This paper considers the role which moral treatment played in the treatment of idiots in the nineteenth century and particularly in the work of Edouard Seguin. It uses this discourse to identify some of the key elements of the definition of what constituted the "moral", viz. teleology, discipline and humane treatment. By way of interpretation, moral treatment and the "physiological method" of treating idiocy are presented as being based more on utility in securing the ends of social and productive subjects than on humanitarian notions of care or treatment. In additon, the paper supports the view that moral teatment allowed physicians to claim effectiveness in a field in which success had otherwise eluded them.