Being interested in the history of the 1930s, I recently picked up a copy of America’s Great Depression by the influential libertarian Murray Rothbard (1926–1995). I choked on the introduction, where Rothbard lays out his theory about theory, which makes no sense to me.
“This book rests squarely on the Misesian interpretation of the business cycle,” he writes, referring to the theories of the older libertarian economist, Ludwig von Mises (1881–1973). “Note that I make no pretense of using the historical facts to ‘test’ the truth of the theory. On the contrary, I contend that economic theories cannot be ‘tested’ by historical or statistical fact. These historical facts are complex and cannot, like the controlled and isolable physical facts of the scientific laboratory, be used to test theory . . . The only test of a theory is the correctness of the premises and of the logical chain of reasoning.”
You have to keep in mind that the map sometimes lies, or maybe tells you a truth different from the one you need to know.
Philosophers make a distinction between statements that are valid and statements that are true. Validity is like math. It’s about logic. If P then Q. It’s theory. Truth is about what’s real, which is not the same thing. Logic is useful, but ultimately what we care about is what’s real.
I am reminded of the accounting classes I took many years ago. I gave up on accounting, but one thing has stuck in my mind: the professor described accounting as a map of the “territory” of a firm, and warned us not to confuse the map with the territory. The “map” might say the company is making money, but the truth might be that it runs out of cash before the owners are paid. (As a business journalist I wrote about some companies like that.) The map is useful; to steer the company you need the map. But you have to keep in mind that it sometimes lies, or maybe tells you a truth different from the one you need to know.
Back to Rothbard. He says that an economic theory is “a priori to all other historical facts.” It can be used to explain the historical record, but it cannot be tested. Here is his argument:
Suppose a theory asserts that a certain policy will cure a depression. The government, obedient to the theory, puts the policy into effect. The depression is not cured. The critics and advocates of the theory now leap to the fore with interpretations. The critics say that failure proves the theory incorrect. The advocates say that the government erred in not pursuing the theory boldly enough, and that what is needed is stronger measures in the same direction. Now the point is that empirically there is no possible way of deciding between them. Where is the empirical “test” to resolve the debate? How can the government rationally decide upon its next step? Clearly, the only possible way of resolving the issue is in the realm of pure theory — by examining the conflicting premises and chains of reasoning.
This strikes me as piffle. There are several ways of deciding between the two claimants. You can compare what happened at times when the policy was imposed with what happened at times when it wasn’t. You might compare the depression of the 1930s with the depressions of 1920–21 or 1893–97 or 1873–79, etc., and see that the one in the 1930s featured the slowest recovery in US history. That is evidence (not proof) that whatever policies were tried didn’t work too well. You can dig deeper. How did investors, entrepreneurs, company managers, workers, and other people in the 1930s respond to the National Recovery Administration? To mass unionization? To the retained-earnings tax? To the abandonment of gold? What did supporters and opponents predict the players would do, and what did they do?
Robert Higgs asks these kinds of questions in Depression, War and Cold War. You can reject what he does — none of his arguments amount to a drop-dead test such as you find in a chemistry lab — but they are ingenious. They are instructive. They make a case.
The social life of humans is more complicated than a test tube.
Rothbard argues, in essence, that such questions are too messy to answer. A theory cannot be “tested” in the way a question in chemistry can be “tested” by heating compounds in a test tube. He’s right in thinking that you can’t test that way with economic policies, but it doesn’t mean that “empirically there is no possible way of deciding between them.” You can look at what lawyers call “the preponderance of the evidence.” “Test” is a high-hurdle word, the wrong word. You can evaluate. You won’t get to 100% certainty, but it’s unlikely that you’ll be stuck at 50-50, either. You can decide, but you have to look at the territory as well as your map — and you may find yourself correcting your map to make it fit the territory better.
Essentially Rothbard denies this.
“Clearly,” he asserts, “the only possible way of resolving the issue [of choosing the best economic policy] is in the realm of pure theory — by examining the conflicting premises and chains of reasoning.” In other words, the only way to decide what to do “in the territory” is to pick the best-looking map without looking at the territory.
No, no, no! Because the social life of humans is more complicated than a test tube, and because cause and effect are mixed up and piled on each other, you have to check your “map” against the territory all the time. Because your theory is only an approximation. A simplification. It is not life.
Praxeology is not primary. Supply and demand curves are not reality.
To quote the philosopher Robert Heinlein: “What are the facts? Again and again — what are the facts?”
If you say, “I don’t care about what facts you have. What experiences, or what statistics, or anything. I have my theory, I’m sure it’s right, and I don’t need to ‘test’ it,” you become irrelevant. You become ignorable. You become the frog at the bottom of the well.