The astute reader will have noticed that the inherit 'truth' of an idea has not been mentioned in this paper. While having an idea be correct may be useful when trying to spread it, correctness is not the final word. People have believed in many weird things that we now can see are incorrect, or that we disagree with on moral grounds. (Millions of people followed Hitler. Millions of people can be wrong.) The ‘truth’ may win out in the long run, but that long run may be a very long time.
Communism is a good example of this. Any economist could, in just a few minutes, explain why communism produces less that capitalism. But it took over 40 years of the Soviet Union for that lesson to come out, and it still hasn't come out in some parts of the world.
How can inherently wrong ideas have such long shelf life? Some ideas are probably just sticky. Communism, for example, sounds great at first. There are probably plenty of other reasons. Here we offer two reason that can be particularly powerful, and open the door to further investigation.
When a group of people have vested interest in maintaining an idea — no matter how silly it is — then that idea will continue to have some weight for a long time. Leaders by their very nature command respect and the ideas that they espouse will generally gain some traction in their followers. Leaders can also try to limit the contact that a group has with the outside world – thus minimizing the effect of contacts outside of the group8.
People who find an idea expedient, because it justifies their claim to power or access to resources, will in general become great proponents of that idea. This can work for good as well for bad. For example someone who thinks he can win in a free and fair election will be a great advocate of democracy9.
Leaders are not the only people who can find an idea expedient. For example, many people find the idea that ‘our problems are not our fault, but the result of those people over there’ to be expedient psychologically. The sweet psychological candy of scapegoating is a powerful force. It can relieve one group of blame and responsibility, and helps some of their politicians gain power.