I've got a theory - an untested, unprovable theory - that the more interesting your life is at any given point, the less lurid and spectacular your dreams will be. Think of it as a balancing procedure carried out by the brain to stop you getting bored to death.

If your waking life is mundane, it'll inject some thrills into your night-time imaginings to maintain a healthy overall fun quotient. So if you work in a cardboard box factory, and your job is to stare at the side of each box as it passes along a conveyor belt, to ensure they're all uniform and boxy enough - and you do this all day, every day, until your mind grows so dissociated and numb you can scarcely tell where the cardboard ends and your body begins - when your daily routine is THAT dull, chances are you'll spend each night dreaming you're the Emperor of Pluto, wrestling a 6ft green jaguar during a meteor storm in the desert just outside Vegas.

All well and good in the world of dreams. But if you continue to believe you're the Emperor of Pluto after you've woken up, and you go into work and start knocking the boxes around with a homemade sceptre while screaming about your birthright, you're in trouble.

I mention this because recently I've found myself bumping into people - intelligent, level-headed people - who are sincerely prepared to entertain the notion that there might be something in some of the less lurid 9/11 conspiracy theories doing the rounds. They mumble about the "controlled demolition" of WTC 7 (oft referred to as "the third tower"), or posit the notion that the Bush administration knew 9/11 was coming and let it happen anyway. I mean, you never know, right? Right? And did I tell you I'm the Emperor of Pluto?

The glaring problem - and it's glaring in 6,000 watt neon, so vivid and intense you can see it from space with your eyes glued shut - is that with any 9/11 conspiracy theory you care to babble can be summed up in one word: paperwork.

Imagine the paperwork. Imagine the level of planning, recruitment, coordination, control, and unbelievable nerve required to pull off a conspiracy of that magnitude. Really picture it in detail. At the very least you're talking about hiring hundreds of civil servants cold-hearted enough to turn a blind eye to the murder of thousands of their fellow countrymen. If you were dealing with faultless, emotionless robots - maybe. But this almighty conspiracy was presumably hatched and executed by fallible humans. And if there's one thing we know about humans, it's that our inherent unreliability will always derail the simplest of schemes.

It's hard enough to successfully operate a video shop with a staff of three, for Christ's sake, let alone slaughter thousands and convince the world someone else was to blame.

That's just one broad objection to all the bullshit theories. But try suggesting it to someone in the midst of a 9/11 fairytale reverie, and they'll pull a face and say, "Yeah, but ... " and start banging on about some easily misinterpreted detail that "makes you think" (when it doesn't) or "contradicts the official story" (when you misinterpret it). Like nutbag creationists, they fixate on thinly spread, cherry-picked nuggets of "evidence" and ignore the thundering mass of data pointing the other way.

And when repeatedly pressed on that one, basic, overall point - that a conspiracy this huge would be impossible to pull off - they huff and whine and claim that unless you've sat through every nanosecond of Loose Change (the conspiracy flick du jour) and personally refuted every one of its carefully spun "findings" before their very eyes, using a spirit level and calculator, you have no right to an opinion on the subject.

Oh yeah? So if my four-year-old nephew tells me there's a magic leprechaun in the garden I have to spend a week meticulously peering underneath each individual blade of grass before I can tell him he's wrong, do I?

Look hard enough, and dementedly enough, and you can find "proof" that Kevin Bacon was responsible for 9/11 - or the 1987 Zeebrugge ferry disaster, come to that. It'd certainly make for a more interesting story, which is precisely why several thousand well-meaning people would go out of their way to believe it. Throughout my twenties I earnestly believed Oliver Stone's account of the JFK assassination. Partly because of the compelling (albeit wildly selective) way the "evidence" was blended with fiction in his 1991 movie - but mainly because I WANTED to believe it. Believing it made me feel important.

Embrace a conspiracy theory and suddenly you're part of a gang sharing privileged information; your sense of power and dignity rises a smidgen and this troublesome world makes more sense, for a time. You've seen through the matrix! At last you're alive! You ARE the Emperor of Pluto after all!

Except - ahem - you're only deluding yourself, your majesty. Because to believe the "system" is trying to control you is to believe it considers you worth controlling in the first place. The reality - that "the man" is scarcely competent enough to control his own bowels, and doesn't give a toss about you anyway - is depressing and emasculating; just another day in the cardboard box factory. And that's no place for an imaginary emperor, now, is it?