 Both common sense folk psychology and medical psychiatry employ concepts of mental disorder or illness. (“Depression” refers to the same mood states and attitudes, for example, whether used by a professionals or non-professionals.) This can foster confusion, and inconsistencies arise at the boundaries where mental disorders meet other kinds of disorder. Rather than traditionally mental symptoms, for example, “hysterical” (“psychosomatic”, “somatoform”, or “conversion”) syndromes exhibit bodily paralyses, minor skin conditions, and intestinal maladies (Shorter 2006; Micale 1995; Scull 2009). Yet they remain mental disorders in common understanding, and long found a place in standard psychiatric  classifications.[3]  Also anomalous, some conditions with apparently mental symptoms are the causal product of what are, indisputably, diseases of and damage suffered by the brain. (Delusions following cerebral hemorrhage are an example.) They are judged to be neurological rather than psychiatric complaints however, and excluded from the class of mental disorders according to both everyday conceptions, and diagnostic taxonomies. Similarly, although perception is widely judged a mental capacity, some conditions affecting sight, such as blindness, are absent from diagnostic classifications.