Quassim Cassam is Professor of Philosophy at the University of Warwick in Coventry. His latest books are Berkeley’s Puzzle: What Does Experience Teach Us?(2014) and Self-Knowledge for Humans(2014)
Meet Oliver. Like many of his friends, Oliver thinks he is an expert on 9/11. He spends much of his spare time looking at conspiracist websites and his research has convinced him that the terrorist attacks on New York and Washington, DC, of 11 September 2001 were an inside job. The aircraft impacts and resulting fires couldn’t have caused the Twin Towers of the World Trade Center to collapse. The only viable explanation, he maintains, is that government agents planted explosives in advance. He realises, of course, that the government blames Al-Qaeda for 9/11 but his predictable response is pure Mandy Rice-Davies: they would say that, wouldn’t they?
Polling evidence suggests that Oliver’s views about 9/11 are by no means unusual. Indeed, peculiar theories about all manner of things are now widespread. There are conspiracy theories about the spread of AIDS, the 1969 Moon landings, UFOs, and the assassination of JFK. Sometimes, conspiracy theories turn out to be right – Watergate really was a conspiracy – but mostly they are bunkum. They are in fact vivid illustrations of a striking truth about human beings: however intelligent and knowledgeable we might be in other ways, many of us still believe the strangest things. You can find people who believe they were abducted by aliens, that the Holocaust never happened, and that cancer can be cured by positive thinking. A 2009 Harris Poll found that between one‑fifth and one‑quarter of Americans believe in reincarnation, astrology and the existence of witches. You name it, and there is probably someone out there who believes it.
You realise, of course, that Oliver’s theory about 9/11 has little going for it, and this might make you wonder why he believes it. The question ‘Why does Oliver believe that 9/11 was an inside job?’ is just a version of a more general question posed by the US skeptic Michael Shermer: why do people believe weird things? The weirder the belief, the stranger it seems that someone can have it. Asking why people believe weird things isn’t like asking why they believe it’s raining as they look out of the window and see the rain pouring down. It’s obvious why people believe it’s raining when they have compelling evidence, but it’s far from obvious why Oliver believes that 9/11 was an inside job when he has access to compelling evidence that it wasn’t an inside job.