Biologists explain organisms' behavior not onlya sh avingb een programmed by genes and shaped by natural selection, but also as the resulto f an organism'sa gency:t he capacity to react to environmental changes in goaldrivenw ays. The use of such 'agential explanations' reopens old questions about how justified it is to ascribea gencyt oe ntities like bacteria or plants that obviouslylack rationality and even anervous system. Is organismic agency genuinely 'real' or is it justauseful fiction?Inthis paper we focus on two questions: whether agential explanations are to be interpreted ontically, and whether they can be reduced to non-agential explanations (thereby dispensing with agency). The Kantian approach we identify interprets agential explanations non-ontically, yetholds agency to be indispensable. Attributing agency to organisms is not to be takenl iterallyint he wayw eattribute physical properties such as mass or acceleration, but nor is it amere heuristic or predictive tool. Rather,it is an inevitable consequence of our ownrational capacity:aslong as we are rational agents ourselves, we cannot avoid seeing agency in organisms.