In the first half of his essay "Ideology and Ideological State Apparatuses", Althusser says that "the resistance of the exploited classes can find means and opportunities to express” (99), that is to say in the ideological state apparatuses. In the second half of the essay, Althusser argues that there are places in the ISA that allow expression of the exploited class, but this expression is an illusion because they can only express themselves in terms of subjects . Althusser separates the State Apparatus into two sections, one being the Repressive State Apparatus (RSA) and the other being the Ideological State Apparatus (ISA). The RSA encompasses elements such as the military, police and government, while the ISA contains elements such as education, religion and family. RSA is fundamentally different from ISAs for two reasons, the first being that RSA is strictly in the public domain whereas ISAs can exist in both the public and private domain. The second difference is that "the repressive state apparatus functions 'through violence,' while the ideological state apparatus functions 'through ideology'" (97). Althusser qualifies this assertion by saying that the RSA truly works through both violence and ideology since no device can work through one alone. Therefore, conversely, ISAs operate primarily through ideology and secondarily through violence, although most of this violence is usually internal to the apparatus. Althusser ends his discussion of the distinction between the RSA and the ISA by saying that "the ideological state apparatuses can be not only the issue, but also the locus of class struggle, and often of bitter forms of social struggle." classes” (99). By this Althusser means that it is inherently difficult to remove ISAs from the "formal" ruling class since they can retain their positions for a longer period than if they were removed from power within the RSA. This also brings us back to the question asked; how do the resistances of the exploited classes find means and opportunities to express themselves in ISAs? Opportunities for expression come from ideology. For Althusser, ideology is “conceived as a pure illusion, a pure dream, that is to say as nothingness. All its reality is external to it” (108). Althusser differs from Marx on the question of who controls this reality. Marx argues that this illusion is controlled by those in power and is used to control those not in power..