Disease Externalism

Abstract When you are ill, where is your illness located? The traditional, and commonsensical, answer is that it is somewhere within your body. But a rapidly expanding literature in the philosophy of psychiatry, along with growing murmurs in the philosophy of medicine more generally, tells a different story. On this view, at least some diseases are constituted in part by factors external to the body, either at the time of the illness or at some previous point. Your illness may be, in a literal sense, outside you. This chapter traces the development of disease externalism from its genesis in philosophical theories of linguistic reference, through the development of “4E”—extended, embedded, embodied, and enacted—theories of cognition, and on to full-blown analyses of psychiatric and somatic illness. It then summarizes the current state of the field, before suggesting potential new lines of investigation, and avenues for novel, environment-focused therapeutic intervention.