Lecture 13

Abstract

Given the major role—which we can hardly exaggerate—that sensory deceptions play in the symptomatology of mental illnesses, seen also to some extent when they have run their course, we should start by using part of the theory of sensory deception, which is indispensable for understanding these symptoms, and for their clinical assessment. Let us stay with the sejunction hypothesis, which I developed earlier, without arguing whether this is the only possible way in which sensory deceptions can arise. Indeed, we will later come across sensory deceptions that probably originate in the stimulation process in projection fields of sensory centres; and it must then be clear that their causa efficiens [W] and the target of the stimulus must be sought in projection fields themselves, regardless of whether these fields are directly affected by an aberrant stimulus, or are affected only indirectly as a result of a sejunction process and the hypothetical backflow of nervous current from complex associative structures. We can say one thing already: The sejunction hypothesis is probably valid for the vast majority of hallucinations, especially those of paranoid states, which are our main concern here.