Marxist used the Labor Theory of Value, which says that the value of a commodity is determined by the labor required to produce it. More specifically, Marx defined the value of a commodity as the Socially necessary labor time required to produce it, the average (taken across all of society) time required to produce a given commodity under the average conditions of production. It follows from this that the [working class] is responsible for the production of all of the [value] (wealth) consumed by all members of society.