Schur invites readers to recall times when they used small lies as social excuses. He raises the question of whether these little mistruths are ethical or not. For instance, when deciding whether to tell a friend that we dislike her shirt, a utilitarian perspective may suggest that pretending to like the shirt will increase happiness, though it is difficult to be sure.

Here, Schur introduces the third major school of moral philosophy: deontology. According to deontological ethics, certain actions are right or wrong, regardless of consequences. The most prominent figure in this school of thought is German philosopher Immanuel Kant. Kant’s most famous argument, known as the categorical imperative, suggests that people should only act in a way that they would wish for everyone else to act. Under this consideration, lying is wrong because a world in which everyone lies would be chaotic and destructive. According to Kant, the motivation for acting morally should be a sense of duty to such universal rules, not any particular emotion. A second key tenet of Kant’s categorial imperative is that people should always be viewed as ends, not used as a means to accomplish something else.