Matt Ridley for the Wall Street Journal:
Michael Shermer, the founder and editor of Skeptic magazine, has never received so many angry letters as when he wrote a column for Scientific American debunking 9/11 conspiracy theories. Mr. Shermer found himself vilified, often in CAPITAL LETTERS, as a patsy of the sinister Zionist cabal that deliberately destroyed the twin towers and blew a hole in the Pentagon while secretly killing off the passengers of the flights that disappeared, just to make the thing look more plausible.
He tells this story in his fascinating new book, The Believing Brain: From Ghosts and Gods to Politics and Conspiracies—How We Construct Beliefs and Reinforce Them as Truths. In Mr. Shermer’s view, the brain is a belief engine, predisposed to see patterns where none exist and to attribute them to knowing agents rather than to chance — the better to make sense of the world. Then, having formed a belief, each of us tends to seek out evidence that confirms it, thus reinforcing the belief.
This is why, on the foundation of some tiny flaw in the evidence — the supposed lack of roof holes to admit poison-gas cans in one of the Auschwitz-Birkenau gas chambers for Holocaust deniers, the expectant faces on the grassy knoll for JFK plotters, the melting point of steel for 9/11 truthers — we go on to build a great edifice of mistaken conviction.
I say “we” because, after reading Mr. Shermer’s book and others like it, my uneasy conclusion is that we all do this, even when we think we do not. It’s not a peculiarity of the uneducated or the fanatical. We do it in our political allegiances, in our religious faith, even in our championing of scientific theories. And if we all do it, then how do we know that our own rational rejections of conspiracy theories are not themselves infected with beliefs so strong that they are, in effect, conspiracy theories, too?
There was a time, when I was younger, when I was confident that I knew how to tell a barmy belief from a rational deduction. I have lost some of that confidence…
[continues at the Wall Street Journal]