Economic analysis is itself value-free, but in practice it encourages a cosmopolitan interest in natural equality. Many economic models, of course, assume that all individuals are motivated by rational self-interest or some variant thereof; even the so-called behavioral theories tweak only the fringes of a basically common, rational understanding of people. The crucial implication is this: If you treat all individuals as fundamentally the same in your theoretical constructs, it would be odd to insist that the law should suddenly start treating them differently.

At least since the 19th century, the interest of economists in personal liberty can be easily documented. In 1829, all 15 economists who held seats in the British Parliament voted to allow Roman Catholics as members. In 1858, the 13 economists in Parliament voted unanimously to extend full civil rights to Jews. (While both measures were approved, they were controversial among many non-economist members.) For many years leading up to the various abolitions of slavery, economists were generally critics of slavery and advocates of people’s natural equality, as documented by David M. Levy, professor of economics at George Mason University, and Sandra J. Peart, dean of the Jepson School of Leadership Studies at the University of Richmond

Professors Levy and Peart coined the phrase “analytical egalitarianism” to describe the underpinnings of this tradition. For example, Adam Smith cited birth and fortune, as opposed to intrinsically different capabilities, as the primary reasons for differences in social rank. And the classical economists Jeremy Bentham and John Stuart Mill promoted equal legal and institutional rights for women long before such views were fashionable. Their utilitarian moral theories placed individuals on a par in the social calculus by asking about the greatest good for the greatest number.

Often, economists spend their energies squabbling with one another, but arguably the more important contrast is between our broadly liberal economic worldview and the various alternatives — common around the globe — that postulate natural hierarchies of religion, ethnicity, caste and gender, often enforced by law and strict custom. Economists too often forget that we are part of this broader battle of ideas, and that we are winning some enduring victories.