This paper is a response to the author's 2009 article "Reflections on Activity Theory." It begins by briefly outlining the themes and aims of that article, and considering developments in the theory and practice of activity theory that have occurred since its publication. Thereafter, the paper embarks on a philosophical exploration of ideas central to the activity approach, including the concept of activity itself, in a way that aspires to bring the insights of its Russian originators into dialogue with recent developments in the philosophy of action. The paper argues that understanding how intentional human action is self-conscious action is essential to understanding the character of the human life form (or human life-activity) in its socio-historical reality. With both Marx and Ilyenkov in mind, the paper examines and refines Leontiev's distinction between action and activity, arguing that some activities have ends that are infinite (that is, ends that are not exhausted by their realisation) and internal (that is, intelligible only to those immersed in the activity itself). Educating and philosophising, it is argued, are, in the ideal, such activities.