Yesterday, Mike Huemer and I had a debate with two anarcho-communists on the topic of left libertarianism vs right libertarianism. It can be viewed on YouTube.

One thing that struck me as interesting was a difference in how we supported our positions. While I made some factual points, my central argument was theoretical, based on the coordination problem. In order for each of us to achieve his objectives he requires the cooperation of thousands, probably millions, of others, as you can see by tracing the supply train for anything we use — what things went into making it, what went into making those things, and so forth — and considering the number of people involved at each stage. Property and trade provide a decentralized way of solving that problem.

My challenge to my opponents was to explain how, without property, they would solve that problem. They never made a serious effort to answer it. Instead, they offered what they claimed was historical evidence that it had been solved, most notably by the Catalonian anarchists during the Spanish Civil War, with a variety of other claimed factual examples.

The problem is that neither I nor they knew if any of that was true. In my experience, if you look carefully at any controversial bit of history, you can find convincing arguments for a range of very different interpretations. I have not tried the experiment, but my guess is that a sufficiently able holocaust denier could offer persuasive arguments that it would take at least an hour or two of research to debunk. I have encountered cases where a false claim, for instance that Hoover's response to the stock market crash was to cut government expenditure or that Adam Smith supported public schooling, is widely believed. Unless one happens to have already spent time and effort investigating a historical claim, there is no way to know if it is cardboard or gospel truth. Even if you have, there is probably no way, in a context like a debate, to prove its truth or falsity to your opponents and audience.

Theory, on the other hand, is something you can actually look at inside your own head, without worrying about biased or otherwise unreliable sources of factual information. My confidence that a minimum wage must always reduce employment opportunities for low skilled workers was answered not by Card and Kruger's very weak factual evidence but by their demonstration, using the conventional price theory I accept, that there was a conceivable situation in which it would have the opposite effect. I doubt that situation has much real world relevance in the U.S. at present, since it depends on the market for such labor being monopsonistic, but it might well be relevant in other environments.

Similarly here. Persuading me that the coordination problem could be adequately solved without some equivalent of private property and trade on historical evidence would be difficult, since I would have to look at lot of historical claims, find people who disputed them, evaluate their arguments for myself. A clean theoretical argument, possibly inspired by looking at real world examples, could do it in twenty minutes. To the best of my knowledge and belief nobody has produced such an argument yet, which makes me suspect that it cannot be done.

None of that, of course, is an argument against doing empirical work — the real world sometimes has lessons to teach us that we were not clever enough to think of for ourselves. It is an argument against giving much weight to claims about such work that you have not yourself investigated with reasonable care or, short of that, seen confirmed by people who have investigated them and whose honesty and competence you have reason to trust.