"Problems of communication often arise when social research is to be used as premises for policy making. In this paper it is argued that the two activities are entirely different, yet that there is a logical parallelism between theory construction and policy making which can be identified in four steps. Where scientists make observations, politicians raise issues. Where scientists propose explanations, politicians propose remedies. Where scientists draw empirical consequences and make predictions from their models, politicians work out possible political implications of their proposals. Where scientists rule out explanations when the predictions from them do not correspond to facts, politicians rule out options or reforms that are not feasible or workable. Where scientists try to explain the actual world, politicians attempt to create possible worlds. Both professions not only demand acuity and test imagination but also summon the capacity to spot import and resolve controversies."