In this article, I examine Michael Bratman’s account of stability in his planning theory of intention. Future-directed intentions should be stable, or appropriately resistant to change, over time. Bratman claims that the norm of stability governs both intentions and plans. The aim of this article is to critically enrich Bratman’s account of stability by introducing plasticity as an additional norm of planning. I construct plasticity as a kind of stability of intentions which supplements Bratman’s notion of “reasonable stability.” Unlike the (...) latter, plasticity applies mainly to cases in which plan states are abandoned without reconsideration. I focus on the intra-theoretical problems of PTI and elucidate: the distinction between future-directed intentions and plans, the conceptual difference between stability and inertia, which is only implicit in PTI, and the role of the environment of the planner, which has a vestigial role in Bratman’s work. I also defend my incorporation of pl... (shrink)