Self-Driving Cars and the Agony of Knowing What Matters

In medicine, false positives are expensive, scary, and even painful. Yes, the doctor eventually tells you that the follow-up biopsy after that bloop on the mammogram puts you in the clear. But the intervening weeks are excruciating. A false negative is no better: "Go home, you're fine, those headaches are nothing to worry about." Anyone who builds detection systems--medical tests, security screening equipment, or the software that makes self-driving cars perceive and evaluate their surroundings--is aware of (and afraid of) both types of scenarios. The problem with avoiding both false positives and negatives, though, is that the more you do to get away from one, the closer you get to the other.