Abstract
Suppose Boeing 747s grew on trees. They would first sprout as embryonic planes, the size of an acorn. Then they would grow until they reached full size, when they would plop off the trees, ready to fly. Suppose also that we knew how to feed and care for them, how to make minor repairs, and of course how to fly them. But let us suppose that all of this transpired at a very early stage in our scientific history, when we did not yet understand the physics or the engineering of flight: Hence the phenomenon was a complete mystery to us. (To keep things simple, let us suppose that no other entity on earth could fly, only 747s.) And for the last ingredient in this fantasy world, suppose that computers likewise grew on trees, and we knew how to use and fix them too.