Like mushrooms after rain, a number of alternative explanations have sprung up in the wake of the events in Pakistan this week. But almost as numerous as these conspiracy theories are the articles debunking them.

Serious commentators like Alexander Chancellor in The Guardian are heaving sighs and rolling their eyes and patiently explaining how very silly it is to be sceptical.

If there are people who believe that Bin Laden is still alive, no photograph will make them accept that he is not. They will assume it is a fake, just as the Americans who believe Obama was born outside the United States and is therefore ineligible to be president assume that his birth certificate is a fake. Nothing will persuade a conspiracy theorist to change his mind.

But this is, quite frankly, an absurdly simplistic proposition, because it reduces the debate to a simple binary relationship: either you believe what the US Government says, or you are a conspiracy theorist and therefore part of the lunatic fringe.

Well, many initially believed that Bin Laden was armed and came out firing, because that's what they were told. Turned out not to be true. In fact, Washington's story has already undergone a series of metamorphoses, suggesting that the "truth" is still a work in progress. That's not a good platform from which to ask for the public trust.

I have no reason to believe that Osama bin Laden is still alive, but if we're to pledge allegiance to simplistic propositions I prefer this one: it's the job of journalists to examine everything governments say, and demand proof to support all claims the bigger the claim, the more proof required. 

If more journalists had followed this principle in 2003, the lie of Iraqi WMDs would have been exposed and the world might be a different place right now.