Marcuse discusses the social meaning of biology - history seen not as a class struggle, but a fight against repression of our instincts. He argues that "advanced industrial society" (modern capitalism) is preventing us from reaching a non-repressive society "based on a fundamentally different experience of being, a fundamentally different relation between man and nature, and fundamentally different existential relations". He contends that Freud's argument that repression is needed by civilization to persist is mistaken, as Eros is liberating and constructive.
Marcuse starts with the conflict described by Freud in Civilization and Its Discontents - the struggle between human instincts and the conscience of repression (superego), which is self-repressing trying to follow the society's mores and norms. Freud claimed that a clash between Eros and civilization results in the history of humanity being one of his repression: 'Our civilization is, generally speaking, founded on the suppression of instincts.' Sex produces the energy, and it is repressed so the energy can be channeled into progress - but the price of progress is the prevalence of guilt instead of happiness. "Progress", for Marcuse, is a concept that provides the explanation and excuse of why the system has to continue; it is the reason the happiness of people is sacrificed (see also pleasure principle).
Marcuse argues that 'the irreconcilable conflict is not between work (reality principle - life without leisure) and Eros (pleasure principle - leisure and pleasure), but between alienated labour (performance principle - economic stratification) and Eros.' Sex is allowed for 'the betters' (capitalists...), and for workers only when not disturbing performance. Marcuse believes that a socialist society could be a society without needing the performance of the 'poor' and without as strong a suppression of our sexual drives: it could replace 'alienated labor' with "non-alienated libidinal work" resulting in "a non-repressive civilization based on 'non-repressive sublimation'".
Marcuse's argument depends on the assumption that instincts can be shaped by historical phenomena such as repression. Marcuse concludes that our society's troubles result not from biological repression itself but from its increase due to "surplus repression" which is the result of contemporary society.