Among psychiatric conditions, delusions have received significant attention in the philosophical literature. This is partly due to the fact that many delusions are bizarre, and their contents interesting in and of themselves. But the disproportionate attention is also due to the notion that by studying what happens when perception, cognition, and belief go wrong, we can better understand what happens when these go right. In this paper, I attend to delusions for the second reason—by evaluating the epistemology of delusions, we can better understand the epistemology of ordinary belief. More specifically, given recent advancements in our understanding of how delusions are formed, the epistemology of delusions motivates a proper functionalist account of the justification of belief. Proper functionalist accounts of the justification of belief hold that whether a belief is justified is partly determined by whether the system that produces the belief is functioning properly. Whatever pathology is responsible for delusion formation, restoring it to its proper function resolves the epistemic condition, an effect which motivates proper functionalism.

在精神疾病中，妄想在哲学文献中受到了极大的关注。这部分是由于许多妄想很奇怪，而且它们的内容本身就很有趣。但不成比例的关注也是由于这样一种观念，即通过研究感知、认知和信念出错时会发生什么，我们可以更好地理解当这些正确时会发生什么。在本文中，我关注妄想的第二个原因——通过评估妄想的认识论，我们可以更好地理解普通信念的认识论。更具体地说，鉴于我们对妄想是如何形成的理解的最新进展，妄想的认识论激发了对信念正当性的适当功能主义解释。正确的功能主义对信念辩护的解释认为，信念是否被辩护部分取决于产生信念的系统是否正常运作。无论何种病理学导致妄想的形成，将其恢复到正确的功能可以解决认知条件，这种影响激发了正确的功能主义。