(b) Legal justice is a more perfect virtue than particular justice or filial piety, since it seeks a higher object (that is, the common good as such) and is more voluntary.
1704. Is the right which the community has to receive from the goods of its members one of legal or one of particular justice?
(a) The right of eminent domain (i.e., the right which the State has over the goods of private persons when they are necessary for the common good) is a right of legal justice, for even without compulsion the citizen should be willing to contribute what is necessary for the community of which he is part.
(b) The right of the members of a government to receive compensation for their services is a right of particular justice, for there is an implicit contract between the rulers and the State that the former will serve the interests of the latter and that the later will pay the expenses of the former, as if both parties were private individuals (see 1708).
1705. Distributive and Commutative Justice.—On account of the inequality or equality of the individuals between whom it exists, particular justice is subdivided into distributive and commutative, which are distinct species of justice.
(a) That the distinction is well-founded is proved by the fact that this justice—that is, relations towards particular persons—is either the relation of whole to part or of part to part. The former relations are governed by distributive justice, which is defined as the virtue that inclines the ruler, as the representative of the community, to portion out the public goods (e.g., money, honors, offices) and burdens (e.g., taxes), not according to favoritism or personal likes, but according to merits and abilities; the latter relations are governed by commutative justice, which is defined as the virtue that inclines the individual to pay to other individuals what is their due, whether the rights be personal (e.g., the right to reputation) or real (e.g., the right to wages or price). Commutative justice receives its name from the fact that it is oftenest called for in commutations (i.e., in exchanges, such as buying and selling).
(b) That the distinction of particular justice into distributive and commutative is specific appears from the fact that the main characteristics of justice (viz., debt owed another and equality between payment and debt) are found in each of these kinds of justice in a way proper to itself. There is a debt in commutative justice when a thing is owed another because he has an individual right to it and it is already under his dominion; there is a debt of distributive justice, when a thing is owed another because he has a community interest in it and a right that it be entrusted to him in view of his merits or abilities.
1706. Thus, the equality observed in commutative justice is arithmetical, or of quantity (e.g., if a horse is worth $100, it is just to pay $100 for it); the equality observed in distributive justice is geometrical, or of proportion (e.g., if one who had an average of 90% in a civil service examination receives a position that pays $90, it is just to give another whose average was 80% a position that pays $80). An indication of the specific difference between distributive and commutative justice is that the same individual may be just in private matters and unjust in public matters. Example: Titus, an office-holder, pays his personal debts faithfully, but he appoints only his friends, whether they be worthy or unworthy, to important honors.
1707. Corrective Justice.—Corrective (i.e., vindicative or punitive) justice is a virtue inclining a public person or a superior, such as a ruler, magistrate, or judge, to inflict on evil-doers penalties adequate to their faults. It is not to be confused with just vengeance or retaliation, which is the virtue that moderates in a private person the desire for punishment of an offense against self, and which is not justice strictly speaking, either commutative or distributive, but only a potential part of justice (as stated below in Article 6).
(a) Thus, corrective justice is elicited by commutative justice, for a punishment is inflicted by a judge in order that there may be equality between the satisfaction made by the evil-doer and the debt owed to another on account of the offense. It aims at redressing an unfairness by taking away so much from the offender and adding so much to the party offended, that both will stand in the same position as before. If the person punished accepts the penalty in the same spirit, he also practises commutative justice.