Moral sciences are back. Natural laws of ethics, envisioned early in the Enlightenment, can now be studied. Scientists are relearning the wisdom of old traditions by objectively rating their performance. And they’re suggesting improvements: any rule system is weaker without “The Golden Punishment Rule.”

Humans, being social, can’t live without rules. Certain rules work better. Game theory provides “behavioral telescopes” to study them.

The naturalistic fallacy says we can derive no ethical lessons from nature. But without seeking good and evil in nature, we can compare the productivity and sustainability of behavioral rules—and map negative ethical spaces, which are inherently unworkable, and thus inherently bad.

For example: we can compare how ethical traditions do in Prisoner’s Dilemmas against the game’s best strategy, called Tit-For-Tat, which is an “evolutionarily stable strategy.” As Tomas Sedlacek asks: What would Christians do? Or practitioners of any religious or secularly sourced Golden Rule?

The results are clear: Rationalists do worse than the Golden Ruled. And Jewish preferences beat Christian ethics. So-called rationalists, dominated by some dire logic, produce no cooperation and low productivity. Two Golden Ruled players cooperate, thus beating rationalists. But New Testament turning-the-other-cheek is exploitable (as Machiavelli and Nietzsche complained). Old Testament eye-for-an-eye comes closer to Tit-For-Tat, if forgiveness follows (which might be divine, but is also evolutionarily adaptive). But punishment sufficient to ensure that cheating doesn’t pay must also prevent escalating revenge. Hunter gatherers avoid such feuds by delegating the severest punishment to close male kin. A “Golden Punishment Rule,” that mimics Tit-For-Tat, enables cooperation by sustainably preventing exploitation. Similar logic likely applies beyond Prisoner’s Dilemma.

Darwin, being un-Darwinian, said “social instincts…with the aid of active intellectual powers… naturally lead to the golden rule.” Game theory shows that simple rigidly followed rules can create workable cooperation. Evolution is a game theorist, endlessly testing behavioral strategies and naturally selecting the more productive.

Another religious idea can clarify evolutionary thinking. Richard Dawkins’s selfish gene errs by overusing the non-exhaustive binary of selfishness vs. altruism. Dawkins uses and inverts the Christian framing that promotes self-sacrifice and discourages self-benefit. Jewish ethics, however, encourages self-benefit, but warn against the dangers of selfishness. Rabbi Hillel said, “If I am not for myself, then who will be for me? And if I am only for myself, then what am I?” Hillel’s self-and-other frame includes the win-win space in which cooperation can evolve (and which Dawkins initially ignored).

It’s still early in the use of game theory, but it seems the behavioral universe has gravity-like pull towards certain stable high productivity social rules. We should use our “active intellectual powers” to adjust what’s deemed rational, and to more intelligently design our economic and political (once called moral sciences) systems.

Illustration by Julia Suits, The New Yorker Cartoonist & author of The Extraordinary Catalog of Peculiar Inventions.

Previously in this series:

It Is in Our Nature to Be Self-Deficient

Inheriting Second Natures

Our Ruly Nature

It Is in Our Nature to Need Stories

Tools Are in Our Nature

We Fit Nature To Us: Evolutions two way street

Justice Is In Our Nature

Behavioral Telescope Shows How Cooperation Works

Selfish Genes Also Must Cooperate