Stability

It’s a shame that more people don’t get a good physics education–if they did, perhaps it would be more difficult to engage in sophistry and chicanery by using physics terms.

For instance, the word “energy” is well defined in physics. It is the ability to perform work, and can be quantified as the product of a force applied through a distance. As an example, dragging a block that requires ten pounds of force to move it, for ten feet, requires one hundred foot pounds of energy. Power is defined as the rate at which energy is expended (that is, the energy divided by the time required). Dragging the block quickly requires more power than doing so slowly.

Unfortunately, people who don’t understand this are taken in by charlatans–purveyors of rocks, under the delusion that certain minerals in certain shapes contain “energy” and “power” that can in turn by transmitted to their owner. This, despite the fact that they contain no quantifiable energy at all, or any apparent means to provide an energy transfer to a human being, at any rate whatsoever.

Another misunderstood concept is that of stability. Stability has a precise meaning to a physicist (and controls analyst). If, in a given position, a body is perturbed (that is, moved) slightly, and it returns to the original position on its own, it is said to be stable. If, on the other hand, a slight perturbation causes it to move away from the original position, it is said to be unstable. There is a third state, called neutral stability, which occurs if the disturbance results in the object staying in the new, perturbed position.

In the simplest physical terms, think of the stable condition as a ball at the bottom of a valley, the unstable one as a ball at the top of a hill, and the neutrally stable one as a ball on a flat surface.

Push the stable ball up the hill a bit, and it will roll back down to the bottom where it started. Push the unstable ball at the top of the hill a bit, and it rolls down the hill, away from its original position, ending up at the bottom, and then stable in its new location. The neutrally stable one on the flat surface, of course, will stay wherever you put it.

Note also that the definition might depend on the direction of the push. If a ball is on top of a plateau, on the edge, it could be neutrally stable in the direction away from the slope, but unstable in the direction toward the slope.

Like the word “natural,” one should not assign intrinsic value judgements to any of these physical states. There is no benefit to the ball being stable in its valley if you want it in, say, your own valley, the next one over.

Similarly, sometimes instability can be useful.

A stable airplane will fly “hands off” and this is how airliners and most general-aviation aircraft are designed, for added safety. But many modern fighter aircraft are designed to be aerodynamically unstable, because it turns out that this is a way to maximize performance. The penalty for flying an unstable aircraft is that it requires active and continuous control to keep it going in the direction you want it to, and pointing in the direction you want it to, and that generally means control by a computer, which results in another potential failure mode. Unstable aircraft are much more difficult (but not impossible) to fly (it actually turned out that the Wright’s original flyer was not an aerodynamically stable design). But there is no inherently right or wrong way–it’s just a matter of your requirements and designing to meet them.

If an entity is in a desirable state, then it’s also desirable that that state be stable, so it’s easy to keep it that way. If, on the other hand, the state is undesirable, stability is a bug, not a feature.

Getting from a stable state to an unstable one, or another stable one, requires the input of energy. If the ball is in the wrong valley, it has to be rolled up and over the hill, so it can roll down into the right one.

All of which is a high-falutin’ way, of course, of explaining why I want to throw something at the television when I see some windy bEUreaucrat on the East River attempting to send shivers down our collective spine by talking about the risk to “stability” of the Middle East if we remove Saddam’s cleated boot from the collective neck of the Iraqi people.

Obeisance to the false god of “stability” has gotten us, and the people of the Middle East, into the current mess.

In 1991, the first Bush administration hoped that Saddam’s regime was actually unstable, and a little push would result in his overthrow, while maintaining the “stability” of a unitary Iraq. Unfortunately, it turned out to be stable, and the little roll up the hill provided by the end of the first phase of the Gulf War (we’re actually about to enter the third, and hopefully final phase) wasn’t sufficient to get it over the hump into another stable regime. Unfortunately, the hill that it had to go up to remove Saddam proved higher than they thought, and they weren’t willing to expend the additional energy required to get it out of his stable valley, to the tragedy of the Kurds, Shi’ites and other Iraqi people over the past dozen years.

Now, again we’re told, as we were then, that removal of Saddam may “destabilize” the region. Unfortunately, the analogy for this perverse love of the status quo would be an airplane, a stable configuration, in straight and level flight, with a madman for a pilot. Ahead of it is a mountain.

Much better, for now to have a maneuverable, albeit unstable, fighter. It will require much more energy to get to that state, in this case in the form of American boots on the ground, and it will require careful and constant command and control, until we can get it over the hill, out of the valley of tyranny, and ultimately into one of liberal democracy.

And for those who think that liberal democracies are intrinsically unstable configurations, consider. Yes, France is on its Fifth Republic in a couple hundred years. But the US is still running fine, albeit with some problems, on its first. That’s the kind of stability that we want to see in the Middle East.