An increasing number of people I know seem to be slipping headlong down the conspiracy-theory route. The topic seems unimportant. The usual pattern is that a friend of a friend of a friend has put a self-serving article onto Facebook - say, Fukushima's radioactive water the Pentagon being bombed on September 11 or businesses owned by Monsanto (an astonishing array of hokum topics) - only rather than look into it or question it or even read the whole thing, they get stuck at the headline, write comments like "oh babe, terrible", and then repost. Intellectually, this is incredibly lazy. These are the same types who are first to complain about how the media isn't to be trusted, and yet they're doing the equivalent of telling people about an amazing article they read in The Onion. What worries me is that they're listening to cranks, and agreeing with them. Rather than applying a little intellectual rigour and asking for proof, there is instead a mute acceptance, almost an expectation. Is it that being able to tap one's nose and say "well, of course it's all about the oil" makes one feel somehow profound? All too often the instant reaction is to agree rather than challenge. And you can challenge without calling someone a liar: it's simple curiosity.

There's an incredibly sad bit in Jon Ronson's excellent book "The Psychopath Test", in which he tells how a victim of 7/7 was so upset by repeated accusations - in fact whole networks of websites - saying that it didn't happen, that she was a government shill, even that she didn't exist, that she went to a meeting of conspiracy theorists, desperate to show herself to them, to make them see her and say it to her face (how could they, having met her)...they don't part on good terms.

Or Oliver Burkeman writing on TheGuardian.com, talks about "the creepiest detail of the JFK assassination" as revealed in William Manchester's account of that day:

The scene is Parkland Memorial Hospital, where the dying Kennedy was rushed within minutes of the shooting. (The new movie Parkland, starring Billy Bob Thornton and Paul Giamatti, takes the hospital as its focus.) Over the following few hours, as news of the assassination began to envelop the planet, the switchboard room at Parkland started receiving hundreds of crank calls. The Army Signal Corps had commandeered Parkland's outgoing lines, but that still left the incoming ones to be handled by the regular switchboard operators, who were soon overwhelmed. Manchester writes:

Already UPI bulletins were stimulating cranks all over the world. In the next two hours one girl, Phyllis Bartlett, would log conversations with England, Canada, Australia, Venezuela, France, and Mexico. She wrote: "Every call coming in long distance is urgent and everyone seems to have a title that demands priority."

Some of the titles were legitimate. Most weren't. Genuine insiders went through Signals, as Ethel Kennedy had. The bulk of the direct-dial long-distance calls came from the curious, the disturbed, the downright demented. A woman in Toledo identified herself as 'The Underground'; she asserted that she had occult powers which would keep Kennedy alive. A man said, 'You nigger lovers, you killed our president.' Another man threatened an operator: 'I know who you are, and you'd better be careful when you start your car.' Most disquieting was a young boy who called three times, talking to a different operator each time. His approach never varied. 'I want to talk to my Daddy,' he would begin plaintively. Asked who his father was, he would say, 'My Daddy – President Kennedy.' Then he would giggle and ring off.

So, what am I saying? Simply that not all the theories you hear come down to the illuminati shrouding the truth. That there are malicious people who delight in disinformation, and that misinformation gives them oxygen to spread further unease. That you have a brain, a good one. Use it to make things better, not worse. Be rigorous in your approach to information, and if you can't do that, be balanced.