In early 2006, as the fifth anniversary of 9/11 approached, I was drawn into what some would view as a right-wing plot to justify a war against Islam, others as a leftist campaign to further the reach of Big Government and still others as a vast Zionist conspiracy. To me, it was just a job.
I was not a spy or even a soldier. I was engaged in a less glamorous, but no less grueling, career - I was a freelance writer. The editors of Popular Mechanics approached me to help them expand one of their recent cover stories into a book. The story, called Debunking 9/11 Lies, was popular - but also hugely controversial. It examined a handful of the most pervasive conspiracy theories surrounding 9/11 to see if they stood up under scientific scrutiny.
At the time, as we say in my native Texas, I did not have a dog in this fight.
I generally believed the official version of what happened on 9/11 but the truth was I spent more time trying to process the horror of that day than questioning whether the official narrative was suspect.
This job required that I do just that, and I subsequently fell down the rabbit hole and into the 9/11 "Truth Movement".
The first whispers about what "really happened" on 9/11 began before the fires were out at Ground Zero. In April 2002, a French journalist named Thierry Meyssan published a book, L'Effroyable Imposture (The Horrifying Fraud), arguing that the attacks were self-inflicted by the US to justify future wars. He sold 200,000 copies. His ideas, and hundreds more like them with countless variations, proliferated on the internet, where they continue to flourish.
Did you know that when the World Trade Center towers fell they became the first steel buildings ever to fall because of fire, and that the collapses bear a striking similarity to controlled demolition? Or that the debris pattern from Flight 93, which crashed in a Pennsylvania field, indicate it was shot down by a missile? Or that an eyewitness told a reporter that he saw a missile heading for the Pentagon? Or that World Trade Center Building 7, an office building near the taller towers that collapsed seven hours after the attacks, housed the offices for the Secret Service, Department of Defense and Securities and Exchange Commission- and even George W Bush's younger brother? It is all very suspicious, isn't it?
Well, it is until you actually look into the facts at the heart of those questions. The magazine assigned me and a couple of fellow researchers to talk to experts in engineering, aviation, fire safety, physics, demolition and whatever other scientific fields were at the core of these conspiracy theories, to see if any of them held up.
We didn't aim to prove or disprove the whole of each theory, just to ascertain whether the theorists were using the facts correctly. Our operating principle came from the late US senator, Daniel Moynihan: "Everyone is entitled to his own opinion but not to his own facts."
To cite one example, we called engineers and fire-safety gurus to discuss how many sceptics point to the fact that fire cannot melt steel, as evidenced by the fact that no steel skyscraper has ever collapsed as a result of fire. Doesn't that indicate that something else brought down the towers? In a way, yes. The impact from two Boeing 767s helped to bring down the towers, as did 38,000 litres of jet fuel, which ignited a raging fire made only hotter by thousands of kilograms of combustible material - carpeting, furniture, papers - in the office buildings. And, the experts explained to us, the fire did not need to be hot enough to melt steel. It needed only to be hot enough to cause the steel to lose some of its structural strength, which it did.
Needless to say, all of the conspiracy theories we studied fell apart under close scrutiny. (We go into a lot more scientific detail on that issue in Debunking 9/11 Myths: Why Conspiracy Theories Can't Stand Up to the Facts, a book I co-edited with David Dunbar, as well as reviewing 19 other persistent theories.)
When the book first came out, we received a lot of positive press but we were also, predictably, the targets for considerable vitriol from the "Truth Movement" - one man, a retired theology professor, even wrote a book debunking our debunking. For many, the only explanation for our project was that we were part of the conspiracy ourselves.
We were accused of being puppets for the left, the right, the Muslims and the Jews. It all depended on who our critics thought were pulling the strings.
This is not new. In a 1964 essay, The Paranoid Style in American Politics, Richard Hofstadter pointed out the long tradition in the US of movements that are rooted in the idea that grand conspiracies are in the works. At various times, large swaths of the population came to believe the Masons, the Catholics, "international bankers", or communists were actively trying to undermine the US. (Hofstadter would no doubt have much to say about the anti-Islamic sentiment that percolates around much of the US this election season.)
But Meyssan - he of the "horrifying fraud" - is a Frenchman and I lived in Abu Dhabi for most of the past two years. If you think the West has a corner on the conspiracy mindset, ask around your local shisha café if anyone thinks Israel was involved in planning the 9/11 attacks. While the course of history makes some people more prone to see plots and machinations, it is also human nature. Whether in religion or politics, we are hard-wired for what Michael Shermer calls "patternicity: the tendency to find meaningful patterns in both meaningful and meaningless data".
In his new book, The Believing Brain, Shermer argues that, if left unchecked, humans can delude themselves into believing anything that fits into their broader world views. "Beliefs come first, explanations for beliefs follow," he writes.
The check against this tendency is the scientific method: take a hypothesis, test it rigorously and determine if it stands up. The results may not be what we hope. But, as with 9/11, they force us to grapple with the ugly truth, and not blindly indulge in sheer fantasy.
Brad Reagan is an editor at The Wall Street Journal. An updated paperback edition of Debunking 9/11 Myths was published last month by Hearst Books.