ARNOLD KLING
August 14, 2011
The Top Political Contributors
August 11, 2011
Gender and the New Commanding Heights
August 11, 2011
Jamie Galbraith Makes an Assumption
August 11, 2011
Macroeconometrics: The Science of Hubris
August 10, 2011
Real and Nominal Bond Yields
BRYAN CAPLAN
August 14, 2011
The Effect of Thumb Sucking on Income
August 12, 2011
The Voice of Cold, Hard Truth to All Would-Be Educators
August 12, 2011
Ability, Morality, and Prosperity: A Paper and a Report
August 11, 2011
The Theory of Time and Frittering
August 10, 2011
Male Variance and the Remnants of the Gender Gap
DAVID HENDERSON
August 9, 2011
Hayek in "Unbroken", Part Two
August 8, 2011
Hayek in "Unbroken"
August 5, 2011
James Bovard on the Peace Corps
August 4, 2011
Summers Way Off on FDR and 1941
August 3, 2011
The "Amazon" Tax
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I wish people knew what a tautology is. In a sense, "MV = PY" is a tautology. But statements about "MV = PY" are not necessarily tautologies, and since it is primarily these statements that concern us, that "MV = PY" is wholly irrelevant. "F = ma" is also a tautology y'know.
Karl Popper popularised the idea that tautologies were scientific no-nos. Unfortunately, few people seem to understand the context of that prohibition.
"MV = PY" is an abstract object with tenuous connections to reality. By itself, the equation of exchange entails nothing about reality. It is not an empirical claim. Its truth or falsity are determined only by the rules of the formal language in which it is expressed.
If money, prices, and production were observed to behave contrary to their corresponding variables in the equation of exchange, then the equation of exchange would not be shown false. It is a tautology. It cannot be false. However, statements about the equation of the exchange may be false, such as that it describes the actually existing phenomena that we observe, may be false, because they are not necessarily tautologies.
Okay, I'll read the rest of the post now.