No one likes to be called a conspiracy theorist. It's a pejorative term.

And yet it's important to distinguish a conspiracy theory from a rigorous analysis of the evidence.

The characteristic feature of a conspiracy theory is, as Richard Hofstetter put it, the

big leap from the undeniable to the unbelievable. Which is a nice turn of phrase, but it's hard

to get people to agree on where that line is, especially when they believe a theory with

almost religious intensity. I discovered that at a public event on 9-11 several years ago.

For the 10th anniversary of the attacks on September 11, 2001, the 9-11 memorial staff in

Lower Manhattan organized a series of panel discussions led by academics and opened to

the public. There were panels on the architecture of the memorial, on volunteerism after 9-11,

and various other non-controversial topics. And then there was my panel on 9-11 conspiracy

theories. The flyer advertising the event said we would discuss, quote, the psychological

underpinnings of these theories, their historical roles in shaping public opinion and how we

should view or evaluate their relevance today. There was a healthy turnout, with most of

the seats occupied. I gave a short talk on the history of the 9-11 truth movement. The

panelists tried to emphasize the reasons that many Americans would question the truthfulness

of the George W. Bush administration, but we did not support the idea that the Bush administration

actually planned 9-11 or knew about it in advance. Throughout the event, the audience

was polite and quiet. And then we took questions. It turned out that many people in the audience

had come with the goal of challenging the whole idea of analyzing 9-11 conspiracy theories.

Because, in their view, there were no 9-11 conspiracy theories. There was only 9-11 truth.

And this truth, they believed, was not accurately represented at the 9-11 Memorial

or Museum, or on this panel. The questioners got so intense and angry that the moderator

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