Kwame Anthony Appiah, professor of philosophy and law at New York University, author of "The Ethicist" for the New York Times Magazine, and author of Cosmopolitanism: Ethics in a World of Strangers (W. W. Norton & Company, 2007) and As If: Idealization and Ideals (Harvard University Press, 2017), argues that multiple viewpoints, and even useful "untruths" are needed to understand the world.