From Anatomy of Error, by Joshua Rothman:
In a 1976 essay, the philosopher Bernard Williams explored a concept that he called “moral luck.” Often, he observed, we are morally responsible for actions that contain an element of chance. Imagine two people who drink too much at the same party, and who both drive home drunk; suppose that one of them hits a pedestrian. The driver in the accident is morally responsible for this outcome, and yet only chance distinguishes him from the other driver. Much of moral life, Williams thought, contains a similar element of luck. We happen to find ourselves in situations that bring judgment upon us. Yet this doesn’t absolve us of responsibility for what we do. It underscores an unsettling fact about moral life—that the distribution of moral fault in the world depends, in many ways, on good and bad luck.