The Diagnostic and Statistical Manual of Mental Disorders (DSM-IV, 2000, cited in the “Stanford Encyclopedia of Philosophy”) defines a delusion as a

false belief based on incorrect inference about external reality that is firmly sustained despite what almost everybody else believes and despite what constitutes incontrovertible and obvious proof or evidence to the contrary. The belief is not one ordinarily accepted by other members of the person’s culture or subculture.

Delusions are beliefs “held with great conviction in spite of little empirical support.” A delusion is a “false belief based on incorrect inferences about external reality that is firmly sustained.” A person is deluded when he holds a particular belief with a “degree of firmness utterly unwarranted by the evidence at hand.”

Hitler and the Nazis embraced a delusion about the Jews and Jewish power, believing Jews were acting to destroy the German people and the civilized world; asserting Jews were equivalent to bacteria or viruses; claiming that “international Jewry” stood behind Roosevelt, Churchill and Stalin--acting to unite these leaders and their nations in a conspiracy to cause Germany to disintegrate.

Hitler and the Nazis created a collective delusion that came to define "reality" for many Germans, 1933-1945. War was waged by Hitler to assert the delusion of the omnipotence of Germany. When Hitler died, the delusion disappeared ("gone like a cool breeze"--Chuck Berry).

The term “delusion” usually refers to a clinical syndrome associated with paranoid schizophrenia. What are we to say about a delusion that comes to dominate an entire society?

I was at a Holocaust Conference where the Jeffrey Herf and I had just presented our papers. We were rapping in the back of the auditorium. He was happy that I agreed with his hypothesis that the Nazis' perception of Jews--the danger they represented to Germany--represented a collective delusion.

But then I said, "So you could say that the Nazis were psychotic." He walked away. Perhaps he was terrified to recognize that the phenomenon he had studied his entire life was rooted in a psychotic delusion.

When Hitler died, the delusion died, gone like a cool breeze. Like waking up from a nightmare.