The legitimacy of psychiatry as a medical discipline is often challenged. Anti-psychiatric arguments fall broadly into two categories: the metaphysical and the epistemological. Critics of psychiatry frequently appeal to one or more of these arguments to discredit the field and to subvert the social power that psychiatrists and mental health workers use to control of the behaviour of people who are allegedly mentally ill. If these arguments had or gained traction, there would be reason to be suspicious of the practice of psychiatry and to be hesitant to invest increasingly scarce resources...