This essay argues that principles should play a limited role in policy making. It first illustrates the dilemma of timely action in the face of uncertain unintended consequences. It then introduces the precautionary and proactionary principles as different alignments of knowledge and action within the policymaking process. The essay next considers a cynical and a hopeful reading of the role of these principles in public policy debates. We argue that the two principles, despite initial appearances, are not all that different when it comes to formulating public policy. We also suggest that allowing principles to determine our actions undermines the sense of autonomy necessary for true action.