This paper studies aggregation of preferences under ignorance, in which everybody knows that the true probability distribution over outcomes lies in some objective set but knows nothing about which one in it is true or which one in it is more likely to be true. We consider two decision models which express the precautionary principle under ignorance, the maximin criterion and the \(\alpha \)-maximin criterion. We show that the Pareto axiom implies dictatorship, in each decision model. The impossibility results force us to choose between two options, one is to give up the precautionary principle as modelled at the social level, the other is to weaken the Pareto axiom. We provide possibility results for each of the options.

本文研究无知下的偏好聚合，其中每个人都知道结果的真实概率分布存在于某个客观集合中，但不知道其中哪一个是真实的，或者其中哪一个更可能是真实的。我们考虑两种表达无知情况下预防原则的决策模型，即最大标准和\(\alpha \) -maximin 标准。我们表明，在每个决策模型中，帕累托公理都意味着独裁。不可能性的结果迫使我们在两个选项中做出选择，一个是放弃在社会层面建模的预防原则，另一个是削弱帕累托公理。我们提供每个选项的可能性结果。