Abstract
To someone coming fairly fresh to this debate, Sykes’ paper is somewhat shocking. The psychogenic inference seems such an obvious fallacy, yet he shows, with detailed reference to both diagnostic practice and the literature on mental disorders, the extraordinary pervasiveness of its influence, extending even to the systematic ambiguities built into key diagnostic terms. Sykes characterizes the inference in the following terms: “If there is no known physical cause for a symptom or disorder, the cause must be psychological” (2010, 290). He notes the glaring fallacy of mistaking an epistemological point (that a physical cause is not, at present, known) for an ontological one (that no such cause exists) and ..