## Thursday, December 29, 2011

### Boy Scientist’s Dud Logic Bomb

Boy Scientist’s Dud Logic Bomb

There once was a poet from Crete
who performed a remarkable feat.
He announced to the wise,
“Every Cretan tells lies,”
thus ensuring their logic’s defeat.

A long time ago, when I was a young lad, I had a strange encounter with logic. I had gotten a Fisher-Price Science kit; it was about circuit-building, and it had batteries and wires and lights and toggles and keys and magnetic relays. The instructions showed how to make AND gates, and OR gates, and NOT gates; I made them all. With the AND gate the light went on only if both keys were pressed; with the OR gate the light went on when either key was pressed; and if you wire the magnetic relay in reverse, the light went on only if you didn’t press the key.
This was good, but I wondered about something. For I had seen those Star Trek shows where Captain Kirk destroyed an evil computer by feeding it a logic paradox. He would call himself a liar, and the machine would fall into a yes-but-no-but-yes-but-no wobble, then short out in a shower of sparks. Cool, I thought; then I wondered; can I do the same thing? It seemed easy enough; wire a magnetic relay to turn on if it’s off, and off if it’s on. A circuit loop, with a twist at the relay; what could be simpler? I wired in a battery, and a light, and – just to be safe – a key, so the whole circuit was activated only when the key’s pressed down.
For those destroyed computers worried me. How would the magnetic relay react to being forced to be in two places at once? Would it break? Would it vanish? Would it short out in a shower of sparks? Would it explode?
I vowed to leap away if something went wrong; but there were worse possibilities. Maybe the confused relay would tear a hole in the space-time continuum, one that monsters could get through. Maybe a single paradox would destroy the Universe…