small and middle technicians, white-collar workers, small and middle executives, petty bourgeois of all kinds. A last portion reaches the summit, either to fall into intellectual semi-employment, or to provide, as well as the ‘intellectuals of the collective labourer,’ the agents of exploitation (capitalists, managers), the agents of repression (soldiers, policemen, politicians, administrators, etc.) and the professional ideologists (priests of all sorts . . .).

Each mass ejected en route is practically provided with the ideology which suits the role it has to fulfil in class society: the role of the exploited (with a ‘highly-developed’ ‘professional,’ ‘ethical,’ ‘civic,’ ‘national; and a-political consciousness); the role of the agent of exploitation (ability to give the workers order and speak to them: ‘human relations’), of the agent of repression (ability to give orders and enforce obedience ‘without discussion,’ or ability to manipulate the demagogy of a political leader’s rhetoric), of the professional ideologist. . . . (155-156)

Althusser’s point is that even though many of these ideologies are also communicated through the other ISAs, none of these others "has the obligatory (and not least, free) audience of the totality of the children in the capitalist social formation, eight hours a day for five or six days out of seven" (156). All in all, therefore, it is by an "apprenticeship in a variety of know-how wrapped up in the massive inculcation of the ideology of the ruling class that the relations of production in a capitalist social formation, i.e. the relation of exploited to exploiters and exploiters to exploited, are largely reproduced" (157). This function is, however, "concealed by a universally reigning ideology of the School . . . which represents the School as a neutral environment purged of ideology" (157).

Having theorised the nature of the State in this way and defined the function of the ISAs as the inculcation of the dominant ideology, Althusser is obliged to turn his attention to theorising the nature of ideology per se. He advances a number of theses in this respect. Firstly, he argues that "ideology has no history" (159). Differentiating between Ideology in general and particular ideologies, he argues that the latter have definable histories "whose determination in the last instance is clearly situated outside ideologies alone" (159). He compares the former to Freud’s notion of a dream in order to argue that, for Marx, ideology is "nothing insofar as it is a pure dream" (160), i.e. pure fiction, and that ideology has no history "which emphatically does not mean that there is no history in it (on the contrary, for it is merely the pale, empty and inverted reflection of real history)" (160), that is, the ‘"day’s residues’ from the only full and positive reality, that of the concrete history of concrete material individuals materially producing their existence" (160). Rather, this means that ideology in general "has no history of its own" (160) in that it is "endowed with a structure and a functioning such as to make it a non-historical reality, i.e. an omni-historical reality, in the sense in which that structure and functioning are immutable, present in the same form throughout what we can call history" (161). Ideology is similar to the unconscious which Freud described as "eternal" (161), that is, "not transcendent to all (temporal) history, but omnipresent, trans-historical and therefore immutable in form throughout the extent of history" (161). In short, the characteristics of Ideology which he will seek to outline below are common to all specific ideologies at all times regardless of the specific socio-historical circumstances in question.

Secondly, turning his attention to the "object which is ‘represented’ in the imaginary form of ideology" (162), Althusser contends that ideology "represents the imaginary relationship of individuals to their real conditions of existence" (162). Ideologies are traditionally thought of as "world outlooks" (162) even though it is also admitted that they are "largely imaginary, i.e. do not ‘correspond to reality’" (162) and "constitute an illusion" (162). However, in this schema, it is thought that ideologies do "make allusion to reality, and . . . need only be ‘interpreted’ to discover the reality of the world behind their imaginary representations of that world (ideology = illusion / allusion)" (162). Althusser mentions that there are two types of interpretation advanced in this regard: the "mechanistic type" (162) in which ideology is a distorted mirror held up to the Real, and the "hermeneutic interpretation" (162) in which the Real is the essence which manifests itself through ideological phenomena. However, the question arises why "men ‘need’ this imaginary transposition of their real conditions of existence in order to ‘represent to themselves’ their real conditions of existence?" (183). The first possible cause of this often advanced is that a certain clique, "Priests or Despots are responsible. They ‘forged’ the Beautiful Lies" (163), in other words, a "falsified representation of the world" (163) designed to "enslave other minds by dominating their imaginations" (163), on which they "base their domination and exploitation of the ‘people’" (163). The second possible cause often advanced is the essentially Hegelian or specifically "Feuerbachian idea that men make themselves an alienated (= imaginary) representation of their conditions of existence because these conditions of existence are themselves alienating" (164). Althusser points out that both these explanations "presuppose . . . that what is reflected in the imaginary representation of the world found in an ideology is the conditions of existence of men, i.e. their real world" (164). However, Althusser advances the view that

it is not their real conditions of existence, their real world, that ‘men’ ‘represent to themselves’ in ideology, but above all it is their relation to those conditions of existence which is represented to them there. It is this relation which is at the centre of every ideological, i.e. imaginary, representation of the real world. It is this ‘cause’ which has to explain the imaginary distortion of the ideological representation of the real world. (my emphasis; 164)

This viewpoint allows a new question to be enunciated: "why is the representation given to individuals of their (individual) relation to the social relations which govern their conditions of existence and their collective and individual life necessarily an imaginary relation? And what is the nature of this imaginariness?" (165). Posed this way, this question eliminates any consideration of the two possible causes mentioned above (the clique / alienation).

Thirdly, Althusser theorises that ideology "has a material existence" (165), arguing that "‘ideas’ or ‘representations,’ etc. do not have an ideal (idéale or idéelle) or spiritual existence, but a material existence" (165). Althusser contends that each ISA is the "realisation of an ideology" (166) as a result of which an ideology "always exists in an apparatus, and its practice, or practices. This existence is material" (166). Arguing that the "material existence of the ideology in an apparatus and its practices does not have the same modality as the material existence of a paving-stone or a rifle" (166), Althusser suggests that an individual’s beliefs are derived "from the ideas of the individual concerned, i.e. from his as a subject with a consciousness which contains the ideas of his beliefs" (167). The individual in question

behaves in such and such a way , adopts such and such a practical attitude, and, . . . participates in certain regular practices which are those of the ideological apparatus on which ‘depend’ the ideas which he has in all consciousness freely chose as a subject. If he believes in God, he goes to Church to attend Mass, kneels, prays, confesses, does penance . . . and naturally repents and so on. . . . [E]very ‘subject’ endowed with a ‘consciousness’ and believing in the ‘ideas’ that his ‘consciousness’ inspires in him and freely accepts, must ‘act according to his ideas,’ must therefore inscribe his own ideas as a free subject in the actions of his material practice. (168-169)

Even if he does not do what his beliefs tell him he ought to do, he merely ends up doing something else which are equally the form which his beliefs take. The "‘ideas’ of human subject exist in his actions" (168). These "actions are inserted into practices" (168) which are "governed by the rituals in which these practices are inscribed, within the material existence of an ideological apparatus, be it only a small part of that apparatus: a small mass in a small church, a funeral" (168), etc. To put this another way, ideas are "inscribed in the actions of practices governed by rituals defined in the last instance by an ideological apparatus" (170). The subject

acts insofar as he is acted upon by the following system (set out in the real order of determination): ideology existing in a material ideological apparatus, prescribing material practices governed by a material ritual, which practices exist in the material actions of a subject acting in all consciousness according to this belief. (170)

The key concept in all this, Althusser declares, indeed, his central concern, is the "notion of the subject" (170).

Fourthly, therefore, Althusser turns his attention to the "category of the subject (which may function under other names: e.g., as the soul in Plato, as God, etc.)" (170-171). He contends that the subject is the "constitutive category of all ideology, whatever its determination (regional or class) and whatever its historical date--since ideology has no history" (171) in so far as "all ideology has the function (which defines it) if ‘constituting’ concrete individuals as subjects" (171). Arguing that ideology performs the two-fold function of "recognition" (172) and "misrecognition" (172), Althusser contends that "you and I are always already subjects, and as such constantly practice the rituals of ideological recognition, which guarantee for us that we are indeed concrete, individual, distinguishable and (naturally) irreplaceable subjects" (172-173). In a famous assertion, he argues that "all ideology hails or interpellates concrete individuals as concrete subjects" (173). Ideology 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 process which I have called interpellation or hailing, and which can be imagined along the lines of the most common everyday police (or other) hailing: ‘Hey, you there.’ . . . [T]he hailed individual will turn around. By this mere one-hundred-and-eighty-degree physical conversion, he becomes a subject. Why? Because he has recognised that the hail was ‘really’ addressed to him. (174)

This is something that most of us would deny in that: those who are in ideology believe themselves by definition outside ideology: one of the effects of ideology is the practical denegation of the ideological character of ideology by ideology" (175). Althusser admits, perhaps bravely, that the "accusation of being in ideology only applies to others, never to oneself (unless is really a Spinozist or a Marxist, which, in this matter, is to be exactly the same thing" (175).

Althusser concludes that "individuals are always-already interpellated by ideology as subjects" (176), which implies that "individuals are always-already subjects" (176), "even before he is born" (176). Althusser notes the "ideological ritual that surrounds the expectation of a ‘birth" (176):

i.e. the forms of family ideology (paternal / maternal / conjugal / fraternal) in which the unborn child is expected: it is certain in advance that it will bear its Father’s Name, and will therefore have an identity and be irreplaceable. Before its birth, the child is always -already a subject, appointed as a subject in and by the specific familial ideological configuration in which it is ‘expected’ once it has been conceived. (176)

All this is part and parcel of the processes of "ideological constraint and pre-appointment, and all the rituals of rearing and then education in the family" (176), he points out.

Using the example of Christianity, Althusser concludes by explicating in greater detail the precise process of interpellation. Differentiating between a "Subject with a capital S"(178) (e.g. God) and "ordinary subjects, with a small s" (178) (you and me), he draws upon Lacan’s notion of the ‘Mirror Stage’ in order to argue that the subject derives his sense of self from the image reflected back to him by the Subject. Within Christianity, "God is thus the Subject, and Moses and the innumerable subjects of God’s people, the Subject’s interlocutors-interpellates: his mirrors, his reflections. Were not men made in the image of God?" (179). He remarks:

the structure of all ideology, interpellating individuals as subjects in the name of a Unique and Absolute Subject is speculary, i.e. a mirror-structure, and doubly speculary: this mirror duplication is constitutive of ideology and ensures its functioning. Which means that all ideology is centred, that the Absolute Subject occupies the unique place of the Centre, and interpellates around it the infinity of individuals into subjects in a double mirror-connexion such that it subjects the subjects to the Subject, while giving them in the Subject in which each subject can contemplate its own image (present and future) the guarantee that this really concerns them and Him. . . . (180)

In short, therefore, the "duplicate mirror-structure of ideology" (180) ensures the interpellation of individuals as subjects, their "subjection to the Subject" (181) and the "mutual recognition of subjects and Subject, the subjects’ recognition of each other, and finally the subject’s recognition of himself" (181).

This is why the system works so effectively to secure the reproduction of the extant social relations of production:

the subjects ‘work,’ they ‘work by themselves’ in the vast majority of cases, with the exception of the ‘bad subjects’ who on occasion provoke the intervention of one of the detachments of the (repressive) State apparatus. But the vast majority of (good) subjects work all right ‘all by themselves,’ i.e. by ideology (whose concrete forms are realised in the Ideological State Apparatuses). They are inserted into practices governed by the rituals of the ISAs. They ‘recognise’ the existing state of affairs, that ‘it really is true that it is so and not otherwise’ and that they must e obedient to God, to their conscience, to the priest, to d Gaulle, to the boss, to the engineer, that thou shalt ‘love thy neighbour as thyself,’ etc. (181)

Althusser points out the paradox implied by the very term ‘subject’: it means both a "free subjectivity, a centre of initiatives, author of and responsible for its actions" (182) and a "subjected being, who submits to a higher authority, and is therefore stripped of all freedom except that of freely accepting his submission" (182).

There is thus an important "ambiguity" (183) installed at the very heart of the concept of the subject: the

individual is interpellated as a (free) subject in order that he shall submit freely to the commandments of the Subject, i.e in order that he shall (freely) accept his subjection, i.e. in order that he shall make the gestures and actions of his subjection ‘all by himself.’ There are no subjects except by and for their subjection. (182)

It is in the "‘consciousness,’ i.e. in the attitudes of the individual-subjects occupying the posts which socio-technical division of labour assigns to them in production, exploitation, repression, ideologisation, scientific practice, etc." (183) that the reproduction of the relations of production is ensured. The reality which is effectively "ignored (méconnue)" (182) and obfuscated by ideology is, precisely, the very process of the "reproduction of the relations of production and of the relations deriving from them" (183). This is what Althusser means when he writes that what ideology misrepresents or distorts is not the real conditions of existence but one’s relation to these conditions (i.e. one’s position in the hierarchy of exploitation--these are the relations of production--as either exploiter or exploited or somewhere in between). What is mystified by ideology is not the real conditions of existence but one's relation to these, that is, the relations of production, one’s subjective place therein, and the function of ideology in ensuring their reproduction.