Abstract
This paper discusses the ambiguities and levels of public policy, with emphasis on the consequences of the visibility of policy statements. The symbolic aspects of public policy are analyzed, and the character of meanings other than those attributed by scientific experts is discussed. Impli cations of "drugs" as related to youth and cultural change help to explain limitations on the use of knowledge in public policy. A distinction is drawn between visible policy and the policy of day-to-day action. Several ways in which knowledge does contribute to policy are then specified.