Although readers have related many biographical factors to Kafka’s writing, none has noticed the importance of his long-standing interest in the deleterious effect of modernization on people. Beginning with the train-transported characters of his early writing and moving to the nervously symptomatic bodies of his later work, I argue that we must understand Kafka’s well-known poetics of indeterminacy within this framework. I analyze Kafka’s writings as an accident-insurance clerk, where he sometimes handled cases of “traumatic neurosis” and “hysteria,” together with his short fiction in order to understand how his aesthetics developed in concert with contemporary medical-legal theories. Kafka’s “literary” suspicion of these theories emerged especially in his later years, when his characters showed hysterical symptoms fully decapitated from apparent causes at the same time that he “despaired” of language’s inability to refer to anything beyond itself. The relation of these “simulating” characters to Kafka’s famous anti-mimetic poetic skepticism gives his writing a surprising social-political significance. In both form and content, it outlines the inability to represent in a medical-legal context that demands nothing less.