No one uses “Malthusian” as a compliment. Since 1798, when the economist and cleric Thomas Malthus first published “An Essay on the Principles of Population,” the “Malthusian” position – the idea that humans are subject to natural limits – has been vilified and scorned. Today, the term is lobbed at anyone who dares question the optimism of infinite progress. Unfortunately, almost everything most people think they know about Malthus is wrong. The story goes like this: Once upon a time, an English country parson came up with the idea that population increases at a “geometrical” rate, while food production increases...