Berlin, 1913: Karl Jaspers "General Psychopathology" is published. Dissatisfied with how mental illness was understood in the medical communities of his day, Jaspers endeavoured to understand mental illness in terms of their form as opposed to their content. As I understood Jaspers, the fact that the patient heard something when there was nothing to be heard was more important than what the patient thought he heard. 
I like this attitude. For me, the form was always more important than content. "Kleider machen Leute" say Germans (Clothes make people).