ABSTRACT
This chapter presents the implications of a hypothesis that many paranoid patients suffer not from a thinking disorder but from a perceptual disorder. A hypothesis is presented regarding the genesis of paranoid delusion that attempts to take into account certain data. Paranoid delusions have been generally regarded as a consequence of an underlying disorder of thinking on the part of the patient. The paranoid individual is assumed to suffer from an inability to make reasonable inferences from data. As the evidence for the presence of perceptual disorder is stronger than the direct evidence for cognitive impairment, the hypothesis places central importance on the former. The hypothesis that a patient suffers from a thought disorder requires testing under conditions wherein the evidence presented to delusional and normal subjects is controlled, and where the range of correct inferences that might be drawn from it is very limited.
