État de la connaissance scientifique et mobilisation du principe de précaution

The precautionary principle is formulated in many different ways. However the differences are not of a fundamental nature. What is fundamental in the principle - i.e. the recognition that decisions must be taken on the basis of uncertain (also called ambiguous) information, in particular uncertain scientific information - is also common to all formulations. But what is exactly meant by uncertain scientific information, and what makes it an acceptable basis for decision ? any non-falsified hypothesis might not be deemed acceptable in this sense. We try to identify what makes an uncertain piece of scientific information acceptable in a decision-making process, drawing from those processes that have dealt with asbestos utilisations, bovine spongiform encephalopathy, antibiotics used as growth factors, and climate change. We consider how to insert this approach in a theory of choice under uncertainty generalizing von Neumman-Morgenstern axiomatics. Classification JEL : D 81 et H 43.