Following the recent recognition that humans are an active force in nature that gave rise to a new geological epoch, this article explores the implications of the shift to the Anthropocene for social theory. The argument assumes that the emerging conditions compel an expansion and deepening of the timescale of the social-theoretical perspective and that such an enhancement has serious repercussions for the concept of human agency. First, the Anthropocene is conceptualized as a nascent cognitively structured cultural model rather than simply a geological epoch. Second, the vast and deep timescale, in the light of which the new time unit and its generative agency alone make sense, is analysed along with the human world’s objective, sociocultural and subjective axes. Finally, the elements of the concept of agency are recomposed in their temporal and relational contexts. At the reflexive level throughout, the need for social theory to develop a cognitive-theoretical approach in conjunction with a weak naturalistic ontology is suggested.