My war with common sense

I keep hearing people I know and respect talk about "common sense" as a good thing.

It's pretty hard to separate common sense from "conventional wisdom," but neither are always reliable. I think of common sense as a straightforward, unthinking conclusion. For example, common sense tells us the sun revolves around the earth. We know this because we can see it with absolute clarity.

Of course, research taught us that the earth revolves around the sun, and not the other way around. Research and common sense can be very much at odds with one another, and I toss my lot in with research as the best way to know things. Sure enough, research can be wrong. However, it's further research that corrects it - not naked, clueless observations.

That being said, there are a lot of people that attempt to know things by using common sense and ignoring research.

Take creationists. These people, well intentioned as they may be, know next to nothing about biology. They do not study biology. Normally, I wouldn't fault a person for that, but these people have a great interest in biology. We know this because they speak about biology all the time. They do not make sophisticated criticisms based on intimate knowledge of the subject, but instead make "common sense" observations on a simplified version of biology. For example, "If we came from monkeys, why are there still monkeys?"

That common sense observation may convince some people, but those who study biology know that we do not come from modern monkeys. Instead, monkeys and humans share a common ancestor. That doesn't make the creationists stupid, but it does show that they are intellectually lazy and rely on "common sense" observations.

I feel the same way about "buy local" activists. These people aren't stupid or dishonest. Instead, they have fallen for a common sense solution that doesn't pan out. Clearly, localists have a deep interest in economics. They talk at length about the multiplier effect, supply and demand and growth. They don't know anything about comparative advantage, economies of scale, opportunity cost or creative destruction. Apparently, their interest in economics isn't strong enough to get them to actually study economics.

That's the part I've never understood, and respected even less. If you have such a strong interest in a science like economics, why would you try to guess your way through it with common sense? Shouldn't you be concerned that something counter-intuitive will come up? As Scottish economist John Kay said on the idea of "Do it yourself economics";

"Anyone who claimed expertise in 'practical physics' derived from their experience of driving an automobile or boarding an airplane would immediately reveal himself a fool. It is a measure of the failure of economists to persuade the public of the value of what they do that those who claim practical knowledge of economics suffer no such reactions. There is almost no DIY dentistry, little DIY history or law, rather more DIY medicine. There is much DIY economics."

Common sense tells us that if there's a problem in our society, we should have the government solve it. It tells us that making guns harder to buy will make us safer. It's common sense that closing sweatshops will make life better for people in poor nations. All of these common sense solutions sounds really good, but have the opposite effect.

Perhaps the flaw in settling for common sense explanations is obvious to someone who wants to know what really motivates the other side of an issue, but the flaw is invisible to someone who jumps to conclusions if they are presented by a trusted source, such as an activist with a similar world view.

Of course, one should ask, how do you know if this activist knows what they're talking about, or is just using common sense?

EDIT - A reader called me on my characterization of government solutions as always counterproductive. I overspoke and to the point of being false. I would have been better off listing specific examples like the embedded link - public transportation. Counter examples, where the government does help, include World War 2 and enforcing property rights.