Better strongly wrong than weakly right

Perhaps you've heard of a Christian group that predicts that the Judgment Day will happen May 21, 2011, followed by the end of the world which will occur October 21 that same year. I submit that people who say things like that are socially much more valuable than people who say things like

America will probably need some added stimulus to kick start employment, but any stimulus right now must be in growth-enabling investments that will yield more than their costs, or they just increase debt. That means investments in skill building and infrastructure plus tax incentives for starting new businesses and export promotion.

I'm saying this even though I know that the first statement will almost certainly turn out to be wrong while the second one will probably turn out right in one way or another. The difference is that, even though it's wrong, statement number one is much more informative. It is verifiable. More precisely, it is falsifiable, in a philosophy of science kind of way. It is a strong prediction, and therefore it can be shown to be wrong. We can learn from this. On the other hand, Friedman's statement can't really be falsified: it is a weak prescription, containing many qualifiers and very little detail. If you tried to follow his advice, and results were less than stellar, the vagueness of his advice will always leave him enough room to accuse you of misunderstanding it.

It's not about being right. It's all about being informative. We can learn much more from statements that are ridiculously wrong than statements that are trivially true. Saying "All else equal, setting a minimum wage higher than the market wage for unskilled labor results in increased unemployment" is much more informative (even if wrong) than saying "Yes, but in real life all else is never equal, things are complicated etc. etc."