That’s it! Fritz Machlup bares it all:
Having introduced Ludwig von Mises as a renowned economist, eminent teacher, and recognized leader of the Austrian school of economics, I have to add a few sentences to guard against a possible mix-up. Mises had very strong views on philosophy of science; in particular, he was an outspoken opponent of logical positivism. But there was another Mises, who was a great defender of the neopositivistic teachings of the “Vienna Circle”: Richard von Mises (1883-1953), professor of applied mathematics and aerodynamics, proponent of the frequency theory of probability; he was the younger brother of Ludwig von Mises. The brothers held diametrically opposite views on epistemology; Richard, the Positivist, and Ludwig, the Anti-Positivist.
Here is the root cause of the Austrian economist’s contempt for evidence: it was a brother thing.
Disclosure to mises.org puritans: This is a joke. Besides, Richard was a strict frequentist:
We state here explicitly: The rational concept of probability, which is the only basis of probability calculus, applies only to problems in which either the same event repeats itself again and again, or a great number of uniform elements are involved at the same time. Using the language of physics, we may say that in order to apply the theory of probability we must have a practically unlimited sequence of uniform observations. (Probability, Statistics and Truth, p. 11).
Richard would have wanted to see QE 1000 before concluding it is not inflationary. Unlike Ludwig (or rather his proselytes).