This article is about the question of social agency in the animation of things, and about how this problematic has been conceptualized in Marxist and Actor-Network Theory (ANT) approaches to human–nature–technology relations. Notwithstanding many obvious differences, we note that each tradition was founded on a radical shift to a relational ontology, a world of relations and processes and not things-in-themselves, and that each has developed, partly as a consequence of this move, analytically useful ways of investigating and talking about the work that things do, or appear to do, in the world. By relating the ANT category of non-human actors to the Marxist concept of dead labor, and by revisiting Marx's own dialectics of technology as embodied in his figure of the “living machine” in Capital, we explore the different implications of these approaches for our understandings of the nature, materiality, and the efficacy of social agents. We argue that ANT's reconfiguration of agency as a collective social and technical process—a process wherein the “nonhuman” can have very real social effects—can be deepened and given some political efficacy only if we take seriously the ontological problems of causality, accountability, and the directedness of social relations (and things) which ANT, and its wider, still evolving ethos among the social sciences and cultural studies, would have us forestall.