Ezra Klein and Sam Harris are usually intellectual adversaries. They butted heads earlier this year on the topic of the science of IQ, which was just one battle in the larger war waged by the “intellectual dark web” against mainstream leftism and identity politics. Yet Klein and Harris are united on one seemingly radical view: Many years from now, our descendants will look back on the use of animals for food—particularly the intense animal suffering in factory farms—as a moral atrocity. In fact, a wide range of public figures have now echoed similar predictions, including science educator Bill Nye, business magnate Richard Branson, Indian politician Maneka Gandhi, author Steven Pinker, and the late conservative columnist Charles Krauthammer. It might seem surprising that the plight of these neglected creatures—by numbers, around 93 percent of farmed animals are chickens and fish—is so compelling an issue given the fact that humans are still plagued by disease, oppression, war, inequality, and other pressing social issues. Many people would assert that human issues are categorically more important than animal issues, …