The principle of respect for autonomy often dominates the bioethical discourse. Yet despite its prominence, the exact contours are not always well defined. Widespread disagreement about the nature of autonomy has led some to conclude that autonomy is hopelessly vague and therefore ought to be abandoned in contemporary bioethics. Despite calls to move beyond it, autonomy remains at the center of bioethical reflection. The challenge, then, if autonomy is to function as a bedrock of contemporary bioethics, is to define more (...) clearly the shape of autonomy, to mark more precisely its conceptual boundaries, and to delineate more carefully how best autonomy is put into practice in medical ethics. In this article, I raise questions about the ways autonomy is used in theory, as well as the ways that it is operationalized in practice. (shrink)