In his introduction to the Critique of Dialectical Reason (1960) Sartre first claimed that his own existentialist philosophy was merely an addendum to Marxism as an historical process. But when he went on to explain what he meant, he said that the success of Marxist liberation for the oppressed would be necessary for the freedom he had described to be accessible to everyone. In other words, he saw the goal of Marxism as the realization of the very freedom he had described.

In one sense, this contradicted his description of freedom as a universal human condition. But in another sense, Sartre believed that the oppressed have the power, based on their individual freedom, to unite and cooperate for collective liberation. So, although he embraced Marxism, he did not embrace its premise of determinism that the individual’s consciousness is the result of the political and economic factors forming his or her social class.