Sins of commission and sins of omission are often treated differently, but it’s not clear they should be. Most of us, for example, would never dream of killing another person. At the same time, about 160,000 people around the world die every day, often of preventable causes. Letting people die — a sin of omission — seems tolerable in a way that killing a person — a sin of commission — does not.
Philosophers such as Peter Singer have argued that people ought to take their obligations to the global poor far more seriously. Yet most people simply go about their lives, and even if they make major donations to charity, it’s not half their incomes. For better or worse, common-sense morality leads most people to devote only a limited amount of attention to problems outside their own social circle.