Science, policy, and ethics: the case of environmental tobacco smoke.

The successful campaign against smoking will long be celebrated as a landmark achievement of public health. Recently, a prominent component of this campaign has been the portrayal of environmental tobacco smoke as a major health risk. To this day, however, the scientific basis for this later contention remains speculative. The elevation of heuristic hypotheses into official precepts raises an intriguing ethical question: Should a claim of best intentions justify representing conjecture as scientific knowledge in public policy formulation?