This paper develops an information-sensitive theory of the semantics and probability of conditionals and statements involving epistemic modals. The theory validates a number of principles linking probability and modality, including the principle that the probability of a conditional If A, then C equals the probability of C, updated with A. The theory avoids so-called triviality results, which are standardly taken to show that principles of this sort cannot be validated. To achieve this, we deny that rational agents update their credences via conditionalization. We offer a new rule of update, Hyperconditionalization, which agrees with Conditionalization whenever nonmodal statements are at stake but differs for modal and conditional sentences.

本文开发了一个关于语义和概率的信息敏感理论，涉及认知模态的条件和语句。该理论验证了许多将概率和模态联系起来的原则，包括条件 If A, then C 的概率等于用 A 更新的 C 的概率。表明此类原则无法得到验证。为了实现这一点，我们否认理性代理通过条件化更新他们的信任。我们提供了一个新的更新规则，即超条件化，它在非模态语句受到威胁时与条件化一致，但在模态句和条件句中不同。