"Anti-psychiatrists" have criticized psychiatric practice on the grounds that it represents not genuine therapy, but a moralistic form of social control. One argument used in support of this critique consists of showing that the concept of "mental illness" is not eternal or self-evident: but has a history in a particular culture, and that this history reveals that it always had a moralistic role. Foucault's account of the history of madness in the "Age of Reason" is considered from this point of view. A counter-critique of anti-psychiatry then is proposed, in which the philosophical value of such a historical account is called into question. Modern concepts of "mental illness," it is argued, are significantly different from older concepts of "madness" in that they include reference to harm suffered by the patient, which justifies the assimilation of mental to bodily illness. The anti-psychiatry movement, however, offers a salutary warning against the temptation to confuse mental illness with social deviancy.