Abstract: Practical deliberation is deliberation concerning what to do governed by norms on intention (e.g. means-end coherence and consistency), which are taken to be a mark of rational deliberation. According to the theory of practical deliberation I develop in this paper we should think of the norms of rational practical deliberation ecologically: that is, the norms that constitute rational practical deliberation depend on the complex interaction between the psychological capacities of the agent in question and the agent's environment. I argue that this view does a better job of justifying particular norms for practical deliberation than intrinsic or constitutivist theories. Finally, I argue against the Myth Theory of deliberation, which takes there to be no such norms on deliberation.