Trust is the oxygen of human society, Augustine says, and believing the testimony of others is at the very heart of the scientific enterprise. Understanding doesn’t transcend belief; it relies on belief. If someone says believing is wrong, Augustine wryly notes, “I do not think he can have any friends. If it is wrong to believe anything, then either one does wrong by believing a friend, or one never believes a friend, and then I do not see how one can call either oneself or the friend a friend.”18
