So there we were, a grab bag of a half-dozen grad students ranging from a brawny Argentine to a tiny Chinese-Filipina, doing our mandatory Outward Bound course, when the instructor pulled out a hula hoop.
The assignment was simple, as might be expected from something involving a hula hoop: we’d gather in a circle, hands in the air, and the instructor would place the hoop on our fingertips. And all we had to do was keep our fingertips touching the hoop. The assignment was simple.
And, as it turned out, the assignment was impossible. No sooner had that hoop dropped onto my fingers than it started, for lack of a better term, levitating. I had to jerk my hand up just to keep touching it, and in a matter of seconds it had soared out of the reach of the tiny Asian woman. And that was the end of our assignment.
The reason the assignment was impossible was not, as some of us speculated, that the hoop was filled with helium, or that there were invisible wires somehow attached to it. You may well have guessed it: everyone had to keep touching the hoop, which meant they were exerting pressure on it in an upward direction. Since hula hoops have no weight worth speaking of, there wasn’t a corresponding downward pressure, and since the assignment was to touch the hoop with our fingertips, but not grasp it, we couldn’t stop it from being driven up that way, either. Accordingly, Newton’s Second Law of Motion caused it to accelerate away from our fingertips, causing us to move our fingers up, causing us to exert more upward pressure on the hoop, causing the whole cycle to repeat until poor little Concepta Suarez couldn’t reach the thing any more.
The point of the exercise was to demonstrate that sometimes, when independent agents act from enlightened self-interest, the result is not, in fact, optimal. This was a tough lesson for a libertarian, which I still was in those days. Yet plainly, here was a situation where the Invisible Hand didn’t reward effort with success but instead whisked our hoop away upwards in a manner reminiscent of Yuri Gagarin.
Not everything in life is a hula hoop: many things have their own weight and can resist pressure from any number of self-interested actors. (You can get a group of people to “levitate” a hula hoop, but good luck getting them to levitate an iron hoop off a barrel, let along a manhole cover.) But for those things that are hoops, that lack their own weight, be sure that at least someone is grasping the thing firmly. (Or perhaps, that some third party is holding the hoop down.)
Otherwise, you are apt to see your hoop soaring heavenward, out of the reach of all but the tallest man’s fingertips.
Cuardach 