Formal models of appearance and reality have proved fruitful for investigating structural properties of perceptual knowledge. This paper applies the same approach to epistemic justification. Our central goal is to give a simple account of The Preface, in which justified belief fails to agglomerate. Following recent work by a number of authors, we understand knowledge in terms of normality. An agent knows p iff p is true throughout all relevant normal worlds. To model The Preface, we appeal to the normality of error. Sometimes, it is more normal for reality and appearance to diverge than to match. We show that this simple idea has dramatic consequences for the theory of knowledge and justification. Among other things, we argue that a proper treatment of The Preface requires a departure from the internalist idea that epistemic justification supervenes on the appearances and the widespread idea that one knows most when free from error.

外观和现实的正式模型已被证明对于研究感知知识的结构特性是卓有成效的。本文采用相同的方法来进行认识论论证。我们的中心目标是对序言做一个简单的说明，在序言中，正当的信念无法凝聚在一起。根据一些作者最近的工作，我们从常态方面理解知识。代理知道p iff p在所有相关的正常世界中都是如此。为了模拟 The Preface，我们诉诸错误的正态性。有时，现实和外表的背离比匹配更正常。我们表明，这个简单的想法对知识和证明理论具有戏剧性的影响。除其他外，我们认为，对《序言》的正确处理需要背离认知证成附在表象上的内在主义思想，以及人们在没有错误时最了解的普遍思想。