Richard Posner had a nice piece over the weekend on the conceptual mistakes that lead people to underprepare for events that they don't think are likely to happen anytime soon. The financial disaster, the BP oil spill, Hurricane Katrina, the earthquake in Haiti -- all could've been prepared for in advance, but all were worsened because people put off the planning. "It seems that no one has much incentive to adopt or even call for safeguards against low-probability, but potentially catastrophic, disasters," writes Posner.

His piece reminded me of a great passage from Douglas Adams' Hitchhiker's Guide to the Galaxy series explaining how things that we've decided won't go wrong not only do go wrong, but are invariably made worse by our overconfidence. When I went back and found the passage, though, it turned out to be an almost breathtakingly perfect summation of not just the financial crisis, but the innovations that preceded it.

The Great Ventilation and Telephone Riots srDt 3454 of had started out as just a lot of hot air. Hot air, of course, was the problem ventilation was supposed to solve and generally it had solved the problem reasonably well up until the point someone invented air-conditioning, which had solved the problem far more throbbingly.

And that was all well and good, provided you could stand the noise and the dribbling, until someone came up with something even sexier and smarter than air-conditioning, which was called in-building climate control.

Now this was quite something.

The major difference from ordinary air-conditioning was that it was thrillingly more expensive, and involved a huge amount of sophisticated measuring and regulating equipment which was far better at knowing, moment by moment, what sort of air people wanted to breathe than mere people did.

It also meant that, to be sure people didn't muck up the sophisticated calculations that the system was making on their behalf, all the windows in the building were built sealed shut. This is true.

While the systems were being installed, a number of people who were going to work in the buildings found themselves having conversations with Breathe-O-Smart system fitters that went something like this:

"But what if we want to have the windows open?"

"You won't want to have the windows open with the new Breathe-O-Smart."

"Yes, but supposing we wanted to have them open for just a little bit."

"You won't want to have them open even for a little bit. The new Breathe-O-Smart system will see to that."

"Hmmm."

"Enjoy Breathe-O-Smart!"

"Okay, so what if the Breathe-O-Smart breaks down or goes wrong or something?"

"Ah! But one of the smartest features of the Breathe-O-Smart is that it cannot possibly go wrong. So. No worries on that score. Enjoy your breathing and go about your day."

It was, of course, as a result of the Great Ventilation and Telephone Riots srDt 3454 that all mechanical or electrical or quantum-mechanical or hydraulic or even wind-, steam-, or piston-driven devices, are now required to have a certain legend emblazoned on them somewhere. It doesn't matter how small the object is, the designers of the object have to find a way of squeezing the legend in somewhere, because it is their attention that is being drawn to it rather than the user's.

The legend is this: "The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at or repair.