The Ominous Parallels there is a good discussion of the anti-reason epistemology from which the Nazis derived their politics. Here’s an excerpt:
On their own, the Nazis could not have begun to achieve what the intellectuals accomplished for them. On their own, the Nazis could not supply the thinking needed to undercut a country, not even the thinking that told men not to think. They could not supply the philosophy, not even the philosophy that told men to despise philosophy. All of this had to be originated, formulated, and spread by intellectuals—ultimately, by philosophers.
But finding a country ready for them, the Nazis knew what to do with it. They knew how to add death-laden goose-steppers to the theory of unreason—and even what to call the combination, which was their version of the zeitgeist. Goebbels and Rosenberg called it: steel romanticism.
These are “times when not the mind but the fist decides,” declared Hitler in Mein Kampf. The philosophers had eliminated the mind and provided him with the times he needed.
“I need men who will stop to think if they’re ordered to knock someone down!” Hitler told Rauschning. He had no trouble finding them.
Epistemology had done its work.