John Locke’s Account of Madness: Its Skeptical Origins and Outcomes

Abstract

John Locke offers an unusual account of madness which, unlike the dominant medical theories of his time, explains it as a pathology of ideas rather than of mental faculties or of physiology. In madness, according to Locke, ideas become associated through a variety of mechanisms that occur outside the ambit of the understanding. Locke contrasts associated ideas with healthy ones, which are connected through the activity of mental faculties like discernment, composition, and abstraction. After presenting Locke’s account of madness as the association of ideas, this paper shows how it drew on his commitments to the tenets of ancient medical skepticism, which discouraged speculation and theorization in favor of observation and experience. It then discusses how Locke mobilized this account to further his philosophical projects – namely his case against nativism – using traditional Pyrrhonian strategies. Locke argued that associated ideas, when used to construct maxims, can lead to false beliefs that seem to have all the certainty and indubitability of inspiration. He used madness to explain the irreconcilable religious and political rifts that engulfed him, and to argue that skepticism about our beliefs, and about the origins of our ideas, is the best prophylactic against dogmatism and zealotry.