The law of informed consent expresses in legal form the ethical principle of autonomy and respect for autonomy. It is intended to enhance self-determination and rational decision-making in medicine. Three tests might be made of whether a law is a good law: (1) Is it clear and unambiguous enough to admit of fair, equal, and consistent enforcement? (2) Does it gain compliance, and widespread ideological agreement? (3) Does it enjoy a measure of success in achieving its intended goals? The law of informed consent does not impressively pass any one of these tests. It is deeply ambiguous, both in its formal structure and its pragmatic implementation. It has not won ideological agreement, doctors having been openly hostile to it, and legislatures having written statutes limiting it. There is little evidence that it has succeeded in its goals. Paradoxically, its pragmatic value might be rooted in its ostensible weakness, its ambiguity, in that this very quality keeps the discussion going. Perhaps the essential problem lies in the fact that the philosophical notion of autonomy is not a phenomenologically accurate description of the condition of the person who seeks medical help–the map is not the territory.