Kant contrasts commutative to distributive justice twice in the Doctrine of Right, once expressly using these terms in discussing a group of “four cases” and once in connection with equity, where he speaks of “equity,” meaning commutative, and of “law in the proper sense (strict law),” meaning distributive, justice. The four cases involve (1) a gratuitous promise, (2) a lending agreement, (3) a good faith purchase of stolen goods, and (4) a court placing a witness under oath. These cases all illustrate implementation of the “Idea of Public Law.” When Kant considers the equity cases (the trading company and the domestic servant cases) he does so in combination with a necessity case to indicate that the idea of public law requires sacrifice. There are “rights that have no judge,” rights that cannot have any judge.

In this chapter, we first review Kant's terminology for commutative and distributive justice (section 1). This review leads into our analysis of the four cases. We show that the four cases lay the foundation for the three institutions of protective, mutually acquiring, and distributive justice in a juridical state (section 2). Finally, we provide an overview of Kant's ideas on rights that have no judge. This overview explains his equity, necessity, infanticide, and dueling cases (section 3).

Kant's terminology on the distinction between commutative and distributive justice

The distinction between commutative and distributive justice provides the key to understanding the four cases. Kant employs Hobbes' definitions of these two types of justice. Commutative justice is the justice of the individual market participant, who determines what is “right” (recht) in a concrete case by reaching his own “private” judgment. In contrast, distributive justice is the justice of the public judiciary in a juridical state, which determines what is “established as right” (Rechtens) by reaching its “public” judgments.