Written by Keven Moore for Jeremy Volume 1, Issue 4 in 1986
Everyone knows what the correct screwdriver is. It is the screwdriver which is about 300mm long with a blade about 7mm wide and 0.7mm thick. This screwdriver is useful for almost any purpose, from screwing in the most general purpose screws to wedging the door open. The only problem with this elegant device is that you can never find one when you need one. You can always find the one that is so small that it is more useful as personal decoration than as a device for driving screws, or the one you could always use as a crowbar, but never the correct one.
Why is this so? The classical explanation is that it is such an incredibly useful device that someone else has borrowed it indefinitely for their own use, or indeed, has wedged the door open with it. This theory was abandoned at the turn of the century as being cynical, in favour of a semiclassical theory which said that screwdrivers come in quantized sizes, none of which are useful.
In the early days of quantum mechanics, it was postulated that the operator corresponding to looking for a screwdriver had only two eigenstates, these being in Dirac notation:
|tiepin> = that tiny little thing useful only as personal decoration
|crowbar> = the monster driver that takes two to lift it
In the late sixties and early seventies, a theory was proposed that screwdrivers conform to the SCREWU(2) class of gauge theories, in which the correct screwdriver was a necessary intermediate particle in spanner decay.
Recent experiments at CERN on the spanner-antispanner collider have detected screwdrivers of the correct size with a lifetime of 1.93x10^-12 seconds, decaying into a |tiepin> or |crowbar> and a screwino, one of silly, short, fat, screwdrivers which are very good for butchering the slots in screws, but well night useless for anything else.
What this means is that you CAN find the correct screwdriver but you've got to be quick.
Image source: