ABSTRACT This article examines the rhetorical transformation of Malthus’s concept of the “redundant population” into what Marx and Engels relabeled the “surplus population” and the “industrial reserve army.” Three rhetorical functions can be observed in this transformation. First, the altered terminology served as a rhetorical marker for a place of theoretical disagreement about economic causality. “Rhetorical marker” refers to a subtle terminological modification that has manifold ramifications for meaning and understanding. Second, this reconstitution of the masses reinforced opposed assumptions about the relationship of people to technology, and third, it provided a type of embodied material proof for Marx’s and Engels’s revolutionary politics.