In the early nineteenth century, the emergent eld of psychiatry inherited the Enlightenment quest to ‘inquire into the original, certainty, and extent of human knowledge’, as John Locke put it in An Essay Concerning Human Understanding.1 As both Roy Porter and Kathleen Grange have shown, in this period the term ‘psychiatry’ encompassed both what we would now call ‘psychology’ and ‘neurology’. e ‘combined moral and medical viewpoint’ of psychiatry allowed both those who saw knowledge as a product of the immaterial mind and those who saw knowledge as contingent on the material operations of the brain to continue Locke’s epistemological quest.2 Psychologists did so by considering the emotional elements latent in Locke’s Essay and neurologists did so by considering latent physiological elements. Like Locke, thinkers in both elds o en invoked examples of mental disability, known in the period as ‘idiocy’, to de ne the negative limit of human knowledge and to shore up larger projects that aimed to establish the connection between epistemology and morality. But, unlike Locke, who invoked the idiot’s lack of ‘Apprehension or thought’ to prove that supposedly universal propositions were not innate, psychologists invoked the idiot to prove that mental illness derived from emotional life.3 Neurologists, on the other hand, relied on case studies of idiots in order to show that the ‘original’ of idiocy, as an inability to create human knowledge, lay in the organization of the brain, a discovery that o ered evidence for the brain as the organ of the mind.4 At the same time that psychologists and neurologists provided case histories of actual idiots as evidence for the validity of their ‘psychiatric’ projects, William Wordsworth wrote ‘ e Idiot Boy’, one of the most famous poems in English about an idiot. is historical con uence has caused some recent critics, including Alan Bewell and Alan Richardson, to consider the degree to which Wordsworth’s poem contributes to the discourse on idiocy in the early Romantic period. Both Bewell and Richardson suggest that Wordsworth’s poem

contributes to this discourse by implicitly critiquing the Enlightenment notion of idiocy as the absence of thought,5 and both make a case for the idiot boy’s presence of thought through reference to the boy’s emotion throughout the poem and his lyric outburst at the end. ough these critics suggest the larger signi cance Wordsworth’s poem has within the context of nineteenth-century discussions of idiocy, their accounts of idiotic thought as innate contra Locke diverge from the model of the mind proposed by Lyrical Ballads, which follows Locke insofar as it aims to trace ‘the manner in which our feelings and ideas are associated in a state of excitement’ and deviates from Locke insofar as it seeks to demonstrate that ‘we have no knowledge, that is, no general principles drawn from the contemplation of particular facts, but what has been built up by pleasure, and exists in us by pleasure alone’.6 I argue that by reading ‘ e Idiot Boy’ in the context of contemporaneous psychiatric debates over idiocy, we see that Wordsworth uses an idiotic character for the same reason that Romantic-era psychiatrists employed case studies of idiots in their psychological and medical projects – to expand Locke’s epistemology, as put forward in his Essay, in order to establish how emotion and the body organize and disorganize knowledge. Like these psychiatrists, Wordsworth proposes a connection between how an individual accrues knowledge and how that individual treats others.I do not suggest that Wordsworth does this to respond explicitly to Locke or to directly contribute to the psychiatric discourse on idiocy, but rather to further his poetic project in Lyrical Ballads, which insists that in order to retrain associations that obstruct sympathy, we must accept, rather than repudiate, the passive model of mind proposed by Locke.7 Wordsworth creates an idiotic character who (despite being denied access to knowledge built through associations by Locke) represents the ne plus ultra of Locke’s passive, associative mind in order to show the minimum cognitive function required for the creation of poetry and of sympathy. By acknowledging Wordsworth’s retention of the Lockean model in his discourse on idiocy, we can see that idiocy, as an extreme example of the wisely passive mind, is foundational, rather than marginal, for the epistemological and moral project of Lyrical Ballads.