It is a consequence of the theory of imprecise credences that there exist situations in which rational agents inevitably become less opinionated toward some propositions as they gather more evidence. The fact that an agent's imprecise credal state can dilate in this way is often treated as a strike against the imprecise approach to inductive inference. Here, we show that dilation is not a mere artifact of this approach by demonstrating that opinion loss is countenanced as rational by a substantially broader class of normative theories than has been previously recognised. Specifically, we show that dilation-like phenomena arise even when one abandons the basic assumption that agents have (precise or imprecise) credences of any kind, and follows directly from bedrock norms for rational comparative confidence judgements of the form ‘I am at least as confident in p as I am in q’. We then use the comparative confidence framework to develop a novel understanding of what exactly gives rise to dilation-like phenomena. By considering opinion loss in this more general setting, we are able to provide a novel assessment of the prospects for an account of inductive inference that is not saddled with the inevitability of rational opinion loss.

中文翻译：

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比较意见损失

不精确信任理论的结果是，存在这样的情况：当理性主体收集到更多证据时，他们不可避免地会对某些命题变得不那么固执己见。主体的不精确信念状态可以以这种方式扩展的事实通常被视为对归纳推理的不精确方法的打击。在这里，我们证明扩张不仅仅是这种方法的产物，通过证明意见损失被比以前认识的更广泛的规范理论视为理性的。具体来说，我们表明，即使人们放弃了主体具有任何类型的（精确或不精确）信任这一基本假设，并直接遵循“我至少是”形式的理性比较信心判断的基本规范，类似扩张的现象也会出现。对p充满信心，就像我对q ' 充满信心。然后，我们使用比较置信度框架对到底是什么导致了类似扩张的现象产生了一种新颖的理解。通过在这种更一般的背景下考虑意见损失，我们能够对归纳推理的前景提供一种新颖的评估，而该归纳推理不会不可避免地遭受理性意见损失的困扰。