This universal and terrible question does have an answer. The answer is less satisfying than we might wish, because we cannot change the fact that bad things will sometimes happen to good people. But the answer is helpful because it is simple and it gives us a way to cope with the horror of America’s 9/11 tragedy and the Asian tsunami.
There are three kinds of bad things. First, one person may intentionally harm another. Second, a person may be harmed while intentionally taking a risk. And third - classically caricatured by a piano falling from an upper window onto a passerby - nature may, without intention, do a job on an unsuspecting innocent.
Each of these bad things makes us unhappy.
The key to understanding the first two is the idea of free will. To make this clear, consider three imaginary worlds, each having different rules about free will:
The "imaginary worlds" exercise implies that if one person has free will, then everyone else should too. Not only is that fair, but it is what thinking people really want. Unfortunately, to enjoy free will is to accept that some people may decide to harm other people. There is no need for a discussion of the nature of evil; free will means freedom to decide between a right action and a wrong action.
It also means freedom to decide to climb the Himalayas, investigate the Bermuda Triangle, or enlist in the military in war time. Free will would meaningless if we did not also have the ability to know (or estimate) the likely consequences of our actions. For many and varied reasons - to save another life, to find new resources, to feel more alive, or just to explore - people willingly embrace significant probabilities of injury or death. This is their freedom.
These adventurous folks would probably argue that people who stay at home in bed risk a great deal, too. Stay-at-homes risk the loss of their physical health, their social lives, and their chance to experience the variety of the world they were born into.
This leaves the third question: What about the hurricane, the earthquake, the falling anvil that wipes out ordinary, intelligent, loving, risk-averse people who have plans and hopes for their future? Applying cold logic to this emotionally charged question may be an unattractive thing to do, but the fact is that the question invites circular reasoning. Life is fragile, and for that reason we consider life to be precious. So far, so good. Then we muse, "Life is so precious, what a tragedy that it is as delicate and vulnerable as it is."
We also manage to make life’s fragility a desirable state of affairs. We are attracted to a potential spouse or lover in part because of his or her vulnerability. We enjoy actors and comics who can reveal the vulnerable everyman in their characters. We have myths and stories featuring immortals who wish most of all to become mortal. Modern examples are the movies City of Angels, starring Meg Ryan and Nicholas Cage, and Highlander, with Christopher Lambert and Sean Connery.
Is this why an anvil falling on a cartoon character is funny? We call this kind of humor "absurd." It tells us we face risks that we don’t know about , in addition to the ones we are aware of, that we worry too much about low-probability events, that anything can happen, and that our lives are indeed fragile and in many ways uncontrollable. Sometimes we laugh at absurd humor out of nervous discomfort. Sometimes we laugh with joy, realizing there is nothing we can do about it, so let’s get on with living.
Sensible precautions against terrorism? Yes. Trying to be more aware of our surroundings? Of course! But we are not going to forbid pianos and anvils to upper-story tenants. Denying the upstairs neighbors their free will won’t make us any safer.
I hope this conclusion will not disappoint people who, worrying long and deeply about "why bad things happen to good people," think the answer has to be more complicated. Others will be comforted and inspired to right action by the fact that the answer is, indeed, short and simple.