My latest Mind and Matter column in the Wall Street
Journal is about what happens when hoaxers own up and nobody
believes them. In the interest of space, I had to leave on the
cutting room floor my favourite, though fictional, example. In The
Life of Brian, Brian insists he is not the Messiah. A woman in the
crowd then shouts: ``Only the true Messiah denies his
divinity!''

Here's the column:
What happens when a hoaxer owns up and nobody believes him? Dan
Gardner's new book "Future Babble" explains the many ways in which
experts refuse to admit that they were wrong about something. They
ignore contrary evidence, point selectively to facts that weigh in
their favor or simply shrug off the mistake as a problem of timing.
Even cultists redouble their faith when the world does not end as
forecast. These biases are also apparent in the astonishing
determination of many people to dismiss the claims of confessed
hoaxers.
Mr. Gardner tells how, in the aftermath of 9/11, a seemingly
spooky Nostradamus prophecy went viral on the Internet: "In the
City of God there will be a great thunder, two brothers torn apart
by Chaos, while the fortress endures, the great leader will
succumb.'' In vain did a Canadian student confess that he had
written it a few years before to mock Nostradamus' vagueness.
Something similar happened with a speech supposedly given
by Chief Seattle in 1854 upon signing a treaty surrendering his
tribe's lands: "How can you buy or sell the sky...man did not weave
the web of life-he is merely a strand in it. Whatever he does to
the web, he does to himself.''
In vain do scholars point out that this hymn to ecology was
written for television in 1971 by a Texan screenwriter named Ted
Perry, who has repeatedly tried to set the record straight. Even Al
Gore, in his book "Earth in the Balance," quotes the whole speech,
though he nods toward the controversy by suggesting-rather
limply-that "the power of his response has survived numerous
translations and retellings."
In the early 1920s, Arthur Conan Doyle, the creator of
Sherlock Holmes and a convinced spiritualist, befriended Harry
Houdini, a determined skeptic. Houdini's problem was that in
playing ingenious tricks to persuade Conan Doyle that spiritualists
were tricksters, he only succeeded in reinforcing Conan Doyle's
view that the magician had spiritual powers.
In one incident, Houdini had a cork ball dipped in white ink
spell out a message on a slate suspended from wires. The message
was the exact phrase that Conan Doyle had written on a scrap of
paper a few minutes before, three blocks away. Houdini had swapped
the cork ball for a ball with an iron core, swapped the message for
a blank sheet of paper (under the pretense of ensuring that it was
folded) and communicated its contents subtly to an assistant behind
the wall, manipulating a magnet.
Something similar happened in 1991 when Doug Bower and Dave
Chorley confessed to having invented crop circles-symmetrical
patterns of flattened wheat that began appearing in southwestern
Britain in the 1980s-after an evening at a pub. By the time they
went public, crop circles had become a huge phenomenon, pored over
by enthusiastic believers who called themselves "cerealogists" and
attributed the patterns to UFOs, ball lightning, plasma vortices
and the like.
Many of these self-styled experts were making a good
living on book sales and were not about to let Doug and Dave rain
on their parade. So, with one or two creditable exceptions, they
insisted that the men's confession was itself a hoax and pointed
credulous reporters to evidence that all the crop circles might not
be man-made (too many circles, no witnesses, no footprints,
etc.)
It was the incidental details that made the story of Messrs.
Bower and Chorley believable. Mr. Bower's wife had grown suspicious
about the high mileage on the family car, and most early crop
circles appeared on Friday nights-pub night. Their technique was
"plank-walking": tying a rope to both ends of a plank of wood and
using it as a sort of treadle to push down corn as they walked.
The moral of the tale for magicians, practical jokers and
screenwriters is that if you perform your trick too well, it may
take on a life of its own and escape into the wild.