Psychiatry is plagued with philosophical questions. What is mental illness? Is it different from a brain disease? Is there any objective way of determining whether behaviors such as criminal activity are mental illnesses? Should we explain ``abnormal'' behavior by reference to psychological forces, learning processes, social factors, or disease processes?The Philosophical Defence of Psychiatry aspires to answer these and other questions. Divided broadly into two halves, the first analyzes the arguments of psychiatry's critics and covers the philosophical ideas of such thinkers as Freud, Laing, Szasz, Sedgwick and Foucault. The second aims to resolve the problems raised in the first half and thereby to establish a philosophical defense of the theory and practice of psychiatry.