If you’ve ever gotten into a discussion with a crank, you know that the conversation will often come to stalemate when the crank says, “Well, then tell me how I’m wrong?” Usually, the crank is so cranky that you can’t even begin to tell them how they are wrong. As one scientist put it, after reading a crank manuscript:
“As I read this, I kept thinking: ‘How hard can it be to prove that this paper is incontrovertibly wrong?’” he said. “But it is hard. Not because his ideas are right. They’re not. But because he’s created a self-consistent system of arguments.”
Clever cranks are even harder to refute, because clever people are better at creating self-consistent (but wrong) systems of ideas. For more, see this earlier post.
If you haven’t had a run in with your local crank lately and miss him (it’s usually a him—often a retired engineer, in my experience), check out Crank Dot Net, a wonderful chrestomathy of crank ideas on math, physics, religion, and other subjects. When reading these, though, think of how you would disprove any of them. In some cases, it would take a long, long time.