[Public health and private decisions]

The violent reactions of some members of the intellectual class with regard to certain political aspects of the fight against smoking oblige us to pose the general problem of the legitimacy of centralised public health decisions. There are three sources of legitimacy for intervention by public authorities: the existence of an externality (the risk that each imposes on the other by his or her behaviour); the invisibility of the risk in the eyes of non-professionals; the technical impossibility of individual protection against the risk. The unequal distribution of risk could be a fourth criteria of legitimate public action but one can also consider inequity as an automatic consequence of the existence of one or more of the first three conditions when they concern the less educated, less affluent, and less influential. The "hygiene" period of preventive policy, at the end of the 19th Century in Europe, corresponds to the strong externalities because of the contagiousness of infectious diseases and the patient inability to treat them in the curative domain. On the other hand, the ability to appreciate the risks, reflecting significant social differences, seems inversely proportional to the expectations of individuals toward the State. The demand for the liberty to protect oneself from health risks is all the stronger when individuals have the cognitive and material means to effectively do so. The fight against smoking thus must constantly update the external negative effects of smoking and the setbacks in curing the ill that it creates.(ABSTRACT TRUNCATED AT 250 WORDS)