Sartre sees Marxism as the dominant philosophy for the current era of history and existentialism as a reinforcing complement.

[4] Sartre breaks modern philosophy down into three eras: mercantile John Locke and René Descartes, industrial Immanuel Kant and Georg Wilhelm Friedrich Hegel, and contemporary Karl Marx.

[8] Karl Jaspers also failed to establish existentialism in a place of historical importance since his theories are directed inward, toward the self instead of outward, to society.

[11] Despite this affinity toward Marx's works, Sartre claims that his generation's interpretation of Marxism remained tainted by idealism and individualism[11] until World War II broke down the dominant societal structures.

Unlike these methods and the generally dominant idealism, existentialism and Marxism offer a possible means of understanding mankind and the world as a totality.

Sartre concludes the chapter by citing Marx from Das Kapital: "The reign of freedom does not begin in fact until the time when the work imposed by necessity and external finality shall cease..."[21] Sartre, following Marx, sees human freedom limited by economic scarcity.

[24] As in the first chapter, Sartre sees Marxism's flaw in rigidity: an "a priori" theory that forces events into "prefabricated molds.

Existentialism does not assume a single, real totality, but sees history as an interactive relationship between events and humans.

[29] He proposes a process of "mediations" to analyze how ideological and social factors guide the course of history, which is only indirectly influenced by economics and class.

[31] The philosopher Walter Kaufmann argues that Sartre's embrace of Marxism represents the end of existentialism, since following the publication of Search for a Method, neither Sartre nor any other major thinker writes as an existentialist (though Kaufmann adds that existentialism understood in a looser sense continues).