One common contemporary usage of the term “diagnostic uncertainty” is to refer to cases for which a diagnosis is not, or cannot, be applied to the presenting case. This is a paradoxical usage, as the absence of diagnosis is often as close to a certainty as can be a human judgement. What makes this sociologically interesting is that it represents an “epistemic defence,” or a means of accounting for a failure of medicine’s explanatory system. This system is based on diagnosis, or the classification of individual complaints into recognizable diagnostic categories. Diagnosis is pivotal to medicine’s epistemic setting, for it purports to explain illness via diagnosis, and yet is not always able to do so. This essay reviews this paradoxical use, and juxtaposes it to historical explanations for non-diagnosable illnesses. It demonstrates how representing non-diagnosis as uncertainty protects the epistemic setting by positioning the failure to locate a diagnosis in the individual, rather than in the medical paradigm.

术语“诊断不确定性”在当代的一种常见用法是指诊断不适用于或不能应用于当前病例的病例。这是一种自相矛盾的用法，因为缺乏诊断通常与人类判断一样接近确定性。使这一社会学有趣的是，它代表了一种“认识论防御”，或一种解释医学解释系统失败的方法。该系统基于诊断，或将个人投诉分类为可识别的诊断类别。诊断对于医学的认知环境至关重要，因为它声称可以通过诊断来解释疾病，但并不总是能够做到这一点。本文回顾了这种自相矛盾的用法，并将其与不可诊断疾病的历史解释并列。