In 2002, having spent more than three years in one residence for the first time in my life, I got called for jury duty. I show up on time, ready to serve. When we get to the voir dire, the lawyer says to me, “I see you’re an astrophysicist. What’s that?” I answer, “Astrophysics is the laws of physics, applied to the universe—the Big Bang, black holes, that sort of thing.” Then he asks, “What do you teach at Princeton?” and I say, “I teach a class on the evaluation of evidence and the relative unreliability of eyewitness testimony.” Five minutes later, I’m on the street.

A few years later, jury duty again. The judge states that the defendant is charged with possession of 1,700 milligrams of cocaine. It was found on his body, he was arrested, and he is now on trial. This time, after the Q&A is over, the judge asks us whether there are any questions we’d like to ask the court, and I say, “Yes, Your Honor. Why did you say he was in possession of 1,700 milligrams of cocaine? That equals 1.7 grams. The ‘thousand’ cancels with the ‘milli-’ and you get 1.7 grams, which is less than the weight of a dime.” Again I’m out on the street.