The varieties of crankery

Okay, the most obvious reason why people sell bunkum is just that -- to obtain money. Pat Robinson has managed to get very wealthy by conning the rubes, but every preacher is out to make a living. True, you don't have to be a creationist to get people to put money in the plate but having your own special truth to which those smart people who laugh at you are hostile builds tribalism and loyalty and helps shake out your pockets.

The same motive applies to homeopaths and naturopaths and chiropractors. They couldn't get into medical school or didn't want to make the serious effort it requires, but this way they get to pretend they are doctors and get a fee.

Most con artists start believing their own bullshit -- it makes them more effective a the con and lets them live with a clear conscience. So they also get to believe they are actually helping sick people or saving souls. It makes the money even sweeter. So these cases are not hard to explain.

Climate change denial is rather similar -- it's mostly financed by the fossil fuel industry and associated tycoons. Just follow the money.

But that doesn't entirely explain why lots of people who aren't making money off of these schemes become passionate believers. These frauds sell in large part because the truths they deny are inconvenient, uncomfortable to downright distressing, or take some hard work to really understand. It feels better, at least for many people, to believe the bunkum, and once they start believing, confirmation bias, tribalism and just avoiding the conclusion that you've been duped all reinforce and maintain the belief against all evidence.

That doesn't explain, for example, Peter Duesberg, the virologist who to this day maintains that HIV does not cause disease. It's cost him career advancement and the respect of his colleagues and gained him nothing, as far as I can tell. But here's what seems to have happened.

When the HIV hypothesis was first proposed, like any hypothesis it took some work to confirm. At the early stages of any emerging scientific idea, it's appropriate to question it, push back, and really make the proponents of the hypothesis prove it. Indeed, most of the time they turn out to have been wrong. If the hypothesis holds up, and the critics say fine, you have overcome my objections, they shouldn't pay any price, in fact they should gain respect. But the dynamic doesn't always work that way, either within the relevant community or the individual critic's psyche. In the process of arguing with his colleagues, Duesberg evolved from a friendly critic to an adversary, and came to see conceding that HIV causes AIDS as a personal defeat. His self-esteem just wouldn't allow it. In other words it was a case of confirmation bias run amok.

The problem is what to do about it. Presenting people with ironclad evidence and irrefutable logic that says they've been just plain wrong all along doesn't work with most folks, most of the time. It just makes them resent you and dig in even deeper. Viz. Duesberg. So we come to an impasse.

My colleague Steve Sloman has an idea. Most people have what he calls the illusion of explanatory depth: they think they have a very sound basis for their belief but it turns out they really can't explain why they believe it or defend their belief effectively if you ask them.  Don't tell them they're ignoramuses or dupes, ask them to explain it to you. They may suddenly find they can't.