It is a matter of some irony that psychiatry's most trenchant critic for over four decades is himself a psychiatrist. I refer to Thomas S. Szasz. Szasz's core thesis may be succinctly rendered: mental illness is a “myth”, a “metaphor” which serves only to obscure the social and ethical “problems in living” we face as human beings. This paper reconsiders the conceptual bases of Szasz's assault on psychiatry and assesses recent counter-arguments of his critical interlocutors. It presents a defence of (...) the Szaszian conception and emphasises the continuing relevance of his earliest work. Additionally, the paper discusses Szasz's thesis in light of the work of the influential French philosopher of medicine, Georges Canguilhem. (shrink)