The Happiness Hypothesis: Putting Ancient Wisdom to the Test of Modern Science

by Jonathan Haidt

I’m in no position to say whether God, heaven, or an afterlife exists, but as a psychologist I am entitled to point out that belief in postmortem justice shows two signs of primitive moral thinking. In the 1920s, the great developmental psychologist Jean Piaget20 got down on his knees to play marbles and jacks with children and, in the process, mapped out how morality develops. He found that, as children develop an increasingly sophisticated understanding of right and wrong, they go through a phase in which many rules take on a kind of sacredness and unchangeability. During this phase, children believe in “immanent justice”—justice that is inherent in an act itself. In this stage, they think that if they break rules, even accidentally, something bad will happen to them, even if nobody knows about their transgressions. Immanent justice shows up in adults, too, particularly when it comes to explaining illness and grave misfortune. A survey21 of beliefs about the causes of illness across cultures shows that the three most common explanations are biomedical (referring to physical causes of disease), interpersonal (illness is caused by witchcraft, related to envy and conflict), and moral (illness is caused by one’s own past actions, particularly violations of food and sexual taboos).