Thursday, June 29, 2006

Is It Really Only 1%?

Cass Sunstein quotes a statement by Vice President Dick Cheney:

We have to deal with this new type of threat in a way we haven’t yet defined. . . . With a low-probability, high-impact event like this . . . If there’s a one percent chance that Pakistani scientists are helping al Qaeda build or develop a nuclear weapon, we have to treat it as a certainty in terms of our response.

Sunstein argues that the Precautionary Principle (which requires a serious response to a low probability but great damage risk) is legit, but in this context should be used cautiously.

I believe Cheney's statement should not be taken literally (that one percent is equal to one hundred percent), but basically means that sometimes even a risk of one percent is sufficient to take seriously.

An example: Let's say we know that a shooter is lurking in New York and there's a 90 percent chance he'll kill 20 people. That's a pretty high risk and if we multiply the risk times the probability, we can assume that 18 people will die if we do nothing. So the government should exert x amount of resources to bring down the risk or the harm.

Now let's say we know there's a 1% chance that a Muslim terrorist will detonate a nuclear bomb that will kill 100,000 people. We can then assume, in the absence of any action, that 1000 people will die. The latter threat, although less likely to occur, is more grave and the government should exert resources that are greater than x.

So it would seem the government should respond more seriously to the latter threat. How should they respond? One effective way is to impose greater restrictions on liberty (for example checking every Muslim at random). Is that a good idea?

Let's say the balance between security and liberty is at its optimal point, which is 50/50. If we changed the balance to 55/45 in favor of security, we'd lessen the probability of the harm. So interestingly it makes more sense to impose serious restrictions on liberty in a case where the probability of harm is only 1% than it does in some cases where the probability is 90%. If we change the numbers in my example from 90% to100% (meaning that if we do nothing we know for sure 20 people will die) and 1% to .1 percent, it still makes more sense to curtail liberty in the second example more than in the first.

Cheney is right. We must take 1% risks seriously where the harm is unimaginable.

I understand that I’m not taking into account the costs imposed by curtailing liberty and other alternative methods of stopping terror. But I’m getting married on Sunday and I don’t have all day. Plus I have a time limit. Thanks DB, you’re the best.

Ok, that's my real post. Hope you all enjoyed it and my time here.

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