If we are to avert even worse disasters, we need to understand what caused the events of Sept. 11. It's clear that Osama bin Laden is a really bad guy, and these were really misguided people, and we need to do something about disabling them in the future. But if we are to ever return to a more lasting state of peace, we have to address the root causes of terrorism. The best method to control something is to understand how it works.
Randomness and determinism are the poles that define the extremes in any assignment of causality. Of course reality is usually somewhere in between. Following Poincare', we say that something is random if the cause seems to have little to do with the effect. Even though there is nothing more deterministic than celestial mechanics, if someone gets hit in the head by a meteor, we say this is bad luck, a random event, because their head and the meteor had little to do with each other. Nobody threw the meteor, and it could just as well have hit someone else. The corresponding point of view here is that bin Laden and his associates are an anomaly, and the fact that they are picking on us is just bad luck. We haven't done anything wrong and there is no reason to change our behavior; if we can just get rid of them, the problem will disappear. This is the view that we would all rather believe because the remedy is much easier.
The other pole is determinism: There were underlying causal factors that led up to these events, and something like this was bound to happen. This is a much harder view to swallow, because deterministic events are by their very nature predictable and controllable. It leads to the conclusion that we might have anticipated these events and done something about it.
With any chaotic system there are two fundamentally different approaches to prediction and control. One is to predict the detailed trajectory that the system will take. For simple systems like roulette wheels, turbulent fluids, and stock markets, I have a lot of experience with this. To predict the trajectory of something, you have to understand all the details and keep track of every little thing. This is like solving terrorism by surveillance and security. Put a system in place that will detect and track every terrorist and prevent them from acting. This is a tempting solution, because it is easy to build a political consensus for it, and it involves technology, which is something we are good at. But if there is one thing I have learned in my twenty five years of trying to predict chaotic systems, it is this: It is really hard, and it is fundamentally impossible to do it well. This is particularly so when it involves a large number of independent actors, each of which is difficult to predict. We should think carefully about similar situations, such as the drug war: As long as people are willing to pay a lot of money for drugs, no matter how hard we try to stop them, drugs will be produced, and smugglers and dealers will figure out how to avoid interception. We have been fighting the drug war for more than thirty years, and have made essentially no progress. If we take the same approach against terrorism we are sure to fail, for the same reasons.
The other road to prediction and control is to change the system in a more fundamental way. Change the parameters and get rid of the behavior you don't want. This is hard too, because it involves a deeper level of understanding and more fundamental change. But it has the advantage that, when you can do it, it is more stable, more reliable, and a much better solution. This corresponds to finding the root causes of terrorism and altering the political landscape so that it dies out. This will be very hard, but it has the enormous advantage that it might actually work.
When I was a high school student I lived in South America for a year. It came as a shock to me to discover how much people hated Americans. Living with a Peruvian family, and hanging out with Peruvian teenagers, I came to see things from their point of view, and to understand how arrogant and self aggrandizing Americans can be to people who live at a great distance, when the consequences are not visible, and few Americans at home know what is really happening.
This horrible disaster has made me reflect on another that killed a similar number of people. Imagine what it would have been like to see the American supported coup in Chile in 1972 if we had CNN giving us the blow-by-blow on video. Suppose we had all seen the people gunned down in the stadium, being tortured with cattle prods, getting punished for their crime of supporting their democratically elected government? I bring this up not to diminish the awfulness of what happened in New York, or to argue for moral relativism, but just to make it clear that there are some very real reasons why some foreigners don't like us very much. Most Americans are fundamentally good people, and if we were more aware of why people dislike us so much, our behavior would change. If we could only see it reflected back at us on CNN. In this case the reason for the hatred is not just our support of Israel, which I think is driven by some idealistic motives, but also the CIA-designed coup that toppled the democratically elected government of Iran, and the roughly half a million people who have died in Iraq of malnutrition, and many other similar events that we should reflect on.
Even if we were unmitigated good guys, as a superpower it's natural that we are targets. The breakdown of the cold war made this much worse, but it also provided an opportunity that we have unfortunately missed so far. The end of the cold war should have freed us to do the right thing, to act as real leaders, and take tangible steps to help the undeveloped world. We have so far squandered this opportunity in favor of policies of short-sighted self interest. But if we take a long range view, we will recognize the control that we have over the situation and alter it. We can get rid of the chaos by changing the parameters. I have been heartened to see that, through calls for actions like "bombing Afghanistan with butter, not explosives", some Americans seem to recognize this. This approach isn't just a matter of goody-goody liberal ideals; it's the only solution that has any hope of working in the long run. This isn't giving the terrorists what they want. Quite the opposite: It is defeating them by removing the basis of their movement, and being better than they thought we were.