A 29-year-old woman says that the moment she saw a red car pull into her street, she instantly and completely knew that she had begun being watched by a government agency. She cannot explain how the car led to this conclusion, only that the certainty arrived all at once. Before revealing the answer: what is this finding, and why does it not simply count as an illusion?
This is a delusional perception. It is not an illusion because there is nothing wrong with what she actually perceived — a red car pulling into her street really happened, and she perceived it accurately. The abnormality lies entirely in the sudden, unwarranted, and unarguable meaning she attached to that accurate perception, not in any distortion of the perception itself.
References
- Casey, P. & Kelly, B. (2019). Fish's Clinical Psychopathology, 4th ed. Ch. 4, 'Disorders of Thought and Speech'.