Deep thinkers about human nature start with assumptions. Freud focused on sexual trauma and repression, Marx on the notion that humans combine rational self-interest with inter-class predation. Machiavelli offered scenarios about power relationships. Ayn Rand postulates that the sole legitimate human stance is solipsism. All are a priori suppositions based on limited and personally biased observations rather than any verified fundamental. Each writer "proved" his point with copious anecdotes. But, as Ronald Reagan showed, anecdotes prove nothing about generalities, only about possibilities. In fact, while the models of Freud, Marx, and Machiavelli (also Madison, Keynes, Hayek, Gandhi etc.) attracted followers, I think a stronger case can be made for tribalism as a driver of history. In this essay, I ask: What might tribalism tell us about human nature, that was missed by Marx and Freud and Rand etc., in their post-literacy myopia? What traits seem to be shared both by tribal and “civilized” societies?