Threats to effective policy-making arising from ubiquitous circumstances of complexity and uncertainty are often taken as reasons to eschew both the attacking of social problems through public policy and cogitation, such as policy analysis, in the policy process. It is suggested here that, as complexity and uncertainty increase, more cogitation is required, not less; but it is crucial that cogitation be of the appropriate sort. Greater use should be made of policy design, as opposed to methods emphasising selection among prespecified alternatives. The required design task varies with the level of difficulty-defined by complexity, uncertainty, and lack of feedback-in any case at hand. A taxonomy of levels of difficulty is developed, together with a preliminary outline of the design task required at each level.