There is a mass of complexity on both sides of this — it isn’t by any stretch of the imagination either simple theory or a simple set of numbers that are implicated in the claim, e.g. relative productivity and equilibrium wage rates and liabilities and all sorts of other elements are part of the “data” not simply gold reserves and national price levels — and great complexity could be described on the theory side as well.

This isn’t easy. But it makes a hash of things to conflate mistakes about empirical numbers with mistakes about causal mechanisms.

The problem is that explications of stuff often uses a mush of combined elements to “illustrate” particular understandings.

And folks like DeLong purposely conflate and muddle these things to trash and marginalize alternative scientific paradigms simply to advance his personal particular political ends.

Another difficult thing is to separate out theory neutral empirical “facts” from theory laden empirical constructions that are NOT shared across scientific paradigms.

Economics is filled with social constructs which are deeply contaminated with question-begging theory.

It takes hard work to do this, but we get no-where if we don’t make the effort.

And we can’t make honest assessments of theory “compared against the data” unless we do so.

Hayek claimed:

“France did not prevent her monetary circulation from increasing by the very same amount as that of the gold inflow”

These are contrary to fact factual/statistical relationship which lie at the bottom of what Hayek is claiming.

We don’t’ even know what data Hayek was working with, or how much of his day he was spending on such numbers. It couldn’t have been more than minutes.