One of the best-known quotations from Adam Smith’s The Wealth of Nations (1776) defines natural liberty: “Every man, as long as he does not violate the laws of justice, is left perfectly free to pursue his own interest his own way, and to bring both his industry and capital into competition with those of any other man.”

Smith inserted the condition “so long as he does not violate the laws of justice” ahead of the directive because it was central to his conception of liberty. What everyone remembers is “free to pursue his own interest,” with the last often turned into “self-interest.” But Smith’s conception of human sociality and economy—I like the word “humanomics”—was far deeper than modern utilitarianism.

What did Smith mean by justice, and why is it so important for understanding his message? The carefully articulated answer was in his first book: The Theory of Moral Sentiments (1759, pp. 78-91).

Justice for Smith was the negative of his proposition on injustice, which stated that improperly motivated (that is, intentionally) hurtful actions alone deserve punishment because they are the objects of a widely shared sense of resentment.

Rules that punished in proportion to resentment emerged naturally in pre-civil society as a means of defense only against real positive evil and to secure innocence and safeguard justice.

Hence, justice is a residual. Justice is the infinite set of permissible actions remaining after specifying the finite limited set of prohibited actions and corresponding penalties.

Imagine a large playing field in which people explore, discover, and innovate, but with well-defined foul boundaries that people are not to breach without penalty; these boundaries will change, based on consent, with experience, culture, and technology.

Smith saw society as seeking human socio-economic betterment through the control of actions that our common experience leads us to judge as hurtful rather than through collective actions designed to achieve future conjectured benefits. The latter is uncertain and fraught with unintended consequences; moreover, history is littered with examples of grandiose failures. The former relies on natural impulses for individuals and assemblies to pursue betterment, risking only their own resources; this framework led him to oppose slavery, colonialism, empire, mercantilism, and taxation without representation at a time when such views were unpopular.

His policy views derive from his belief that every person’s socio-economic achievements should depend as much as possible on merit and as little as possible on privilege.