After a public lecture in 2005, I was buttonholed by a documentary filmmaker with Michael Moore-ish ambitions of exposing the conspiracy behind 9/11. “You mean the conspiracy by Osama bin Laden and al Qaeda to attack the United States?” I asked rhetorically, knowing what was to come.

“That’s what they want you to believe,” he said. “Who is they?” I queried. “The government,” he whispered, as if “they” might be listening at that very moment. “But didn’t Osama and some members of al Qaeda not only say they did it,” I reminded him, “they gloated about what a glorious triumph it was?”

“Oh, you’re talking about that video of Osama,” he rejoined knowingly. “That was faked by the CIA and leaked to the American press to mislead us. There has been a disinformation campaign going on ever since 9/11.”

Conspiracies do happen, of course. Abraham Lincoln was the victim of an assassination conspiracy, as was Austrian archduke Franz Ferdinand, gunned down by the Serbian secret society called Black Hand. The attack on Pearl Harbor was a Japanese conspiracy (although some conspiracists think Franklin Roosevelt was in on it). Watergate was a conspiracy (that Richard Nixon was in on). How can we tell the difference between information and disinformation? As Kurt Cobain, the rocker star of Nirvana, once growled in his grunge lyrics shortly before his death from a self-inflicted (or was it?) gunshot to the head, “Just because you’re paranoid don’t mean they’re not after you.”

But as former Nixon aide G. Gordon Liddy once told me (and he should know!), the problem with government conspiracies is that bureaucrats are incompetent and people can’t keep their mouths shut. Complex conspiracies are difficult to pull off, and so many people want their quarter hour of fame that even the Men in Black couldn’t squelch the squealers from spilling the beans. So there’s a good chance that the more elaborate a conspiracy theory is, and the more people that would need to be involved, the less likely it is true.

Why do people believe in highly improbable conspiracies? In previous columns I have provided partial answers, citing patternicity (the tendency to find meaningful patterns in random noise) and agenticity (the bent to believe the world is controlled by invisible intentional agents). Conspiracy theories connect the dots of random events into meaningful patterns and then infuse those patterns with intentional agency. Add to those propensities the confirmation bias (which seeks and finds confirmatory evidence for what we already believe) and the hindsight bias (which tailors after- the-fact explanations to what we already know happened), and we have the foundation for conspiratorial cognition.

Examples of these processes can be found in journalist Arthur Goldwag’s marvelous new book, Cults, Conspiracies, and Secret Societies (Vintage, 2009), which covers everything from the Freemasons, the Illuminati and the Bilderberg Group to black helicopters and the New World Order. “When something momentous happens, everything leading up to and away from the event seems momentous, too. Even the most trivial detail seems to glow with significance,” Goldwag explains, noting the JFK assassination as a prime example. “Knowing what we know now … film footage of Dealey Plaza from November 22, 1963, seems pregnant with enigmas and ironies — from the oddly expectant expressions on the faces of the onlookers on the grassy knoll in the instants before the shots were fired (What were they thinking?) to the play of shadows in the background (Could that flash up there on the overpass have been a gun barrel gleaming in the sun?). Each odd excrescence, every random lump in the visual texture seems suspicious.” Add to these factors how compellingly a good narrative story can tie it all together — think of Oliver Stone’s JFK or Dan Brown’s Angels and Demons, both equally fictional.

What should we believe? Transcendentalists tend to believe that everything is interconnected and that all events happen for a reason. Empiricists tend to think that randomness and coincidence interact with the causal net of our world and that belief should depend on evidence for each individual claim. The problem for skepticism is that transcendentalism is intuitive; empiricism is not. Or as folk rock group Buffalo Springfield once intoned: Paranoia strikes deep. Into your life it will creep…

The problem is that there’s no baloney detection module in the brain that says, “That’s a true pattern; that’s a false pattern” with some consistent algorithm that helps us discriminate those. We tend to assume all patterns are real and that they’re infused with intentional agency. And that’s where I think the belief in spirits and ghosts and souls and gods and God and conspiracy theories and so forth comes in.

That isn’t to say that there aren’t hidden agents and predators and conspiracies out there. There are. But, yet again, we only have our intuitions from evolution. In many ways, it is adaptive, in terms of forming beliefs — we have to form beliefs — and to that extent, those adaptations are still vital to survival. But on the other hand, there’s a lot of bogus nonsense out there, and we’re susceptible to believing that as well. And that’s where it’s nonadaptive.

It’s a two-edged sword. If we got rid of all weird beliefs, it would mean, really, that we’re getting rid of all beliefs. I wrote a book called Why People Believe Weird Things. Well, why do people believe weird things? Because they have to believe things, and the weird things go right along with them. In that sense, I’ll always have job security. There will always be people believing these things.

Now, I do think that mass education and the age of science and all that does make a difference, compared with, say, 500 years ago. People are a lot less superstitious than they were then. But, nevertheless, people still harbor all kinds of goofy, weird beliefs. For example: 9/11 was a conspiracy by the Bush administration, flying these planes with remote control devices after the passengers were taken off and whisked away to Canada to be gassed. That’s just the tip of the goofiest part of that particular conspiracy. How could anybody believe that? But they do — lots of people do. So it’s still around. Roughly a third to a half of Americans believe in astrology and tarot cards and psychics that can talk to the dead and UFOs and aliens and Bigfoot. The percentages are striking. Still, it’s not 90 percent. It’s better than it used to be.

This article was originally published on Science and Religion Today.

Ever since Skeptic magazine published an investigative article on the 9/11 “Truth Movement” and analyzed their claims, which were found wanting, I have been hounded by the so-called 9/11 “truthers” because I am the editor of the magazine and therefore am suppose to be a “skeptic” of the official explanation for 9/11.

In fact, throughout January I have been on a book tour for The Mind of the Market, my book on behavioral economics and evolutionary economics, and at every event during the Q & A one of these “truthers” pretends to ask a question about economics but then quickly shifts to a rant about what “really happened” on September 11, 2001.

At my appearance at Powell’s bookstore in Portland, Oregon (January 21), for example, someone with a video camera captured the rambling screed and posted it on YouTube the same night:

For my appearance in Seattle (January 23), my webmeister, Emrys Miller, came prepared with a video camera just in case the “troofers” showed up. Sure enough, one did:

There was no need for a camera in Philadelphia (January 15), as the 9/11 conspiratorialists came prepared with their own recording equipment, and captured the moment here:

What’s going on here? As Bill Maher discovered one day during the taping of his HBO series “Real Time,” their goal is just to be heard — in any venue at any time under any circumstances. In spring of 2005, for example, I gave a lecture at the Los Angeles Public Library, after which I was buttonholed by a documentary filmmaker with Michael Moore-ish ambitions of exposing the “truth” about the 9/11 conspiracy, and he wanted to know if he could interview me. I responded, “you mean the conspiracy by Osama bin Laden and his nineteen Al-Qaeda operatives to fly planes into buildings?”

“That’s what they want you to believe,” he said.
“Who is ‘they’,” I queried.
“The government,” he whispered in hushed tones, as if “they” might actually be listening in at that very moment.
“Yeah, well, ‘the government’ is a little vague for me,” I suggested. “Who in the government wants me to believe that Al-Qaeda did it?”
“The Bush administration,” was the by now predictable answer.
“But didn’t Osama and some members of Al-Qaeda not only say they did it,” I reminded him, “they gloated about what a glorious triumph it was over America and western capitalism, materialism, and secularism?”
“Oh, you’re talking about that video of Osama,” he exclaimed knowingly. “That was faked by the C.I.A. and leaked to the American press to mislead us. There has been a disinformation campaign going on ever since 9/11.”
“How do you know?” I inquired.
“Because of all the unexplained anomalies surrounding 9/11,” he answered.
“Such as?”
“Such as the fact that steel melts at a temperature of 2,777 degrees Fahrenheit, but jet fuel burns at only 1,517 degrees Fahrenheit. No melted steel, no collapsed towers.”

At this point I ended the conversation and declined to be interviewed, knowing precisely where the dialogue was going next — if I cannot explain every single minutia about the events of that fateful 11th day in September, 2001, that lack of knowledge, in his mind at least, equates to direct proof that 9/11 was orchestrated by Bush, Cheney, Rumsfeld, and the CIA in order to implement their plan for global domination and a New World Order, to be financed by G.O.D. (Gold, Oil, Drugs) and launched by a Pearl Harbor-like attack on the World Trade Center and the Pentagon, thereby providing the justification for war. The evidence is there in the details, he explained, handing me faux dollar bill (“9-11” replacing the “1” and Bush supplanting Washington) choc-a-block full of web sites. Where have I heard all this before?

In the early 1990s I launched a full-scale investigation of the Holocaust deniers, initially as the cover story for Skeptic magazine and subsequently expanded into a book length treatment, Denying History: Who Says the Holocaust Never Happened and Why Do They Say it? The deniers employ this tactic of anomalies-as-proof to great effect. David Irving, for example, claims that there are no holes in the roof of the gas chamber at Krema 2 at Auschwitz-Birkenau. So what? So plenty, he says. No holes in the roof of the gas chamber at Krema 2 means that the eyewitness account of SS guards climbing up on the roof and pouring Zyklon-B gas pellets through the holes and into the gas chamber below where the prisoners were herded into, means that the eyewitness account is wrong, which means that no one was gassed in Krema 2, which means that no one was gassed at Auschwitz-Birkenau, which means that no one was gassed at any prison camp, which means that no Jews anywhere were systematically exterminated by the Nazis. In short, “no holes, no Holocaust,” says David Irving, a slogan emblazoned on t-shirts of his supporters at his London trial in which he sued a historian for calling him a Holocaust denier.

No holes, no Holocaust. No melted steel, no Al-Qaeda attack. The parallels are equal, and equally flawed. And just as I never imagined that Holocaust denial would wend its way into the mainstream press (Irving’s trial was front page news for months), after my above conversation with the filmmaker I never imagined that 9/11 denial would get media legs. But now it has legs for days, and so we have been forced to provide a public response. To read our complete analysis of the claims of the 9/11 conspiracy theorists, read eSkeptic from September 11th, 2006.

Noted French left-wing activist Thierry Meyssan’s 9/11 conspiracy book, L’Effroyable Imposture, became a best-seller in 2002. But I never imagined such an “appalling deception” would ever find a voice in America. At a recent public lecture I was buttonholed by a Michael Moore–wannabe filmmaker who breathlessly explained that 9/11 was orchestrated by Bush, Cheney, Rumsfeld and the Central Intelligence Agency as part of their plan for global domination and a New World Order. That goal was to be financed by G.O.D. (Gold, Oil, Drugs) and launched by a Pearl Harbor–like attack on the World Trade Center and the Pentagon, thereby providing the justification for war. The evidence is there in the details, he explained, handing me a faux dollar bill (with “9-11” replacing the “1,” a picture of Bush supplanting that of Washington) chockablock with Web sites.

In fact, if you type “World Trade Center conspiracy” into Google, you’ll get more than 693,000 hits. From these sites, you will discover that the Pentagon was hit by a missile; that U.S. Air Force jets were ordered to “stand down” and not intercept Flights 11 and 175, the ones that struck the twin towers; that the towers themselves were razed by demolition explosives timed to go off soon after the impact of the planes; that a mysterious white jet shot down Flight 93 over Pennsylvania; and that New York Jews were ordered to stay home that day (Zionists and other pro-Israeli factions, of course, were involved). Books also abound, including Inside Job, by Jim Marrs, The New Pearl Harbor, by David Ray Griffin, and 9/11: The Great Illusion, by George Humphrey. The single best debunking of this conspiratorial codswallop is in the March issue of Popular Mechanics, which provides an exhaustive point-by-point analysis of the most prevalent claims.

The mistaken belief that a handful of unexplained anomalies can undermine a well-established theory lies at the heart of all conspiratorial thinking (as well as creationism, Holocaust denial and the various crank theories of physics). All the “evidence” for a 9/11 conspiracy falls under the rubric of this fallacy. Such notions are easily refuted by noting that scientific theories are not built on single facts alone but on a convergence of evidence assembled from multiple lines of inquiry.

For example, according to www.911research.wtc7.net, steel melts at a temperature of 2,777 degrees Fahrenheit, but jet fuel burns at only 1,517 degrees F. No melted steel, no collapsed towers. “The planes did not bring those towers down; bombs did,” says www.abovetopsecret.com. Wrong. In an article in the Journal of the Minerals, Metals, and Materials Society, Thomas Eager, an engineering professor at the Massachusetts Institute of Technology, explains why: steel loses 50 percent of its strength at 1,200 degrees F; 90,000 liters of jet fuel ignited other combustible materials such as rugs, curtains, furniture and paper, which continued burning after the jet fuel was exhausted, raising temperatures above 1,400 degrees F and spreading the inferno throughout each building. Temperature differentials of hundreds of degrees across single steel horizontal trusses caused them to sag — straining and then breaking the angle clips that held the beams to the vertical columns. Once one truss failed, others followed. When one floor collapsed onto the next floor below, that floor subsequently gave way, creating a pancaking effect that triggered the 500,000-ton building to crumble. Conspiricists argue that the buildings should have fallen over on their sides, but with 95 percent of each building consisting of air, they could only have collapsed straight down.

All the 9/11 conspiracy claims are this easily refuted. On the Pentagon “missile strike,” for example, I queried the would-be filmmaker about what happened to Flight 77, which disappeared at the same time. “The plane was destroyed, and the passengers were murdered by Bush operatives,” he solemnly revealed. “Do you mean to tell me that not one of the thousands of conspirators needed to pull all this off,” I retorted, “is a whistle-blower who would go on TV or write a tell-all book?” My rejoinder was met with the same grim response I get from UFOlogists when I ask them for concrete evidence: Men in Black silence witnesses, and dead men tell no tales.