Book excerpt: Valerie Gray Hardcastle argues that both professional and lay definitions of pain are wrongheaded -- with consequences for how pain and pain patients are treated, how psychological disorders are understood, and how clinicians define the mind/body relationship. Pain, although very common, is little understood. Worse still, according to Valerie Gray Hardcastle, both professional and lay definitions of pain are wrongheaded -- with consequences for how pain and pain patients are treated, how psychological disorders are understood, and how clinicians define the mind/body relationship. Hardcastle offers a biologically based complex theory of pain processing, inhibition, and sensation and then uses this theory to make several arguments: (1) psychogenic pains do not exist; (2) a general lack of knowledge about fundamental brain function prevents us from distinguishing between mental and physical causes, although the distinction remains useful; (3) most pain talk should be eliminated from both the folk and academic communities; and (4) such a biological approach is useful generally for explaining disorders in pain processing. She shows how her analysis of pain can serve as a model for the analysis of other psychological disorders and suggests that her project be taken as a model for the philosophical analysis of disorders in psychology, psychiatry, and neuroscience.